Small Ruminant Research, 7 (1992) 185-188 Elsevier Science Publishers B.V., Amsterdam
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Technical Note
Resting heat production in Barbari and Black Bengal goats D.C. Shukla and B.B. Mahapatro Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar, U.P. 243122, India (Accepted 23 April 1991 )
ABSTRACT D.C. Shukla and B.B. Mahapatro, 1992. Resting heat production in Barbari and Black Bengal goats. Small Rumin. Res., 7: 185-188. Resting heat production was determined in 56 Barbari and Black Bengal male kids at the 5th, 7th, 9th and 1lth months of age. Black Bengal kids had significantly higher resting heat production per unit metabolic body weight ( 10.77 _+0.52 kcal kg°'75/h ) than Barbari kids (9.63 _+0.40 kcal kg°-75/h ). Heat production per unit body weight was found to be inversely related to body weight and age. Younger kids irrespective of breed, had higher heat production per unit metabolic body weight. Higher metabolic rate in Black Bengal kids may be important considering the high reproductive rate of this breed.
INTRODUCTION
Goats play an important role in the Indian economy although little information is available about their nutrient requirements, ability to digest feedstuffs and energy metabolism. A large number of goat breeds are available on the Indian subcontinent and they vary greatly in size, productivity and reproductive efficacy. The Black Bengal goat is a short breed having a very high rate of reproduction, triplet and quarduplet kidding being common. In contrast, the Barbari breed is heavier than the Black Bengal and is not so prolific, the twinning percentage being only 20-30%. Because information on basal heat production in these animals is not available, an investigation was made to study resting heat production in these breeds. MATERIALS AND METHODS
Fifty six Barbari and Black Bengal male kids aged about 4 months, were divided into two groups. One group was maintained on 100% (high plane) 0921-4488/92/$05.00 © 1992 Elsevier Science Publishers B.V. All rights reserved.
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and the other on 75% (low plane ) of the ARC ( 1980 ) recommendation. The ratio of concentrate (crushed 60% maize; 15% groundnut cake; 22% wheat bran; 2% mineral mixture; 1% salt) to roughage (oat hay, Arena sativa) intake was maintained at 50: 50 on a dry matter basis. Resting heat production was determined as oxygen consumption during the 5th, 7th, 9th and 1 !th month of life by indirect calorimetry using a Benedict Roth metabolism aiaparatus (Warren E. Collins, Inc., Boston, U.S.A. ). Oxygen consumption was recorded between 09.00 and 10.00 h, before any feed or water was offered to kids (Shukla and Pal, 1972 ). Data were analysed for differences due to age, breed and plane of nutrition by analysis of variance (Snedecor and Cochran, 1967 ). RESULTS AND DISCUSSION
Resting heat production (RHP) was calculated as kcal k g ° 7 5 / h for each breed at different ages and nutritional planes. Mean values (~_+ s.c. ) for the different periods and breeds are in Table 1. The overal mean RHP was 9.51 _+0.48 kcal k g ° ' 7 5 / h . RHP was not significantly different between the two planes of nutrition used here. Differences between periods were significant ( P < 0.01 ); RHP was higher at the 5th month (12.11_+0.56 kcal k g ° ' 7 5 / h ) and decreased significantly at the 7th, 9th and 1 lth months (7.09 _+0.42 kcal k g ° ' 7 5 / h ) . These differences suggest an inverse relationship between heat production (per unit body weight) and body weight. Since the kids gained weight during this period, their heat production per unit weight decreased. This is in agreement with observations made earlier (Kleiber, 1947; Blaxter, 1962; Rao et al., 1966; Shukla and Pal, 1972). Heat production has been observed to be inversely correlated with age, and since these kids grew by about 5.0 kg during 6 months between periods I and TABLE 1 Resting heat production in Barbari and Black Bengal kids Period ~ Body weight (kg) Ambient temperature (°C) Maximum Minimum Vapour pressure (mm Hg) Heat production (kcal kg°75/h) Breed means kcal kg° 75/h
I
II
III
IV
7.56_+0.83
8.56_+0.91
10.05_+0.23
11.09-+0.73
34.1 +0.4 19.8+0.4 24.5+0.5 12.11+0.56 a Barbari 9.63 + 0.40 a
28.8+0.6 8.5+0.4 13.5+0.4 9.72+0.54 b
23.5+0.5 9.2+0.5 10.8+0.3 9.25+0.48 b Black Bengal 10.77 + 0.52 b
29.2+0.5 13.5+0.5 13.8+0.4 7.09+0.42 b
Within rows, values with different superscripts are significantly different ( P < 0.01 ). ~Periods I-IV= 5th, 7th, 9th, 1 lth month of age of kids; n = 56.
RESTINGHEATPRODUCTIONIN GOATS
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IV, this might also have contributed to lower heat production at the older age (Rogerson, 1960; Shukla et al., 1972). Black Bengal kids had significantly (P< 0.01 ) higher RHP than Barbari kids. This breed difference may again be due to the higher body weigh of Barbari kids. Sadhu and Bhatnagar ( 1965 ) have reported even lower values for Jamunapari goats, which are almost double the body weight of the kids used here. Breed differences in resting heat production have also been observed in poultry ( Damme et al., 1986 ), sheep (Olthoff and Dickerson, 1987 ), and cattle (Mullick, 1959; Frisch and Vercoe, 1977 ). CONCLUSION
These results confirm breed differences in heat production, which might be due to characteristic differences in their body weights. Barbari goats are characteristically heavier (av. adult weight 30-40 kg, 15 kg for Black Bengal) (Jindal, 1984), which may be responsible for lower resting heat production per unit body weight. ACKNOWLEDGEMENTS
The authors are thankful to the Director, Indian Veterinary Research Institute, and to the Head, Division of Physiology and Climatology, for providing facilities.
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Rogerson, A. 1960. The effect of environmental temperature on the energy metabolism of cattle. J. Agric. Sci., 55: 389-364. Sadhu, D.P. and Bhatnagar, S.P., 1965. Measurement of oxygen consumption in goats under resting and basal conditions. Indian J. Exp. Biol., 3: 263-265. Shukla, D.C. and Pal, A.K., 1972. Effect of dietary protein to energy ratio on energy metabolism of sheep. Indian J. Anim. Sci., 42: 507-512. Shukla, D.C., Rao, M.V.N. and Sadhu, D.P., 1972. Effect of age and climate upon the oxygen consumption in Haryana calves. Indian J. Anita. Res., 6:31-35. Snedecor, C.W. and Cochran, W.C., 1967. Statistical Methods, 6th edn. Oxford and IBP Publishing Co., New Delhi, India, pp. 299-334.