Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-26T20:32:50.818Z Has data issue: false hasContentIssue false
  • English
  • Français

A model for the effects of energy nutrition on the pregnant ewe

Published online by Cambridge University Press:  02 September 2010

Pamela A Geisler  and
Heather Neal
Pamela A Geisler
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
Heather Neal
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
Get access

Abstract

A computer-based model of the response of the ewe to energy nutrition during pregnancy is described, based on a previous analysis of energy requirements. A ewe of specified weight and body condition 30 days from conception, carrying a known number of lambs, is predicted to grow them to an optimal weight if the nutritional regime allows. Daily energy requirements of the ewe-foetus system are calculated as the sum of requirements for maintenance and for growth and are compared with the daily energy supplied.If the feed provides energy surplus to requirements, the ewe herself gains weight; otherwise, the ewe mobilizes her own reserves, within limits, to protect the foetus. If this does not produce the energy required for optimal growth, foetal growth is reduced.

Published experimental results are compared with predictions of the model when run under similar conditions; in general, predictions of total maternal weight at the end of pregnancy are within 5 % of those observed in the experiments. Model predictions of the effects of some particular nutritional regimes during pregnancy are presented and the sensitivity of the predictions of the model to certain of the assumptions made in its construction are discussed.

Type
Research Article
Information
Animal Production , Volume 29 , Issue 3 , December 1979 , pp. 357 - 369
Copyright
Copyright © British Society of Animal Science 1979

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Blaxter, K. L. 1962. The Energy Metabolism of Ruminants, p. 100. Hutchinson, London.Google Scholar
Edey, T. N. 1969. Prenatal mortality in sheep: a review. Anim. Breed. Abstr. 37:173–190.Google Scholar
Everitt, G. C. 1968. Prenatal development of uniparous animals with particular reference to the influence of maternal nutrition in sheep. In Growth and Development of Mammals, Proc. 14th Easter Sch. agric. Sci., Univ. Nottingham, pp. 131–157. Butterworth, London.Google Scholar
Geisler, P. A. and Fenlon, J. S. 1979. The effects of body weight and its components on lambing performance in some commercial flocks in Britain. Anim. Prod. 28: 245–255.CrossRefGoogle Scholar
Geisler, Pamela A. and Jones, C. Merryl. 1979. A model for calculation of the energy requirements of the pregnant ewe. Anim. Prod. 29: 339–355.Google Scholar
Hammond, J. 1944. Physiological factors affecting birth weight. Proc. Nutr. Soc. 2: 8–12.Google Scholar
Jefferies, B. C. 1961. Body condition scoring and its use in management. Tasm. J. Agric. 32: 19–21.Google Scholar
Ministry Of Agriculture, Fisheries And Food, Department Of Agriculture And Fisheries For Scotland And Department Of Agriculture For Northern Ireland. 1975. Energy allowances and feeding systems for ruminants. Tech. Bull. 33. Her Majesty's Stationery Office, London.Google Scholar
National Research Council. 1968. Nutrient Requirements of Domestic Animals. No. 5, Nutrient Requirements of Sheep. National Academy of Sciences, Washington, DC.Google Scholar
Prior, R. L. and Christenson, R. K. 1976. Influence of dietary energy during gestation on lambing performance, and glucose metabolism in Finn-cross ewes. J. Anim. Sci. 43: 1114–1124.CrossRefGoogle ScholarPubMed
Robinson, J. J. 1977. The influence of maternal nutrition on ovine foetal growth. Proc. Nutr. Soc. 36: 9–16.CrossRefGoogle ScholarPubMed
Robinson, J. J. 1978. Response of lactating ewes to variation in energy and protein intake. In Milk Production in the Ewe. (ed. Boyazoglu, J. G. and Treacher, T. T.), pp. 53–63. Eur. Ass. Anim. Prod., Publ. 23.Google Scholar
Robinson, J. J., McDonald, I., Fraser, C. and Crofts, R. M. J. 1977. Studies on repro- duction in prolific ewes. I. Growth of the products of conception. J. agric. Sci., Camb. 88: 539–552.CrossRefGoogle Scholar
Robinson, J. J., McDonald, I., McHattie, I. and Pennie, K. 1978. Studies on reproduction in prolific ewes. 4. Sequential changes in the maternal body during pregnancy. J. agric. Sci., Camb. 91: 291–304.CrossRefGoogle Scholar
Robinson, J. J., Smart, R. I. and Pennie, K. 1978. The energy requirements of twinbearing ewes in late pregnancy and the extent of body tissue mobilization. Anim. Prod. 26: 390–391 (Abstr.).Google Scholar
Russel, A. J. F., Doney, J. M. and Gunn, R. G. 1968a. Subjective assessment of body fat in live sheep. J. agric. Sci., Camb. 72: 451–454.CrossRefGoogle Scholar
Russel, A. J. F., Gunn, R. G. and Doney, J. M. 1968b. Components of weight loss in pregnant hill ewes during winter. Anim. Prod. 10: 43–51.CrossRefGoogle Scholar
Russel, A. J. F., Maxwell, T. J., Sibbald, A. R. and McDonald, D. 1977. Relationships between energy intake, nutritional state and lamb birth weight in Greyface ewes. J. agric. Sci., Camb. 89: 667–673.CrossRefGoogle Scholar
Thomson, W. and Aitken, F. C. 1959. Effect of plane of nutrition of ewe on fertility, reproduction and lactation. In Diet in Relation to Reproduction and the Viability of the Young. II. Sheep: World survey of reproduction and review of feeding experiments. Tech. Commun. Commonw. Bur. Anim. Nutr. No. 20, pp. 67–76.Google Scholar
Treacher, T. T. 1970. Effects of nutrition in late pregnancy on subsequent milk production in ewes. Anim. Prod. 12: 23–36.Google Scholar