- Volume 18 Issue 5
Individual production traits, such as reproduction and mortality rates, are partial measures, but may be used to evaluate the performance of different systems by comparing the rate of flock growth and potential offtake. The productivity of two existing sheep production systems, one extensive, one intensive, was compared with an alternative semi-intensive system. The future flock sizes, offtakes and structures were predicted based on the age structure of the flock and age-specific reproduction, mortality and growth rates. The measurements were illustrated with reference to growth of a sheep flock of different age and sex categories. The flock was in a socalled dynamic situation. During the dry period, the digestible organic matter intake of the animals in the intensive system and both extensive and semi-extensive systems was 36 and 20.1 g kg
- Bosman, H. G. 1995. Productivity assessments in small ruminant improvement programmes. A case study of the West African Dwarf Goat. PhD thesis, Wageningen Agricultural University, Wageningen, The Netherlands.
- White, D. H., P. J. Bowman, F. H. W. Morley, W. R. McManus and S. I. Filan. 1983. A simulation model of a breeding ewe flock. Agric. Syst. 10:149-189.
- Graham, N. McC. and T. W. Searle. 1979. Studies of weaned lambs before, during and after a period of weight loss. I. Energy utilization. Aust. J. Agric. Res. 30:513-523.
- Kamalzadeh, A., J. Van Bruchem, W. J. Koops, S. Tamminga and D. Zwart. 1997. Feed quality restriction and compensatory growth in growing sheep: feed intake, digestion, nitrogen balance and modelling changes in feed efficiency. Livest. Prod. Sci. 52:209-217.
- Upton, M. 1993. Livestock productivity assessment and modelling. Agric. Syst. 43:459-472.
- Crow, J. F. 1986. Basic concepts in population, quantitative, and evolutionary genetics. W. H. Freeman and company, New York, pp. 11-17.
- Miao, Z. H., P. C. Glatz and Y. J. Ru. 2004. Review of production, husbandry and sustainability of free-range pig production systems. Asian-Aust. J. Anim. Sci. 17(11):1615-1634.
- Monem, M. 1984. Iranian sheep breeds (Persian). Research publication 47. Animal Husbandry Research Centre, Karaj, Iran. pp. 36-51.
- ARC. 1980. The Nutrient Requirements of Ruminant Livestock. Commonwealth Agricultural Bureaux, Farnham Royal, England.
- Akinsoyinu, A. O., A. U. Mba and F. O. Olubajo. 1977. Studies on milk yield and composition of the West African Dwarf goat in Nigeria. J. Dai. Res. 44:57-62.
- Knipscheer, H. C., U. Kusnadi and A. J. De Boer. 1984. Some efficiency measures for analysis of the productive potential of Indonesian goats. Agric. Syst. 15:125-135.
- Gingins, M., H. Bickel and A. Schurch. 1980. Efficiency of energy utilization in undernourished and realimented sheep. Livest. Prod. Sci. 7:645-671.
- Hogg, B. W. 1992. Compensatory growth in ruminants. In: Growth regulation in farm animals (Ed. A. M. Pearson and T. R. Dutson). Advances in Meat Research. Volume 7. London. UK. pp. 103-134.
- Ledin, I. 1983. Effects of restricted feeding and realimentation on compensatory growth, carcass composition and organ growth in lambs. Swed. J. Agric. Sci. 13:175-187.
- Kabbali, A., W. L. Johnson, D. W. Johonson, R. D. Goodrich and C. E. Allen. 1992. Effects of undernutrition and refeeding on weights of body parts and chemical components of growing Moroccan lambs. J. Anim. Sci. 70:2859-2865.
- Peacock, C. P. 1987. Measures for assessing the productivity of sheep and goats. Agric. Syst. 23:197-210. https://doi.org/10.1016/0308-521X(87)90066-7
- Flock dynamics of desert Barki sheep in relation to age structure vol.41, pp.6, 2009, https://doi.org/10.1007/s11250-008-9277-4