Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-17T15:32:03.717Z Has data issue: false hasContentIssue false
  • English
  • Français

Foetal stunting in sheep: 2. The effects of high ambient temperature during gestation on wool follicle development in the foetal lamb

Published online by Cambridge University Press:  27 March 2009

G. A. Cartwright  and
C. J. Thwaites
G. A. Cartwright
Affiliation:
Department of Livestock Production, University of New England, Armidale, N.S.W., Australia, 2351
C. J. Thwaites
Affiliation:
Department of Livestock Production, University of New England, Armidale, N.S.W., Australia, 2351
Get access Rights & Permissions [Opens in a new window]

Summary

Hotroom treatment of ewes during the last two-thirds of gestation resulted in the birth of lambs which were significantly lighter than lambs born to nutritionallydeprived ewes. Neither high temperature nor undernutrition had significant effect on the density of either primary or immature secondary wool follicles, but the total number of mature secondary follicles tended to decline in the lambs from unheated ewes as the level of nutrition declined, and was significantly reduced by a further 30 % in the hotroom group.

In a second experiment, heated and unheated ewes fed to appetite were compared with unheated ewes pair-fed to the hotroom level of feed intake. High temperature had no apparent effect on maternal wool growth, but did reduce total wool follicle number in new-born lambs by approximately 50%. This effect was most marked with respect to mature secondary follicles (only 18% of unheated mean), less so in immature secondaries (56% of unheated mean), and barely discernible amongst primary follicles (93% of unheated mean). None of the differences in follicle numbers between the two unheated groups was significant.

The results suggest that the effects of high temperature on wool follicle development in the sheep foetus are akin to those of extreme undernutrition.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 86 , Issue 3 , June 1976 , pp. 581 - 585
Copyright
Copyright © Cambridge University Press 1976

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

Alexander, G. & Williams, D. (1971). Heat stress and development of the oonoeptus in domestic sheep. Journal of Agricultural Science, Cambridge 76, 53–72.CrossRefGoogle Scholar
Cartwright, G. A. (1972). The influence of high ambient temperature during gestation on the development of wool follicles in the foetal lamb. Journal of Reproduction and Fertility 28, 151–2.CrossRefGoogle Scholar
Cartwright, G. A. & Thwaites, C. J. (1976). Foetal stunting in sheep. 1. The influence of maternal nutrition and high ambient temperature on the growth and proportions of the Merino foetus. Journal of Agricultural Science, Cambridge 86, 573–80.CrossRefGoogle Scholar
Clarke, T. D., Stuart, L. S. & Frey, R. W. (1937). Cited by , Wodzicka (1958).Google Scholar
Malan, A. P. & Curson, H. H. (1936). Studies in sex physiology. No. 16. Surface area in the foetus of the Merino sheep. Onderstepoort Journal of Veterinary Science 7, 251–9.Google Scholar
Schinckel, P. G. & Short, B. F. (1961). The influence of nutritional level during pre-natal and early postnatal life on adult fleece and body characters. Australian Journal of Agricultural Research 12, 176–202.CrossRefGoogle Scholar
Shelton, M. (1964). Relation of environmental temperature during gestation to birth weight and mortality in lambs. Journal of Animal Science 23, 360–4.CrossRefGoogle Scholar
Shelton, M. & Huston, J. E. (1968). Effects of high temperature stress during gestation on certain aspects of reproduction in the ewe. Journal of Animal Science 27, 153–8.CrossRefGoogle ScholarPubMed
Thwaites, C. J. (1968). Heat stress and wool growth in sheep. Proceedings of the Australian Society of Animal Production 7, 259–63.Google Scholar
Turner, H. N., Hayman, R. H., Riches, J. H., Roberts, N. F. & Wilson, L. T. (1953). Physical definition of sheep and their fleeces for breeding and husbandry studies with particular reference to Merino sheep. Division of Animal Health and Production Report No. 4, C.S.I.R.O., Melbourne, Aust.Google Scholar
Wodzicka, M. (1958). Studies on the thickness and chemical composition of the skin of sheep. II. Variations during growth. New Zealand Journal of Agricultural Research 1, 592–600.CrossRefGoogle Scholar
Yeates, N. T. M. (1958). Foetal dwarfism in sheep – an effect of high atmospherio temperature during gestation. Journal of Agricultural Science, Cambridge 51, 84–9.CrossRefGoogle Scholar