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Season of birth and the response to hemicastration in lambs

Published online by Cambridge University Press:  02 September 2010

R. B. Land ,
D. J. Drury  and
Marjorie Fordyce
R. B. Land
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
D. J. Drury
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
Marjorie Fordyce
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
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Abstract

Testis diameter and body weight were recorded for 37 Finn-Dorset ram lambs born in winter and 38 born in summer 1977 from 8 to 24 weeks of age. Testis growth in summer-born ram lambs reared during a period of decreasing daylength was more rapid than that of winter-born lambs reared during a period of increasing daylength. Hemicastration at 12 weeks of age (19 of the winter-born and 18 of the summer-born lambs) increased the rate of growth of the remaining testis. Season of birth did not affect the response to hemicastration. It was deduced that the feed-back of gonadal hormones on gonadotrophin release was similar in both seasons.

Type
Research Article
Information
Animal Production , Volume 29 , Issue 3 , December 1979 , pp. 379 - 384
Copyright
Copyright © British Society of Animal Science 1979

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References

REFERENCES

Courot, M., de Reviers, Marie M. and Pelletier, J. 1975. Variations in pituitary and blood LH during puberty in the male lamb. Relation to time of birth. Annls Biol. anim. Biochim. Biophys. 15: 509–516.CrossRefGoogle Scholar
Hochereau-de Reviers, Marie T., Loir, M. and Pelletier, J. 1976. Seasonal variations in the response of the testis and LH levels to hemicastration of adult rams. J. Reprod. Fert. 46: 203–209.CrossRefGoogle ScholarPubMed
Land, R. B. 1976. The sensitivity of the ovulation rate of Finnish Landrace and Blackface ewes to exogenous oestrogen. J. Reprod. Fert. 48: 217–218.CrossRefGoogle ScholarPubMed
Land, R. B. and Carr, W. R. 1975. Testis growth and plasma LH concentration following hemicastration and its relation with female prolificacy in sheep. J. Reprod. Fert. 45: 495–501.CrossRefGoogle ScholarPubMed
Land, R. B., Carr, W. R. and Thompson, R. 1979. Genetic and environmental variation in the LH response of ovariectomized sheep to LH-RH. J. Reprod. Fert. 56: 243–248.CrossRefGoogle ScholarPubMed
Land, R. B., Wheeler, A. G. and Carr, W. R. 1976. Seasonal variation in the oestrogen induced LH discharge of ovariectomized Finnish Landrace and Scottish Blackface ewes. Annls Biol. anim. Biochim. Biophys. 16: 521–528.CrossRefGoogle Scholar
Legan, Sandra J., Karsch, F. J. and Foster, D. L. 1977. The endocrine control of seasonal reproductive function in the ewe: a marked change in response to the negative feedback action of estradiol on luteinizing hormone secretion. Endocrinology 101: 818–824.CrossRefGoogle Scholar
Scaramuzzi, R. J. and Baird, D. T. 1977. Ovarian steroid secretion in sheep during anoestrus. In Sheep Breeding (ed. Tomes, G. J., Robertson, D. E. and Lightfoot, R. J. W.), pp. 330–337. Australian Institute of Technology.Google Scholar