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A note on crossbreeding for fat-lamb production in the hot tropics

  • J. P. Sehgal (a1), S. A. Karim (a1), Manohar Singh (a1) and R. M. Acharya (a1)

Abstract

To compare the genetic group differences in live-weight gains, efficiency of food conversion (in terms of dry matter, total digestible nutrients, digestible crude protein, digestible energy and metabolizable energy) and physiological responses related to heat balance, a total of 24 male lambs (91 to 180 days old), four each of Malpura, Sonadi, and their crosses with Dorset and Suffolk breeds, were given a ration having a roughage to concentrate ratio of 250:750g/kg and metabolizable energy content of 100MJ/kg dry matter. Live-weight gain per day was higher and the food conversion ratio (the intakes of total digestible nutrients, digestible energy and metabolizable energy per kg gain) was lower in the crossbreds than in the native sheep. The crossbreds had higher respiratory rates (153 per min) than the natives (140 per min) but there was no significant difference in rectal temperature between purebreds and crossbreds. The crossbred lambs in the present experiment grew faster, consumed more food and utilized the food more efficiently than did the native lambs, despite the fact that they dissipated more energy as body heat. It was, therefore, concluded that the crossbreds performed better than the native breeds between 3 and 6 months of age, even though they were not permanently acclimatized to hot environmental conditions.

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Association Of Official Analytical Chemists. 1970. Official Methods of Analysis of the Association of Official Analytical Chemists. 11th ed. Association of Official Analytical Chemists, Washington, DC.
Duncan, D. B. 1955. Multiple range and multiple F tests. Biometrics 11: 142.
Hales, J. R. S. 1973. Effects of heat stress on blood flow in respiratory muscles in the sheep. Pflügers Arch. ges. Physiol. 345: 123130.
Kleiber, M. 1961. The Fire of Life: an Introduction to Animal Energetics, p. 262. John Wiley, New York.
O‘Shea, J. and Maguire, M. F. 1962. Determination of calorific value of feedstuffs by chromic acid oxidation. J. Sci. Fd Agric. 13: 530534.
Singh, M. and Acharya, R. M. 1977. A note on the mode of heat dissipation in different types of sheep. Indian J. Anim. Sci. 47: 367368.
Singh, M., More, T. and Rai, A. K. 1980. Heat tolerance of different genetic groups of sheep exposed to elevated temperature conditions. J. agric. Sci., Camb. 94: 6367.
Swift, R. W., Bratzler, J. W., James, W. H., Tillman, A. D. and Meek, D. C. 1948. The effect of dietary fat on utilization of the energy and protein of rations by sheep. J. Anim. Sci. 7: 475485.
Yousef, M. K., Hahn, L. and Johnson, H. D. 1968. In Adaptation of Domestic Animals (ed. Hafez, E. S. E.), p. 239. Lea and Febiger, Philadelphia.

A note on crossbreeding for fat-lamb production in the hot tropics

  • J. P. Sehgal (a1), S. A. Karim (a1), Manohar Singh (a1) and R. M. Acharya (a1)

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