Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-07-05T15:36:57.872Z Has data issue: false hasContentIssue false
  • English
  • Français

Exogenous progesterone and oestrous cycle length in the ewe

Published online by Cambridge University Press:  27 March 2009

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

Summary

One hundred and sixty mature Merino ewes were randomly allocated to a factorial experiment designed to investigate the effects of short-term progesterone administration on oestrous cycle length. Groups of ewes received a series of four daily injections of 0, 10, 25 or 40 mg progesterone in peanut oil beginning either on the day of oestrus (day 0) or the next day. Equal numbers of ewes (ten per group) received subcutaneous and intramuscular injections, and those in the control groups received injections of the vehicle only.

Oestrous cycle length was significantly reduced in all progesterone-treated groups, but a consistent trend for this reduction to be greatest in ewes treated first on day 0 gave rise to a significant ‘day x dose’ interaction (P < 0·001). Route of progesterone administration had no significant effect on subsequent cycle length which, in control ewes, averaged 17·2 ± 0·1 days. For ewes first treated on days 0 and 1, mean oestrous cycle lengths for groups receiving 0, 10, 25 and 40 mg of progesterone per day were 17·3, 14·6, 12·1 and 10·7 days and 17·1, 15·2, 13·6 and 13·0 days respectively.

Type
Short Note
Information
The Journal of Agricultural Science , Volume 77 , Issue 1 , August 1971 , pp. 147 - 149
Copyright
Copyright © Cambridge University Press 1971

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

Ginther, O. J. (1968). Influence of exogenous progesterone and the uterus on ovarian activity in sheep. Endocrinology 83, 613–15.CrossRefGoogle ScholarPubMed
Ginther, O. J. (1969). Length of estrous cycle and size of corpus luteum in guinea pigs and sheep treated with progesterone at different days of the estrous cycle. Am. J. vet. Res. 30, 1975–8.Google ScholarPubMed
Lewis, P. E., Taylor, W. C. & Inskeep, E. K. (1968). Exogenous progesterone on ovine corpora lutea. J. Anim. Sci. 27, 1193.Google Scholar
Smith, J. F. & Robinson, T. J. (1969). Luteal function in the Merino ewe and the effect of exogenous progestagen. J. Endocr. 44, 79–89.CrossRefGoogle ScholarPubMed
Thwaites, C. J. (1968). Luteal regression and embryo mortality in the heat-stressed ewe. Proc. 2nd World Conf. Anim. Prod. p. 433.Google Scholar
Thwaites, C. J. (1970). Embryo mortality in the heat stressed ewe. III. The role of the corpus luteum, thyroid and adrenal glands. J. Reprod. Fert. 21, 95–107.CrossRefGoogle Scholar
Woody, C. O., First, N. L. & Pope, A. L. (1967) Effect of exogenous progesterone on estrous cycle length. J. Anim. Sci. 26, 139–41.CrossRefGoogle ScholarPubMed
Woody, C. O., Ginther, O. J. & Pope, A. L. (1966a). Effects of hysterectomy and exogenous progesterone on the corpus luteum of the ewe. J. Anim. Sci. 25, 933.Google Scholar
Woody, C. O., Ginthek, O. J. & Pope, A. L. (1966b). Effects of exogenous progesterone on corpora lutea induced in anestrous ewes. J. Anim. Sci. 25, 1263.Google Scholar
Woody, C. O., Ginther, O. J. & Pope, A. L. (1967). Effects of exogenous progesterone on corpora lutea induced in anestrous ewes. J. Anim. Sci. 26, 1113–15.CrossRefGoogle ScholarPubMed
Woody, C. O., Ginther, O. J. & Pope, A. L. (1968). Effects of exogenous progesterone and hysterectomy on corpora lutea in ewes. J. Anim. Sci. 27, 1383–86.CrossRefGoogle Scholar
Zimbemian, R. G., Pope, A. L. & Casida, L. E. (1959). Effect of exogenous progesterone on the corpus luteum of the bred ewe. J. Anim. Sci. 18, 1327–32.CrossRefGoogle Scholar