Black''''s veterinary dictionary 21st edition - S pptx

S Sabulous Gritty, sandy Sacks Sacks may be a means of passing infection from one farm to another, for when empty they are put to many uses Poisoning has occurred through contamination of feeding-stuffs by sacks previously used for sheep-dip For these reasons, non-returnable paper sacks have advantages over jute sacks Sacrum The part of the spinal column lying between the lumbar region and the tail It consists of vertebrae in the horse and ox, in the sheep and pig, and in the dog and cat, fused together in each case It is roughly triangular in shape in all animals, and forms the roof of the pelvic cavity, lying midway between the ‘points of the hip’ or ‘haunch bones’ Saddle-Sores Saddle-sores are formed through uneven pressure upon the back by some part of the saddle They may be found in the middle line, immediately over the upper ends of the spinous processes; they may occur on either side of the middle line where the fore-arch of the saddle-tree presses; or they may be found just behind the elbow, when they are caused by badly fastened girths, and are often called ‘girthgalls’ The injuries consist of raw areas from which the hair has been rubbed or chafed off and, later, ulcers Alternatively, patches of the skin, varying in size from 2.5 cm in diameter to almost cm, may become hard and leathery, pus being formed underneath These are known as ‘sitfasts’ Treatment Attention must first of all be paid to the saddles They should fit evenly all over the back, and the stuffing or padding should be adequate to protect the skin from pressure by the rigid framework of the saddle-tree The hollow of the arch of the saddle should never press upon the middle line of the back, and the girth should never be fastened with the skin folded under it Rest from work will be necessary (See ULCER; WOUNDS.) Sagittal A structure or section running transversely across the trunk or a limb Sainfoin (Onobrychis sativa) A leguminous forage crop which fixes its own nitrogen; it contains tannins, so its rumen protein degradability is low (this means that the protein is used more efficiently); and it does not cause bloat Voluntary intake by animals is high – intakes of sainfoin can be 25 per cent higher than that of ryegrass Furthermore, it is drought-resistant Unfortunately, sainfoin does not grow as well as bred strains of grasses, clovers and lucerne; 30 per cent less yield than lucerne is quoted St John’s Wort This plant, Hypericum perforatum, which may be present in hay, does not lose its poisonous character when dried It causes LIGHT SENSITISATION in cattle, sheep, and pigs, especially in Australia St Louis Encephalitis Transmitted by mosquitoes, and caused by a flavivirus, this disease occurs in North and South America, affecting wild birds, bats, horses and man (in which it may cause encephalitis and death in the elderly, although only fever in other people) Salicylic Acid and Salicylates Originally derived from the willow (genus Salix), salicylic acid and its salts have long been used in pain relief ASPIRIN, which is acetylsalicylic acid, largely replaced the other salicylates as pain relievers (see ANALGESICS), and has been given in fevers It must be used with extreme caution in cats, which metabolise aspirin very slowly A standard 250 mg tablet given daily to a cat may prove fatal in 12 days Salicylate poisoning has occurred in young animals following overdosage Symptoms include depression, loss of appetite and vomiting Treatment involves the use of an emetic or gastric lavage and respiratory stimulants Saline (see under NORMAL SALINE) Salinomycin An IONOPHORE used as a coccidiostat in chickens, and also (outside the UK) as a growthpromoting feed additive for pigs Its use had to be phased out within the EU by January 2006 622 Salivary Glands Salinomycin poisoning Four hundred ‘Salmon Poisoning’ in Dogs point-of-lay turkeys died within a week after the introduction of a diet containing 50 ppm salinomycin In horses the signs of poisoning are eyelidswelling, anorexia, colic, weakness, ataxia ‘Salmon poisoning’ in dogs occurs on the Pacific coast of the USA, and is the result of eating salmon or trout infested with the fluke Troglotrema salmincola, containing a rickettsia The latter, Neorickettsia helminthoeca, produces a haemorrhagic gastroenteritis which is usually fatal unless antibiotics are used in time Salivary Glands Salivary glands include the parotid gland, lying in the space below the ear and behind the border of the lower jaw; the submaxillary gland, lying just within the angle of the lower jaw, under the lower part of the parotid; and the sublingual gland, which lies at the side of the root of the tongue Each of these glands is paired, so that actually there are glands, not all of which function at the same time Salivary Glands, Diseases of Calculi and tumours may occur In rabies, the salivary glands must become infected before transmission of the virus to another host can occur through a bite (See also MUMPS.) A foreign body, such as a grass seed, may cause an obstruction to one of the ducts, particularly in the dog Salivary-gland tumours in dogs and cats are rare The majority of 138 tumours in dogs (81) and cats (57) involved animals of 10 years of age or more, were malignant and of epithelial origin (84 per cent) Local recurrence after excision occurs frequently, and metastasis to regional lymph nodes and beyond is common Salivation S ‘Foaming at the mouth’, to use a colloquial but apt expression, is seen in the dog, e.g in an epileptic or other fit (See FITS.) ‘Drooling of saliva’ is seen in the dog with a bone wedged across the roof of its mouth, or in a cat with a needle embedded in its tongue – or in cases of RABIES in all species Salivation is a symptom of CHOKING, of almost any painful condition of the mouth or tongue, and of poisoning (e.g by benzoic acid in the cat), arsenic, lead, phosphorus and organophosphorus compounds; see also TOAD Salivation is also an important symptom of FOOT-AND-MOUTH DISEASE, and of other diseases and conditions mentioned under MOUTH Salmincola Parasites on the gills of salmonid fish which affect respiration Affected fish show reduced growth and delayed sexual maturity Salmonellosis Infection with organisms of the salmonella group is of importance from distinct aspects: (1) food poisoning in man; and (2) disease in domestic animals Salmonella poisoning – routes of infection (see diagram) In cattle and calves Salmonellosis and brucellosis have points in common – both diseases are important from the public health point of view; both can lead to abortion in cattle, to a carrier state likely to perpetuate infection on the farm, and to considerable financial loss to the farmer While the salmonella group of bacteria includes more than 1000 different serotypes, the of most importance to the dairy farmer are Salmonella dublin and S typhimurium Either can produce acute or subacute illness in adult cattle and in calves S typhimurium infection is of greater publichealth importance, and is a notorious cause of outbreaks of food poisoning in man S typhimurium type 204C has been a major source of problems in calves bought from markets and is highly resistant to antibiotics An outbreak of this same infection involved more than 200 cows on a single farm, and led to the death or slaughter of 29 of them S typhimurium 104 also has a relatively high resistance to antibiotics It can result in severe illness and deaths in small groups of cows or calves; it is the second most common salmonella in food poisoning S dublin infection may be associated with abortion, sometimes without any other symptoms being observed Animals which recover may excrete the organisms for years Besides this carrier state, which may keep infection on the farm, there is also a latent carrier state in which the organism remains dormant within the animal until it is subjected to some stress or superimposed disease, when excretion of the organism occurs and fellow members of the herd become infected Salmonellosis 623 Salmonella poisoning – routes of infection (With acknowledgements to World Health Organisation, Technical Report No 774.) S An electron-micrograph of Salmonella dublin (Magnification × 50,000.) (Reproduced by courtesy of the Department of Veterinary Preventive Medicine University of Liverpool.) Signs The infections are usually very similar and can be distinguished only by laboratory tests In the acute form of the disease, the cow becomes dull, feverish, goes off her food, and the milk yield suddenly drops Scouring is usually severe, and the animal may pass blood and even shreds of mucous membrane from the intestine Death may occur within a week If treatment is delayed, mortality may rise to 70 per cent or so; whereas early treatment can 624 S Salmonellosis bring the death rate down to 10 per cent In animals which recover, scouring may persist for a fortnight, and it may be several weeks before the cow is fit again The subacute form in adult cattle runs a milder course and, indeed, the infection may exist without any symptoms being shown A latent infection may become an overt one following stress of any kind or when another disease becomes superimposed – sometimes masking the symptoms of salmonellosis itself A liver-fluke infestation may be a precipitating factor Salmonellosis may run through calves out of a batch of 10, and kill of them Some calves collapse and die without ever scouring; others become very emaciated as a result of persistent scouring Pneumonia, arthritis, and jaundice may be among the complications; occasionally the brain is involved, giving rise to nervous symptoms S typhimurium infection seldom persists from one season to another on any particular farm because there are fewer ‘carrier’ animals than there are with S dublin; it is often brought on to the farm by calves bought in from markets and suffering from the effects of stress, rough travelling conditions, lack of food or a change of diet The infection occurs in many species of animal including, as the name suggests, mice S dublin infection arises mostly from other cattle It can be spread from farm to farm via slurry and streams Infection may enter even a closed herd if it is grazing flooded pasture land Lack of shelter, overcrowding, dirty surroundings, and faulty feeding have all been implicated in outbreaks In adult cattle, the fortnight after calving is regarded as a danger period, especially where the calving has been a difficult one S dublin can survive in slurry for at least 12 weeks It is also known that salmonella organisms can survive for months or so in dung and litter, and S dublin can survive for up to 307 days, if not longer, on dung splashes on a wall, so that thorough cleaning and disinfection of buildings are necessary, and reliance must not be placed on a simple ‘resting period’ between batches of calves Salmonella organisms may be present in domestic sewage, and river pollution from this source has led to outbreaks of salmonellosis in cattle Preventive measures include trying to keep rats and mice off cattle feed, avoiding pig and poultry effluent for organic irrigation, having piped drinking water for cattle, and not buying in through markets or dealers but rather from farms with a known health record The earlier housing of cattle in the autumn may help, and it is important not to neglect liver-fluke infestation which can sometimes act as a ‘trigger’ to outbreaks of salmonellosis in which the infection was hitherto latent Treatment Drugs used include antibiotics, potentiated sulfonamides and sulfadimidine A range of vaccines and antisera-vaccine combined preparations is available for prophylaxis and therapy They usually contain E coli, Pasteurella and S typhimurium and S dublin strains In sheep S typhimurium has caused diarrhoea and abortion S agona has caused abortion, death of ewes from septicaemia, death of lambs within a week of birth, and sometimes diarrhoea S dublin is likewise a cause of abortion and diarrhoea One outbreak in an upland sheep flock was characterised by rapid spread and heavy mortality in ewes and young lambs Clinical signs included diarrhoea and abortion Abomasitis (inflammation of the abomasum) was the most striking and consistent post-mortem lesion Vaccination was the only control method that was apparently successful Infection also occurred in the cattle, farm personnel, and a dog (See also ABORTION – Ewes.) In pigs The term ‘salmonellosis’ is now usually reserved for a severe septicaemia S cholerae suis causes this; symptoms include fever, huddling together, purple discoloration of ears, unsteady gait, and sometimes scouring The Seasonal incidence of salmonellosis (With acknowledgements to the British Veterinary Journal.) Salmonellosis same organism may give rise to a chronic infection with scouring The organism can infect man Infection with S dublin sometimes occurs in pigs, and may give rise to dysentery More common is infection with S typhimurium This causes fever, scouring, vomiting, and unsteady gait – usually in younger pigs than the first-named organism Sulfadimidine has proved useful in treatment In horses S typhimurium has caused serious outbreaks of illness in young horses Horses may also be symptomless carriers of this infection In 1976 an outbreak of S newport infection caused the death of many horses in the UK (See also FOALS, DISEASES OF.) Outside the UK, S abortus equi is a cause of abortion in mares Stress, associated with the hospitalisation of horses, is said to have led to acute enteritis, often from S senftenberg In dogs Illness may be mild, with fever and malaise; or there may be severe gastroenteritis and death Many salmonella serotypes infect dogs It is possible for a dog to become a symptomless carrier of S typhimurium and to infect man Feeding raw offal to dogs had been suspected as an important source of salmonellosis in Berlin Accordingly, 408 samples of edible offal (liver, lungs, heart, bovine rumen, and porcine oesophagus) were examined bacteriologically It was found that 231 samples (57 per cent) were infected with salmonella S typhimurium was the most prevalent of 24 serotypes 625 development Death can be expected between the ages of 10 days and weeks It was found that survivors did not react to a blood test carried out with standard S pullorum antigen, but reacted strongly to antigen prepared from the variant strain This probably accounts for carrier birds having remained undetected in the past During a 5-year period, birds in 144 flocks in Sweden were given cultures of caecal contents as a means of controlling salmonella infection by the competitive exclusion technique In all, 2.86 million birds were treated and it was concluded that this treatment was associated with a reduction in salmonella infections No adverse effects were reported Salmonellae will remain alive for periods of up to months or more in dung and litter Therefore such material should be stacked so that heating occurs; no animals should have access to the heap As mice may play a significant role in maintaining S enteriditis infection in flocks, rodent control and disinfection of housing may be effective in dealing with the problem A vaccine prepared from S enteriditis phage type is available (Salenvac; Intervet) In ducks Salmonella species sometimes cause a high mortality in ducklings Fatal cases of human food poisoning have occurred as a result of infected ducks’ eggs In geese S typhimuriam may be found in goslings, affecting only the eye; the vitreous body is totally destroyed Public health As already mentioned, salmo- In cats Infection with S enteritidis and S typhimurium may be set up following the catching of infected rats and mice For this reason cats should not be allowed to lie on uncovered food-stuffs Cats may also become infected through eating contaminated meat In poultry As a specific disease, salmonellosis is rare except in broilers, although it is involved in numerous other disease conditions Over 50 members of the salmonella group have been isolated from poultry in the UK, and several have caused outbreaks of disease in broiler plants (See PULLORUM DISEASE; FOWL TYPHOID.) Arthritis, due to a variant strain of S pullorum, gives rise to a mortality of per cent or so, as a rule, but in one outbreak 200 deaths occurred in a 1000-bird unit Apart from lameness and swelling of the foot and hock joints, symptoms include poor feathering and under- nellosis is an important cause of food-poisoning in man, often leading to serious illness Numerous instances linking food-processing with outbreaks have been investigated S seftenberg has been linked with isolates from human beings and a poultry processing plant S kiambu and S enteritidis were isolated from frozen turkeys from the same batch which caused 64 cases of illness in people S panama and S brandenburg were similarly isolated from abattoirs/processing plants and human beings S agona is a public-health problem in the USA, the UK, the Netherlands, and Israel In each country the original source of the infection was Peruvian fish meal used in animal feeds It has been demonstrated that animal feeds can play an important role in the transmission of salmonellosis to man Unpasteurised milk is another source of human salmonellosis A 65-year-old woman was S 626 Saloliths infected in this way, and was ill with diarrhoea and meningitis After her death a brain abscess was found Both the latter and meningitis are ‘rare complications of salmonellosis in man’ Seventeen other people were ill with salmonellosis from drinking the unpasteurised milk Viable salmonellae were found in the meat fraction of domestic refuse from 120 houses This source could provide a reservoir of infection accessible to wild animals Tipping should be carefully controlled, and refuse covered immediately The protective gloves, worn by a veterinary surgeon while calving a cow, unfortunately burst Within 48 hours numerous non-pruritic papules had appeared over both arms, especially the upper arm, where the gown cuffs had chafed the skin The papules developed into pustules which burst and resolved in approximately 10 days without treatment No other symptoms were observed A pustule was swabbed and a pure growth of Salmonella species was recovered (See also under SAUSAGE.) Saloliths These are CALCULI, found mainly in STENSON’S of horses DUCT Salpingitis Salpingitis is inflammation in the Fallopian tubes or oviducts, sometimes the cause of sterility in cattle (See INFERTILITY.) Salt A chemical substance in which a metal is substituted for the hydrogen of an acid Sodium chloride (common salt) (NaCl) is an essential ingredient of body fluids S Sodium depletion results, ultimately, in circulatory collapse Salt is an appetiser, and commonly incorporated in animal feeds in carefully measured proportions Ruminants will avidly consume salt; any excess is harmlessly excreted in the urine and faeces Salt licks It has been suggested that a 500-kg (10-cwt) cow needs 30 g (1 oz) of salt a day for maintenance and a further 3.5 g (1⁄8 oz) for 4.5 litres (1 gallon) of milk produced Therefore, a 3200-litre (700-gallon) cow requires about 14 kg (30 lb) of salt yearly On some pastures, or under some systems of management, cattle may not obtain sufficient salt To obviate this danger, salt licks are commonly provided In some salt licks traces of iodine are incorporated, together with other trace elements such as copper, manganese, cobalt, and magnesium (See ‘LICKING SYNDROME’.) Salt Poisoning Salt poisoning has been reported in both pigs and poultry It is essential that pigs are not kept short of water, or given food that is too salted An outbreak, reported from Scotland, involved piglets aged weeks brought indoors from field arks at weaning A proprietary meal was fed dry The water bowls in the house were not very accessible, and some of the piglets were not strong enough to depress the levers Two days after being housed, 23 out of the 32 piglets were showing symptoms of salt poisoning, and some died Signs Often a number of pigs are found dead without signs having been observed, the remainder being weak and very thirsty Vomiting and diarrhoea may occur (For other signs, see under MENINGOENCEPHALITIS.) In poultry, adult birds show excessive thirst and diarrhoea, with sometimes cyanosis of the wattles, somnolence, and sudden death In young birds gasping and ascites may occur Samoyed A medium-sized breed of dog characterised by thick straight cream or white hair Like the chow-chow, they tend to be ‘one-person’ dogs Haemophilia has been recorded; pulmonic stenosis may be inherited Sand Horses on the seashore or along tidal mud flats learn that the sand contains salt, and may lick up large quantities of it in their endeavour to get the salt The signs set up are chiefly those of COLIC with impaction Cattle feeding on the seashore take in quantities of sand, which in some cases may be so great as to hinder the movements of the rumen (where the sand always collects), and, by upsetting digestion, may cause unthriftiness and even emaciation Sand Tampan (Ornithodorus Savignyl) (see TICKS – Family Argasidae) Sandcrack Sandcrack is a pathological condition affecting horses’ feet, in which a deep fissure or crack forms Sarcoptes at some part of the wall of the hoof, extending downwards from the coronet, and usually involving the whole of the thickness of the wall Causes Anything which interferes with the proper nutrition of the horn at the coronet predisposes to sandcrack, the actual splitting of the horn occurring as the result of the strains put upon the foot Treads on the inside of the coronet, occasioned by hurried turning when at work, are frequent causes in the fore-feet, and continual pressure on the coronary matrix by the 2nd phalanx, especially when the toes have been allowed to grow too long, appears to be the commonest cause in the hind-feet A predisposition to sandcrack may be inherited With all cases it is advisable to place the animal under veterinary care (See HOOF REPAIR.) ‘Sandflies’ (see under FLIES) 627 Sarcocystis A genus of protozoal, coccidian parasites having a 2-host life-cycle Carnivorous animals such as dogs, cats and foxes ingest the cysts when eating infected flesh of cattle, sheep, pigs and horses Human infection also occurs, and sarcocystis is a zoonosis (see ZOONOSIS) While the cysts in the intermediate host’s muscles may not have any serious effect upon health, the second-generation schizonts are certainly harmful – damaging the endothelium of blood vessels, and causing serious illness in many cases Signs Cattle showed loss of appetite, fever, anaemia, and wasting, after ingesting sporocysts from canine faeces, and some cattle died within 33 days Sarcocystosis has also killed sheep In horses, signs of central nervous system damage may be seen, as well as signs of muscle inflammation, resulting in lameness Santa Gertrudi Prevalence In Europe 61 per cent of slaughtered cattle have been found to be infected In Germany a prevalence rate of per cent in pigs has been recorded This breed of cattle are 5⁄8 Shorthorn and 3⁄8 Brahman in origin Human sarcocystosis may give rise to Sanguineous Sanguineous means containing blood Saponins These are natural detergents, present in some plants such as corncockle and soapwort Saponins contain a sugar and a steroid-like compound, and with water form a lather Poisoning by them results in gastroenteritis The central nervous system may also be affected, with consequent paralysis Saponins break down red blood cells In the USA the leaves and nuts of the tung tree, grown for the sake of its oil, can cause fatal poisoning Saprolegnia A fungus that can infect fish It is sometimes found as a secondary infection to another condition such as ulcerative dermal necrosis in salmonids, and autumn aeromonad disease in adult brown trout The infection can be controlled by bathing the fish in zinc-free malachite green but the healing process is prolonged In a salmon hatchery, it is important to remove dead and infertile eggs as these can be invaded by the fungus and passed on to healthy eggs Sarco- abdominal pain, diarrhoea, fever, tachycardia, and an increased respiratory rate ‘Sarcoid’ A tumour which resembles histologically a sarcoma (see CANCER), but which is regressive in character, disappearing within a matter of months It has the appearance of a reddish button, raised about 0.30 mm (1⁄8 in) above the surrounding skin It affects the dog A fibroma-like sarcoid is perhaps the most common tumour of equines, especially older ones, occurring on limbs or head Believed to be caused by a virus, the equine sarcoid commonly ulcerates and recurs following surgery Cryosurgery may be tried, or a BCG vaccine; the latter may be more successful in donkeys A guarded prognosis should be given Bovine papillomavirus is involved in the process by which sarcoids develop from normal equine fibrous tissue Sarcoma (see CANCER) Sarcoptes Sarco- is a prefix signifying flesh or fleshy Sarcoptes are members of a class of parasitic acari, which cause MANGE in animals and man Sarcolemma The membrane covering each voluntary (striated) muscle fibre Sarcoptic mange occurs in cattle, horses, sheep, pigs, and dogs – also in man, when it is S 628 Sarcosporidia, Sarcosporidiosis called scabies – and is caused by the parasitic mite S scabei (See MANGE.) Cats are only very rarely infected Sarcosporidia, Sarcosporidiosis (see SARCOCYSTIS) Sars A form of AVIAN INFLUENZA that is transmissible to man, often with fatal results Outbreaks occured in several Far Eastern countries in 2004; many poultry flocks were destroyed in an attempt to prevent the disease from spreading Fears that migrating wild fowl would carry the SARS virus to Western Europe led ??? consider preventive measures Sausage Discarded portions of sausage, or sausage-skin, can be a source of infection when fed, unboiled, to pigs, etc Foot-and-mouth disease has been transmitted in this way African swine fever and swine fever could similarly be spread by this means (See SWILL.) The incidence of salmonella-contamination of pork and beef and pork sausages taken from a large factory during the course of production was 65 and 55 per cent respectively The salmonella serotypes isolated (in descending order of incidence) included Salmonella derby, S dublin, S newport, S stanley, S typhimurium, S heidelberg, S infantis and S agona Schistosoma, o, µ, and egg Autopsy Findings Liver necrosis, petechial haemorrhages, and sometimes degeneration of the kidney tubules Scabies A common name for sarcoptic mange (See under MANGE – Sarcoptic mange.) ‘Scad’ A colloquial name for a transitory lameness, in sheep, which may follow frost (See ‘SCALD’.) Savaging of Litters by Sows S ‘Scald’ Various causes of this have been suggested, including: an inherited tendency; absence of any straw for nesting purposes; a painful udder; insufficient time to have become used to her farrowing quarters; and fright resulting from the use of a farrowing crate (See PIGS, SEDATION OF.) (see under BEDDING and MASTITIS) Inflammation between the digits of young sheep resulting from infection by Bacteroides nodosus; it causes acute lameness Its onset is said to be associated with frosts and moisture Recovery may occur spontaneously under dry conditions The term is vague, however, and has been used to include the non-progressive ‘benign’ form of foot-rot It has to be differentiated from foot-and-mouth disease (See also ‘SCAD’; OVINE INTERDIGITAL DERMATITIS.) Sawflies Scalds Four-winged insects which have a saw-like ovipositor The larvae can cause poisoning if swallowed (see BURNS) Sawdust Sawfly poisoning This affects both sheep ‘Scaly Leg’ (see MANGE – Mange in fowls) and goats Scanner, Body Cause The larvae of the birch sawfly (Arge A device utilising computer tomography to produce an image of a section of the whole body (See X-RAYS.) pullata) Signs Depression, anorexia, muscular incoordination with a difficulty in rising to their feet Scanning (see RADIOISOTOPES) Sclera (Sclerotic Coat) 629 Scaphoid Schmorl’s Disease The name given in human anatomy to a small bone present in the carpus and tarsus In the racing greyhound, fracture of the right hind scaphoid is a common accident Treatment has included the removal of bone fragments and the successful insertion of a plastic ‘scaphoid’ Schmorl’s disease is a disease of rabbits, involving areas of necrosis of skin or mucous membrane, and caused by Bacteroides necrophorus (often after the animal’s resistance has been lowered by some other pathogen) Scapula Schnauzer The scapula is the shoulder blade – the large, triangular, flat bone that lies on the outside of the front of the chest, to which are attached many of the muscles that unite the fore-limb to the trunk A German breed of dog with wiry coat that forms characteristic eyebrows, mouth and chin whiskers There are miniature, standard and giant forms The standard has fewer defects than the miniature, which is predisposed to cataracts and progressive retinal atrophy Scheduled Diseases Schradan (see under NOTIFIABLE DISEASES) An organophosphorus insecticide used in agriculture and a potential danger to farm livestock (See also PARATHION.) Symptoms of poisoning may include vomiting, lachrymation, salivation, straining, twitching, distressed breathing, and coma Schistosomiasis Infestation with Schistosoma worms or flukes, which are also known as bilharzia worms They inhabit the portal and mesenteric veins mostly, one species preferring veins of the urinary bladder, and another the veins of the nose Cattle and sheep and virtually all domestic animals, and man, may become infested Several species have been reported from mammals in India, Africa, and Europe S bovis may cause anaemia, emaciation and death of cattle in Africa, or the infestation may be subclinical In India S nasalis may produce a nasal discharge and difficulty in breathing, with sometimes the formation of a granuloma In the Far East S japonicum occurs in water-buffalo and infests man, in which the disease is very serious The life-cycle differs from the typical case, in that the free cercaria may pierce the skin of its host instead of being swallowed The sexes are separate, and are usually found with the female lying in a groove formed by the incurved edges of the male Control Provision of clean drinking water and treatment of pasture with molluscicides such as copper sulphate to kill the intermediate host will reduce infection However, such measures are rarely practicable in affected areas Drugs such as praziquantel may be effective in treatment Schistosomus Reflexus A deformity of the bovine fetus, in which the spine is bent, so that head and tail curve towards each other, causing dystokia Fetal intestine may be visible at the vulva, or located in the vagina Sciatica Sciatica means pain connected with the sciatic nerve which runs down the thigh Scintigraphy The application of nuclear medicine to the diagnosis of bone pathology and lameness It has applications for dogs and horses (See NUCLEAR MEDICINE.) Scirrhous Cord Scirrhous cord is a condition in which there is a chronic fibrous enlargement of the cut end of the spermatic cord following castration In most cases the castration wound does not completely heal, but a small sinus discharging a thick white pus persists The discharge may cease later, but the swelling of the cord goes on increasing slowly in size, until eventually it may be nearly as large as a man’s head In extreme cases the swelling extends upwards through the inguinal canal and into the abdomen and a mass weighing as much as 45 kg (100 lb) has occasionally been encountered in the horse on postmortem examination Treatment is entirely surgical Scirrhus Scirrhus is a term applied to a growth or to other hard fibrous conditions of various organs Sclera (Sclerotic Coat) Sclera (sclerotic coat) is the outermost hard fibrous coat of the EYE S 630 Scleritis Scleritis ‘Scottie Cramp’ Scleritis means inflammation of the sclerotic coat of the eye Lateral curvature of the spine A condition apparently confined to the Scottish terrier, and occurring usually for the first time at to months of age There is cramp following exercise In mild cases the animal may be seen to be in difficulties when negotiating steps; in severe cases 100 metres’ brisk trot will cause the animal to double up and collapse, and in a few instances excitement without exertion will give rise to cramp Mild attacks often become worse, reaching a maximum severity at 12 or 15 months of age At around years of age the dog may have outgrown ‘Scottie cramp’ The cause is unknown Intravenous injections of calcium borogluconate, or parathyroid extract administration, have been recommended The condition could be eliminated by breeders Scombiotoxic Poisoning Scottish Fold Scombiotoxic poisoning is a type of foodpoisoning which occurs as a result of eating fish that contains large amounts of histamine The histamine is produced by bacterial degradation of histadine when the fish – particularly tuna, bonito and mackerel, and also sardines, pilchards and herrings – are stored for prolonged periods at elevated temperatures The symptoms commonly found are rash, diarrhoea, flushing and headache A breed of droop-eared cat Although no major problems should be seen, owners are advised to check regularly for ear mites and infection Some individuals may have a thickening and shortening of the tail that may be accompanied by thickening of the limbs and overgrowth of cartilage at the joints Scleroderma (see CHANCRE) Sclerosis Sclerosis means hardening of tissues Scolecobasidium A soil-dwelling fungus which may infect salmonids, causing swelling of the skin and, if it penetrates the body, in the kidney Scoliosis Scorpions Their venom affects the nervous system, causing pain, salivation, erection of hair, dilated pupils, increased blood pressure, and muscular spasm Scottish Terrier A small wiry dog, black, white or brindled Von Willebrand’s disease may be inherited and the breed is prone to craniomandibular osteopathy, deafness and Perthe’s disease Intervertebral disc disease may be found in the neck region; it may possibly be due to the weight of the head in relation to the body in some individuals S Scrapie Streptococcus Cause Streptococcus equi Strangles is commonest and most serious in horses under years of age Mature horses living in a stable where an outbreak has occurred are frequently unaffected Signs Typical attacks begin with dullness, lack of appetite, rise in temperature to between 39.5° and 40.5°C (103° and 105°F) and congestion of the visible mucous membranes, especially of the nose and eyes Nasal discharge is at first thin and watery, but soon becomes thicker, and profuse There is often a cough One or both of the submaxillary nodes, or perhaps one of the pharyngeal nodes, becomes enlarged, hot, tense, and painful to the touch; until a soft spot, usually over a most prominent part of the swelling can be detected This indicates the ‘pointing’ of the abscess Following its resolution the horse improves greatly; temperature falls, appetite returns, and the animal becomes much brighter Complication: occasionally a suppurative pneumonia occurs There may also be abscess formation in the liver or other abdominal organs Treatment The owner should call in a veterinary surgeon Immediate isolation of the affected horse is necessary (The box or stall where it stood must be disinfected as carefully and thoroughly as possible, and should be left vacant for to weeks afterwards.) The sick horse should be clothed and made comfortable Soft foods, such as mashes, are indicated, as swallowing may be painful (See NURSING OF SICK ANIMALS.) Antibiotics and/or sulfa drugs are used Prevention An efficient vaccine can be produced only if encapsulated S equi is used (i.e from very young cultures) and the capsule not destroyed by formalin and excessive heat In older cultures, the capsule is lost and the organism no longer invasive Human Infection by S equi has been recorded Strangulated Hernia The term is applied to a loop of intestine becoming trapped in a hernia, so that the blood supply to that section of it is cut off (See HERNIA; ‘GUT-TIE’; VOLVULUS; INTESTINES, DISEASES OF.) 671 an inflammatory condition situated in the kidneys, bladder, or urethra Straw (see under BEDDING; DAIRY HERD MANAGEMENT; DEEP LITTER) Straw feeding of cattle Straw is commonly included in diets, particularly when treated with sodium or ammonium hydroxide It has been used in a strict maintenance diet of kg (4 lb) each of barley and a low protein-mineral-vitamin concentrate with some 4.5 to 5.5 kg (10 to 12 lb) barley straw Experimentally, up to 30 per cent of ground straw has been incorporated into beef rations, along with 10 to 20 per cent molasses, 45 per cent cereals, and per cent total minerals, vitamins and urea to provide a complete ration Fed ad lib, this is claimed to have consistently given daily liveweight gains in excess of 1.3 kg (2.8 lb) with Friesian steers in commercial trials The main snag with feeding ground straw is its tendency to produce frothy bloat (with loss of appetite and loss of weight in subclinical cases) This has been overcome, it is claimed, by inclusion in feeds of an anti-bloat preparation (Poloxalene) (See also NITRITE POISONING.) Straw is a very useful bedding material for livestock ‘Strawberry Foot-Rot’ The colloquial name applied to a condition caused by the fungus Dermatophilus pedis or D congolensis ‘Stray Voltage’ (see under ELECTRIC SHOCK) Streams As a source of drinking water for cattle these should always be suspect, since they often carry infection from one farm to another, e.g COCCIDIOSIS; JOHNE’S DISEASE; SALMONELLOSIS ‘Street’ Virus This term refers to the naturally occurring rabies virus, such as may be isolated from a rabid dog Streptococcal Meningitis (see under PORCINE STREPTOCOCCAL MENINGITIS) Strangury Streptococcus Difficulty and pain in passing more than a few drops of urine at a time It is a sign of A micro-organism which under the microscope has much the appearance of string beads It is S 672 Streptococcus Suis responsible for strangles, mastitis, acute abscess formation, etc (See BACTERIA.) Streptococcus Suis Streptococcus suis infection is a cause of meningitis and lymphadenitis in pigs Streptodornase, Streptokinase Enzymes used to dissolve pus, fibrin, and blood clot in infected wounds They have also been used in the treatment of mastitis Streptomycin An aminoglycoside antibiotic obtained from Streptomyces graces Active almost entirely against Gram-negative organisms, streptomycin has given good results against infection with Corynebacterium (Actinomyces) pyogenes, Staphylococcus pyogenes, C renale, E coli, and Pasteurella septica It has been used in cases of calf pneumonia and calf scours, some types of bovine mastitis, and complications of viral diseases in the dog, and in septic conditions in the cat (In medical practice, streptomycin is regarded as one of the most toxic of the antibiotics in common use It may cause deafness and vestibular disturbance in dogs and cats.) Resistance to this antibiotic develops readily and is usually multiple For these reasons, other anti-biotics are to be preferred when suitable Streptothricosis S Infection with streptothrix organisms In Britain, the name is applied to the disease in cattle equivalent to lumpy wool or wool rot, caused by Dermatophilus dermatonomus A scurfy, scaly condition of the skin is produced, and scabs come away with a bunch of hairs attached if plucked Anything which lowers the resistance of a hitherto healthy animal facilitates infection; and prolonged wetting, insect bites, thistle pricks, and other tiny breaks in the skin may all predispose to infection In the tropics, the name is applied to infection with D congolensis The onset of the rains brings an increase in the incidence and severity of the disease, which is of great economic importance in Central and West Africa Flies, ticks, and thorn bushes appear to play some part in the production and spread of the disease Zebu cattle, as exotic cattle, appear highly susceptible; while N’dama and Muturu humpless cattle are resistant It seems that infection does not give rise to later immunity Treatment with antibiotics or sulfonamides offers most chance of success, but is impracticable in many areas (See DERMATOPHILUS.) Streptothrix Dermatophilus congolensis (see STREPTOTHRICOSIS and SENKOBO) Stress In human medicine it is now recognised that mental stress, anxiety and frustration can exert a profound effect for the worse upon bodily health Similar effects may be found in animals Stress can adversely affect production in food animals and behaviour in companion animals On a farm in New Zealand where theoretical considerations were all against high milk yields, the yields were, in fact, extremely high After a detailed investigation it was concluded that the reason could only be sympathetic handling at milking time by the farmers – father, son, and daughter – who were strikingly ‘in harmony’ with their cattle By contrast, on another New Zealand farm where everything – staff, milking machines, and herd management – remained the same, the strangeness of a new milking shed was apparently the sole cause of a 15 per cent reduction in milk yield (See also CALF HOUSING.) Stress is recognised as a predisposing cause of diseases in pigs, following the mixing of litters, castration, etc.; and in all species following parturition Subjection of animals to noise in intensive livestock production, or in the course of transport, can be a source of stress Reduction of noise could have considerable economic benefits (See TRANSPORT STRESS.) Sheep Problems can arise in paddock grazing The grassland breeds need a greater space, if stress is to be avoided They are the hedgebreakers and fence-testers They ‘work away’ at weak places with a will to escape Where a very large number of sheep are dealt with in one unit, it has been shown that it is especially desirable to reduce the flock to units of 80 ewes during the intensive management period at grass Stress can result in a subclinical infection turning into overt illness (See also BUNT ORDER; INTENSIVE LIVESTOCK PRODUCTION; INFECTION.) Dogs Stress may result from being left tied up for long periods, or alone in an otherwise empty house; sometimes from ill-treatment by one member of a family Dog fights are another cause, or merely the presence of a large dog in the vicinity, known to be a fighter Being lost or abandoned, placed in boarding String as a Foreign Body 673 Controlled grazing, showing use of an electric fence (Farmers Weekly.) kennels, change of ownership, etc., can all cause stress Diarrhoea, sometimes vomiting, and ‘compulsive’ polydipsia may result Cats The presence of a particularly aggressive tom (perhaps newly arrived in the district); the addition of another cat or dog to the household, or a mother paying less attention to the cat after the birth of a baby; or too many cats in the same house or confinement in a boarding cattery – these are all potential causes of stress During times of stress, a cat may develop a transient hyperglycaemia This could lead to a mistaken diagnosis of diabetes Stricture Where there is sufficient moisture the eggs hatch in about 12 hours and the resulting larvae attack the skin with their mouths and secretions, causing raw areas The consequent moisture favours the larvae, and their excreta attracts further blowflies which give rise to further generations of larvae Signs A characteristic twitching of the tail is seen when the hindquarters are affected Tufts of white wool, discoloured wool, and the odour are indications of strike in other parts of the body Death may occur within a week, and the mortality may be high among hill sheep especially, as the trouble may in them go undetected An abnormal narrowing of one of the natural passages of the body, such as the oesophagus, bowel, or urethra Treatment consists in the use of a dressing Strike Prevention (see DIPS; INSECTICIDES) Blowfly myiasis, the condition resulting from infestation of the living skin of sheep by the larvae of blowflies which, in certain circumstances, lay their eggs in the wool The flies are, apparently, attracted by putrefactive odours, and strike accordingly most often occurs in the region of the hindquarters in sheep which have been scouring Some cases of strike begin, however, in the clean wool covering the shoulders and loins; and other parts may be affected which will kill the larvae and facilitate healing of the wounds String as a Foreign Body It might reasonably be thought that string would be the least dangerous of foreign bodies, but such is not the case Gravy-soaked string may inadvertently be included in a dog’s or cat’s meal of chicken scraps or leftovers from a joint of beef Occasionally string will form a loop around the base of the tongue, but more often it will pass into the stomach, causing local inflammation and sometimes obstruction In S 674 Stringhalt the intestine, swallowed string is apt to lead to an accordion-pleated appearance of the bowel wall, which may perforate One dachshund had no fewer than 15 such perforations, each of which had to be sutured during the course of a life-saving operation Stringhalt Stringhalt is the sudden snatching up of one or both hind-legs of the horse when walking or, less often, when trotting All classes and ages of horses may be affected, although it is perhaps commonest in older horses It often appears about the time when maturity is reached, i.e to years or a little sooner Causes The cause of stringhalt is unknown An Australian form of stringhalt is seasonal in incidence, and possibly associated with plant poisoning Several horses in a locality may be affected Recovery occurs after weeks or months, but not in all cases Neither pain nor lameness is associated with stringhalt, but the condition constitutes an unsoundness, and is incurable Strip-Cup (see MASTITIS) Strip-Grazing S Strip-Grazing of cattle behind an electric fence tends to give greater production per acre, but it carries with it a risk of worm infestation under lush condition unless a back-fence is brought up at 5-day periods, and ‘resting pastures’ avoided The use of an electric fence for strip-grazing on ‘early-bite’ is valuable It induces the cattle to eat the whole plant instead of nibbling off the most succulent leaf-tips which predisposes to bloat (See illustration, page 673.) Stroma Struvite A magnesium-aluminium-phosphate compound found in urinary calculi (see FELINE UROLOGICAL SYNDROME) Strychnine Strychnine is one of the chief alkaloids of the seed of Strychnos nux-vomica, an East Indian tree – the other being brucine, which is less powerful and not used medicinally, although its actions are similar to those of strychnine Strychnine itself is a white crystalline substance, possessing an intensely bitter taste Strychnine (or nux vomica) was at one time much used as a tonic, especially during convalescence from debilitating illnesses, in pneumonia, and in atony of the bowels It is now used only for the killing of moles, under strict control Strychnine Poisoning Signs In the larger animals the symptoms consist of convulsive seizures, characterised by a pronounced spasmodic contraction of the muscles of the limbs and trunk, and by a drawing back of the head and hollowing of the back (opisthotonus) In the horse, the eyeballs roll and the eyelids are seen quivering and often becoming drawn back, exposing the white of the eye In the smaller animals the same symptoms are seen, but the seizures are of a more violent nature, and the periods of relaxation are shorter First-aid If a large dose has been taken, an emetic should be given to the smaller animals at once, preferably apomorphine given hypodermically; the larger animals should have their stomachs emptied as far as possible by the use of the stomach-tube Tannic acid or strong tea is indicated for immediate first-aid Tissue which forms the structure of an organ but does not play a part in its function For example, the stroma of a secretory gland does not itself secrete Treatment Expert advice should be sought without loss of time The patient should be anaesthetised Strongyles An over-production of sebum by the modified sebaceous glands on the dorsal aspect of a cat’s tail The fur tends to become matted, and bare patches may occur The precise cause is unknown, but it has been suggested that close confinement, and a consequent failure of the cat to groom itself, leads to ‘stud tail’ Prolonged treatment may be necessary, on the line of that for acne Roundworms (red worms) of the family Strongylidae They are parasitic in many farm animals and can cause anaemia, unthriftiness, debility, intermittent colic (See FOALS, DISEASES OF; and under ROUNDWORMS.) Strontium (see under RADIOACTIVE STRONTIUM) Stud Tail Sudorifics Stunning, Electric, of Cattle This is practised in Sweden and the Netherlands by means of the Elther apparatus (prior to Jewish ritualistic slaughter or otherwise) It is used also for calves, sheep, and goats Stunning, Electric, of Pigs This has been practised extensively since the 1930s, and involves the use of brine-soaked electrodes, applied on each side of the pig’s face, by means of which the electric current is passed A voltage of not less than 75 is recommended and a current of not less than 250 milliamperes, assuming 50 cycles-per-second alternating current An electroplectic fit is caused, with anaesthesia lasting for about 60 seconds, when conditions are satisfactory After 60 seconds, there may be a half-minute period of paralysis during which sensation is present Therefore, the pigs must be stuck during the first 60 seconds If care is not taken and the apparatus be faulty or unsuitable, paralysis only, and not anaesthesia, may result; the pig being conscious when stuck High-voltage stunning The trend towards the use of 180 to 600 volts has been impeded by the commonly held belief that it might adversely affect ‘bleed out’ However, the ARC’s Meat Research Institute has shown that this need not be so Stunted Chick Disease This syndrome in chickens was first recognised by Kouwenhoven and others in 1978, and has since been found to occur worldwide The cause is believed to be a virus, possibly exacerbated by Campylobacter spp and spirochaetes Sturdy A neurological disease in sheep caused by Coenurus cerebalis, it is also known as GID Stye (see EYE) Styfziekte 675 the animal-owner Examples: subclinical mastitis, which by lowering the milk yield of a herd of cows may be of considerable economic importance; similarly, a subclinical infestation with parasitic worms (See also STRESS.) Subcutaneous Subcutaneous means anything pertaining to the loose connective tissue lying under the skin, such as a subcutaneous injection, where the injected fluid is introduced below the skin (See under INJECTIONS.) Subluxation A partial dislocation Atlantoaxial subluxation is a cause of neck pain and muscle dysfunction in some toy breeds of dogs Treatment In 13 cases the atlas and axis were stabilised with a wire suture; in 10 cases lag screws were used for fixation of the ventral articular facets Nine of them recovered within months Sucking (Intersucking) This habit or ‘vice’ occurs among dairy calves If allowed to go unchecked, the practice may become habitual, involving a risk to the health of the calves, and, if persisting into adulthood, the welfare of the herd in general may be affected In a herd of 50 Friesian cows the habit grew so pronounced that the herd became uneconomic and had to be dispersed Cattle of all ages were involved and milk loss was considerable Purchased calves acquired the same habits after a short while Intersucking is a problem in only a small proportion of herds, usually those of above average size, where the calves are bucket fed, or where they are grouped at or shortly after birth The most effective remedy is to separate the calves after feeding, but if this is not practicable, mechanical devices or the provision of dry food are good alternatives It seems that a useful preventive measure is to delay grouping calves until they are more than weeks of age Styfziekte is a name meaning ‘stiff sickness’, which is used to describe either the symptoms associated with chronic aphosphorosis, which is the forerunner of lamziekte in South Africa, or those associated with a mineral deficiency in certain parts of northern Nigeria Suckling Subclinical Sudorifics are drugs and other agents which produce a copious flow of perspiration (See DIAPHORETICS.) A disease is said to be subclinical when the symptoms are so slight as to escape the notice of (see CALF REARING) Sudden Death (see under DEATH) Sudorifics S 676 Suffocation Suffocation (see ASPHYXIA and CHOKING) Sugar Sugar is a substance containing the elements carbon, hydrogen, and oxygen, and belonging therefore to the chemical group of carbohydrates This group includes three main subdivisions as follows: (1) Monosaccharides, or glucoses (C6H12O6): e.g Dextrose or grape-sugar, Levulose (2) Disaccharides, or sucroses (C12H22O11): e.g Cane-sugar, Lactose or milk-sugar, Maltose or malt-sugar (3) Polysaccharides, or amyloses (C6H10O5)n: e.g Starch, Glycogen (animal starch), Dextrin and other gums Glucose is the form of sugar present in the blood, and reserves are stored in the liver in the form of glycogen Starch is mentioned under a separate heading, and its use as a food-stuff is described under DIET AND DIETETICS Sulfaquinoxaline Mixed in food or drinking water, for the control of coccidiosis in poultry Sulfasalazine (see EYE, DISEASES OF – ‘Dry eye’) Sulfonamides S A group of drugs which are, to susceptible organisms (e.g streptococci), bacteriostatic (rather than bactericidal); that is to say, they prevent the multiplication of bacteria rather than killing them Sulfonamide drugs are all synthetic and closely related to p-aminobenzoic acid, which is believed to be essential to bacteria, and which is absorbed by them; and it is believed that the sulfonamides are absorbed by the bacteria similarly, with the result mentioned above Individual sulfa drugs not have specific action against specific bacteria; their differences lie in the differing concentration or level which can safely be obtained in the animal’s bloodstream, and their excretion route Uses Sulfonamide drugs are extensively employed in veterinary medicine for dressing wounds, for the prevention of post-operative sepsis, and in the treatment of pneumonia, metritis, enteritis, ‘joint-ill’, foul-in-the-foot of cattle, and arthritis in young pigs, etc They must be used in full dosage, or resistant strains of bacteria may be set up Residues Traces of sulfonamide are occasionally found in pig kidneys Where sulfa drugs are prescribed for farm use, management procedures should be examined to avoid risk of residues Likely causes of residue problems include: sows having access to medicated creep in farrowing pens; barrows used to carry medicated feed being used for carrying feed for finishing pigs without being cleaned; failure to clean pens used for medicated pigs before restocking Toxicity Sulfonamides may have an adverse effect upon the host’s cells as well as upon the invading organisms For this reason (and to avoid giving rise to resistant strains), sulfonamides should be used only under veterinary advice and not indiscriminately Fortunately, however, domestic mammals, with the exception of the goat, show few signs of intolerance Sulfanilamide is, however, highly toxic to birds Names of individual compounds The list of these is being continually extended, but mention may be made here of: Sulfadiazine Has been used in the treatment of calf pneumonia, etc Sulfadimidine Of value in foul-in-the-foot in cattle, pneumonia, enteritis Is readily accepted in the food by all animals Sulfaguanidine Used in the treatment of white scour of calves, necrotic enteritis in pigs, and enteritis in other animals Readily taken in the food Sulfamerazine Has been used in the treatment of calf pneumonia, etc Sulfamethoxipyridazine Used to treat coccidiosis in sheep Sulfanilamide Of value as a dry dusting powder for wounds, teat sores, etc May be combined with per cent neutral proflavine sulphate Sulfaquinoxaline Used in the control and treatment of coccidiosis in chickens and turkeys Sulfathiazole Has been used in the treatment of calf pneumonia Sulpha (Sulfa) Drugs (see SULFONAMIDES) The International Nonproprietary Name (sulfa-) has superseded the original UK form (sulpha-) Superpurgation Sulphur Sulphur is a non-metallic element which is procurable in several different allotropic forms, e.g ‘flowers of sulphur’ As a parasiticide, sulphur has been largely replaced by more effective substances, although proprietary organic preparations of sulphur are still used in the treatment of mange Internally, sulphur was at one time a popular laxative and mild tonic, and no doubt still enjoys a vogue among some animal-owners Poisoning Overdosage must be avoided: 85 g (3 oz) of flowers of sulphur has killed cattle Dosing by guesswork on the part of a shepherd killed 140 ewes in a single flock Accidental poisoning by sulphur occurred in 14 horses, of which died Sulphur Dioxide A poisonous gas which is a constituent of diesel engine exhaust fumes (See SMOG.) Summer Mastitis Summer mastitis is caused by Actinomyces pyogenes and Peptococcus indicus Both the headfly and P indicus are implicated in the aetiology of this disease (See MASTITIS; FLIES.) Summer Sores Summer sores in horses are caused by infective Habronema larvae deposited in wounds by stableor house-flies They are very itchy Eyelids may be affected The infestation results in the formation of fibrous nodules which may later ulcerate Summer sores are uncommon in Britain Sunburn LIGHT SENSITISATION; EYE, DISEASES OF; CANCER) This is a hazard for a number of (see 677 For example, a cow is got in calf at one service, comes on heat again, and settles to a further service – in due course producing a calf as the result of the first mating, but more often than not having little or no milk She later calves again, as the result of the second mating, and this time lactation begins Calves born in this way are not, of course, twins Although contemporaries within the dam, they are of different ages, and can have different sires An elderly cow, which had always had single calves, was ‘put to AI again and subsequently on occasions at normal intervals, after which she appeared to hold’ Presuming that she had held to the last service, her owners were very surprised to find her one morning, months before she was expected to calve, licking a full-term heifer calf which was ‘quite obviously hers’ The milk yield was poor, and so the cow was left at grass to suckle her calf Two months later she ‘suddenly bagged up well and calved a live, full-term bull calf in circumstances that left no doubt it was hers also’ Subsequent blood tests, carried out in Copenhagen, showed that the first calf was not by the AI centre’s bull as stated The second was The remarkable features of this example of ‘double pregnancy’ are that artificial insemination did not disturb a 2-month embryo; and the stress and exertion of calving did not affect a 7-month fetus, either Superinvolution Superinvolution is the contraction of the uterus after parturition when the shrinkage proceeds beyond the normal, and the organ is less in size than before conception It may proceed to such an extent that the dam is subsequently unable to breed, or it may result in a reduction in size of the organ, which is not very important animal species White pigs must be protected from sunburn by providing shade Small animals, particularly those with short coats, can be affected: Mexican hairless dog, shar-pei, sphinx cat etc A type of sunburn can occur in some fish in clear water where no shade is available The production of extra (mammal’s) eggs It can be induced by means of hormones (See TWINNING.) Sunlight Superpurgation under RICKETS; INFERTILITY; SENSITISATION; TROPICS) (see LIGHT Sunstroke (see HEAT-STROKE) Superfetation The presence in the uterus of fetuses of different ages, due to successive services Superovulation Superpurgation is excessive purgation which continues for some considerable time, and may end fatally It is most serious in the horse, where it may follow the administration of aloes It may also arise through the ingestion of food-stuffs which are unwholesome, such as sprouted potatoes and decomposed mouldy oats; and it may result from horses breaking out from a stable and getting into a field of S 678 Supplementary Feeding clover or lucerne (See COLIC.) PURGATIVES; LAXATIVES; Supplementary Feeding FLUSHING OF EWES; FEED BLOCKS; UREA; SUPPLEMENTS; CREEP-FEEDING) (see Supplementary Veterinary Register First-aid Fomentations, or application of a liniment may be helpful until the acute symptoms subside; thereafter a run at grass generally results in improvement In the dog there may be permanent paralysis, sometimes requiring amputation of the leg or other surgery Suramin (see under VETERINARY SURGEONS ACT 1966) A drug used against trypanosomes Supplements Surfactants Products for use at less than per cent of the total ration in which they are included, and designed to supply planned proportions of vitamins, trace minerals, one or more non-nutrient additives and other special ingredients Substances that reduce the surface tension of a liquid; soap and detergents are examples Surfactants are used in frothy bloat to allow the release of gas from the bubbles which are formed Suppository A suppository is a small conical mass made of glycerine or a similar substance, and containing drugs intended for introduction into the rectum Suppuration The formation or discharge of pus (see under ABSCESS; CELLULITIS; FISTULA; INFLAMMATION; PHAGOCYTOSIS; WOUNDS) Suprarenal Bodies (see ADRENAL GLANDS) Suprascapular Paralysis S Suprascapular paralysis occurs as a result of injury to the suprascapular nerve The term ‘slipped shoulder’ is applied to the symptoms which are shown in a typical case The supraspinous and infraspinous muscles act as ligaments of the shoulder-joint, and when they are paralysed the shoulder slips outward each time the foot is placed upon the ground and when weight is put upon it After the paralysis has been in existence for some few days, distinct hollows appear over the shoulder, due to atrophy of the muscles, and the spine of the scapula stands out prominently between these hollows When viewed from in front the animal appears to have lost the symmetry of the shoulder regions In typical cases there is difficulty in bringing the limb forward, and often the leg appears to swing outwards with a circular movement When a horse stands quietly, the affected limb is usually brought well under the body, and may even take up a position across the middle line of the body The paralysis may disappear in weeks; but in more severe cases, 18 months may elapse before the horse is fit for work Surgical Spirit A preparation of alcohol used, for example, as a skin cleanser before giving an injection It consists of industrial methylated spirit with the addition of castor oil (2.5 per cent), methyl salicylate (0.5 per cent) and diethyl phthalate (2 per cent) Surra Surra is a disease of most economic importance in camels and horses, but it can affect all the domestic animals The disease occurs in Africa (north of the tsetse fly belt), Asia, Central and South America In the latter, Trypanosoma equinum is responsible; elsewhere it is caused by T evansi The infection is spread by blood-sucking flies, such as tabanids and stable flies Vampire bats are believed to transmit the infection also Animals which eat the meat from carcases infected with trypanosomes may themselves become infected in the case of surra In the Sudan, surra affects mainly camels, which die within weeks or a few months, after showing symptoms of fever, anaemia, progressive emaciation, oedema, and paralysis In Asia, surra in camels is often a chronic disease which may persist for years In horses, symptoms are similar, but the dropsical swellings (oedema) are especially noteworthy, affecting several parts of the body (as they also in the dog) Mortality is high, and occurs in horses after a matter of weeks or months Loss of power in the hind limbs, and exaggerated heart sounds may precede death In Central America the names ‘murrina’ and ‘derrengadera’ have been used for vampire-bat and fly-transmitted infection with T equinum Sweat (Perspiration) Treatment involves use of drugs such as antrycide, diminazine and suramin which have specific action on trypanosomes Fly control is also important in reducing the incidence of the disease Suspected Adverse Reaction Surveillance Scheme (SARSS) In the UK, the Veterinary Medicines Directorate monitors reports of unusual unexpected adverse reactions to veterinary medicines and lack of efficacy The manufacturers are kept informed of such reports so that they can take appropriate action Suture Suture is the name given either to the close union between adjacent flat bones of the skull at their edges, or to a series of stitches by which a wound is closed (See WOUNDS.) Swabs Swabs are used for sampling mucus, etc., for diagnostic purposes; the material subsequently being cultured so that pathogenic organisms, if present, may be identified For swabbing as a guide to infertility in the thoroughbred mare, see under EQUINE GENITAL INFECTIONS Swallowing As soon as food ready for swallowing enters the pharynx, it touches areas of mucous membrane supplied with nerves which automatically inhibit breathing, in order to prevent food going the wrong way; close the larynx, which is pulled forwards and upwards, while the base of the tongue folds the epiglottis over the opening of the larynx The pharynx is shortened and its muscles force the food into the oesophagus, where peristalsis takes the food to the stomach Swallowing is one-third voluntary and twothirds reflex The voluntary part is placing the Swayback – a characteristic posture 679 food on the upper surface of the tongue which is raised, tip first, against the hard palate towards the rear At the same time the soft palate is raised, closing the gateway to the nose The base of the tongue forces food into the pharynx The next stages of swallowing are involuntary, reflex actions (For difficulty in swallowing, see DYSPHAGIA.) Swamp Cancer A condition affecting horses in Australia The lesion is, in fact, a fungal granuloma caused by Hyphomyces destruens Swamp Fever (see EQUINE INFECTIOUS ANAEMIA) Swayback Swayback is a copper deficiency disease seen in the last 3rd of pregnancy in the ewe or in newborn and young lambs It is characterised by progressive cerebral demyelination, which results in paralysis and often death It occurs in many parts of the UK Signs A staggering gait or inability to walk Severely affected cases all die Newborn lambs cannot rise and suckle Treatment None Prevention Allow the pregnant ewes access to copper licks or give injections of a suitable copper preparation Sweat (Perspiration) The excretion produced by the sudiparous glands of the skin; it exerts a cooling effect by evaporation In the horse, there are parts of the skin which sweat more readily than others, e.g the bases of the ears, under the fore-arm, and around the dock, and generally speaking, fore-parts of the trunk sweat more quickly than the hinder parts Mules and donkeys not sweat readily, and when they it is generally confined to the bases of the ears In cattle, sweating occurs chiefly at the neck and over the chest In Brahman cattle the hump is an important sweating site Panting (and loss of water vapour from the lungs) is the chief means of heat loss in sheep, but they sweat The dog, cat, and pig are, for all practical purposes, non-sweating animals, though sweating may occur from the pads of the feet of dogs and cats; dogs rely mainly on panting (See also ANHIDROSIS; HYPERTHERMIA; HYPOTHALAMUS; TROPICS.) S 680 Sweat Glands Sweat Glands (see SKIN) Like all other tissue, the sweat glands can become the site of cancer For example, 10 cases were diagnosed in cats at the New York State College of Veterinary Medicine during a 2-year period Head, neck, pinna of the ear and base of the tail were affected in cats aged to 17 years Sweating Sickness This is a tick-borne disease of cattle in southern Africa, affecting mainly calves (Sheep can also become naturally infected.) Signs Fever, eczema (See also TICKS.) Swedish Red and White Cattle This is the main breed of Sweden The herdbook dates from 1928, when the Swedish Ayrshire and the Swedish Red-White breeds – similar in origin and characteristics – were amalgamated Each was the result of breeding from old Swedish stock to which had been introduced some Dairy Shorthorn and Ayrshire blood It is a long-lived breed, with an overall milk yield average in excess of 4300 litres (950 gallons) at 4.1 per cent butter fat There is very little white in the coat-colour; and some animals are entirely red premises where it was the practice to use daily only 2275 litres (500 gallons) out of a total of 9095 litres (2000 gallons) of steam-sterilised swill, the remainder being stored There was no further trouble after the tank was emptied and the swill fed as soon as possible after processing ‘Swimmers’ The colloquial name for puppies showing the juvenile femoral rotation syndrome They are unable to rise on to their hind-legs at the usual age, due to the head and neck of the femur being wrongly positioned on the shaft Sometimes the name ‘flat pup’ syndrome is applied Swine Dysentery An important disease, characterised by haemorrhagic enteritis, and dependent for its cause upon synergism between the spirochaete Serpulina hyodysenteriae and Bacteroides vulgatus and other bacteria About in pigs in a herd become ill, and the mortality rate is 10 to 60 per cent Chronic scouring, without dysentery, may persist The faeces are greyish Prevention and Treatment Antibacterials such as tiamulin or dimetridazole may be added to drinking water or the feed of susceptible animals, or tiamulin given by injection ‘Sweet Itch’ S Swine A seasonal inflammation of the skin of horses, caused by hypersensitivity to the bites of Culicoides midges Lotions containing benzoyl benzoate or pyrethrins are used to control the midges; calamine and antihistamine cream helps relieve the symptoms Fly repellents are effective for such short periods as to be worthless for control, probably best achieved by stabling in the early evening; a Vapona strip being in the stable to kill any midges entering Retarded growth rate and delayed onset of egg production in pullets have, as one of the causes, infection with S hyodysenteriae Pullets reared on deep litter with indirect contact with pigs have become infected Sweet Vernal Grass (Anthoxanthum Odoratum) Hay containing this has caused poisoning owing to its DICOUMAROL content The dicoumarol content of the grass varies, but may increase in hay which has become overheated or mouldy Swill The feeding of unboiled swill – a practice which is illegal in the UK – is a frequent source of swine fever, swine vesicular disease, and foot-and-mouth disease infections Scouring and deaths occurred among swill-fed pigs on dysentery and chickens Swine Erysipelas Swine erysipelas is an infectious disease of pigs and characterised by high fever, reddish or purplish spots on the skin, and haemorrhages on to the surfaces of certain of the internal organs in acute cases; and by general debility, lameness, and difficulty in breathing in chronic cases In these latter there are usually found characteristic cauliflower-like masses on the valves of the heart The disease may occur in man; also in chickens, turkeys, ducks, pheasants and grouse According to American research, dogs are susceptible to one strain of the organism, which gives rise to bacterial endocarditis Incidence In Europe it is usually prevalent both in the acute form and in the chronic, and at times it assumes the nature of an epizootic, sweeping throughout large territories, and Swine Fever (Classical Swine Fever) leaving a high percentage of death in its wake In the UK the chronic form is usually met with in small outbreaks in different parts of the country, but from time to time in certain areas, especially in East Anglia, and during hot dry summer weather, it breaks out in a more menacing form, and large numbers of pigs become affected with the acute form, and considerable numbers die Cause Erysipelothrix rhusiopathiae, which may also infect sheep at shearing or dipping time through small wounds or abrasions Signs There are recognised forms of swine erysipelas: the subacute, the acute, and the chronic Mild or subacute attacks come on suddenly; there is high fever, loss of appetite, dullness, a tendency to lie buried in the litter, and when moved, to so reluctantly: the skin over the chest, neck, back, and over the thighs becomes flushed at first, and soon changes to a red or purple colour The outlines of the areas affected are often square, or they may be the shape of the playing-card diamond, from which the disease gets one of its names – ‘diamond disease’ The areas are usually raised above the level of the surrounding skin, are painful to the touch at first, but not so later, and, appearing about the 2nd or 3rd day of the attack, last for days, and then disappear Recovery may be followed by the chronic form In some cases, pigs may show painful swellings of the knees and hocks, but this is not invariable Young pigs between and or months old are most commonly attacked; it is rare before months, but may occur in older animals Acute type, or septicaemic type, often results in sudden death Chronic type is the most insidious, and pigs affected with it are probably responsible for causing most of the outbreaks of the previous types, since, being bad thrivers, they are often disposed of through the open market and bought by owners of clean herds They feed, but not always finish their food; they have a normal temperature, but are easily distressed when made to take exercise Breathing becomes shallow, and a cough generally develops The pulse becomes thready, and if the heart is listened to, a flowing murmur can be heard over the left side of the chest This is due to the vegetative (or verrucose) endocarditis, which is almost the characteristic feature of post-mortem examination of pigs dead from chronic swine erysipelas The chronic form may last for several weeks, or even for or months, especially in strong robust young breeding 681 gilts, but towards the end emaciation and prostration become very obvious Infertility, involving abortion, stillbirths, and mummified fetuses, commonly results from erysipelas Treatment Antibiotics have been used Prevention Avoid any pigs in the open market which appear to be thin and not thriving, especially sows and boars, or older pigs Any showing wrinkling of the skin of the ears, or patches or flushing on the skin, those which have swollen joints, or those which have diarrhoea, should not be bought Pigs showing extreme breathlessness upon mild exertion should be likewise avoided Vaccinate piglets from non-immune sows at days old, repeated at weeks; pregnant sows and gilts should be vaccinated at and weeks before farrowing and a booster given weeks before subsequent farrowings Arthritis and heart disease may be a result of pigs becoming hypersensitised to the bacteria, and not the result of attack by the bacteria themselves This must be borne in mind when prescribing the vaccine Public health Stockmen exposed to infection must be careful to wash their hands Swine Fever (Classical Swine Fever) Also called hog cholera or pig typhoid, this is a highly infectious and contagious disease of pigs It is a NOTIFIABLE DISEASE in Britain and the EU Cause The cause of swine fever is a pestivirus (a member of the Togavirus family) Secondary bacterial invaders include Salmonella suipestifer and Pasteurella suiseptica None of these secondary organisms is, however, necessary for the production of swine fever It inevitably happens that pigs harbouring the virus of swine fever, but not yet showing symptoms of the disease, are slaughtered for human food Under such circumstances, the virus can survive in the skin and muscle for 17 days In frozen pork the survival time has been quoted as over years; in bacon, 27 days No wonder that unboiled swill is responsible for so many outbreaks At public markets, the urine of infected pigs often drains into adjoining pens and alleyways The urine may, too, get splashed on to clothing, boots, etc., and droplets of it find their way into lorries and on to farms In one instance about 30 outbreaks, spread over 10 counties, arose S 682 Swine Fever, African from the sale of a single infected pen at a large market It seems probable that the virus may be carried by rats and mice for short distances at least Horse-flies can carry the virus, which – according to an American report – can be harboured by larvae of the pig lungworm These larvae are, in turn, harboured by earthworms The use of antibiotics contained in feedingstuffs has had the effect of masking the classical symptoms of swine fever, and is sometimes said to have extended the incubation period Signs In young pigs the disease is often acute S or peracute, while in older pigs it tends to assume a chronic form, although they also may be affected with the severe rapidly fatal form Acute type: After an incubation period of to 10 days, signs of the disease include thirst, sometimes vomiting, shivering, loss of appetite There is a tendency to lie with backs arched and tails uncurled If forced to move, pigs are seen to be unsteady on their legs If their temperature is taken, it is found to be high Initial constipation is usually followed by diarrhoea, with a foul odour There is often a discharge from the eyelids The skin becomes reddened or purplish Some pigs may cough or show laboured breathing Convulsions may precede death The mortality rate can be as high as 90 per cent Pneumonia is a common post-mortem finding and ‘button ulcers’ may be present in the intestines Chronic Type The pigs are dull and unthrifty, lose weight, have a variable appetite; coughing and/or diarrhoea may be other signs The temperature may be only slightly raised or as high as 41°C (106°F) A partial recovery may be followed by relapse and death Subclinical Swine fever may exist in a herd in a subclinical form; pregnant sows showing no obvious signs (though fever may be present), and the disease remaining unsuspected until the finding of a few dead piglets, or of others showing muscular tremors Death of the fetus may occur (see MUMMIFICATION) or weak or deformed piglets may be born If infected late in pregnancy, piglets may die without signs of swine fever Meanwhile, being viraemic, they may have infected others Infection of a pregnant sow can be followed by the presence of virus in her piglets, either stillborn or living The sow is not a carrier in the usually accepted sense, since after the birth of her piglets the virus – having crossed the placental barrier – no longer remains within her body A period of 56 days may elapse between the last deaths on a farm and a recrudescence of the disease Diagnosis The fluorescent antibody test Prevention Swill must be boiled for at least an hour, and it must be prepared only in registered premises for pieces of infected pig meat may otherwise give rise to an outbreak of the disease NB: Swill feeding is illegal in the UK since the 2001 outbreaks of foot-andmouth disease Pigs introduced into a herd should be from premises shown to be free from the disease Visits by pig-dealers should be discouraged Control A swine fever eradication programme, with compulsory slaughter, and compensation, was introduced in 1963 The disease was eradicated in 1966, but re-appeared briefly in Yorkshire in 1971; and a single outbreak occurred in 1986 In 2000, a serious outbreak occurred in East Anglia, resulting in the imposition of movement restrictions on animals from affected areas and the slaughter of thousands of pigs Sixteen areas were affected, the first case being confirmed on August 8; the final restricted area was cleared on December 30 The outbreak might have originated from a pork pie, made from imported pork, discarded where free-range pigs could have consumed it Swine Fever, African This disease, formerly indigenous in the African continent, appeared in Spain and Portugal during 1960 During 1978 there was an outbreak in Malta; eradication was effected by slaughter of the entire pig population and restocking in a quarantine station on the island of Comino An outbreak in Sardinia, also in 1978, spread into the wild boar population, in which it remains endemic The risk of introduction to other countries is a serious one; there were outbreaks in Belgium in 1985 The disease may be caried by airline meals or by passengers The disease is also known as wart-hog disease, as these animals besides bush-pigs are affected In some parts of Africa, pig-raising has had to be abandoned on account of the disease, which is highly contagious, nearly always fatal, and gives rise to carriers – those few that survive often transmitting the infection to other pigs for a year or more Swine Pox Cause A pestivirus, resistant to heat, drying, and putrefaction, and which can survive in smoked or partly cooked sausage and other pork products The virus attacks blood-vessel cells and the disease is accordingly characterised by haemorrhages Signs After an incubation period of to 15 days, there is fever, the pig running a temperature of 40.5°C (105°F) or so This is followed by blotching of the skin, depression, anorexia, diarrhoea and weakness of the hind-quarters with a disinclination to rise Death may occur within a day or two Clinically, the disease is indistinguishable from acute classical swine fever Control African swine fever is a DISEASE; NOTIFIABLE control is by slaughter At the beginning of 1978 there were approximately 80,000 pigs in the islands of Malta and Gozo, supplying the inhabitants with all their requirements of fresh pork and bacon By the end of January 1979 there were no pigs at all It was the first time that any country had slaughtered all the surviving members of a species in order to eliminate a disease – in this instance, African swine fever The decision to slaughter all survivors was taken when the pig population had fallen to 13,975 Swill feeding and the movement of weaners to fattening premises helped to spread the disease 683 Swine Influenza A common problem which can rapidly spread through a pig unit; affected animals usually recover within a week, but other respiratory problems may be precipitated An H1N1 virus was causing the disease in Europe in 1986, and was isolated from an outbreak involving a 400sow unit in the UK Morbidity was nearly 100 per cent, but all recovered H3N2 virus is also present in the UK In many outbreaks, several deaths are to be expected (See also INFLUENZA and ENZOOTIC PNEUMONIA.) Cause An orthomyxovirus; important secondary invaders include Haemophilus influenzae suis, Pasteurella suiseptica, Brucella bronchiseptica, and streptococci Signs Coughing, fever, anorexia, laboured breathing (See also INFLUENZA.) Swine Plague Swine plague is the term applied to what in Britain is considered to be the pneumonic form of swine fever, but what in America and the continent of Europe has been regarded as a separate disease (See SWINE FEVER.) Swine Pox A virus disease identified by lesions on the abdomen, in adults, and on the face in piglets, S The virus causing swine vesicular disease is shown bottom right, labelled It 1/66 Extreme left is the bulletshaped virus of vesicular stomatis (VSV), and top right is the virus of vesicular exanthema (VEV) Centre bottom picture shows foot-and-mouth disease virus All these viruses affect pigs and have to be differentiated (The scale shown 20mm = 0.00002 mm Photographs by electron microscope, with acknowledgements to C J Smale and the Animal Virus Research Institute, Pirbright.) 684 Swine Vesicular Disease (SVD) in which the disease is more serious; they also have conjunctivitis and some may die The cause is infection with swine poxvirus and/or vaccinia virus (see POX) Swine Vesicular Disease (SVD) A NOTIFIABLE DISEASE An enterovirus disease whose signs resemble those of foot-and-mouth disease It first appeared in the UK in 1972 In the Staffordshire outbreak of that year it was at first mistaken for foot-and-mouth disease, from which it cannot be differentiated on clinical grounds alone However, it was shown at the Animal Virus Research Institute, Pirbright, that the virus was not that of foot-and-mouth disease but related to an enterovirus which had caused outbreaks in Italy and Hong Kong All cases in the UK were linked either to swill feeding of pigs or to the movement of pigs from infected to clean premises The disease appears to be spread rapidly through contact, with an incubation period of perhaps to days Airborne infection appears less likely than with foot-and-mouth disease A similar disease has been reported in Austria among pigs imported from Poland, and also in France SVD virus is very closely related to Coxsackie B5 virus, which causes not only influenza-like symptoms in man but also sometimes heart disease and meningitis It is thought possible that SVD arose as a result of pigs becoming infected by people ill because of Coxsackie B5 virus, which locally then became adapted to pigs or underwent mutation SVD has been transmitted to laboratory workers, so precautions must be taken Control Experience has shown that the S incidence of the disease has been quickly reduced by the imposition of Controlled Area measures, and this fact led to the Movement and Sale of Pigs Order 1975, and subsequent legislation, designed to slow down the movement of pigs so that infection can show up and be dealt with before it spreads further Licences are required for all movement of pigs; entry of pigs on to a farm precludes movement of animals off that farm for 21 days, except for those going direct to slaughter Swill-fed pigs can move only to a slaughterhouse All pigs consigned to a slaughter market or to a slaughterhouse must be marked with a red cross of specified dimensions Sporadic outbreaks have occurred since the original outbreak The infection can be subclinical Mode of Infection Although the SVD virus belongs to the enterovirus group, it has been difficult to obtain evidence for infection by mouth Many experiments, in which precautions were taken to prevent entry of virus by other routes, have failed to produce the disease In contrast, infection by rubbing or scarification of the skin regularly produces infection, and it seems that the most likely route of infection in the field is through damaged skin Swinge Coat An abnormality in which the hair is short, sparse and curly Swollen Head Syndrome of Chickens (SHS) Signs An oedematous swelling beginning round the eyes and progressing to the intermandibular tissue There is coughing and a nasal discharge Opisthotonus may be seen If picked up the birds become incoordinated, roll over, and have difficulty in regaining a normal posture; diarrhoea may be seen The disease lasts about weeks Cause A paramyxovirus Symbiosis Symbiosis means an obligatory association between different species for their mutual benefit Sympathetic Nervous System (see CENTRAL NERVOUS SYSTEM; AUTONOMIC NERVOUS SYSTEM) Symphysis A joint, in which bones are united by a flattened disc of fibro-cartilage SynSyn- is a prefix signifying union Synapse (see NERVES) Synchronisation Of Oestrus (see CONTROLLED BREEDING) Syncope (Fainting) Syncope (fainting) is generally due to cerebral anaemia occurring through weakened pulsation of the heart, sudden shock, or severe injury It is common in dogs and cats, especially when old; cases have however been seen in all animals Systole 685 Syncytial Viruses Synotia (see RESPIRATORY SYNCYTIAL VIRUS) The (virtual) absence of head in a stillborn animal Syncytium Synovial Membrane Tissue composed of a mass of nucleated protoplasm without cell boundaries, such as the outer layer of the trophoblast of a placenta; or a mass of cells united by protoplasmic bridges Synovial membrane forms the lining covering the surfaces of the opposed articular cartilages, which enter into the formation of a joint (See JOINTS.) Syndrome Synovitis A group of symptoms Inflammation of the membrane lining a joint It is usually accompanied by effusion of fluid within the synovial sac of the joint It is found in various injuries and inflammation of joints Synechia Adhesions in the eye, e.g involving the tissues of the iris to the cornea or lens (see EYE, DISEASES OF – Iritis) Synergism Synergism is the opposite of antagonism Synergism between drugs, e.g trimethoprim and sulfadiazine, may be of practical value, for with the two it may be possible to obtain the required effect with a dosage of one which, if used alone, would be insufficient, but which cannot be increased because larger amounts would cause side-effects Another advantage of using two drugs is the possibility that this would tend to prevent the multiplication of strains resistant to one of the compounds The word ‘synergism’ is also used to describe an interaction between a virus and bacteria in their combined invasion of, for example, the lungs; implying that the result of the ‘combined forces’, as it were, is greater than the sum of the effects produced by the agents individually Synergism occurs in calf pneumonia between Mycoplasma bovis and Pasteurella haemolytica (For another example, see SWINE DYSENTERY.) Synostosis Synostosis is the term applied to a union by bony material of adjacent bones usually separate It may occur in the spinal column in old animals (See also HORSES, BACK TROUBLES IN.) Synovitis, Infectious This is a disease of chicks, of about to 10 weeks old, and of turkeys; first diagnosed in Britain in 1959 Cause Mycoplasma synoviae Signs Reluctance to move, lameness, swelling of joints, anorexia The confined conditions under which broilers are raised appear to render them particularly susceptible to this disease Mortality is low, but a third of the survivors may be downgraded, so that severe financial loss may be caused Control depends upon hygiene, and being careful about the breeding stock Syringe, Hypodermic A pump-like device used to introduce solutions to, or withdraw them from, the body (see INFECTIONS, DETERGENT RESIDUE; also PROJECTILE SYRINGE) Systole Systole means the contraction of the heart as opposed to the resting phase, which is called ‘diastole’, and which alternates with the former contracting period In the cardiac cycle systole takes about one-third, and diastole about two-thirds, of the whole period of the heartbeat (See HEART DISEASES.) S ... Fly Stable fly is a serious pest to horses and other animals, and transmits diseases such as surra and anthrax in the tropics (See FLIES – Fly control measures; SUMMER SORES.) Stable Vices And... knee (See BONES and JOINTS.) In horses, stifle lameness is often the result of OSTEOCHONDROSIS dissecans or of subchondral bone cysts In 42 cases of stifle lameness in cattle, the diagnoses included... Trypanosoma gambiense and T rhodesiensis (See TRYPANOSOMES; TROPICS; FLIES.) Sleeping sickness caused by T rhodesiensis can also be transmitted from person to person ‘Sleepy Foal Disease’ Infection