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Seasonality of oestrus and ovulation in Corriedale ewes: repeatabilites and phenotypic correlations

Published online by Cambridge University Press:  27 March 2009

R. M. Rodriguez Iglesias
Affiliation:
Departamento de Agronomía, Universidad National del Sur, 8000 – Bahía Blanco, Argentina
H. Irazoqui
Affiliation:
Departamento de Agronomía, Universidad National del Sur, 8000 – Bahía Blanco, Argentina
N. H. Ciccioli
Affiliation:
Departamento de Agronomía, Universidad National del Sur, 8000 – Bahía Blanco, Argentina
C. Giglioli
Affiliation:
Departamento de Agronomía, Universidad National del Sur, 8000 – Bahía Blanco, Argentina

Summary

Oestrus and ovulation data from 104 adult Corriedale ewes, recorded daily from February 1988 to May 1990 in Argentina, were analysed to estimate repeatabilities of and phenotypic correlations between onset and cessation of the breeding season, duration of the anoestrus and ovulation rate.

The repeatability of dates of onset and cessation of the breeding season and duration of the anoestrus was 0·48±0·080, 0·49±0·075 and 0·50±0·081, respectively.

The duration of the anoestrus was significantly correlated both with onset (r = 0·24; P < 0·05) and with cessation (r = –0·47; P < 0·01) of the previous and subsequent breeding seasons, respectively.

There was no correlation between dates of onset and cessation of the breeding or non-breeding seasons.

Repeatability estimates of ovulation rate were 0·27 ± 0·034, 0·34 ± 0·081 and 0·43 ± 0·094 using the normal, logit and probit scales, respectively. Phenotypic correlations between ovulation rate and the components of the breeding and non-breeding seasons were all non-significant.

Type
Animals
Copyright
Copyright © Cambridge University Press 1993

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References

REFERENCES

Dufour, J. J. (1974). The duration of the breeding season of four breeds of sheep. Canadian Journal of Animal Science 54, 389392.CrossRefGoogle Scholar
Dýrmundsson, Ó. R. (1978). Studies on the breeding season of Icelandic ewes and ewe lambs. Journal of Agricultural Science, Cambridge 90, 275281.CrossRefGoogle Scholar
Fahmy, M. H. & Dufour, J. J. (1986). The breeding season and ovulation rate of DLS ewes as determined by laparoscopy. Canadian Journal of Animal Science 66, 297301.CrossRefGoogle Scholar
Fletcher, I. C. (1971). Effects of nutrition, liveweight, and season on the incidence of twin ovulation in South Australian strong-wool Merino ewes. Australian Journal of Agricultural Research 22, 321330.CrossRefGoogle Scholar
Gilmour, A. R. (1985). REG – A Generalised Linear Models Program. Miscellaneous Bulletin No. 1. Department of Agriculture, New South Wales, Australia.Google Scholar
Gilmour, A. R., Anderson, R. D. & Rae, A. L. (1987). Variance components on an underlying scale for ordered multiple threshold categorical data using a generalized linear mixed model. Journal of Animal Breeding and Genetics 104, 149155.CrossRefGoogle Scholar
Gunn, R. G., Doney, J. M. (1979). Fertility in Cheviot ewes. 1. The effect of body condition at mating on ovulation rate and early embryo mortality in North and South Country Cheviot ewes. Animal Production 29, 1116.Google Scholar
Hanrahan, J. P. & Quirke, J. F. (1986). Breeding season and multiple births in small ruminants. In Proceedings of the Third World Congress on Genetics Applied to Livestock Production, Volume XII, pp. 3045, Lincoln, Nebraska.Google Scholar
Irazoqui, H. & Menvielle, E. E. (1982). Ovulation rate of Corriedale ewes at Bahia Blanca, Argentina. Animal Production 35, 313320.Google Scholar
Montgomery, G. W., Scott, I. C. & Johnstone, P. D. (1988). Seasonal changes in ovulation rate in Coopworth ewes maintained at different liveweights. Animal Reproduction Science 17, 197205.CrossRefGoogle Scholar
Oldham, C. M. (1980). A study of sexual and ovarian activity in Merino sheep. PhD Thesis, University of Western Australia.Google Scholar
Oldham, C. M., Lindsay, D. R. & Martin, G. B. (1990). Effects of seasonal variation of live weight on the breeding activity of Merino ewes. In Reproductive Physiology of Merino Sheep – Concepts and Consequences (Eds Oldham, C. M., Martin, G. B. & Purvis, I. W.), pp. 4158. The University of Western Australia.Google Scholar
Österberg, S. (1981). Breeding season of the Finsheep ewe. Ada Agriculturae Scandinavica 31, 1116.CrossRefGoogle Scholar
Patterson, H. D. & Thompson, R. (1971). Recovery of inter-block information when block sizes are unequal. Biometrika 58, 545554.CrossRefGoogle Scholar
Pearce, G. P. & Oldham, C. M. (1988). Importance of nonolfactory ram stimuli in mediating ram-induced ovulation in the ewe. Journal of Reproduction and Fertility 84, 333339.CrossRefGoogle ScholarPubMed
Quirke, J. F., Hanrahan, J. P., Loughnane, W. & Triggs, R. (1986). Components of the breeding and non-breeding seasons in sheep: breed effects and repeatability. Irish Journal of Agricultural Research 25, 167172.Google Scholar
Robinson, J. E. & Karsch, F. J. (1988). Timing the breeding season of the ewe: what is the role of daylength? Reproduction, Nutrition, Developpement 28, 365374.CrossRefGoogle ScholarPubMed
Rodrigueziglesias, R. M., Ciccioli, N. H., Irazoqui, H. & Rodriguez, B. T. (1991). Importance of behavioural stimuli in ram-induced ovulation in seasonally anovular Corriedale ewes. Applied Animal Behaviour Science 30, 323332.CrossRefGoogle Scholar
Rodriguez Iglesias, R. M., Giglioli, C. & Irazoqui, H. (1988). A note on the breeding season of Lincoln ewes at Bahia Blanca, Argentina. Animal Production 47, 145147.Google Scholar
Rodriguez Iglesias, R. M., Irazoqui, H. & Ciccioli, N. H. (1992). Response of anovular Corriedale ewes to teasing in spring. Small Ruminant Research 6, 317322.CrossRefGoogle Scholar
Vosniakou, A. G., Doney, J. M. & Tsakalof, P. (1989). A note on the seasonal oestrous period in three breeds of Greek dairy sheep. Animal Production 49, 147150.Google Scholar
Wayne, N. L., Malpaux, B. & Karsch, F. J. (1989). Social cues can play a role in timing the onset of the breeding season of the ewe. Journal of Reproduction and Fertility 87, 707713.CrossRefGoogle ScholarPubMed