Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-30T18:57:54.976Z Has data issue: false hasContentIssue false
  • English
  • Français

Relationships among uterine and placental factors in prolific ewes and their relevance to variations in foetal weight

Published online by Cambridge University Press:  02 September 2010

S. M. Rhind ,
J. J. Robinson  and
I. McDonald
S. M. Rhind
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
J. J. Robinson
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
I. McDonald
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
Get access

Abstract

Observations were made on the distribution of ovulations between the two ovaries, the distribution of foetuses between the two uterine horns, the total numbers of cotyledonary burrs, and the weights and numbers of foetal cotyledons for each foetus in 80 Finnish Landrace × Dorset Horn ewes killed between 50 and 145 days of gestation. While ovulations were randomly distributed between right and left ovaries, viable foetuses were more evenly distributed between right and left uterine horns. Migration of embryos between the horns contributed to this relative balance but early foetal mortality, which increased with ovulation rate, tended to upset it. The mean number of foetal cotyledons per foetus depended on litter size and distribution, and at any fixed litter size was substantially reduced in those ewes with six or more ovulations. Foetal weights were also relatively low in these ewes. The total weight of cotyledons per foetus decreased by about 12% for each increase of one in number of foetuses, as compared with a 20% decrease in number of cotyledons but only a 7 to 11 % decrease in the weight of the individual foetuses. Comparisons between foetuses within the same litter led to similar trends in the ratios of cotyledon numbers, cotyledon weights and foetal weights. It is suggested that the presence of some very small lambs in large litters should not be attributed to maternal under-nutrition in late pregnancy.

Type
Research Article
Information
Animal Production , Volume 30 , Issue 1 , February 1980 , pp. 115 - 124
Copyright
Copyright © British Society of Animal Science 1980

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

Alexander, G. 1964. Studies on the placenta of the sheep (Ovis aries L.). Placental size. J. Reprod. Fert. 7: 289–305.CrossRefGoogle ScholarPubMed
Amoroso, E. C. 1952. Placentation. In Marshall's Physiology of Reproduction. 3rd ed. (ed. Parkes, A. S.), Vol. 2, pp. 127–311. Longmans Green, London.Google Scholar
Boshier, D. P. 1969. A histological and histochemical examination of implantation and early placentome formation in sheep. J. Reprod. Pert. 19: 51–61.CrossRefGoogle ScholarPubMed
Casida, L. E., Woody, C. O. and Pope, A. L. 1966. Inequality in function of the right and left ovaries and uterine horns of the ewe. J. Anim. Sci. 25: 1169–1171.CrossRefGoogle ScholarPubMed
Cook, B. and Hunter, R. H. F. 1978. Systemic and local hormonal requirements for implantation in domestic animals. J. Reprod. Fert. 54: 471–482.CrossRefGoogle ScholarPubMed
Rhind, S. M., Robinson, J. J., Fraser, C. and McHattie, I. 1980. Ovulation and embryo survival rates and plasma progesterone concentrations of prolific ewes treated with PMSG. J. Reprod. Fert. In press.Google Scholar
Robinson, J. J., McDonald, I., Fraser, C. and Crofts, R. M. J. 1977. Studies on reproduction 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, T. J. 1951. The control of fertility in sheep. Part II. The augmentation of fertility by gonadotrophin treatment of the ewe in the normal breeding season. J. agric. Sci., Camb. 41: 6–63.CrossRefGoogle Scholar
Stegeman, Jenny H. J. 1974. Placental development in the sheep and its relation to fetal development: a qualitative and quantitative anatomic and histologic study. Bijdr. Dierk. 44: 3–72.CrossRefGoogle Scholar
Wallace, L. R. 1948. The growth of lambs before and after birth in relation to the level of nutrition. Parts II and III. J. agric. Sci., Camb. 38: 243–302.CrossRefGoogle Scholar
Wimsatt, W. A. 1975. Some comparative aspects of implantation. Biol. Reprod. 12:1–40.CrossRefGoogle ScholarPubMed