+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

The effect of stilboestrol administered during an autumn mating on reproduction in Merino sheep



The effect of stilboestrol administered during an autumn mating on reproduction in Merino sheep



Australian Jour Agric Res 14(5): 660-669



Ewes were injected subcutaneously with stilboestrol for 3 weeks prior to and during an autumn mating. Doses of 32 and 128 [mu]g daily during mating almost completely prevented pregnancy. The conception percentage during treatment in a group receiving 8 ug was 58, whereas 75% is expected in untreated ewes. This and other evidence indicated that doses as low as 8 [mu]g have adverse effects on fertility. No effect of 8 ug was observed on oestrus, but 32 and 128 [mu]g initially stimulated but later inhibited oestrus. The higher doses had little effect on the average length of oestrous cycles, but increased the variance by causing abnormally long or short cycles. Normal oestrous cycles did not recur in many ewes within 9 weeks of the last injection. However, fertility, the ratio of pregnancies to services, appeared somewhat recovered within about 3 weeks after the last injection. These results indicate that the fertility of Merino ewes is very vulnerable to adverse effects of oestrogen administered during an autumn mating. The significance of this is discussed in relation to possible permanent and temporary oestrogenic effects of subterranean clover pastures, and the importance of losses which may be caused by ingestion of oestrogens during mating.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 014242572

Download citation: RISBibTeXText

DOI: 10.1071/ar9630660


Related references

The effect of live ewe weight at mating on some reproduction traits in Konya Merino sheep. Indian Veterinary Journal 77(8): 683-685, 2000

Studies on the efficiency of mating in Merino sheep: mating behaviour of Merino, Dorper and Namaqua-Afrikaner rams during different seasons of the year. 1968-1972. Final report. Agricultural Research 1974: 73, 1975

Studies on the efficiency of mating in Merino sheep: effect of management, season of birth and breeding season on the reproduction of young maiden ewes. 1969-1970. Final report. Agricultural Research 1974: 73-74, 1975

Effect of variation of time of mating, mating frequency and semen dose rate on conception in Merino sheep. Aust. vet. J 33: 88-91, 1957

The effect of selected minerals and vitamin E on the reproduction of the Polish merino sheep. II. Reproduction and rearing lambs. Animal Science Papers & Reports 12(2): 53-61, 1994

Investigation of the advantages and problems associated with spring and autumn mating of ewes in East Griqualand: effect of intermittent teasing prior to spring mating on the incidence of oestrus in Merino ewes. 1966-1967. Final report. Summ. Rep. in Agric. Res, Pretoria., Pt I, 103-105, 1969

Effect of mating seasons on growth of Deccani sheep and their crosses with Merino and Rambouillet. Haryana Agricultural University Journal of Research 4(2): 158-161, 1974

The performance of crossbreds obtained by mating Polish Merino ewes with F1 Finnish Landrace X Merino rams. 3. The reproduction of ewes. Roczniki Naukowe Zootechniki, Monografie i Rozprawy ( 29): 73-80, 1991

Effect of early mating on development in long-wooled Merino sheep with semifine wool. Tierzucht 31(6): 266-268, 1977

The performance of crossbreds obtained by mating Polish Merino ewes with F1 Finnish Landrace X Merino rams. 3. The suitability of crossbred ewes for early (less than 1 year of age) use in reproduction. Roczniki Naukowe Zootechniki, Monografie i Rozprawy ( 29): 81-88, 1991

Effect of some important feeds on meat quality of Merino, Merino x Kivircik and Merino x White Karaman sheep.. Lalahan Zootek. Arast. Enst, Yayin: 12, 133, 1962

The effect of nutrition level on the reproduction activity of merino sheep in the winter season. 1978

The effect of selenium and vitamin E on reproduction in Merino sheep in South-western Australia. J. Aust. Inst. agric. Sci 32: 216-217, 1966

Reproduction of autumn- and spring-mated Merino ewes. Agroanimalia 7(1): 5-8, 1975

Mating of fine-wool sheep from Soviet Union and Merino sheep practiced for ten years now. Tierzucht 9(7): 292-296, 1985