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Buenos Aires, Abril 2010 771 PRODUCTION SYSTEM Circadian variations in heat production and heat loss in Murrah buffaloes during different season Vaidya, M.; Kumar, P.; Vir Singh, V.S. Dairy Cattle Physiology Division. National Dairy Research Institute, Karnal -132001 (India) ABSTRACT Rhythmicity in physiological parameters is an important process both as convenient and reliable markers of operation of the biological clock and as an indicator of general health of an animal. Keeping the hypothesis in mind, 6 each of growing (8-12 months) and adult (18-24 months) female Murrah buffaloes were selected from NDRI herd to monitor the circadian physiological functions during winter (Dec- Jan), spring (Feb-March) and summer (April-May) season. Physio- logical functions were recorded at 4.00 hrs interval i.e. 6.00, 10.00, 14.00, 18.00, 22.00 and 2.00 hrs. Physiological responses [respiration rate (RR), rectal temperature (RT), skin temperature (ST) and pulse rate (PR)], oxygen consump- tion, heat production and heat loss through sweating and panting were recorded at four hourly intervals round a day. Environmental variables viz. dry bulb and wet bulb temperature, relative humidity, minimum and maximum temperature, wind speed was also recorded at the same interval and THI was calculated. Physiological responses (RR, RT, ST and PR) increased significantly (p<0.01) during spring and summer season compared to winter in both growing and adult buffaloes. Oxygen consumption of growing and adult Murrah buffaloes was found to be significantly higher (p<0.01) at 14.00 hrs than at 2.00 hrs during summer compared to spring and winter. Heat storage and heat production differed significantly (p<0.01) among adult and growing buffaloes during spring and summer season. Heat loss through skin and pulmonary system was higher (p<0.01) in adult compared to growing buffaloes during summer. Significantly higher (p<0.05) heat load was observed in adult compared buffaloes during summer. THI showed a positive correlation with physiological responses, oxygen consump- tion, heat production, heat storage and negative with heat loss. The circadian rhythmicity in physiological functions with change in environmental variables was found to be maximum at 14.00 hrs which enabled Murrah buffaloes to maintain the thermal balance. Therefore, buffaloes required special protection particularly during summer stress (10.00 to 16.00 hrs) for maintaining normal physiological conditions and productivity. Keywords: circadian, variations, buffaloes INTRODUCTION Rhythmicity of physiological parameters in farm animals is important from an economic perspective because knowledge of these processes can lead to improvements in stress and disease management through better knowledge of animal's rhythmic behavior, with respect to environmental variables. In order to find out the rhythmicity in heat production and heat loss in Murrah buffaloes during different seasons present study was carried out. Proceedings 9 th World Buffalo Congress 772 PRODUCTION SYSTEM MATERIALS AND METHODS Twelve Murrah buffaloes were selected from the NDRI, Karnal herd and further divided equally into two groups i.e. growing (8-12 months) and adults (24-48 months). The study was conducted during winter, spring and summer season. The physiological parameters viz. rectal temperature (RT), respiration rate (RR), pulse rate (PR) and skin temperature (ST); oxygen consumption, heat production (oxygen consumed) and heat loss through sweating and panting were recorded at 4-hourly intervals during 24 hours a day. The oxygen consumption (Vo2) was recorded by using modified Benedict-Roth- Collins Spirometer. Heat loss through skin was measured using ventilated capsule method 5 . Heat loss through respiratory tract was measured by ventilated mask method. The environmental variables viz. minimum and maximum temperature, dry and wet bulb temperature, relative humidity were recorded at the similar intervals and temperature humidity index (THI) was calculated. The data were analyzed statistically using suitable statistical models. RESULTS AND DISCUSSION Physiological responses: During winter, spring and summer season, the RT increased by 1.40C, 0.70C and 0.90C in adult and 0.8 0C, 0.80C and 1.20C in growing Murrah buffaloes at 2.00pm compared to 2.00am, respectively (Fig.1). The RR increased by 4.0, 7.0 and 8.0 breaths/min at 2.00pm over 6.00am in adult Murrah buffaloes during winter, spring and summer season respectively. Almost similar increasing trend in RR was observed in growing buffaloes (Fig.1). The PR increased by 8, 5.5 and 6.0 beats /min and 5,5 and 10 beats /min in adult and growing Murrah buffaloes at 2.00pm compared to 2.00 am during winter, spring and summer season respectively (Fig.2). RT RR and PR recorded during afternoon and night differed significantly (p<0.01) in both the groups of buffaloes. Increase in all the physiological responses was recorded as the ambient temperature increased in both the group of animals maintained inside and outside the shelter 6, 7. Circadian change in the heart rate of Murrah buffalo calves and adults 3 . During winter, spring and summer season, ST was increased by 9.30C, 70C and 10 0C; 7.10C, 50C and 9.20C in adult and growing Murrah buffaloes at 10.00am compared to 6.00am respectively (Fig.2). The overall mean values varied signifi- cantly during spring. Diurnal variation in skin temperature of different body parts was reported in response to heat stress in male buffalo 3 . RT (0C RR (breaths/min) Fig.1: Circadian variations in RT (0C) and RR (breaths/min) of adult and growing Murrah buffaloes dur- ing different seasons. PR (beats/min) ST (0C) Fig. 2: Circadian variation varia- tions in PR (beats/min) and ST (0C) in adult and growing Murrah Buffaloes during different seasons. Buenos Aires, Abril 2010 773 PRODUCTION SYSTEM REFERENCES 1. Amakiri, S.F. and Funsho, O.N. 1979. Studies on rectal temperature, respiratory rate and heat tolerance in cattle in humid tropics. Animal Prod, 28: 329-335. 2. Brody, S. 1945. Bioenergetics and growth. Reinhold Publ. Corp., New York, U.S.A. 3. Das, S.K, Upadhyay R.C. and Madan, M.L. 1999. Heat stress in Murrah buffalo calves. Livestock Prodn Sci 61: 71-78. 4. Finch, V.A. 1985. Comparison of non evaporative heat transfer in different cattle breeds. Australian J Agri. Re, 36: 497-508. 5. McLean, J.A. 1963a. Measurement of cutaneous moisture vaporization from cattle by ventilated capsules. J Physiol 167: 417-426 6. Salam, I.A. 1980. Seasonal variation in some body reactions and blood constituents in lactating buffaloes and Friesian cows with reference to acclimatization. J. Egyptian Vet. Med. Association, 40:63. 7. Soly, M.J. 2001. Physiological and hematological responses of crossbred males under different housing conditions. M.Sc. Thesis, NDRI Deemed University, Karnal. (Haryana), India. 8. Thakur, T.C. Singh, M.P. and Singh B. 1989. Studies on physiological responses of man and animals with different tillage tools under field conditions. Indian J Dairy Sci 42:332. During winter, spring and summer, oxygen consumption increased significantly (p<0.05) by 0.45, 0.45 and 2.1 in adult and 0.66, 0.66 and 0.8 l/m growing Murrah buffaloes at 2.00pm compared to 2.00am (Fig.3). During winter, spring and summer season, heat Production increased significantly (p<0.05) by 588, 1640 and 2597 kJ/h in adult and 1226, 755 and 970 kJ/h in growing buffaloes at 2.00pm as compared to 2.00am. Heat production in animals has been shown to vary with environmental temperature 2 . During spring and summer heat loss through skin increased significantly (p<0.05) by 485 and 1041 in adult and 100 and 308 kJ/h in growing Murrah buffaloes at 2.00pm as compared to 2.00am (Fig.4). During summer the heat loss through pulmonary system increased significantly (p<0.01) by 240 and 127 kJ/h in adult and growing Murrah buffaloes respectively at 2.00pm as compared to 2.00am. Evaporation from the skin is the major route of heat dissipation in cattle exposed to hot environment as compared to pulmonary evaporative losses 4 . SUMMARY AND CONCLUSION The physiological responses (RT, RR, PR and ST) and heat production increased significantly (p<0.01) at 2 pm as compared to respective values at 2 am. in both adults and growing buffaloes during different seasons. Heat loss through the skin was found to be major route accounting for about three forth of the total heat loss. The result of the study indicated suitable manangemental practices should be followed for reducing thermal heat load. Fig. 3: Variation in Vo2 (l/min)heat production (kj/h) in adult and growing Murrah buffaloes Fig. 4: Variation in heat loss through skin and heat loss through pulmonary system (kJ/h) in adult and growing Murrah Buffaloes dur- ing different seasons. Oxygen consumption (l/min) Heat Production (kJ) HLSK (kj/h) HLPS (kj/h) Proceedings 9 th World Buffalo Congress 774 PRODUCTION SYSTEM Comparison of Bodyweight and Body Size of Growing Buffaloes between Large and Small Scale Farms in Nepal Hayashi, Y.1; Shah, M. K.2; Kumagai, H.3; Shah, S. K.2 1Experimental Farm, Faculty of Agriculture, Meijo University. Postal Address: 4311-2, Hishigaike, Takaki-cho, Kasugai, 486-0804 Japan. 2Institute of Agriculture and Animal Science, Tribhuvan University, Rampur, Chitwan, Nepal.3Graduate School of Agriculture, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 Japan. *The study was supported by a fund for research project in 2007 from Meijo Asian Research Center and a grant-in aids for scientific research (No. 19405041) from the Japanese Society for the Promotion of Science (JSPS). E-mail: yoshiha@ccmfs.meijo-u.ac.jp ABSTRACT The bodyweight (BW), body length (BL), withers height (WH), criss-cross height (CH), heart girth (HG) and hip width (HW) in the total 143 head of growing buffaloes raised by a large-scale farm (LF) in Kaski and small-scale farms (SF) in Chitwan were measured for presenting the growth differences of the buffaloes in Nepal. The development of the body measurements, the BW ratio (BWR) and the withers height ratio (WHR) of each body trait was compared between LF and SF. The phenotypic correlation coefficient between every pair of traits in the buffaloes was calculated. The maximum of BW, BL, WH, CH, HG and HW in the buffaloes less than 24 months old of LF reached to 365.0 kg, 123.8 cm, 123.5 cm, 126.3 cm, 169.0 cm and 47.5 cm, respectively. On the other hand, the corresponding values of SF reached to 200.0 kg, 109.8 cm, 113.2 cm, 115.0 cm, 140.0 cm and 37.0 cm, respectively. The following equations to show the average BW (kg) with age of month (AM) in the buffaloes of LF were calculated: The male BW=9.79AM+50.14; The female BW=9.21AM+41.11. The corresponding equations of SF were as follows: The male BW=6.88AM+30.03; The female BW=5.31AM+38.85. The development of the buffaloes was faster in LF than in SF. The BW of the 24 months old buffaloes calculated by the equations differed around 90 kg between LF and SF. The BWR in male and female had higher average values in SF than in LF (P<0.01). The mean WHR of BW, BL, HG and HW was higher in LF than in SF (P<0.01). However, the average WHR of CH in SF was higher than that in LF (P<0.01). The correlation coefficient between BW and HW was 0.97 in the both sex (P<0.01). The comparison indicated that the improvement of feeding and breeding managements in buffaloes was still required for the efficient growth of buffaloes in SF. Keywords: body size, bodyweight, buffalo, comparison, growth, Nepal INTRODUCTION Buffaloes are essential animals which have been raised for draught and dairy in Nepal. In addition, the consumption of milk and meat produced by buffaloes has been increasing in Nepal1, 2). As Nepalese do not eat beef due to their religious reasons, buffaloes are remarkable for the meat production in the country. Therefore, the improvement of growth rate in buffaloes is required for efficient dairy and meat production. A few studies on body size variation of growing buffaloes have been conducted3, 4). Although there are different developments of buffaloes between large-scale and small-scale farms, the variance of the growth remains obscure. Hence, the present study is conducted to compare the body dimen- sion of growing buffaloes raised by large-scale and small-scale farms. Buenos Aires, Abril 2010 775 PRODUCTION SYSTEM MATERIALS AND METHODS The total 143 head of buffaloes which unused for dairy and drought raised by a large-scale farm (LF), Livestock Development Farm in Lampatan, Kaski and private small-scale farms (SF) in Chitwan were selected for the survey from July 2007 to March 2009. The bodyweight (BW), body length (BL), withers height (WH), criss-cross height (CH), heart girth (HG) and hip width (HW) of the growing buffaloes, the BW ratio (BWR) and the withers height ratio (WHR) of each body trait was compared between LF and SF. The values of age, BW and WH were used for the regression analyses to establish the formulae to estimate BW and WH with age in the growing buffaloes. The phenotypic correlation coefficient between every pair of traits in the buffaloes was calculated. The present study was carried out with the regard to the ethical treatment of animals. RESULTS AND DISCUSSION Totally 84 and 59 head of buffaloes in LF and SF were studied, respectively. The breed of buffaloes was Murrah and Murrah- cross. Sixty five percent of the total buffaloes were born from June to October when pasture was available to be taken by the animals5). The buffaloes were considered to have a seasonal breeding. The age of the buffaloes was from 4 to 24 months old in male and from 5 to 24 months old in female. The maximum of BW, BL, WH, CH, HG and HW in the buffaloes of LF reached to 365.0 kg, 123.0 cm, 123.5 cm, 126.3 cm, 169.0 cm and 47.5 cm in male, and 319.0 kg, 123.8 cm, 120.6 cm, 123.3 cm, 150.0 cm and 46.0 cm in female, respectively. On the other hand, the corresponding values of SF reached to 200.0 kg, 108.8 cm, 108.2 cm, 112.6 cm, 135.0 cm and 37.0 cm in male, and 176.0 kg, 109.8 cm, 113.2 cm, 115.0 cm, 140.0 cm and 36.0 cm in female, respectively. The following equations to show the average BW (kg) with age of month (AM) in the buffaloes of LF were calculated: The male BW=9.79AM+50.14; The female BW=9.21AM+41.11. The corresponding equations of SF were as follows: The male BW=6.88AM+30.03; The female BW=5.31AM+38.85. The develop- ment of the buffaloes was faster in LF than in SF. The BW of the 24 months old buffaloes calculated by the equations differed around 90 kg between LF and SF (Figure 1). The formulae to estimate WH with AM in the buffaloes of LF were as follows: The male WH=1.45AM+85.73. The female WH=1.34AM+85.61. The corresponding formulae of SF were calculated: The male WH=1.71AM+73.86. The female WH=0.92AM+81.42. (Figure 2). The BWR and WHR of each body trait of the buffaloes in LF and SF were shown in Table 1 and 2, respectively. The BWR in male and female had higher average values in SF than in LF (P<0.01). This condition indicated that the proportion of BW with body size in SF was lower than that in LF. The mean WHR of BW, BL, HG and HW was higher in LF than in SF (P<0.01). However, the average WHR of CH in SF was higher than that in LF (P<0.01). The results indicated that the body of buffaloes in SF was thinner than that in LF. The development of body was considered to be slower in SF than in LF. The phenotypic correlation coefficient between every pair of traits in the buffaloes in LF and SF was shown in Table 3. The every pair of traits had high correlation (P<0.01). The correlation coefficient between BW and HW was 0.969 and 0.966 in male and female, respectively. The possibility of efficient growth in buffaloes with the improvement of feeding and breeding in SF was suggested. Although the BW is usually estimated using HG, HW is also assumed to be the effective body trait for BW estimation of growing buffaloes. Proceedings 9 th World Buffalo Congress 776 PRODUCTION SYSTEM REFERENCES 1. Food and Agriculture Organization of the United Nations (FAO). 2005. Livestock Sector Brief, Nepal. Livestock Information, Sector Analysis and Policy Branch, Rome, Italy. 2. Food and Agriculture Organization of the United Nations (FAO). 2008. FAOSTAT. [cited 28 December 2009] URL: http://faostat.fao.org/site/ 569/default.aspx#ancor 3. Hayashi Y, Shah MK, Tabata Y, Kumagai H, Shah SK. 2008. Feeding trait and body dimension of growing buffaloes raised by small-scale farms in Tarai, Nepal. Proceedings CD of the 13th Animal Science Congress of the Asian-Ausralasian Association of Animal Production Sciences (2.Ruminal nutrition, feeding and management, Oral, 08). 4. Hayashi Y, Shah MK, Kumagai H, Shah SK. 2009. Body weight and body size of growing buffaloes raised in Nepal. Pakistan Journal of Zoology 9: 143-145. 5. Hayashi Y, Maharjan KL, Kumagai H. 2006. Feeding traits, nutritional status and milk production of dairy cattle and buffalo in small-scale farm in Terai, Nepal. Asian-Austral Asian Journal of Animal Sciences 19: 189-197. Acknhowledgements: The study was supported by a fund for research project in 2007 from Meijo Asian Re- search Center and a grant-in aids for scientific research (No. 19405041) from the Japanese Society for the Promotion of Science (JSPS). Table 1: Bodyweight ratio (BWR) in the buffaloes less than 24 months old Table 2: Withers height ratio (WHR) in the buffaloes less than 24 months old Table 3: Phenotypic correlation between every pair of traits in the buffaloes Male above the diagonal and female under the diagonal. P<0.01. ab: P<0.01 ab: P<0.01 Buenos Aires, Abril 2010 777 PRODUCTION SYSTEM Effect of the climatic conditions of the brazilian eastern amazon in the tolerance to the heat in buffaloes (bubalus bubalis) created on the shading and sun Silva, J.A.R.1; Santos, N.F.A.2; Araújo, A.A.3; Lourenço Júnior, J.B.4; Garcia, A.R.5; Viana, R.B.6;; Nahúm, B.S.5. 1 Graduate degree of Rural Federal University of Amazonia - UFRA - Tv. Tancredo Neves, s/n. Belém, Para State, Brazil. DSc. Student in Zootecnic, Federal University of Ceara UFC. e-mail: jamileandrea@yahoo.com.br 2 DSc. Student in Agricultural Sciences, Rural Federal University of Amazonia - UFRA. Tv. Tancredo Neves, s/n. Belém, Para State, Brazil. 3 Postgraduate degree of Federal University of Ceara - UFC. Av. Paranjana, 1700 - Campus do Itaperi, Fortaleza, Ceara State, Brazil. 4 Postgraduate degree of Federal University of Para State - UFPA and Federal Rural University of Amazonia - UFRA - Tv. Dr. Eneas Pinheiro s/n. Belem, Para State, Brazil - 5 Researcher Embrapa Eastern Amazon. Tv. Dr. Eneas Pinheiro s/n. Belem, Para State, Brazil - CEP 66.095-100. 6 Graduate degree of Rural Federal University of Amazonia - UFRA - Tv. Tancredo Neves, s/n. Belém, Para State, Brazil.CEP 66.095-100. ABSTRACT The effect of the climatic conditions of the Brazilian Eastern Amazon on the rectal temperature (RT), respiratory frequen- cy (RF) and index of tolerance to the heat (ITH) - Benezra was evaluated, 20 female buffaloes of the Murrah race, entirely randonized distributed, in two experimental groups (Group Without Shading - WS and Group With Shading - S), in silvopas- toral system, with Brachiaria humidicola, in rotationed grazing. The buffaloes of Group S (n=10) had remained in pasture shadings for the leguminous Acacia mangium, while of Group WS (n=10) was kept in pasture without access to the shade. All the animals had access to the water to drink and mineral salt "add libitum". The period of adaptation of the animals to the systems was of 14 days. The physiological variable was taking in two turns in the morning (7 AM) and in the afternoon (13 PM). The statistical analysis presented differences significant (P<0.05) between the turns, for the two treatments, the RT of the turn in the afternoon, 38.6 and 38.8ºC, respectively of Groups WS and S, was superior to temperatures takes in the morning, 38.4 and 38.4ºC. The RF, in Group WS, in the turn of the afternoon, was different (P<0.05) between the months, with bigger values in May (38 movement/minute) and lesser in June (31 movement/minute). The average values of the ITH only showed differences between the turns of the morning (2.24) and the afternoon (2.46). Keywords: Bioclimatology, physiological variable, rectal temperature, respiratory frequency, silvopastoral system, Brachiaria humidicola. INTRODUCTION The climate of the Eastern Amazon Region is characterized for presenting high temperatures and relative humidity of the air. These climatic conditions are a challenge for the homoeothermic animals that has difficulties in wasting heat to restore its thermal balance corporal. The buffaloes, pertaining to this group, have specific structural characteristics, with raised concentration of melanin in the skin, reduced amount of sweat glands and density of hair, what it becomes very sensible to the direct solar radiation. Being thus, this research aims to evaluate the effect of the availability of shade of trees (leguminous Acacia mangium), in two periods of the day (7 A.M. and 1 P.M.) in the rectal temperature, respiratory frequency and index of tolerance to the heat of buffaloes of the Murrah race, in the climatic conditions of the Eastern Amazon Region. Proceedings 9 th World Buffalo Congress 778 PRODUCTION SYSTEM MATERIALS AND METHODS This Work was lead in the Unit of Research "Senator Alvaro Adolpho" (01°.26'.03" S and 48°.26'.03" W), Belem, Para State, Brazil, pertaining to the Embrapa Eastern Amazon, of January to June 2009. The local climatic type is the Afi, according to Köppen. The pluvial precipitation annual average is 3,001 mm, annual average relative humidity of air 85%, annual average temperature 27ºC and 2,400 hours of annual insolation 2.Were used 20 Murrah buffaloes, between four and five years old, average weight 359kg, cyclical, non-lactating. The animals were distributed, randomized, in two experimental groups (Group S - with shade and Group WS - without shade). The period of adaptation was of 14 days. Group S (n=10) remained in rotation pasture, in poles with shade of trees of the leguminous Acacia mangium, in silvopastoral system, while Group WS (n=10) was kept without access to the shade, also, in rotation pasture. The feeding was of the pasture "quicuio-da-Amazônia" (humidicola Brachiaria), with access the water to drink and mineral salt ad libitum. The studied physiological variable, rectal temperature (RT) and respiratory frequency (RF) was surveyed two times per week, to 7:00 A.M. and 13:00 P.M., with the aid of clinical thermometer veterinarian, with scale until 44ºC, and for the inspection and counting of the thorax-abdominal movements, during one minute (movement/minute). The Index of tolerance to the heat of Benezra 3 was used, values next the two (2.0) indicate that the animals are adapted to the environment. The calculation was effected using the formula: ITH = RT/38.33 + RF/23, where RT: rectal tempera- ture and RF: respiratory frequency. The climatic variable referring to the temperature of air (AT) and relative humidity of air (RHA) were gotten in the Meteorological Station of the INMET - 2º DISME, located the 500 meters of the experimental area, and from them, was calculated the Index of Temperature and Humidity (ITH) 8: ITH: [0.8 x T + (RH/100) x (T-14.4) + 4.4], where: T = temperature (ºC) and RH = relative humidity of air (%). Descriptive analyses and of variance were made, 0.05% of significance, in the SYSTAT, version 12. RESULTS AND DISCUSSION The averages of climatic variable and the index of temperature and humidity, in the experimental period, per the morning and to the afternoon, are in Table 1. Table 1. Average values of the relative humidity of air (HRA), temperature of air (AT) and index of temperature and humidity (ITH), of January to June of 2009, in Belem/Para State, Brazil. In Figure 1 is illustrated the variation of the RT in the experimental period. Significant differences (P<0.05) between averages of the turns and treatments had been observed, with 38.6 and 38.8ºC, in Groups WS and S, per the afternoon, superiors to the the morning, 38.4 and 38.4ºC. Figure 1: Variation of rectal temperature of buffaloes created without shade (WS) and shade (S), of morning (7:00 A.M.) and to the afternoon (1:00 P.M.), in Eastern Amazon. Figure 2: Variation of respiratory frequency of buffaloes cre- ated without shade (WS) and shade (S), of morning (7:00 A.M.) and to the afternoon (1:00 P.M.), in Eastern Amazon. Buenos Aires, Abril 2010 779 PRODUCTION SYSTEM In the experimental period had significant differences (P<0.05) in all months, between Groups WS and S and turns. In Group WS, in both the turns, had significant difference (P<0.05) between the months, with lesser values in June (38.55ºC), that it can have occurred due to adaptation acquired for the animals, in elapsing of the period of collection of data, when they presented differentiated behavior, in mud puddles formed by the water of rain. In them, the animals lay down, in order to keep the body temperature in normal levels, considering it that in this group it did not have shade availability. This behavior was waited, therefore as research executed in São Paulo State, Brazil 1, buffaloes has preference for water for bath, when they desire to thermorregular. In both the studied groups, the RT was significantly superior in the turn of the afternoon, when the ambient temperature if found higher. Research in Rondônia State, Brazil, with buffaloes created in silvopastoral system 6, had presented resulted similar, where the RT passed of 38.7ºC for 39.2ºC, per the morning and late, respectively, what demonstrates that the rise of the ambient temperature influences in this physiological variable. The variation of the RF of the animals studied, during the experimental period, is presented in Figure 2. In March and April had significant differences (P<0.05) between Groups WS and S and turns. In January, February, May and June the differences (P<0.05) had been only between the turns. In Group WS, to the afternoon, the difference (P<0.05) occurred between the months, with bigger values in March (38 mov./min.) and minors in June (31 mov./min.). These results are in accordance with literature 9. In pasture without shade, the buffaloes present significant rise in the RT, of 38.3 for 39.1ºC, and in the RF, of 22.6 for 48.4 mov./min., as form to waste the excess of corporal heat, in result of thermal stress, that it harms its productive performance 7. The daily average value of the index of tolerance to the heat of Benezra was 2.32, in Group S, and 2.38, in Group WS. Per the morning and to the afternoon, the average results were, respectively, 2.22 and 2.41 (Group S) and 2.25 and 2.50 (Group WS). The variance analysis disclosed differences significant (P<0.05) of the index, in Group WS, to the afternoon, probably due to rise of the ambient temperature and the direct solar radiation on the skin of the animals, since they did not have availability of shaded areas to be protected. Figure 3: Index of tolerance to the heat of Benezra, in the experimental period. In January, March and April had differences (P<0.05) between Group S and WS and turns. In February, May and June the difference (P<0.05) was only between turns. The averages of the index of tolerance to the heat of Benezra, in the experimental period, are in Figure 3. Similar results had been gotten in Eastern Amazon 4, where it was observed that the ITH of the animals kept in the system with shade is next the 2,0, in 70% of the carried through comments, what it proves the importance of the shade in the animal ambience, tropical climates, as of the Brazilian Amazon. In Table 2 are the average results of the rectal temperature, respiratory frequency and index of tolerance to the heat of Benezra, in buffaloes created to the shade and the sun, per the morning and to the afternoon. Table 2: Averages of the rectal temperature, respiratory frequen- cy and index of tolerance to the heat of Benezra (ITH), buffaloes created to the shade and the sun, per the morning and to the af- ternoon, in Belem, Para State, Brazil. Proceedings 9 th World Buffalo Congress 780 PRODUCTION SYSTEM The systems that allow access to the shade, as the silvopastoral, promote better tolerance of the buffaloes to the tropical heat, in comparison to the kept in area without shade. The simple shade in the pastures can have positive consequences in the productivity of the buffalo, although the temperature, relative humidity of air and index of temperature and humidity to affect the physiological variable and the index of tolerance to the heat, mainly, in the period of the afternoon. Acknowledgements. To the Supervision of Development of Amazon - SUDAM, for the financial resources. To the Embrapa Eastern Amazon, for the availability of the area and experimental animals. To the National Institute of Meteorology - INMET/2º District of Meteorology, for the supply of the climatic data. REFERENCES 1. Ablas, D.S.; Titto, E.A.L.; Pereira, A.M.F.; Titto, C.G.; Leme, T.M.C. 2007. Comportamento de bubalinos a pasto frente a disponibilidade de sombra e água para imersão. Ciência Animal Brasileira (UFG), Goiânia, v. 8, n. 2, p. 167-176. 2. Bastos, T.X.; Pacheco, N.A.; Nechet, D.; Sá, T.D.A. 2002. Aspectos climáticos de Belém no últimos cem anos. Belém: Embrapa Amazônia Oriental. 31 p. (Embrapa Amazônia Oriental. Documentos, 128). 3. Benezra, M.V. 1954. A new index measuring the adaptability of cattle to tropical conditions. Journal of Animal Science, v. 13, n. 4, p. 1015. 4. Lourenço Júnior, J.B.; Costa, N.A.; Garcia, A.R.; Nahum, B.S.; Araujo, C.V.; Dutra, S.; Matos, J.C.S.; Matos, L.B. 2006. Sistema silvipastoril e pastejo rotacionado intensivo na produção leiteira de búfalas na pequena propriedade da Amazônia Oriental. In: Congreso Latino Americano de Agroforesteria para la Producción Pecuaria Sostenible, 4; Simposio sobre Sistemas Silvopastoriles para la Producción Ganadera Sostenible, 3, 2006, Varadero, Cuba. Anales. 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The averages of ACI (Table 5) calculated for experimental animals, to 6 A.M., 12 P.M and 18 P.M., in Periods 1 and 2 of the experimental year, were, respectively, for SSP1 and SSP2, of 2.90 ± 0.74 and 2.80 ± 0. 73, in Period 1, and 2.90 ± 0.72 and 3. 00 ± 0.74, in Period 2 The extreme values of 3. 45± 0 .30 and 2.42± 0.66 ACI, both surveyed in the animals of the SSP2 There's significant effect of the hour... mov/min, above the levels considered normal, and ST ranged from 23. 6±8 .3 and 31 .7±5.4°C In both periods of the year and the two SSP's, the ACIs were considered higher than ideal, ranging from 2.46±0 .33 to 3. 31±0.62 (SSP1) and 2.42±0 .30 to 3. 45±0.66 (SSP2) Nevertheless, animals presented no clinical signal of stress or discomfort, which can be indicative of buffalo environmental adaptability or necessity... frequency-RF and skin temperature-ST); it was calculated the temperature and humidity index (THI) and the Benezra´s animal comfort index (ACI), in two phases of the year, and they were compared by Tukey test (P . normal, and ST ranged from 23. 6±8 .3 and 31 .7±5.4°C. In both periods of the year and the two SSP's, the ACIs were considered higher than ideal, ranging from 2.46±0 .33 to 3. 31±0.62 (SSP1) and. the RT of the turn in the afternoon, 38 .6 and 38 .8ºC, respectively of Groups WS and S, was superior to temperatures takes in the morning, 38 .4 and 38 .4ºC. The RF, in Group WS, in the turn of the. between averages of the turns and treatments had been observed, with 38 .6 and 38 .8ºC, in Groups WS and S, per the afternoon, superiors to the the morning, 38 .4 and 38 .4ºC. Figure 1: Variation of rectal