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Resumption of oestrous and ovarian cyclicity during the post-partum period in autumn-lambing ewes is not influenced by age or dietary protein content

  • L. M. Mitchell (a1), M. E. King (a1), F. E. Gebbie (a1), M. J. Ranilla (a1) and J. J. Robinson (a1)...


The objective was to determine the effect of age and dietary protein content on post-partum oestrous and ovarian cyclicity in autumn-lambing ewes. Twenty-four multiparous (age 4·5 (s.e. 0·61) years) and 24 primiparous (age 1·5 years) ewes which lambed on 28 October (s.e. 0·2) and were rearing 2·0 and. 1·7 (s.e. 0·13) lambs, respectively, were equally allocated to two dietary treatments in a 2 × 2 factorial design. Diets comprised a d libitum hay supplemented with concentrate (12·5 MJ metabolizable energy per kg dry matter (DM) and either 210 or 140 g crude protein per kg DM), offered at a daily allowance of 1·2 kg per ewe from lambing to weaning (18 December) and 0·4 kg per ewe thereafter. Throughout the study (3 November to 24 May) ewes were group-housed in straw-bedded pens under natural photoperiod at 57°N and their live weights and body condition scores were assessed at 2-week intervals. A raddled vasectomized ram was continually present with each group and ewes marked by the ram were recorded thrice weekly. Blood samples were obtained thrice weekly for measurement of peripheral progesterone concentrations and ovulation rate was determined by laparoscopy during January and March. There was no significant effect of dietary protein content on any of the variables measured. For multiparous and primiparous ewes, mean live weights and body condition scores at lambing were 79·5 (s.e. 1·41) v. 58·4 (s.e. 1·54) kg (P < 0·001) and 2·5 (s.e. 0·05) v. 2·2 (s.e. 0·05) (P < 0·001) and daily live-weight losses over the suckling period were 153 (s.e. 19·3) v. 85 (s.e. 21·1) glday (P < 0·05). Intervals from parturition to first overt oestrus were 39 (s.e. 3·2) v. 33 (s.e. 2·3) days and to the onset of ovarian cyclicity were 29 (s.e. 4·9) v. 25 (s.e. 1·5) days. Durations of ovarian cyclicity were 133 (s.e. 27·1) and 110 (s.e. 5·7) days (P < 0·01) during which 7·6 (s.e. 0·32) and 6·5 (s.e. 0·34) (P < 0·05) ovarian cycles were recorded respectively. Fifteen ewes had initial short cycles (≤10 days), six had prolonged cycles (≥21 days) and 11 had extended inter-luteal phase intervals (≥8 days). All ewes had recent ovulations at the January laparoscopy but only 19 multiparous and nine primiparous ewes had ovulations in March. Mean ovulation rates were: January 2·2 (s.e. 0·14) and 1·4 (s.e. 0·13) (P < 0·001), and March 1·6 (s.e. 0·23) and 1·2 (s.e. 0·15) for multiparous and primiparous ewes, respectively. It is concluded that, for ewes lambing at their normal time of mating, (i) the strong seasonal drive for reproduction results in the resumption of oestrous and ovarian cyclicity during the early post-partum period; (ii) initial luteal phases may be of short or extended duration; (Hi) there is no effect of age or dietary protein content, within the range studied, on the onset of ovarian cyclicity; and (iv) multiparous ewes experience a greater number of ovarian cycles and achieve higher ovulation rates than primiparous ewes.



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Aitken, R. P., Robinson, J. J. and Wallace, J. M. 1995. Is early resumption of ovarian activity detrimental to the re-establishment of pregnancy in the lactating ewe? Biology of Reproduction 52: (suppl. 1) 107.
Al-Gubory, K. H. and Martinet, J. 1986. Comparison of the total ovarian follicular populations at day 140 of pregnancy and at day 5 postpartum in ewes. Theriogenology 25: 795808.
Bartlewski, P. M., Beard, A. P. and Rawlings, N. C. 1995. The presence of the corpus luteum and/or embryo during pregnancy influences ovarian follicular development in the post-partum ewe. Journal of Reproduction and Fertility, Abstract Series 16: 9.
Boyd, J. S. and Ducker, M. J. 1973. A method of examining the cyclic changes occurring in the sheep ovary using endoscopy. Veterinary Record 90: 4043.
Cahill, L. P. and Mauleon, P. 1980. Influences of season, cycle and breed on follicular growth rates in sheep. Journal of Reproduction and Fertility 58:321328.
Chamley, W. A., Jonas, H. A. and Parr, R. A. 1976. Content of LH, FSH and growth hormone in the pituitaries of pregnant and anoestrous sheep. Endocrinology 98: 15351538.
Dyrmundsson, O. R. 1978. Studies on the breeding season of Icelandic ewes and ewe lambs. Journal of Agricultural Science, Cambridge 90:275281.
Foxcroft, G. R. 1992. Nutritional and lactational regulation of fertility in sows. Journal of Reproduction and Fertility, Supplement 45:113125.
Fredriksson, G. 1985. Release of PGF2∞ during parturition and the postpartum period in the ewe. Theriogenology 24: 331335.
Hare, L. and Bryant, M. J. 1982. Characteristics of oestrous cycles and plasma progesterone profiles of young female sheep during their first breeding season. Animal Production 35:17.
McKelvey, W. A. C., Robinson, J. J., Gebbie, F. E., Lindsay, E. and Dingwall, W. S. 1997. The identification and treatment of aberrant luteal activity during anoestrus in Suffolk ewes submitted for artificial insemination. Proceedings of the British Society of Animal Science, 1997, p. 182.
McNeilly, A. S. and Baird, D. T. 1983. Direct effect of prolactin, induced by TRH injection, on ovarian oestradiol secretion in the ewe. Journal of Reproduction and Fertility 69: 559568.
McNeilly, A. S. and Fraser, H. M. 1987. Effect of gonadotrophin releasing hormone agonist induced suppression of LH and FSH on follicle growth and corpus luteum function in the ewe. Journal of Endocrinology 115: 273282.
Mandiki, S. N. M., Bister, J. L. and Parquay, R. 1990. Effects of suckling mode on endocrine control of reproductive activity resumption in Texel ewes lambing in July or November. Theriogenology 33:397413.
Mitchell, L. M., King, M. E., Aitken, R. P. and Wallace, J. M. 1997. Influence of lambing date on subsequent ovarian cyclicity and ovulation rate in ewes. Animal Science 65: 7581.
Nett, T. M. 1987. Function of the hypothalamic-hypophysial axis during the post-partum period in ewes and cows. Journal of Reproduction and Fertility, Supplement 34:201213.
Quirke, J. F., Stabenfeldt, G. H. and Bradford, G. E. 1983. Resumption of ovarian function in autumn lambing Dorset, Rambouillet and Finnish Landrace ewes. Theriogenology 19: 243248.
Rubianes, E. and Ungerfeld, R. 1993. Uterine involution and ovarian changes during early post partum in autumnlambing Corriedale ewes. Theriogenology 40: 365372.
Russel, A. J. F., Doney, J. M. and Gunn, R. B. 1969. Subjective assessment of body fat in live sheep. Journal of Agricultural Science, Cambridge 72:451454.
Schirar, A., Cognie, Y., Louault, F., Poulin, N., Levasseur, M. C. and Martinet, J. 1989. Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes. Journal of Reproduction and Fertility 87: 789794.
Schirar, A., Cognie, Y., Louault, F., Poulin, N., Meusnier, C., Levasseur, M. C. and Martinet, J. 1990. Resumption of gonadotrophin release during the post-partum period in suckling and non-suckling ewes. Journal of Reproduction and Fertility 88:593604.
Schirar, A. and Levasseur, M. C. 1989. Resumption of ovarian activity in post-partum ewes: carry-over effect of the corpus luteum of pregnancy. Animal Reproduction Science 19:9197.
Sharpe, P. H., McKibbin, P. E., Murphy, B. D. and Manns, J. G. 1986. First postpartum ovulations and corpora lutea in ewes which lamb in the breeding season. Animal Reproduction Science 10:6174.
Smart, D., Singh, I., Smith, R. F. and Dobson, H. 1994. Opioids and suckling in relation to inhibition of oestradiol-induced LH secretion in postpartum ewes. Journal of Reproduction and Fertility 101:115119.
Wallace, J. M. 1995. Factors limiting re-establishment of pregnancy soon after birth. Annual report of the Rowett Research Institute.
Wallace, J. M., Thompson, M. G., Aitken, R. P. and Cheyne, M. A. 1993. Oxytocin receptor concentrations, inositol phosphate turnover and prostaglandin release by endometrium from ewes induced to ovulate during the early post-partum period. Endocrinology 136:1725.
Wheeler, A. G. and Land, R. B. 1977. Seasonal variation in oestrus and ovarian activity of Finnish Landrace, Tasmanian Merino and Scottish Blackface ewes. Animal Production 24:363376.
Williams, G. L. 1990. Suckling as a regulator of post-partum rebreeding in cattle: a review. Journal of Animal Science 68:831852.
Wise, M. E., Glass, J. D. and Nett, T. M. 1986. Changes in the concentration of hypothalamic and hypophyseal receptors for estradiol in pregnant and postpartum ewes. Journal of Animal Science 62:10211028.
Zarco, L., Stabenfeldt, G. H., Kindahl, H., Quirke, J. F. and Granstrom, E. 1984. Persistence of luteal activity in the non-pregnant ewe. Animal Reproduction Science 7:245267.
Zurek, E., Foxcroft, G. R. and Kennelly, J. J. 1995. Metabolic status and interval to first ovulation in postpartum dairy cows. Journal of Dairy Science 78: 19091920.


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Resumption of oestrous and ovarian cyclicity during the post-partum period in autumn-lambing ewes is not influenced by age or dietary protein content

  • L. M. Mitchell (a1), M. E. King (a1), F. E. Gebbie (a1), M. J. Ranilla (a1) and J. J. Robinson (a1)...


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