Importance of non-olfactory ram stimuli in mediating ram-induced ovulation in the ewe

Pearce, G.P.; Oldham, C.M.

doi:10.1530/jrf.0.0840333

Cited by 85 publications

(40 citation statements)

References 22 publications

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“…In a similar way, in ewes in contact with rams, the introduction of new males induced ovulation in a similar percentage of females (85%), than those that had previously been totally separated from the rams (86%) [16]. Finally, in ewes, Pearce and Oldham [10] found that between 89% and 95% of ewes remaining in anestrus after 65 days in contact with rams, ovulated 4 days after the introduction of novel rams. However, these results should be carefully considered before assuming that the introduction of new males may not be effective in other breeds or periods.…”

Section: Previous Separation Between Sexesmentioning

confidence: 72%

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Importance of the signals provided by the buck for the success of the male effect in goats

et al. 2006

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-Under temperate and subtropical latitudes, ewes and goats display a reproductive seasonal pattern and their sexual activity during the anestrous period can be stimulated and synchronized by the introduction of males in the group, which is called the "male effect". The response of females to the male effect in the middle of the anestrous season is weak or absent. This failure may be due to the inability of the female to respond to males, as a result of a refractoriness of the female to the male stimulus. But, it may also be due to a low quality stimulus provided by the male which is, as the females, in seasonal rest. We tested this latter hypothesis in seasonally inactive goats kept under subtropical conditions by comparing the use of males with their sexual behavior stimulated or not by photoperiodic treatments. Treated males were able to induce estrous activity of females during the whole anestrus season. We have also determined that previous separation of the males and continuous contact during teasing are not absolute requisites when active bucks are used. While odor from the male and its sexual behavior play a primary role in inducing ovulation, vocalizations appear to facilitate the display of the does' estrous. It remains to be determined to which extent these conclusions apply under temperate latitudes and with more seasonal breeds.goat / male effect / buck vocalizations / male odor / sexual behavior / photoperiodic treatment

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Section: Previous Separation Between Sexesmentioning

confidence: 72%

“…Pearce and Oldham [10] exposed ewes to various degrees of contact with rams (e.g. full physical contact, contact through an openwork fence, contact through an opaque fence, contact with rams' wool in facial masks or complete isolation from males).…”

Section: Degree Of Contact Between the Two Sexesmentioning

confidence: 99%

Importance of the signals provided by the buck for the success of the male effect in goats

et al. 2006

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“…The females in these groups were respectively on day 0, 3, 8, 12 or 14 on July 17 th , when two adult Pelibuey rams were introduced to the pen and left continuously there until all the ewes had shown their following estrus. During the experiment each of the rams remained in a 4 × 2 m mesh-fence pen located within the pen where the ewes of the experimental groups were kept, since it has been reported that total contact through a clear mesh fence is sufficient to induce ovulation in a high proportion of anestrous ewes (Pearce and Oldham 1988). Estrus detection was carried out three times a day for periods of 30 min at 8:00, 14:00, and 20:00 h starting on the day of the first exposure to the males.…”

Section: Methodsmentioning

confidence: 99%

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Jarquin¹,

Roldán²,

Zarco³

et al. 2014

CZECH J ANIM SCI

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Forty non-lactating, cyclic adult Pelibuey ewes were randomly divided into six groups. Estrus was synchronized within each group using intravaginal sponges and prostaglandin F2α injection at the time of the sponge removal. The sponges were inserted and removed on different dates in each group, but all the groups except the control one were first exposed to rams on the same date (July 17 th ), so that at the time of the first exposure the ewes were either on day 0 (group D0; n = 7), 3 (group D3; n = 7), 8 (group D8; n = 7), 12 (group D12; n = 7) or 14 (group D14; n = 7) of their synchronized estrous cycle. Thereafter the ewes of these groups remained continuously exposed to the males until all the females showed estrus. The ewes in the control group (CG; n = 5) remained isolated from all the males, except for 5-minute periods at the time of estrus detection, which was carried out three times a day. Progesterone concentrations were determined in plasma samples taken daily from two days before the initial exposure to the males until the onset of the next estrus. There were no differences in estrous cycle length between the groups exposed to rams and the control group (P > 0.05). The interval from the assumed onset of the estrous cycle (48 h after sponge removal) until the occurrence of luteolysis was not different between the control group and any of the groups exposed to the males. The interval from luteolysis to estrus was not modified by exposure to the males (P > 0.05). Estrus duration was shorter (P < 0.06) in the control group than in group D3. It is concluded that the exposure of cyclic Pelibuey ewes to males does not advance the time of luteolysis and does not affect the length of the estrous cycle. Therefore, the male effect does not synchronize the next estrus of cyclic Pelibuey ewes.

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“…Whereas this effect of the male seen in ewes is evident during the late anestrous season, only a few ewes show this male effect during the early and mid-anestrous seasons in the high and midlatitude regions [1][2][3][4].…”

mentioning

confidence: 94%

Reproductive Response in Seasonally Anestrous Suffolk Ewes After a Treatment Combining Melatonin Feeding and the 'Male Effect'.

Kusakari

Ohara

1996

Journal of Reproduction and Development

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Abstract. Fifty-eight anestrous Suffolk ewes, raised in Hokkaido, were randomly divided into 2 groups, with or without melatonin feeding as follows: Group 1 ewes (n=33) were fed melatonin daily for 45-90 days from the early or mid-anestrous season (late March to June) and Group 2 ewes (n=25) were not. All the ewes were introduced to fertile rams for 6-12 weeks starting between April and July. The incidence of estrus in Group 1 ewes during the joining of the rams was higher than that in Group 2 ewes (100% vs. 32%, p<0.01). The first estrus in Group 1 was observed 7-10 weeks after the beginning of melatonin feeding. The intervals from the ram introduction to the onset of estrus in 8 ewes that showed estrous response in Group 2 were not distinguishable from those in the ewes fed melatonin for over 5 weeks before the ram introduction in Group 1. The conception rate in Group 1 was higher than that in Group 2 (93.9% vs. 8%, p<0.01). The prolificacy in the Group 1 and 2 ewes was 148% and 8%, respectively. These results indicates that Suffolk ewes were responsive to the 'male effect' 5 weeks onward after the start of the melatonin feeding during early and mid-anestrous season.

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Importance of non-olfactory ram stimuli in mediating ram-induced ovulation in the ewe

Cited by 85 publications

References 22 publications

Importance of the signals provided by the buck for the success of the male effect in goats

Importance of the signals provided by the buck for the success of the male effect in goats

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Reproductive Response in Seasonally Anestrous Suffolk Ewes After a Treatment Combining Melatonin Feeding and the 'Male Effect'.

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