Black''''s veterinary dictionary 21st edition - P doc

P Pacemaker An electronic device implanted under the skin of the chest which stimulates the heartbeat Pacemakers have been successfully implanted into dogs which show an impaired conduction of the impulse that regulates the heartbeat, so that a lack of coordination between the beating of the atria and that of the ventricles occurs Following repeated episodes of loss of consciousness, which heart medication failed to obviate, a 2-year-old dachshund in Switzerland had a pacemaker electrode inserted into the right ventricle of its heart via the jugular vein The batteries were inserted between abdominal muscles Local irritation from the battery implant was stated to be slight Two years later the heart had given no further trouble A pacemaker was inserted in a pregnant mare at the Royal Veterinary College The mare foaled normally and she and the foal fared well Pacheco’s Disease Pacheco’s disease is caused by a herpesvirus which is present in South American psittacines (parrots, parakeets) In the wild it does not appear to cause any harm In aviaries, however, sudden onset of disease and death may occur, with up to 100 per cent mortality The birds become weak and have diarrhoea Post-mortem examination shows necrosis of the liver and spleen Pachymeningitis Inflammation of the dura mater of the brain and spinal cord (See MENINGITIS.) Pacinian Corpuscles (see under TOUCH, SKIN) Packed Cell Volume (see under BLOOD – Composition) Paddocks These often become reservoirs of parasitic worm larvae – a point for animal-owners to bear in mind Paddocks need ‘resting’ for 12 months, or grazing by a different species of animal, periodically Pain (For relief of pain, see ANALGESICS; ANAESTHESIA.) Animals which are natural hunters (predators) may cry out when suffering pain Species which are, or were, normally hunted may not so because it would reveal that they are injured or hiding Thus, because an animal does not cry out, or show signs of restlessness, it should not be assumed that it is free from pain The clinical signs of pain can differ from species to species Pain can be a cause of aggressiveness The effect of pain can last longer than the pain itself: it has been shown that as long as a month after foot pain has been corrected in cattle, cows still behave as if in pain, as the animal’s body has not returned to normal In sheep, this can last even longer As a result, bodily condition and milk production may not return to normal until some time after the animal has made an apparent recovery Paint (see HOUSE DECORATING, POISONING; LEAD POISONING, CAGE AND AVIARY BIRDS, DISEASES OF) Palatability (see under DIET AND DIETETICS) Palate Palate is the partition between the cavity of the mouth below, and that of the nose above It consists of the hard palate and the soft palate The hard palate is formed by the bony floor of the nasal cavity covered with dense mucous membrane, which is crossed by transverse ridges in all the domesticated animals These ridges assist the tongue to carry the food back to the throat The hard palate stretches back a little beyond the last molar teeth in animals, and ends by becoming continuous with the soft palate This latter is formed by muscles covered with mucous membrane, and in the horse acts as a sort of curtain between the cavity of the mouth and that of the pharynx Material brought up from the stomach must pass out by way of the nostrils In racehorses, distressed breathing may arise as the result of inflammation or partial paralysis of the soft palate, which may be linked with paresis or paralysis of the vocal cords Partial resection of the soft palate has been carried out as treatment for this latter condition (See GUTTURAL POUCH DISEASE.) Prolonged soft palate is a recognised inherited abnormality of the short-nosed breeds of dogs, e.g boxers, bulldogs, Pekingese, pugs, cocker spaniels It makes breathing difficult at times, with snoring or even loss of consciousness resulting An operation to correct the condition is often very successful 510 Pale Soft Exudative Muscle (PSE) Severe injury to the hard palate is not uncommonly seen in cats which have fallen from a height, and suturing may be required (see PORCINE STRESS SYNDROME) degenerative pancreatic atrophy, and chronic pancreatitis Signs include a ravenous appetite, loss of weight, fatty faeces, and a dry scurfy coat Treatment includes supplementation of the diet with pancreatin as oral powder or granules Cimetidine may be used in addition in severe cases Palo Santo Trees Parasites which may be found in the pancre- The leaves, fruit, and seeds cause poisoning in cattle in South America Signs include tympany, depression, and convulsions atic ducts include Toxocara canis and, in cats in America, the pancreatic fluke Eurytrema procyonis The latter may interfere with the gland’s exocrine function to a great extent Fenbendazole is effective against the fluke Pale Soft Exudative Muscle (PSE) Palpebral Relating to the eyelids PanPan- is a prefix meaning all or completely Pancreas P Pancreatin A preparation of the exocrine part of the pancreas used to treat pancreatic deficiency in dogs and cats Pancreas is partly an endocrine gland, producing hormones; and partly an exocrine gland, producing the pancreatic juice for digestive purposes The pancreas is situated in the abdomen, a little in front of the level of the kidneys and a little below them When fresh it has a reddish-cream colour The pancreatic juice is secreted into the small intestine to meet the food which has undergone partial digestion in the stomach The juice contains alkaline salts and at least enzymes: e.g trypsin, which carries on the digestion of proteins already begun in the stomach; amylase, which converts starches into sugars; and lipase, which breaks up fats; as well as a substance that curdles milk (See DIGESTION, ABSORPTION and ASSIMILATION – Intestinal digestion.) The pancreas also has groups of cells, the islets of Langerhans (See INSULIN; DIABETES MELLITUS; GLUCAGON; HORMONES.) Here alpha-cells produce glucagon, and beta-cells, insulin Pancreatitis Pancreas, Diseases of (see under NODULAR PANNICULITIS) (see PANCREAS, DISEASES OF) Pancytopenia A reduction in the number of red cells, white cells, and platelets in the blood; usually due to a bone-marrow dyscrasia Panhypopituitarism A condition caused by development failure of the pituitary gland, destruction of the pituitary tissue or a cyst or tumour in the gland In puppies, the milk teeth and puppy coat are retained for longer than normal and the animals are stunted There may be alopecia with skin pigmentation The gonads may be abnormally small Polydipsia and polyuria may develop; affected animals may be aggressive Treatment will depend on the cause Panleucopenia Feline infectious enteritis Panniculitis These include DIABETES MELLITUS, inflammation, suppuration, atrophy, tumour formation, etc (See INSULINOMA.) Pannus Acute pancreatitis occurs in obese dogs, Panosteitis more rarely in cats Signs include abdominal tenderness or pain Hyperglycaemia and shock may follow Treatment includes witholding food, and intravenous fluid therapy to maintain the balance of fluid and electrolyte A condition in which an entire bone is inflamed Exocrine pancreatic insufficiency in dogs has main causes: congenital hypoplasia, Pantothenic Acid (see EYE, DISEASES AND INJURIES OF) Pansteatitis (see STEATITIS) (see VITAMINS – Vitamin B) Paralysis Papain An enzyme extracted from the pawpaw (custard apple) and used to tenderise meat Papilla A small projection Papilloma 511 be given regularly as it prevents the absorption of vitamin D and may cause rickets Externally, the hard and soft paraffins are used in the preparation of various ointments and lubricants Parafilaria A wart (see A genus of filarial worms P bovicola causes serious skin lesions in cattle in several parts of the world (See FILARIASIS.) animal species a papilloma may, through the action of sunlight, lead to a squamous cell carcinoma Paragle Fly Papilloma Virus Group Paragonimiasis WARTS; PAPILLOMA; VIRUS GROUP; also VIRAL INFECTIONS; TUMOUR) In some (see under FLIES) Papilloma virus group includes viruses infecting cattle, sheep, goats, horses, dogs, rabbits, etc Infestation with LUNG FLUKES of Paragonimus species in dogs, cats, foxes, mink Papillomatosis Para- Infection with this is widespread in sheep in the UK; the virus is also a cause of CALF PNEUMONIA and of respiratory diseases in the horse (See EQUINE RESPIRATORY VIRUSES.) Parainfluenza5 infects the dog, and may be associated with KENNEL COUGH (See also INFLUENZA.) Para- is a prefix meaning near, aside from, or beyond Parakeratosis The development of multiple WARTS Papule A pimple Paracentesis The technique of puncturing a body cavity, e.g the abdomen, with a hollow needle or by means of a trocar and cannula in order to extract fluid; or to obtain a sample of tisse for a biopsy Paracetamol (Acetaminophen) An analgesic It should not be given to cats, in which it is toxic Symptoms include cyanosis and facial oedema Acetylcysteine, given orally, is an antidote Paraffin Paraffin is the general term used to designate a series of saturated hydrocarbons The higher members of the series are solid at ordinary temperatures, some being hard and others soft Lower in the scale comes petroleum, which is liquid at ordinary temperatures Naphtha, petroleum spirit, and hydramyl are members of the series lower still, which are very volatile bodies, and finally lowest comes methane or marsh-gas Uses Internally, only medicinal liquid paraffin is used; it is a gentle laxative, but has the disadvantage that it is liable to become tolerated by the system and lose its effect when given continually as a routine laxative It should not Parainfluenza Virus The name applied to a scaly, elephant-like skin The condition has been seen in pigs suffering from a zinc deficiency It occurs in pigs fed dry meal ad lib, and gradually clears up when a change to wet feeding is made It often begins with a red pimply condition of the skin on the flanks, abdomen, etc Thin, dry yellowish or greyish scales may be seen on the skin, which later becomes thickened It responds to small doses of zinc sulphate (See CALCIUM SUPPLEMENTS.) Inherited parakeratosis has been reported in calves of Friesian descent, and although a zinc supplement proved successful in treating the encrusted skin of head, neck and limbs, the lesions returned after cessation of the supplement Paraldehyde A narcotic It is used in some slug pellets and poisoning in domestic pets can follow ingestion Paralysis Paralysis, in its widest sense, may mean loss of nerve control over any of the bodily functions, loss of sensation, and loss of the special senses, but the term is usually restricted to mean loss of muscular action due to interference with the nervous system When muscular power is P 512 Paralytic Myoglobinuria merely weakened, without being lost completely, the word ‘paresis’ is often used Various terms are used to indicate paralysis distributed in different ways (See HEMIPLEGIA; PARAPLEGIA; QUADRIPLEGIA.) Paralysis should be regarded as a symptom rather than as a disease by itself Varieties P Cerebral paralysis: conditions resulting from brain lesions, such as encephalitis, tumour formation, fracture of the skull with depression of a portion of bone, haemorrhage, etc., are accompanied by severe general or local paralysis, either of the whole body (when death usually follows very rapidly), or of one side (hemiplegia) Paralysed limbs when examined are found to be flaccid, with the muscles totally relaxed, and passive movements are not resisted Sensations of pain may be felt, however, and an indication that sensation is not destroyed is shown by raising the head, or struggling with the sound limbs when a pinprick is made in a paralysed part In cases of cerebral haemorrhage, the seizure is sudden; in encephalitis there is usually some co-existing disease, such as influenza or distemper, and the brain symptoms develop as a complication – or the encephalitis may be the result of a primary viral infection, such as equine encephalitis or rabies With fracture and depression there is an immediate loss of power, just as when an animal is stunned Spinal paralysis or paraplegia is most often due to fracture of, or severe injury to, the vertebrae (See PARAPLEGIA.) In complete paralysis death usually takes place within 12 to 48 hours after the injury (See SPINE AND SPINAL CORD, DISEASES AND INJURIES OF; and, for horses, under COMENY’S INFECTIOUS PARALYSIS OF HORSES and EQUINE VIRAL RHINO PNEUMONITIS.) Peripheral paralysis: there is usually some injury to a nerve trunk, or lesion of the nerve-endings in the muscle fibres (See SUPRASCAPULAR PARALYSIS; RADIAL PARALYSIS.) Brachial paralysis results from road accidents, collisions, or stake wounds Gluteal paralysis is very uncommon: wasting of the muscles of one hindquarter and a tendency to carry the limb out to one side occur ‘Paralysis of the sciatic nerve’ causes a loss of power in all the muscles of the thigh except those situated above and to the front of the stifle joint, i.e the quadratus group The limb hangs loosely and the animal jerks it forward when attempting to walk; although the stifle is advanced, the hock and the fetlock remain flexed and the front of the foot comes to the ground When there is severe injury to the side of the thigh from a fall, kick, or other similar cause, paralysis of the external popliteal nerve (common peroneal) may occur, resulting in an inability to extend the foot or flex the hock When the horse is made to walk, the limb is drawn out backwards into a position resembling that seen in dislocation of the stifle, but the fetlock is flexed instead of being fully extended The limb is then carried a short distance forward and the foot comes to rest upon the ground on its anterior face instead of on the sole In ‘crural paralysis’ (paralysis of the femoral nerve) the quadriceps muscles above the stifle, which normally extend that joint, are paralysed When weight is put upon the limb the stifle sinks to the level of the hock or below it, all joints are flexed, and there is a peculiar drop of the hindquarter on the same side (See also PARAPLEGIA.) Paralysis in the dog (see also DISTEMPER; BOTULISM; THROMBOSIS; SPINE, DISEASES OF; TICK PARALYSIS; LEAD POISONING; RABIES; RACOONS; ORGANOPHOSPHORUS POISONING) Aid A wheeled trolley which supports the hindquarters can be an alternative to euthanasia for some paraplegic dogs Paralytic Myoglobinuria (see MUSCLES, DISEASES muscular dystrophy) OF – Nutritional Paraminobenzoic Acid A growth factor produced in bacteria which is blocked by certain antibacterials, such as sulphonamides Paramphistomiasis A disease caused by RUMEN FLUKES of the genus Paramphistomum Paramyxoviruses An important group of disease-causing viruses Parainfluenzavirus, morbillivirus and pneumovirus are the genera of paramyxovirus (See Paramyxovirus parainfluenza virus in the table under EQUINE RESPIRATORY VIRUSES.) Two paramyxoviruses infecting dogs are the canine distemper virus (a mobillivirus), and canine parainfluenza virus/SV5 (See also PIGEONS and NEWCASTLE DISEASE.) Paraphimosis A constriction preventing the penis from being withdrawn into the prepuce This is not Paraquat uncommon in the dog, and is serious, for gangrene may occur unless relief is afforded As a first-aid measure, swab the penis with ice-cold water Surgical interference under anaesthesia may be necessary The use of hyaluronidase in normal saline, by injection, has been recommended For paraphimosis in horses and cattle see under PENIS AND PREPUCE, ABNORMALITIES AND LESIONS Paraplegia of the hindlegs It may be accompanied by paralysis of the muscles which control the passage of urine and faeces to the outside It is seen following accidents involving injury to the spine – frequently in the dog knocked down by a car – and may also be associated with ‘disc’ lesions A rare cause is thrombosis of the femoral arteries In the dog, this may occur suddenly – the animal playing one minute, and collapsing with a yelp the next Absence of pulse in the femoral arteries assists a diagnosis (See also under THROMBOSIS; COMENY’S INFECTIOUS PARALYSIS OF HORSES.) PARALYSIS Parapox Viruses Apart from those affecting domestic animals (see table under VIRUSES), a parapox virus carried by grey squirrels, but apparently harmless to them, has had a devastating effect on the native red squirrel A parapox viruse is also though to be the cause of high mortality in British frogs in certain parts of Britain 513 Paraquat This herbicide has caused fatal poisoning in man, usually through accidental ingestion of the undiluted concentrate; an emetic is now included Poisoning in the dog gives rise to lung oedema, congestion and consolidation; also kidney damage Three cases, and the outcomes, are reported below Paraquat was detected in the urine of out of dogs showing acute respiratory distress, leading to cyanosis after days’ illness Three of the dogs died, and euthanasia was resorted to with the others In New South Wales, a dog died and a cat recovered (partially if not completely); the latter animal had been seen eating grass from a lawn of which the weedy areas had been treated with undiluted Gramoxone (20 per cent paraquat) In both animals vomiting was a symptom, as well as distressed breathing Cyanocobalamin has been suggested as an antidote for small animals, though it is generally held that no effective antidote exists However, complete recovery was achieved for a dog taken to the University of Dublin’s veterinary clinic, with a history of weakness, and rapid breathing over the previous hours The animal’s condition deteriorated, despite intensive treatment Nursed at home, the patient was seen at the clinic daily On the 15th day came improvement: although the dog was still breathing through its mouth, respirations were down to 120 per minute It was weeks before they had come down to 60 P Adult worms in the air passages of a calf’s lungs In a heavily infected animal several thousand lungworms may be present 514 Parasites and Immunity The patience and perseverance of both owner and clinic staff were rewarded, for when seen again and then 18 months later, the dog was well and fully active again Parasites and Immunity Parasite antigens are a potent stimulus for antiparasite antibodies of the IgE class (see IMMUNOGLOBULINS), and parasite infection can potentiate a pre-existing IgE response to an unrelated antigen Examples of the effect of parasitism on the immune response are given under CANCER and ALLERGY Parasitic Bronchitis This occurs in cattle, sheep and goats; on account of the husky cough produced, the disease is commonly called ‘husk’ or ‘hoose’ in the UK Although of greater economic importance in calves, nevertheless the cost of an outbreak in a dairy herd may be very high – not so much as a result of deaths (which occur in adult cattle) but on account of reduced milk yields and the need for extra feed Marshy land and mild, wet weather both favour the parasites, as does overstocking Cause In cattle the lungworm Dictyocaulus viviparus is the important species (see ROUNDWORMS; also illustration, page 513) Parasitic P bronchitis normally affects cattle in their first grazing season Affected animals experience a drop in the saturation level of oxygen in their blood to 70 per cent even before clinical signs become apparent In clinical cases the percentage may be reduced to 30 Workers at Glasgow University defined infection with the parasite into phases: penetration, pre-patent, patent, post-patent, and reinfection In all but the first phase, oedema and emphysema are found In a case of parasitic bronchitis, the neck is held extended and there may be continual coughing and/or distressed breathing Spread of the worm larvae is assisted by their rocket-like propulsion by the fungus Pilobolus, which is found in faecal deposits on pasture The worm larvae are projected along with the fungal spores, often between 10.00 and mid-day Signs The characteristic husky cough is a symptom in the milder cases, but in acute cases may be absent, with the main symptom being dyspnoea (laboured breathing) In calves, death may occur from actual suffocation due to masses of worms obstructing the air passages, or it may result from general debility or pneumonia In adult cattle pneumonia develops, with Actinomyces pyogenes acting as a secondary invader Oedema of the lungs may occur, and cause death Prevention and treatment Live oral vaccines are available A number of including albendazole, ivermectin and fenbendazole, may be used to treat infected cattle Some anthelmintics are available in bolus form If the animal is exposed to infection while the anthelmintic bolus is active, the animal will develop immunity without showing signs of the disease (see under WORMS, FARM TREATMENT AGAINST) ANTHELMINTICS, Parasitic Disease, Nature of Parasitic diseases are caused by organisms that live within an animal (endoparasites) or on its surface (ectoparasites) Endoparasites include worms and flukes; ectoparasites include fleas, mites and ticks Disease is seldom caused by one or a few parasitic organisms, but as a rule depends on mass infestations There are exceptions to this, however, as a single Ascaris may obstruct the bile-duct with fatal results Parasites, with few exceptions, not spend all their lives in the animal body, but always need to spend a certain proportion of their life-cycle outside the host They may cause damage to the host in the following ways: (1) By abstraction of nourishment properly belonging to the host, e.g many of the intestinal worms; (2) By mechanical obstruction of passages or compression of organs, e.g gapes (in chickens) and hydatid; (3) By feeding on the tissues of the host, e.g blood-sucking worms or flies; (4) By production of toxins with varying effects; (5) By actual traumatic damage, e.g by piercing and destroying skin (ticks, mites, flies, etc.), by depositing eggs in the tissues Parasitism (lung-worms), by migrations of larvae (Ascaris and Trichinella), by clinging to surfaces by means of sharp hooks (tapeworms), and in many other ways; (6) By facilitating the entrance of bacteria, e.g stomach worms in pigs allow the entrance of Fusiformis necrophorus (the necrosis bacillus); (7) By transmitting diseases for which they act as intermediate hosts, e.g ticks and babesiosis; (8) By causing inflammatory or neoplastic reactions in the invaded tissues, e.g pneumonia, gastritis, and fluke adenomata in the liver These are only some of the more obvious methods of injuring the host Apart from the loss due to actual deaths, the depreciation in value of hides, meat, milk, and work is enormous, and, although less spectacular than a bacterial epizootic, the loss is more constant, and in the aggregate is probably even greater than the loss due to bacterial diseases (See BRAIN DISEASES – Parasites, for parasites which migrate to the brain.) Parasitic Gastroenteritis of Cattle This is an insidious and economically important disease, and the cause of death in many calves and yearlings It is known that the output of worm eggs in the faeces does not bear any constant relation to the number of worms present It rises to an early peak and then declines, and is not a reliable guide to the degree of infestation Cause Infestation with various species of ROUNDWORMS Signs A gradual loss of condition; a harsh, staring coat; sometimes, but not always, scouring; pale mucous membranes; progressive weakness and emaciation In adult cattle, which acquire a high degree of resistance (only broken down when under-feeding, chilling, pregnancy, or massive contamination of pasture occurs), no symptoms may normally be shown, but nevertheless the animal’s efficiency is lowered Treatment Dosing with an appropriate anthelmintic should not be delayed until the stock are weak Prevention Calves should be dosed once with an anthelmintic in mid-July and moved to pasture which has not been grazed that season by other cattle Dose again in the autumn 515 (See WORMS, FARM TREATMENT AGAINST; PASTURE, ‘CLEAN’.) Parasitic Gastroenteritis of Sheep It is likely that outbreaks in early lambs in March and April are the result of over-wintered larvae In experiment, worm-free lambs were turned on to a pasture – ‘rested’ during the winter – in the spring and became infested with 12 species of gastrointestinal worms Lambs may also be infected by eggs in the dung of ewes at lambing, when a periparturient rise occurs Treatment and prevention Routine use of, e.g., Tetramisole (See WORMS, FARM TREATMENT AGAINST; PASTURE, ‘CLEAN’.) Parasitic Tracheobronchitis (see TRACHEAL WORMS) Parasitism Parasitism is the association of organisms, of which (the parasite) benefits by nourishing itself at the expense of the other (the host) but without normally destroying it The following types of parasitic relations are recognised: (a) ectoparasites, which live on the host; and (b) endoparasites, which live within the body of the host; (a) accidental parasites, which are normally free-living animals but may live for a certain period in a host; (b) facultative parasites, which are able to exist free or as parasites, e.g blowfly larvae; and (c) obligatory parasites, which are completely adapted to a parasitic type of life and must live in or on a host, e.g most parasitic worms; (a) temporary or transitory parasites, which pass a definite phase or phases in their life-history as parasites and during which time the parasitism is obligatory and continuous, e.g botflies, ticks; (b) permanent parasites, which always live for the greater part of their life as parasites, e.g lice, tapeworms, coccidia, etc.; and (c) periodic, occasional, or intermittent parasites, which only visit the host for short periods to obtain food, e.g blood-sucking flies, fleas; (a) erratic parasites, which occur in an organ that is not their normal habitat, e.g Fasciola hepatica in the lungs; (b) incidental parasites, which, exceptionally, occur in an animal that is not their normal host; they are incidental only in this first host, e.g Dipylidium caninum is incidental in man; and (c) specific parasites, which occur in a particular species of host or group of hosts, e.g D caninum is specific for dogs and cats P 516 Parasympathetic Nervous System PARASITES and PARASITOLOGY PAGE P Anaplasmosis 24 Arachnida 34 Babesiosis 49 Balantidium 55 629 Blood flukes (see SCHISTOSOMIASIS) Blood parasites of cattle (UK) 71 Blow-flies (see FLIES) 264 Bots (see FLIES) 266 Canine babesiosis 114 Chicken mites (see MANGE) 436 Coccidiosis 143 687 Cysticercosis (see TAPEWORMS) Ear mange (see EAR, DISEASES OF) 210 East Coast fever – (see THEILERIOSIS) 700 Fleas 260 ‘Flesh’ flies (see FLIES) 265 Flies 261 Flour mites (see MITES) 461 (see FLOUR-MITE INFESTATION) 271 Flukes 420, 425, 510, 618, 629 Forage mites (see MITES) 461 Fungal diseases 290 Gadflies (see FLIES) 262 (see WARBLES) 769 Gapeworm (see GAPES) 294 Giardia (see GIARDIASIS) 305 Globidiosis 307 Gnats (see FLIES) 262 ‘Green-bottle’ flies (see FLIES) 264 Haemobartonella 320 Harvest mites (see MITES) 461 Hookworms (see ROUNDWORMS) 614 House flies (see FLIES) 263 Husk and hoose 348, 337 Jaundice, malignant (see CANINE BABESIOSIS) 114 Ked, sheep 357 Leeches 409 Leishmaniasis 409 Lice 414 462 Linguatula (see MITES) Parasympathetic Nervous System The parasympathetic nervous system is division of the autonomic nervous system; the other division being the sympathetic (See AUTONOMIC NERVOUS SYSTEM; CENTRAL NERVOUS SYSTEM.) Parathion Parathion is chemically diethyl-paranitrophenyl-thiophosphate and is used for agricultural purposes to destroy aphis and red spider In man and domestic animals it is a cumulative poison which readily enters the system through inhalation, by the mouth or by absorption through the skin Animals PAGE Liver-flukes Lung flukes Lungworms Mange mites (see MITES) Midges Mites Mosquitoes (see FLIES) Myiasis (see FLIES) Nematodes (see ROUNDWORMS) Nematodirus Red-water fever Ringworm Roundworms in the horse Roundworms in ruminants Roundworms in the pig Roundworms in the dog and cat Roundworms in poultry (see GAPES) Rumen flukes Sarcocystis ‘Scaly leg’ (see MANGE) Schistosomiasis ‘Screw-worm’ fly Sheep nostril fly (see FLIES) Sheep scab Strongyles (see ROUNDWORMS) (see STRONGYLES) Summer sores Tapeworms in the dog and cat Tapeworms in the horse Tapeworms in the pig Tapeworms in ruminants Texas fever Theileriosis Ticks Toxoplasmosis Trichomoniasis Trypanosomiasis Tumbu flies (see FLIES) Warble flies (see FLIES) (see WARBLES) 420 425 514, 613 401 455 461 262 264 611 482 593 606 611 613 615 616 294 618 627 438 629 631 267 639 612 674 677 688 688 689 688 699 700 704 714 719 725 265 266 769 should not be allowed to graze under trees sprayed with parathion for at least weeks In man, symptoms of poisoning include headache, vomiting, and a feeling of tightness in the chest Later there is sweating, salivation, muscular twitching, distressed breathing and coma (See ORGANOPHOSPHORUS POISONING.) In animals, copious salivation and lachrymation, twitching, and increased intestinal movement are shown Cattle are apparently tolerant of parathion, being able to break it down chemically The danger of spray drift, and the risk to dogs and cats wandering in sprayed areas, are obvious Parenchyma SOME OF THE EFFECTS OF PARATHYROID HORMONE AND CALCITONIN, THE REGULATION OF BLOOD CALCIUM 517 MAJOR HORMONES CONTROLLING THE Parathyroid hormone Calcitonin Mode of action Separates fast and slow components Increases cell membrane permeability Activates adenyl cyclase enzyme systems Uncertain Effect on kidney Increases P excretion by decreasing tubular reabsorption Decreases Ca excretion by increasing tubular reabsorption Increases Na excretion by decreasing tubular reabsorption Increases Ca, P, Na, and K excretion Decreases Mg excretion Effect on intestine Increases Ca, P and Mg absorption ? Decreases P absorption Decreases volume and acidity of gastric juice Effect on bone Increases resorption Stimulates osteoclast and osteocyte activity Inhibits formation Suppresses osteoblast activity Inhibits resorption Resultant effect on blood calcium Elevated Diminished (With acknowledgements to Professor D Bennett and to The Veterinary Record.) Parathyroid Glands Parathyroid glands are small structures situated either wholly within, or upon the surface of, the thyroid gland Their secretion, the parathyroid hormone, is important in the control of the level of blood calcium Insufficiency of this hormone leads to muscular twitchings or tremors or, in more severe cases, to convulsions (See TETANY.) The hormone also controls phosphate excretion via the urine (See table.) Hyperparathyroidism in dogs Of 21 dogs with primary hyperparathyroidism, 20 had a parathyroid adenoma and had a parathyroid carcinoma The most common clinical signs were polydipsia/ polyuria, listlessness, muscular weakness and inappetence The only consistent biochemical abnormality was persistent hypercalcaemia (12.1 to 19.6 mg/100 ml) The external parathyroid tumours, found in of the 19 dogs which underwent surgery, were easily removed; internal parathyroid tumours were removed by thyroidectomy Primary hyperparathyroidism in a cat A 12-year-old cat showed clinical signs of lethargy, reluctance to move and pain along the back Radiological examination revealed multifocal lesions, particularly in the skeleton There was bilateral parathyroid hyperplasia but no evidence of neoplastic change Histological examination revealed that a large proportion of bone had been resorbed and replaced by fibrous connective tissue and that osteoclasts were numerous It is suggested that hyperparathyroidism should be considered in the differential diagnosis of conditions involving skeletal pain and lethargy in the cat Paratuberculosis A synonym for JOHNE’S DISEASE Paratyphoid Infection with any species of salmonella; a synonym for SALMONELLOSIS Parenchyma Parenchyma is a term used for the functional cells of an organ, as opposed to its supporting, connective tissue (interstitial) cells In a gland the parenchyma is the mass of secreting cells; in the lung, similarly, the parenchyma comprises the cells concerned with respiration, not the fibrous supporting tissue P 518 Parenteral Parenteral Partridges Administration of a medicinal substance other than via the digestive system, e.g by injection (see GAME BIRDS, MORTALITY) Paresis (see MILK FEVER and ‘DOWNER COW’ SYNDROME) A state of slight or temporary PARALYSIS, also called ‘fleeting paralysis’ (See MILK FEVER; MUSCLES, DISEASES OF – Nutritional muscular dystrophy; LEAD POISONING; GUTTURAL POUCH DISEASE.) Parietal Parietal is the term applied to anything pertaining to the wall of a cavity, e.g parietal pleura, the part of the pleural membrane which lines the wall of chest Paronychia Paronychia is inflammation near to the nail (See RINGWORM.) Parotid Gland P Parotid gland is one of the salivary glands It is situated just below and behind the ear on either side, in the space between the angle of the jaw and the muscles of the neck From its base commences a duct, the parotid duct, or Stenson’s duct, which in the horse runs within the border of the mandible for a distance, and then turns round its rim to the side of the face in company with the external maxillary artery and vein, and ends by opening into the mouth opposite the anterior part of the 3rd upper cheek tooth; in other animals it runs straight across the face instead of along the lower jaw bone The SALIVARY GLANDS are composed of collections of secreting acini held together loosely by a certain amount of fibrous tissue, but they not possess a distinct capsule Parovarium Parovarium is the name of rudimentary structures situated near the ovary, which are the remnants of the Wolffian bodies The name Paroophoron is also used These structures are often the seat of cysts in the young adult (See OVARIES, DISEASES OF.) Parrots (see PSITTACOSIS; also BIRD IMPORT CONTROLS and PACHECO’S DISEASE) Parthenogenesis Asexual reproduction, in which the ovum develops into an embryo without fertilisation by a spermatozoon.This is a common method of reproduction among invertebrate animals, particularly insects, including ants and bees Parturient Paresis Parturition Parturition is the expulsion of the fetus (and its membranes) from the uterus through the maternal passages by natural forces, and in such a state of development that, in domesticated animals at least, though not in the marsupials, the fetus is capable of independent life The process is called ‘foaling’ in the mare, ‘calving’ in the cow, ‘lambing’ in the ewe, ‘kidding’ in the goat, ‘farrowing’ in the sow, and ‘whelping’ in the bitch It is more likely to proceed successfully without than with human interference in the great majority of cases (See CALVING, DIFFICULT for information on traction.) Stages in parturition Although the act is really a continuous one, it is customary to divide it into stages: (1) Preliminary stage; (2) Dilatation of the cervix stage; (3) Expulsion of the fetus stage; (4) Expulsion of the membranes stage (1) Preliminary stage may occupy some hours or even days The udder swells, becomes hard and tender, and a clear waxy fluid material oozes from the teats or may be expelled by pressure of the hand The external genitals become swollen, enlarged, and their lining is reddened A vaginal secretion appears The abdomen drops and becomes pendulous The quarters droop and the muscles and ligaments of the pelvis slacken The animal separates itself from its fellows if at pasture; if at liberty, it seeks a remote or an inaccessible place in which to bring forth its young, and some, such as the sow, bitch, and cat, prepare a bed or nest (2) Dilatation of the cervix stage merges with the preceding Restlessness is evident The mare paces around the loose-box (often with tail raised) – perhaps lying down and rising again several times Sweating occurs under the mane and tail, and soon over most of the body During the 2nd stage of labour, the mare is usually lying down on her side, and in some cases will show symptoms of COLIC, i.e kicking at the belly, turning and gazing at her flanks, or wandering round in an aimless fashion Meanwhile the labour pains have been getting more and more powerful and the intervals between them shorter The pulse is quickened, and the breathing rapid When a pain has passed the animal calms down and remains 564 Pregnancy and Gestation PERIODS OF GESTATION Average period Shortest period young born alive Animal Months (calendar) Days Mare Ass Cow Ewe and goat (merinos) Sow Bitch Cat 11 121/ — — — — 340 374 283 or 284 144 to 150 (150) 114 58–63 55–63 Longest period young born alive 340 365 200 135 414 385 439 160 110 55 — 130 76 — PERIODS OF DEVELOPMENT DURING PREGNANCY State of pregnancy Ewe and goat Sow Bitch 14 days Ovum mm 14 days Ovum 1.25 to 1.5 mm 14 days Ovum 1.25 to 1.5 mm 10 days Ovum 1.25 to 1.5 mm Fertilised ovum has reached uterus from oviduct Duration II Cow 14 days Ovum mm Stages in development I Mare Duration of period Length of fetus to weeks Length of fetus Stages to weeks to weeks to weeks 10 days to weeks 12 mm mm mm 12.5 mm mm Traces of fetus appear; head, body and limbs are discernible by end of this period Duration Length of fetus to weeks 55 mm Stages First indications of hoofs and claws visible as little pale elevations at ends of digits IV Duration Length of fetus Stages to 13 weeks to 12 weeks to weeks to weeks 5th week 150 mm 140 mm 90 mm 75 mm 64 mm Stomach well defined in foal, pig and puppy; differentiation of four stomachs in ruminants at end of this period V Duration Length of fetus Stages 14 to 22 weeks 13 to 20 weeks 10 to 13 weeks to 10 weeks 6th week 33 cm 30.5 cm 15.25 cm 12.5 cm 90 mm Large tactile hairs appear on lips, upper eye-lids, and above eye Teats visible in female fetuses VI Duration Length of fetus Stages 23 to 24 weeks 21 to 32 weeks 13 to 18 weeks 11 to 15 weeks to weeks 68.5 cm 60 cm 35.5 cm 18 cm 12.5 cm Eye-lashes well developed A few hairs appear on tail, head and extremities of limbs Duration 35 to 48 weeks III P VII Length Stages to weeks 45 mm to weeks 32 mm 33 to 40 weeks 19 to 21 weeks to weeks 45 mm to weeks 25 mm 9th week (8th in cat) 107 cm 91 cm 46 cm 230–300 cm 15–20 cm (kitten 13 cm) Fetus attains full size Body becomes gradually covered with hair, hoofs and claws complete, but soft except after repeated breeding, and in from to weeks the dam has returned to normal to all intents and purposes, always excepting the flow of milk in the mammary glands In most uniparous animals – producing young at a time – the horn of the uterus which becomes pregnant greatly enlarges and becomes straightened out so as to be practically continuous with the body of the uterus, and the non-pregnant horn appears as a small appendage projecting from its side; in the multiparous animals, however, both horns usually carry a share of the number of the young, and both are consequently nearly alike in size As the organ gradually increases in size to accommodate its contents, the broad ligament, 15 to 17 weeks which supports it from the roof of the abdomen, increases in length and strength to allow the uterus to move further and further forward and downward in each animal, so that eventually it may occupy the greater part of the abdominal cavity At the same time there is a very great increase in the muscular coat of the uterus Duration of pregnancy This varies greatly in different species and to some extent in different individuals Male fetuses are carried longer than females Debility, weakness, or illness in the dam shortens the duration of pregnancy (See table.) Pregnancy and Gestation A prolonged gestation period in ewes has been reported on occasion In an incident in western Scotland, gestation periods extended up to months; unless relieved of their fetuses surgically, the ewes usually died Long hairy coats, skeletal deformities, and extensive liquefaction of the central nervous system were characteristic of the fetuses The cause is unknown, but could be a toxic plant A similar syndrome occurs in southwest Africa, associated with feeding on the shrub Salsola tuberculata var tomentosa; and in the USA prolonged pregnancy in ewes has been linked to the plant Veratum californicum Signs of pregnancy When well advanced, the typical signs of pregnancy are sufficiently known to the majority of livestock owners, and require no mention here; but in the earlier stages they are not always so clear, and for the first few weeks in the larger animal it is often difficult to diagnose pregnancy by clinical signs The chief changes and differences to be looked for are as follows: Cessation of oestrus: in the majority of cases, but not in all animals, the female exhibits no desire for the male after conception occurs There are many instances, however, when service is allowed until late on in pregnancy, and there may be all the usual signs of oestrus evident on each occasion In such cases abortion of the fetus may occur, or no harm may result When the bull refuses to serve a cow which is apparently in season it may be taken as a strong sign that she is pregnant Alteration in temperament: vicious, troublesome, or easily excited mares generally become very much more tractable and quiet after conception, whereas if they are served and not conceive they are frequently more intractable than previously The same signs are sometimes seen in the cow Fattening tendency: in the sheep and the cow particularly, condition markedly improves during the first few weeks of pregnancy, but during the latter stages when the abdomen has increased in size the opposite effect is seen in all animals Easily induced fatigue: in the later stages, pregnant animals almost always show an increased desire to rest as much as possible Enlargement of the abdomen: this occurs in every direction, and is a most important sign of pregnancy; it occurs at about the same rate as the rate of development of the young, which is greatest towards the end of the period The abdomen descends or ‘drops’; the flanks become hollow; the spine appears more prominent, and 565 its line tends to become flat or even concave in the thoracic and lumbar region; the muscles of the quarters appear to fall in, making the haunches and the root of the tail appear more prominent; and the pelvis tilts into a more vertical position Enlargement of the mammary glands: this commences very soon in pregnancy in those animals which are bearing young for the first time The glands become larger, and firmer, and more prominent Increase in weight: this is of course, a sine qua non of normal pregnancy in a healthy, wellnourished animal (See PREGNANCY DIAGNOSIS.) Care of the dam during pregnancy In all species of animals, exercise (or work) is essential if the vigour of the dam is to be retained, and if her circulatory, digestive, muscular, and nervous systems are to be maintained in a fit state for the strains they will have to withstand at parturition Food is of great importance: no sudden changes in the ration should be made It is better to give an extra feed each day rather then unduly to increase the quantities given at each feed This avoids excessive distension of stomach and intestines which may lead to nausea and indigestion Mares should be treated as usual until the time that the abdomen begins to increase in size During the last month an extra feed per day should be given, and if clover (or, better, lucerne) hay is available it should be given in preference to other kinds of hay Lucerne, being rich in lime and magnesium salts, provides a plentiful supply of these for the mare’s milk, as well as for the developing foal During this last month it is well to allow the mare to sleep in the foaling-box, so that she may become accustomed to it, and settle better The box should have previously been thoroughly cleaned out, its walls scrubbed with boiling water containing a suitable disinfectant, especially where joint-ill exists upon a farm Where the climate is mild, mares may, with great advantage, be allowed to foal out of doors The foal is often born during the night Food given should be gently laxative; for this purpose the addition of pulped roots, carrots, bran, or treacle to the food is good (For further information see under PARTURITION.) Cows are usually allowed to calve in a loosebox (See under STEAMING-UP.) Ewes may be either kept out on the hill, or brought down to lower land, and housed in a P 566 Pregnancy Complications lambing-pen during the last week or so of pregnancy, but otherwise little special attention is necessary Chasing by dogs, crowding through gateways, and all other forms of rough treatment are to be avoided Care is needed when catching Heavy in-lamb ewes should not be turned up to have their feet dressed Sows greatly benefit from having access to an old pasture or paddock, where they will not be disturbed by other animals, and where they may take as much exercise as they desire But at night they should have a clean, warm, dry bed to sleep on Pregnant sows are best fed individually or in twos: otherwise some sows get more than their fair share, while others suffer from under-feeding Wet, cold floors and cold, draughty premises predispose to mastitis and agalactia Bitches must be given regular exercise, and after the first month extra meals of protein-rich food, including a little liver once a week An improvised whelping box is useful (See also SUPERFETATION; BREEDING OF DOGS; PARTURITION; PREGNANCY DIAGNOSIS.) Pregnancy Complications In the mare these include twin foals (see ABORTION) and PREPUBIC TENDON RUPTURE (See also PREGNANCY ECTOPIC; MUMMIFICATION OF FETUS; SUPERFETATION.) Pregnancy Diagnosis P As well as traditional techniques such as rectal or abdominal palpation, confirmatory tests for pregnancy are widely used There are types: those relying on the detection of hormones in blood, urine or milk; and those depending on visualisation of the fetus by ultrasound scanning instruments Farm animals In cattle, rectal palpation is widely used It may be carried out or weeks after insemination in cows and by weeks in the heifer Among more sophisticated tests is that for PROGESTERONE, based on a radioimmuno-assay technique for the detection of progesterone in a sample of milk The milk sample is taken 24 days after the last insemination A test based on the measurement of oestrone sulphate in milk uses a milk sample taken 15 weeks or more after insemination An enzyme method of milk pregnancy testing, using do-it-youself kits, is available; the test takes about 45 minutes Real-time ultrasonic scanning is widely used for the early detection of pregnancy The technique, which requires special equipment, is applicable to most species Bitch Pregnancy cannot be diagnosed in the early stages From 24 to 32 days is the best time for abdominal palpation; after 35 days pregnancy may be difficult to recognise by this means, though occasionally posterior fetuses can be felt at 45 to 55 days (when the fetal skeleton can be palpated) Auscultation of fetal hearts in the final week of pregnancy will differentiate pregnancy from pyometra and show that the fetuses are alive Pregnancy has to be differentiated also from pseudo-pregnancy, ascites, adiposity, and diabetes mellitus Eighty-two bitches were examined for pregnancy using several different techniques Abdominal palpation 26 to 35 days after mating was 82 per cent accurate in detecting bitches that would whelp, and 73 per cent accurate in identifying those that would not so Amode ultrasound was best used 32 to 62 days after mating, and was 90 per cent and 83 per cent accurate in diagnosing pregnancy and non-pregnancy respectively The better of the ultrasound instruments used was 85 and 100 per cent accurate in detecting pregnancy in the periods 36 to 42 days and 43 days to term respectively It was completely accurate in detecting bitches which were not pregnant Mares An ultrasonic scanner is often used for pregnancy diagnosis in mares It is possible to detect the presence of a developing fetus with great accuracy as early as 14 days after conception, and this technique is particularly useful in the diagnosis of twin pregnancies Pregnancy, Ectopic The presence of a fetus (or more than one) inside the abdomen but outside the uterus Many cases occur as the result of trauma, e.g in a dog or cat struck by a car The uterus is torn and the fetus becomes dislodged and undergoes mummification The latter also occurs when a fertilised egg has ‘gone the wrong way’; i.e instead of taking the normal route down the Fallopian tube to the corresponding horn of the uterus, it develops outside the uterus Pregnancy Examination Pregnancy examination of cattle, when carried out by means of rectal palpation, requires expert knowledge not only of anatomy but also of physiology and pathology It is not always a simple matter and an accurate diagnosis is not achieved every time The dangers of attempts by herdsmen and other untrained people to Premunition carry out such an examination include: rupture of the heart of the embryo calf; perforation of the rectum; and abortion due to malhandling of the ovaries In the mare, rectal palpation is a common method of pregnancy diagnosis (See also PREGNANCY AND GESTATION – Signs of pregnancy; PREGNANCY DIAGNOSIS.) Pregnancy, False (see PSEUDO-PREGNANCY and ‘CLOUDBURST’) Pregnancy, Termination of 567 in store condition for the first months of pregnancy Treatment Ewes should be dosed at once with glycerine 150 ml (2 tablespoonfuls) in water; or glucose, 60 g in 300 ml (2 oz in 1⁄2 pint) warm water; or, preferably, glucose solution may be given intravenously A number of ready madeup proprietary products, most based on the glucose precursor propylene glycol, are available (See ACETONAEMIA.) Termination of pregnancy following misalliance of a bitch may be achieved with oestradiol benzoate, used with to days of mating In cattle, termination using prostaglandins may be undertaken up to 150 days gestation Abortion also occurs from a variety of causes (See RESORPTION; MUMMIFICATION OF FETUS; PARTURITION, DRUG-INDUCED; CLOPROSTENOL.) Pregnant Mare’s Serum Pregnancy Toxaemia in Ewes Use of a drug or drugs before administration of a general anaesthetic An analgesic will relieve pain in an animal awaiting surgery, and a tranquilliser will relieve anxiety and facilitate handling Both effects may be obtained by the same drug (See ANALGESICS; TRANQUILLISERS.) An acute metabolic disorder occurring during the last few weeks of pregnancy; perhaps more accurately, a number of disorders – one of which may be acetonaemia Causes In the more typical outbreaks, ewes are generally in good bodily condition, are carrying twins or triplets in utero, or have a particularly large single lamb They are on good rich grazing, seldom getting much exercise Bad weather, e.g a fall of snow, has often occurred previous to the outbreak It has been claimed that the disease can be produced experimentally by a short period of starvation during advanced pregnancy, and that ewes which become fat during the first months of pregnancy are especially susceptible Signs The first symptoms are incoordination of movement, the animal lagging behind others when driven, stepping high, and often staggering and falling In another hour or the ewe lies down and can only be induced to rise with difficulty She stands swaying and will fall or lie down again almost immediately In general appearance she is dull, hangs her head, her eyes appear to be staring – owing to widely dilated pupils – and breathing is laboured or stertorous Fluid may be copiously discharged from the nostrils Acetonaemia may be present, giving rise to the characteristic odour from breath and urine A comatose condition develops Death occurs within to days Prevention It has been recommended that after the pre-tupping flush, ewes should be kept (see PMSG under CONTROLLED BREEDING – Synchronisation in ewes; HORMONES) Premature Birth ABORTION and PARTURITION, and the table under PREGNANCY) (see Premedication Premilking (see under PREPARTUM MILKING) Premunition Premunition is a term used in relation to the type of resistance shown by animals against severe illness caused by infection Animals which are premunised are infected with a micro-organism but are not affected by it The term has often been used in veterinary medicine in relation to trypanosomiasis Cattle which are premunised will not succumb to trypanomiasis although infected by trypanosomes There are types of premunition recognised: (1) natural premunition, which occurs inside or in close proximity to a fly-belt, where trypamomiasis is endemic; and (2) artificial premunition, which results from the administration of a substerilising dose of a trypanocidal drug Unfortunately, it seems very probable that, at least in the majority of cases, natural premunition only gives protection against local strain of trypanosomes, and cattle which are thus premunised against a local strain may succumb when exposed to infection with a different strain of the same species; if, for instance, they are moved out of one fly-belt to another The occurrence of intercurrent diseases of other varieties may also lead to a breakdown in premunition Similarly, artificial premunition can P 568 Prepartum Milking only be relied upon to protect against a single strain (See also TSETSE FLY.) Prepartum Milking Milking a heifer or cow a few days before the birth of her calf Where this is practised, the calf when born must be provided with colostrum from another cow Prepotency The ability of one parent, in greater degree than the other, to transmit a characteristic (e.g high milk yield) to the offspring Prepubic Tendon, Rupture of A possible complication of pregnancy, especially in heavy mares Diagnosis is difficult but the condition should be suspected whenever ventral oedema occurs suddenly in late gestation, and is associated with considerable pain (due to the trauma) The condition is usually fatal, and may be a cause of sudden death Prepuce The fold of skin covering the end of the penis Crystals on the hairs here in the calf are seen in some cases of UROLITHIASIS (See also PENIS AND PREPUCE, ABNORMALITIES AND LESIONS.) Presbyopia P Presbyopia is the term used to indicate the changes that normally affect the eye in old age, quite apart from any disease The most important of these changes is a diminution of the natural elasticity of the lens of the eye, resulting in an impaired power of focusing objects near at hand Prescription Diets Specially formulated dog and cat foods designed to assist the treatment of certain metabolic and functional disorders Available in both dry and moist form, from veterinary surgeons Prescription-only Medicines (POM) Medicines that may be supplied only on the prescription of a doctor, veterinary surgeon or dentist Under the terms of the MEDICINES ACT 1968, veterinary surgeons in the UK may supply prescription-only medicines only for animals or herds under their care, and not to the public at large Presentation (see under PARTURITION) Pressor Pressor is the term applied to anything that increases the activity of a function, e.g a pressor nerve or pressor drug Producing a rise in blood pressure is its most common meaning Prevalence This is defined as the number of cases of disease or infection existing at any given time in relation to the unit of population in which they occur It is a static measure as compared with the dynamic measure, INCIDENCE Preventive Veterinary Medicine This is the keynote of modern veterinary practice, and is of increasing importance in these days of intensive livestock husbandry and of very large units (See HEALTH SCHEMES FOR FARM ANIMALS.) Priapism Persistent erection of the penis Cases of priapism in horses, with protrusion, oedema and paresis of the penis, have been recorded after neuroleptanalgesia and anaesthesia using acepromazine with etorphine chloride and other anaesthetic agents It is recommended that following the use of neuroleptic drugs a check should always be made to ensure that penile retraction is taking place as the effects of the drug wear off If not, treatment should be started without delay (See also PENIS; PENIS AND PREPUCE, ABNORMALITIES AND LESIONS.) Primary Mosaicism Primary mosaicism is a sequel to fertilisation of an ovum by spermatozoa derived from the same zygote but having different chromosomes (See ERYTHROCYTE MOSAICISM; GENETIC ENGINEERING.) Secondary mosaicism occurs in the FREEMARTIN Primates These include about 200 species, ranging in size from the tree-shrew, weighing about 100 g, to the gorilla, weighing up to 275 kg Two suborders are recognised: New World monkeys; and Old World monkeys, apes, and man Prions Prions are proteins found in the brain which are, apparently, self-replicating In mice, experimentally removing the gene responsible for producing prions resulted in their being totally resistant to spongiform encephalopathies (See BOVINE FELINE SPONGIFORM ENCEPHALOPATHY; SPONGIFORM ENCEPHALOPATHY; SCRAPIE.) Progeny Testing 569 Privet Poisoning Prodromal Privet poisoning is very rare, and occurs only when horses and cattle have free access to privet hedges, or break into gardens and shrubberies containing this common ornamental shrub Privet (Ligustrum vulgare) contains a glucoside (ligustrin), which causes loss of power in the hind-legs, dilated pupils, slightly injected mucous membranes, and death in 36 to 48 hours Prodromal is a term applied to symptoms of a disease which are among the first seen, but which are not necessarily characteristic Probang A rod of flexible material designed to aid removal of foreign bodies from the oesophagus (See CHOKING.) Probiotics Preparations containing live micro-organisms such as lactobacilli and yeasts; yoghurt is an example They are used in some animal-feed supplements to act as growth-promoters Probiotics are believed to act by preventing colonisation of the gut by pathogenic organisms ‘Production Disease’ A name suggested to embrace all the syndromes formerly classified as metabolic disease It has been used particularly in connection with intensive farm husbandry, because high production is frequently expected on diets which are not always suitable for the purpose GENERAL CHARACTERISTICS No % Size Large Medium Small 21 34 38 60 Temperament Quiet Nervous 54 96 Ease of Milking Satisfactory Hard Too easy 55 — 98 — Procaine Hydrochloride Proestrus Procaine hydrochloride is used in solution as a local anaesthetic, and for EPIDURAL ANAESTHESIA It is, generally speaking, as effective as cocaine (except for anaesthetising the cornea, for which cocaine is preferable) but far less toxic and safer to use, besides not coming under the Controlled Drugs Regulations; it is a prescription-only medicine It is often combined with adrenaline, in order to lessen haemorrhage during minor surgery The 1st phase of the oestrous cycle, when the ovary is producing hormones which bring about enlargement of uterus, oviducts, and vagina, and when the ovarian follicle containing the ovum is also increasing in size (See OESTRUS.) Toxicity Excessive amounts of procaine hydrochloride cause stimulation of the central nervous system In the horse, mg per lb bodyweight gives rise to nervousness (tossing of the head, twitching of the ears, stamping of the feet, snorting, or neighing), while muscular incoordination and convulsion follows larger doses In the dog, 20 mg per lb causes salivation and vomiting, with muscular tremors and incoordination Procaine penicillin The procaine salt of penicillin is often used, the concentration of penicillin in the blood remaining for a longer period, and the injection being less painful However, procaine penicillin G can sometimes cause a febrile reaction in pigs The toxicity can be potentiated by swine erysipelas Proctitis Irritation situated about the anus It is a sign of the presence of parasitic worms in almost all animals Progeny Testing A method of assessing the value of, e.g a bull as a sire, by examining the milk yield, etc., figures for an unselected sample of his daughters Dam:daughter comparisons may show whether a high-yielding cow can transmit her capability to her progeny, but these comparisons are valid only under identical systems of feeding and management Conformation Selection of proven bulls for use as artificial insemination sires depends not only on the production figures of the daughters, but also on an assessment of (as many as possible) daughters Qualities of commercial importance taken into account are size, temperament, ease of milking – plus appearance, dairy character, udder, legs, feet, etc Gradings are Excellent, Very Good, Good Plus, Good, Fair and Poor Below is shown a summary for a particular bull which had 56 daughters inspected by a type assessment panel It will be noted that all but of his daughters were quiet, and over half of them were in the top ratings The score of 107 indicates that the fore udder was the best point when compared with the national average P 570 Progesterone Other traits which need recording, such as weak pasterns, teats not plumb, or high pelvis, can be dealt with by means of a list of miscellaneous characteristics Progesterone A sex hormone from the corpus luteum and (in the pregnant animal) the placenta which prepares the reproductive tract for pregnancy It inhibits follicle-stimulating hormone (FSH) and action of oxytocin (See under ENDOCRINE GLANDS.) Progestogens The progeny group illustrated in the diagram would have very high rear udders, legs about midway between very straight and very sickle, and would be rather sharper, cleaner cut animals than average, though not excessively so (MMB.) Linear assessment This is widely used in the USA and Canada, and in the UK It does away with the idea of scoring against an ideal, makes no attempt to define good or bad, but simply describes where, between the biological extremes for agreed traits, an individual animal comes The linear system identifies the point between the extremes at which an animal is felt to come by describing it numerically in the range to Since the total number of single biological traits is very large, the most important ones have to be selected to keep the total a manageable one P Name Altrenogest Delmadinone Megestrol acetate Product, or other name Regumate Tardak Ovarid Medroxyprogesterone acetate MAP (Methyl acetoxy progesterone), Perlutex Promone, Veramix Cronogest Fluorogestone (Flugestone) acetate Norgestomet in Crestar NB The list is not comprehensive A common set of 16 traits was agreed following discussions with the British Friesian Cattle Society and the Associated AI Centres The traits are: stature, chest width, body depth, angularity, rump angle, rump width, rear legs (side view), rear legs (rear view), foot angle, fore udder attachment, rear udder attachment, udder support, udder depth, teat placement (rear view), teat placement (side view), teat length These drugs are used in CONTROLLED BREEDING and have a progesterone-like action A progestogen is administered over a period of time so that the established oestrous cycle is arrested at the point at which all corpora lutea have regressed The removal of the progestogen then allows the continuance of reproductive activity Examples of progestogens are: Their use can sometimes lead to diabetes in dogs and cats Proglottis A segment, of an adult tapeworm, capable of reproduction Progressive Retinal Atrophy (PRA) Degenerative diseases of the eye leading commonly to night blindness and ultimately total loss of vision In the UK there is a joint scheme operated by the British Vet-erinary Association and the Kennel Club to reduce the incidence of this disease in any breed of dog; certificates are issued to dog-owners (See EYE, DISEASES OF.) The disease also occurs in some breeds of cats The genetic defect responsible for causing the disease in Irish setters has been identified by US and UK researchers, and could provide a means for eliminating the condition from the breed Projectile Syringe Fired from a cross-bow, gun or blowpipe, this instrument is useful for immobilising and/or anaesthetising wild animals The use of dart guns is, in the UK, restricted under section of the Firearms Act 1968 Blowpipes and dart guns are short range – up to 36 m (40 yards) only They use a compressed air discharge system to shoot a small hypodermic syringe loaded with the appropriate drug They facilitate the treatment of dangerous or unapproachable animals with safety They are often used to administer antibiotics, vaccines, and so are not purely for anaesthetics Prostaglandins Projectile Vomiting 571 This term is used when the vomitus is thrown some distance (up to a metre) from the body – a symptom of pyloric stenosis in the dog will result in death The cause is unknown At post-mortem exmination, fluid is found in the abdominal cavity and the kidneys and spleen appear grey and swollen Prolactin Prolonged soft Palate A hormone associated with lactation and secreted by the PITUITARY GLAND Also called leuteotropic hormone or leuteotropin PALATE.) Prolan An old name for chorionic gonadotrophin Prolapse Prolapse means the slipping down of some organ or structure The term is applied to the displacements of the rectum and female generative organs, which result in their appearance to the outside The best plan is to seek professional assistance at once (See UTERUS, DISEASES OF; RECTUM, DISEASES OF.) Prolapse of Oviduct This condition is fairly frequently encountered in fowls, particularly in birds which have been laying heavily It is nearly always associated with some aberration from normal of the cloaca or oviduct, irritation resulting and causing the bird to strain Occasionally it is seen after an endeavour to pass a large or malformed egg, yolk concretion, etc., and in cases known as ‘egg bound’ It is also sometimes met with in cases of vent gleet The prolapsed oviduct appears as a dark red swelling protruding from the vent Other birds are attracted by the swelling and peck at it, frequently leading to evisceration and death Treatment consists in removing the affected bird from the flock The prolapse should be washed with warm water containing a mild antiseptic, and then gently pressed back into the abdominal cavity after first removing the egg or other foreign body, if the presence of such can be detected It greatly aids return to have the bird held head downwards by an assistant Proliferative Enteropathy (PE) An infectious intestinal disease of pigs associated with Lawsonia intracellularis There may be diarrhoea but no specific clinical signs Proliferative Haemorrhagic Enteropathy in Pigs (see HAEMORRHAGIC GASTROENTERITIS) Proliferative Kidney Disease A disease mainly of fingerling salmonids; affected fish show abdominal swellings and any stress An inherited abnormality of dogs (See under Promazine Hydrochloride An effective sedative and prenarcotic, administered to the dog by intravenous or intramuscular injection Pro-Oestrus A period in the oestrus cycle when the Graafian follicles are increasing in size (see OVARIES) and the female reproductive organs are being prepared for possible pregnancy Prophylaxis Prophylaxis means any treatment that is adopted with a view to preventing disease Propionate, Sodium A bacteriostatic and fungicide which has been recommended in the treatment of obstinate infections of the conjunctiva and cornea Propionic Acid (see MUSCLES, DISEASES OF – Nutritional muscular dystrophy) Propofol One of a group of alkyl phenols, propofol (Rapinovet; Schering-Plough) is useful as an intravenous anaesthetic for dogs and cats, as well as for minor surgical procedures and caesarian section Recovery from it is quiet and rapid – an advantage when the patient has to be returned to the owner’s care with the minimum delay Propylene Glycol Propylene Glycol is used in the treatment of acetonaemia in cattle and pregnancy toxaemia in sheep It is often formulated with minerals Prostaglandins A group of hormone-like compounds which can cause contraction of the uterus, lower blood pressure, have an effect on platelets, and lower body temperature Prostaglandin F2α or its analogues cloprostenol, dinoprost, luprostiol and tiaprost, are used in veterinary practice to bring about regression of the corpus luteum for control of oestrus or to induce abortion or parturition P 572 Prostate Gland A code of practice relating to the use of prostaglandins in cattle and pigs has been agreed by the RCVS and the BVA Care must be taken when handling prostaglandin products to avoid skin contact and self-injection Asthmatics and women of child-bearing age are particularly at risk Prostaglandins can cause local ischaemia at the intramuscular injection site, followed by diffuse swelling and emphysema In one case, sloughing of skin and muscle occurred, and Clostridium chauvoei was isolated from the exudate The mare became recumbent, and euthanasia was decided upon (See CONTROLLED BREEDING; PYOMETRA; RETAINED PLACENTA See also UTERUS, DISEASES OF – Chronic metritis.) Prostate Gland P Prostate gland is one of the accessory sexual glands that lies at the neck of the bladder in the male animal, and partly surrounds the urethra at that point Hyperplasia is an enlargement of the prostate and is seen in older animals When greatly enlarged, not only does it interfere with urination, but it may also obstruct the passage of faeces Affected animals will show constipation, and eventually tenesmus with the production of ribbon-like faeces The condition can cause perineal hernia Oestrogens are used in treatment but castration may have to be carried out Apart from this gradually occurring hyperplasia of the gland in dogs over years old, enlargement may be due to an acute infection, when evidence of pain (with arched back and a stifflegged gait) may be added to the symptoms Cancer of the prostate is not rare in the dog; cysts sometimes occur (See also BRUCELLOSIS.) Prostatitis Inflammation of the prostate ocurring as a result of infection ascending the urethra Affected animals are anorexic, show malaise and may vomit There is severe abdomnal pain with arching of the back Urination will be difficult and painful Antibiotics, oestrogens, smooth muscle relaxants and castration have been used in treatment, but in chronic cases the prognosis for improvement is not good Prosthesis An artificial replacement of a part of the body Protection of Animals Act 1911 (Protection of Animals [Scotland] Act 1912) These are the Acts under which actions for cruelty to animals are taken in Britain Both have been amended subsequently The Acts make it an offence to carry out an act, or to something, that results in a domestic or captive animal suffering unecessarily either by deliberate cruelty or neglect Protection of Animals (Anaesthetics) Act 1964 (see under ANAESTHESIA) Protein Calories A measure of the nutritional value of a food, not of a requirement by the animal Protein Concentrates Products specifically designed for further mixing with planned proportions of cereals and other feeding-stuffs, either on the farm or by a feed-stuff compounder Protein Equivalent This provides the measure of the value of a feeding-stuff, taking into account the protein content plus the non-protein nitrogen content, capable of being converted into protein by the animal’s digestive system It is expressed as a percentage For example, the protein equivalent of linseed cake is 25 per cent; i.e 100 kg of the cake is equivalent to 25 kg of protein and potential protein The protein equivalent of grass silage is about per cent; that of kale, 1.3 per cent Protein, Hydrolised A mixture of amino acids and simple polypeptides prepared by enzyme digestion of whole muscle A valuable source of protein used in cases of shock, malnutrition, convalescence, fevers, chronic nephritis, etc It may be given by mouth or injection Protein Shock A reaction following parenteral administration of a protein (See ANAPHYLACTIC SHOCK.) Proteins Proteins are complex chemical compounds containing nitrogen, carbon, hydrogen and oxygen, found in every body tissue and living cell Proteins are formed from (and convertible to) amino acids (See DIET.) Proteoglycans Proteins which are combined with a carbohydrate Protetamphos A compound used as a sheep dip, and also for fly strike and control of keds, ticks and lice Pruritus, Pyrexia, Haemorrhagic Syndrome Proteus A genus of bacteria Proteus species are common pathogens affecting the urinary system of the dog and generalised infections of duck Prothrombin A substance formed in the liver with the assistance of vitamin K, and essential for the clotting of blood Protoplasm (see CELL) Protothecosis Poisoning by a colourless alga, prototheca; possibly a mutant form of chlorella, a green alga (See MASTITIS.) Protozoa Single-celled organisms Proven Sire Proven Sire is one having an adequate number of measured progeny (See PROGENY TESTING.) Proventriculus The true, glandular stomach of birds In it digestion is effected by hydrochloric acid and enzymes (See diagram below.) 573 Proventricular region of the horse’s, and pig’s, stomach is near the oesophagus Proximal Proximal is a term of comparison applied to structures which are nearer the centre of the body or the median line, as opposed to more ‘distal’ structures PrP A protein found on the surface of neurons (nerve cells) and involved in the development of transmissible spongiform encephalopathies, including BOVINE SPONGIFORM ENCEPHALOPATHY Pruritus Pruritus is the symptom of itching which is a prominent feature of most parasitic skin diseases, and of Aujeszky’s disease and scrapie (In human medicine, an iron deficiency is recognised as one cause of pruritus.) Pruritus, Pyrexia, Haemorrhagic Syndrome A syndrome recorded mainly in dairy cows fed large amounts of silage, often after use of a silage additive The signs vary but include fever and persistent skin lesions which sometimes result in self-mutilation and haemorrhages The P Proventriculus Its position in the digestive tract of the fowl is indicated (5) Other numbers indicate beak and tongue (1 and 2); oesophagus (3); crop (4); gizzard (6); duodenum (7); small intestine (8); large intestine (9); cloaca (10); caeca (11); liver (12); gall bladder (13); pancreas (14) (Reproduced with permission from the UFAW Handbook on Care and Management of Farm Animals, Churchill Livingstone.) 574 Prussic Acid outcome is often fatal It has also been reported in cattle fed on citrus pulp which was mouldy and contained citrinin Prussic Acid (see HYDROCYANIC ACID) Psammoma In another reported series, a total of 81 per cent of pseudo-pregnancies responded to treatment with bromocriptine, and 80 per cent of the behavioural or psychological problems were resolved (See REPRODUCTION; BREEDING; ‘CLOUDBURST’.) Psammoma is a small hard tumour of the brain Pseudo-Rabies Pseudo-Cowpox DISEASE Caused by a parapox virus, this infection is characterised by inflammation of the teats of cows, and of the hands of milkers Pseudo-Tuberculosis Pseudomonas Psittacines A genus of bacteria P pyocyanea is a motile, Gram-negative rod, 1.5 to µ long It flourishes in suppurating wounds, and has been found in cases of otitis in the dog It has also been reported as causing outbreaks of disease in turkey poults and other birds as well as in sheep Chronic mastitis, with diarrhoea and wasting resembling Johne’s disease, has been caused in cows by P aeruginosa This organism, often found in non-mains water supplies, is thought likely to be increasingly involved in mastitis in cattle It appears to have an increased incidence during August, September and October (See WOUNDS; also MELIOIDOSIS.) Parrots, parrakeets, cockatiels, budgerigars and other members of the order Psittaciformes Pseudo-Pregnancy P Pseudo-pregnancy is a condition commonly seen in the bitch, but probably occurring in all breeding female animals to a lesser degree In it the physical signs of pregnancy are exhibited in the absence of fetus or fetuses The abdomen increases in size, the uterus becomes swollen and turgid, its walls are thickened, and in extreme cases mammary development may occur and milk may be secreted The bitch may actually make a bed In time, since no fetuses are present, the organs and tissues return to their normal state without the occurrence of parturition; heat returns, and successful breeding may occur subsequently The condition has been described as an intensification and prolongation of metoestrus The essential feature is persistence of the corpora lutea in the ovaries The condition can – where necessary – be treated by injection of the appropriate hormone In a review of 442 cases of pseudopregnancy in a total of 142 bitches, 19 had only pseudo-pregnancy, 31 had 2, 54 had 3, and 39 had or more pseudo-pregnancies A name occasionally used for AUJESZKY’S (see YERSINIOSIS; CASEOUS LYMPHADENITIS) Psittacosis (‘Parrot Fever’) A NOTIFIABLE DISEASE in the UK It causes severe respiratory illness in man and birds of the parrot family (psittacines), including budgerigars and cockatiels It is caused by Chlamydia psittaci (See CHLAMYDIA; ORNITHOSIS.) Psoas Psoas is the name of muscles, psoas major and psoas minor, which lie along the roof of the abdomen immediately beneath the last or thoracic and the whole of the lumbar vertebrae, and stretch into the pelvis The psoas minor is inserted in the psoas tuberele of the ilium, and the psoas major runs to the inner or lesser trochanter of the femur in common with the iliacus muscle The action of these muscles is to bend the pelvis on the rest of the trunk, or if those of one side of the body are acting alone, to bend the posterior part of the trunk towards that side The act of crouching preparatory to kicking is accomplished by these muscles and others, and they are largely concerned in the movements of galloping Disease or injury, such as a severe sprain, is shown by a difficulty in walking both forwards and backwards, by a crouching appearance of the back, and by extreme difficulty in rising from the ground Psoriasis Psoriasis is a chronic inflammatory skin disease with scurf formation Psoroptic Mange A type of mange caused by various species of Psoroptes mites It can affect most animals, and causes sheep scab, ear mange in horses and widespread skin lesions in cattle (See under MANGE.) Pulpy Kidney Disease Ptosis The drooping of the upper eyelid, due to paralysis of the oculomotor nerve It is seen in the horse after accidents involving the head; and also in GUTTURAL POUCH DISEASE A case of ptosis in a bird was treated by the topical application of phenylephrine, which rapidly resolved the condition Ptyalin Ptyalin is the name of the enzyme contained in the saliva, by which starchy food-stuffs are changed into sugars, and so prepared for absorption Ptyalism The overproduction of saliva It may be the first clinical sign of eplepsy in dogs Puberty Ewes, sows, and bitches may mate when only or months old; mares reach puberty at from 15 to 18 months old; heifers from to 15 months old In the cat oestrus may occur as early as 31⁄2 months, or occasionally be delayed until the queen is about a year old In the male, puberty commonly occurs at an age of 10 to 12 months, but here again there may be considerable variation Some toms may reach puberty as early as months, while others not mate until their 2nd spring 575 Signs Loss of appetite, diarrhoea with watery or whitish evacuations and, sometimes, darkening of the comb Birds appear drowsy About 10 per cent die The cause is a REOVIRUS Pullorum Disease of Chicks (Bacillary White Diarrhoea) Pullorum Disease of Chicks (Bacillary White Diarrhoea) has been virtually eradicated in the UK It is an acute, infectious, and fatal disease of chicks, causing much loss during the first weeks of life Adult fowls, especially laying hens, act as carriers and transmit infection through their eggs to the chick before hatching They may also spread infection in their droppings Cause Salmonella pullorum, which is found in the ovary and oviduct of carrier hens – birds which themselves contracted the disease when young, but which survived Signs Lameness, with swelling of the hocks, is characteristic of chronic pullorum disease Prevention This can be achieved by testing all birds, eggs from which are to be used for hatching, by an agglutination test Pulmonary Adenomatosis (Jaagsiekte) Pubis is the bone that forms the lower anterior parts of the pelvis The pubes of right and left sides meet each other at the ‘symphysis of the pubes’, which in old age is no longer a separable union, bony fusion having taken place Pulmonary adenomatosis (jaagsiekte) is caused by a retrovirus, often in association with a herpesvirus (see HERPESVIRUSES) and is a contagious neoplasm of the lung of adult sheep First recognised in South Africa, it occurs also in the UK, Iceland, and the USA In Britain, one East Anglian farmer lost 50 out of 200 half-bred ewes from jaagsiekte Public Health Pulmonary Diseases (see MILK; FOOD INSPECTION; ANTIBIOTIC RESISTANCE; and information given under the main animal diseases communicable to people See also ZOONOSES) (see LUNGS, DISEASES OF) Pubis Puffer Fish (see TOADFISH) Pug A small dog with large rounded head, prominent eyes, smooth coat and tail arched over the back It is suceptible to Perthe’s disease but other inherited defects are not common ‘Pullet Disease’ A transmissible enteritis of pullets and turkey poults, first described in the USA in 1951 (See also VISCERAL GOUT.) Pulpy Kidney Disease Pulpy kidney disease attacks lambs between about and 18 weeks of age, particularly those which are thriving The disease has been seen in lambs under a week old; its occurrence is widespread Cause Clostridium welchii type D Signs As a rule the affected lambs are found dead without having previously been noticed ailing Usually the lambs in the best condition are the first to be affected The loss may be very heavy, especially with the larger earlier maturing breeds The liver usually shows haemorrhagic spots on its surface P 576 Pulse Prevention It is recommended that immunity be maintained by autumn vaccination, with a second dose of vaccine in the spring, preferably about 10 days before lambing – unless the ewes are to be moved to a better pasture prior to lambing, when the second dose should be given before the move is made These doses should protect the ewe through the spring months and allow her to pass to the lamb via the colostrum sufficient antibodies to protect it for the first to 12 weeks of life That temporary immunity in the lamb should be converted to an active one by the use of vaccine Pulse P Roughly speaking, the smaller the animal, the faster the pulse The same principle applies to animals of one species but of different sizes or of different breeds: e.g the pulse of the Shire stallion is usually about 35 per minute, while that of the Shetland pony is 45 or more These facts must be taken into account when counting the pulse of any given animal (See also under HEART.) (see FADING; TOXOCARA) The forcing of blood from the heart into the arteries of the systemic circulation causes a pulsation (regular expansion and relaxation) in them The beating of the heart drives blood out from the left ventricle into an already full aorta, in which it is imprisoned by the closing of the aortic semilunar valves To accommodate this extra blood the aorta dilates, and the blood already in it moves onwards throughout the vessel, and through the larger branches arising from it The wave of dilatation also travels along the course taken by the blood, and is therefore distributed along all the larger arterial trunks If the fingers are placed over any of these latter, which lie near the surface, a periodic thrill or ‘pulse’ can be felt, occurring at a regular frequency according to the species; in the horse, it is about 35 to 45 times per minute The pulse-rate varies according to the state of the animal’s health, being faster in fevers, and slower and weaker in debilitating non-febrile diseases; according to the age of the animal (faster in the very young and very old); according to the climate; according to bodily condition; and under other circumstances During and immediately after exercise it is greatly increased, but in health it subsides rapidly subsequently During sleep and unconsciousness it is slower The normal pulse-rates of the domesticated animals at rest are as follows: Per minute Horse 36 to 42 Ox 45 to 50 Sheep 70 to 80 Pig Dog 90 to 100 Cat 110 to 120 and of certain other animals as follows: Per minute Elephant 25 to 28 Camel 28 to 32 Buffalo 40 to 45 Reindeer 60 to 65 Mouse 130 to 150 } Pupil (see EYE) Puppies, Newborn, Infection in Purgation Evacuation of the bowel following administration of a cathartic medicine It must be applied, if at all, with moderation Excessive purgation involves dangers which include potassium depletion Purgatives This is the age of LAXATIVES rather than purgatives The old drastic purgatives are obsolete; they tended to make the patient’s condition worse Purpura Haemorrhagica Purpura haemorrhagica often occurs in a horse recovering from a respiratory infection such as influenza or strangles; Streptococcus equi is frequently involved The disease is characterised by oedema of the head and also of the lower parts of the body There may be kidney lesions Signs appear suddenly; often overnight Swellings, very often the same on each side of the body, are found on the limbs, the breast, the eyelids, and almost always about the muzzle and nostrils These swellings may be diffuse from the first, or they may begin as isolated circumscribed flat prominences which coalesce in the course of a day or more; when pressed with the point of the thumb, a little pit remains afterwards for some moments Petechial haemorrhages are present in the nostrils (from which a bloodstained discharge is often seen) and on any mucous membrane The horse is dull, loses its appetite, moves stiffly and with difficulty, and if the swellings of the nostril are large, shows rapid and laboured breathing Swollen lips may prevent a horse from feeding or drinking; swollen eyelids may hinder or prevent vision; and a swollen sheath in the male may make the act of micturition difficult The temperature usually remains Pyogenic between 39° and 40°C (102° and 104°F); the pulse is soft, feeble, generally rapid, and may be very irregular The percentage of recoveries is not large in well-marked cases, and even where death does not occur, complete recovery takes a long time with relapses common It is said that cases showing nervous complications always end fatally, and the same may be said of those with pneumonia Treatment The most careful nursing and feeding are essential in all cases of purpura (See NURSING OF SICK ANIMALS.) Good results often follow the intravenous injection of an antihistamine After apparent recovery the horse must have a long period of convalescence Pus This thick, often yellowish fluid, found in abscesses and sinuses, and on the surfaces of ulcers and inflamed areas where the skin is broken, comprises blood serum, bacteria, white blood cells, and damaged tissue cells (See ABSCESS; STREPTODORNASE; PHAGOCYTOSIS.) ‘Pushing Disease’ A colloquial name for poisoning of cattle by ‘Staggers weed’ (Matricaria nigellaefolia) in South Africa Pustule Pustule means a small collection of pus occurring in the skin, or immediately below it (See ABSCESS.) ‘Malignant pustule’ is the name applied to the form that anthrax most commonly takes when it affects the human being Putty Eating of this can result in lead poisoning A discarded drum of putty thrown into a field led to 12 bullocks dying within 24 hours, and a further 40 requiring treatment (Vl Service report) 577 Pyelonephritis This term is used when both the pelvis and much of the rest of the kidney are involved, as described under PYELITIS Contagious bovine pyelonephritis is a specific infection of cattle caused by Corynebacterium renale, giving rise to inflammation and suppuration in kidneys, ureters and bladder As a rule, only cow in a herd is attacked though others may be carriers The passage of bloodstained urine and abdominal pain are symptoms Penicillin is useful in treatment Otherwise, death may occur (sometimes after several weeks) In the pig, an infectious pyelonephritis is caused by C suis It is a common cause of death or culling Pyloric Stenosis This occurs as a rare congenital defect in the dog Only liquid food can pass into the stomach Projectile vomiting is a symptom The defect can be corrected by means of surgery (See PYLORUS.) Pylorospasm Pylorospasm means spasm of the pyloric portion of the stomach This interferes with the passage of food in a normal, gentle fashion into the intestine, and causes distress from half an hour to hours after feeding It is associated with severe disorders of digestion Pylorus Pylorus is the name of the lower opening of the true stomach Exit of food from the stomach is controlled by a strong ring of muscular tissue called the ‘sphincter of the pylorus’, which opens under nervous activity and allows escape of small amounts of partly digested food material into the small intestine (See STOMACH; DIGESTION.) Pyo- The presence of pus in the bloodstream Pyo- is a prefix attached to the names of various diseases to indicate the presence of pus or the formation of abscesses Pyelitis Pyoderma Pyelitis means a condition of pus-formation in the kidney which produces pus in the urine It is due to inflammation of the part called the ‘pelvis of the kidney’, which is connected with the ureter The condition is commonest among cows after calving, when infection has reached the bladder, invaded the ureters, and has arrived at the pelvis of the kidney Pyogenic Pyaemia A pustular condition of the skin In dogs allergic skin disease is regarded as predisposing to infection by staphylococci Pyogenic is a term applied to those bacteria which cause the formation of pus, and so lead to the production of abscesses P 578 Pyometra Pyometra A collection of pus in the uterus: a condition not uncommon in maiden bitches, and occurring in all species (See UTERUS, DISEASES OF.) Pyorrhoea Haemophilia may be inherited and the breed is disposed to osteochondritis dissecans and hip dysplasia Pyrethroids Inflammation of the gums, in which suppuration is produced and ultimately interference with the integrity of the teeth It is a common condition in aged dogs and cats (See TARTAR.) Synthetic equivalents of some of the active principles of pyrethrum flowers are useful and potent insecticides Commercial preparations are widely available (See FLIES – Control.) Pyosalpinx Pyrexia Distension of a Fallopian tube with pus (see FEVER) Pyothorax Pyridine The presence of pus within the chest It may be a sequel to pneumonia, or to a penetrating wound of the chest, perhaps a bite This is a fairly common condition in the cat, which is likely to rest on its brisket, be disinclined to move, and to have laboured breathing Cyanosis may be present Tenderness of the chest is another symptom The temperature may be 37°C (98.6°F) In many cases the condition develops very rapidly in the cat, death occurring before treatment has been obtained Treatment involves aspiration of the pus, and the introduction of an antibiotic In cats, however, the mortality despite treatment may be 50 per cent Pyramidal Disease P An exostosis affecting the pyramidal process (extensor process) of the 3rd phalanx of the horse’s foot It is usually found in association with low ringbone (See RING-BONES.) Pyrenean Mountain Dog One of the largest breeds of dog, powerfully built with a thick, usually white, coat Pyridine is an alkaloidal substance derived from coal-tar, tobacco, etc It is added to methylated spirit in order to render this unpleasant to drink Pyridoxine Vitamin B6 Pyrrolizidine Alkaloids These cause poisoning in animals which have eaten ragwort (See RAGWORT POISONING.) Pyruvic Acid An organic acid which is an intermediate product in carbohydrate and protein metabolism Excessive quantities accumulate in the bloodstream in cases of vitamin Bl deficiency Pyuria Pus in the urine produced by suppuration in some part of the urinary tract (See URINE.) ... foal Posological Relating to dosage Posthitis (see PENIS AND PREPUCE) Post-Mortem Examination (see under AUTOPSY) Post-Partum Following parturition P Post-Parturient Fever of Sows Post-parturient... the fluke Pale Soft Exudative Muscle (PSE) Palpebral Relating to the eyelids PanPan- is a prefix meaning all or completely Pancreas P Pancreatin A preparation of the exocrine part of the pancreas... protein Polypeptides are proteins composed of several amino-acids linked by the peptide grouping CH– CO–NH–CH Synthetic polypeptides have potential uses as vaccines, e.g against foot-and-mouth