First postpartum ovulations and corpora lutea in ewes which lamb in the breeding season

Sharpe, P.; McKibbin, P.E.; Murphy, Bruce D.; Manns, J. G.

doi:10.1016/0378-4320(86)90140-5

Cited by 19 publications

(5 citation statements)

References 39 publications

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“…Cognié, unpublished data). However, in the present work as well as in other studies in naturally ovulating ewes (Sharpe et al, 1986;Schirar et al, 1989) and cows (Hinshelwood et al, 1982) a higher incidence of abnormal luteal phases was observed in non-suckling than in suckling ewes. This finding, and the small delay (6 days) in the resumption of normal oestrous cycle, suggests that suckling, rather than delaying the return of potential fertility, primarily affects the conditions of this return by acting as a protective or a regulatory mechanism to ensure an harmonious post-partum resumption of ovarian activity.…”

Section: Discussioncontrasting

confidence: 51%

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes

Schirar

Cognie²,

Louault³

et al. 1989

Reproduction

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Section: Discussioncontrasting

confidence: 51%

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes

Schirar

Cognie²,

Louault³

et al. 1989

Reproduction

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“…The occurrence of short cycles after first ovulation in this study was not surprising, as short cycles occur spontaneously before oestrus in prepubertal heifers (Berardinelli et al, 1979) and ewe lambs (Keisler et al, 1983), and following parturition in cows and ewes Sharpe et al, 1986). Follicular development during short cycles is associated with the development of a single dominant follicle (Savio et al, 1990).…”

Section: Discussionmentioning

confidence: 76%

Induced ovulation of the first postpartum dominant follicle in beef suckler cows using a GnRH analogue

Crowe¹,

Goulding²,

Baguisi³

et al. 1993

Reproduction

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There is a low incidence of ovulation of the first dominant follicle that develops in the early postpartum period of beef suckler cows, which prolongs the interval from calving to first ovulation. The objective of this study was to determine whether a single injection of a GnRH analogue would ovulate the first postpartum dominant follicle. Limousin x Friesian beef suckler cows were assigned at parturition, over two years (16 cows in year 1; 19 cows in year 2), to one of three treatments: (1) untreated (control; n = 12), (2) GnRH analogue (20 micrograms buserelin i.m.) administered in the growing-plateau phase of the first postpartum dominant follicle (GnRH-G; n = 12) and (3) GnRH analogue administered in the declining phase of the first postpartum dominant follicle (GnRH-D; n = 11). From day 8 or 9 post partum, the ovaries of each cow were examined daily by ultrasound to determine the time of GnRH injection and ovulation. Blood samples were collected daily for progesterone measurement to confirm ovulation and in year 2 to determine the duration of the first oestrous cycle. The mean (+/- SEM) number of days from parturition to development of the first dominant follicle was 11.0 +/- 0.3, 10.3 +/- 0.5 and 10.1 +/- 0.7 for cows assigned to treatments 1-3, respectively (P > 0.05). The proportion of cows ovulating the first dominant follicle was higher (P < 0.05) following GnRH treatment (12 of 12 and 7 of 10; GnRH-G and GnRH-D, respectively) than with controls (2 of 12).(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Sharpe et al (1986) reported that corpora lutea obtained from post-partum ewes are lighter and have lower LH receptor populations than those obtained from cyclic ewes, while Wallace (1995) demonstrated a lower steroidogenic capacity in vitro. Sharpe et al (1986) reported that corpora lutea obtained from post-partum ewes are lighter and have lower LH receptor populations than those obtained from cyclic ewes, while Wallace (1995) demonstrated a lower steroidogenic capacity in vitro.…”

Section: Discussionmentioning

confidence: 99%

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

Mitchell¹,

King²,

Gebbie³

et al. 1998

Anim. Sci.

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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 X 2 factorial design. Diets comprised ad 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 strawbedded pens under natural photoperiod at 57 °N and their live weights and body condition scores were assessed at 2week 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) 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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First postpartum ovulations and corpora lutea in ewes which lamb in the breeding season

Cited by 19 publications

References 39 publications

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes

Induced ovulation of the first postpartum dominant follicle in beef suckler cows using a GnRH analogue

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

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