Seasonal and hormonal control of pulsatile LH secretion in the dairy goat (Capra hircus)

Chemineau, Philippe; Martin, Graeme; Saumande, J.; Normant, Elisabeth

doi:10.1530/jrf.0.0830091

Cited by 43 publications

(20 citation statements)

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“…Additionally, the dominant follicle of the third wave was smaller than that observed in the fourth and five waves. These observation support the negative action of P4 on follicular growth suggested by Chemineau et al (1988), and may be due to the differences in P4 plasmatic levels between the middle and the onset, or the end, of the estrous cycle as proposed by Ginther and Kot (1994). The shorter length of the growing phase of the dominant follicle in the second wave than the first and fifth waves and the greater length of the regression phase of the dominant follicle in first wave, with the exception of the fifth wave, also support these assumptions.…”

Section: Discussionsupporting

confidence: 88%

Follicular dynamics in Serrana goats

Simões

Almeida

Valentim

et al. 2006

Animal Reproduction Science

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Twenty-two Serrana goats were studied through two successive estrous cycles in order to characterize their follicular dynamics during the breeding season. The ovaries of the goats were scanned daily by realtime ultrasonography and all follicles ≥3 mm were measured and classified. The data were classified by the number of follicular waves per goat to test the hypothesis that temporal and morphological differences between the last follicular wave of an ovary, irrespective of ovulation, will affect the selection of the next ovulatory wave.The mean interovulatory interval was 20.7 ± 1.0 days (mean ± S.D.). Three to five waves per estrous cycle were observed and 61.3% (19/31) of cycles had four waves. In estrous cycles with four waves, the day of onset of the first, second, third and fourth wave was 1.4 ± 1.0, 6.9 ± 1.4, 11.6 ± 1.8 and 16.8 ± 1.6, respectively. No differences (P > 0.05) were found between the day of onset of the first and second waves for estrous cycles with three, four or five waves. However, the day of onset of the third and fourth waves occurred later when the number of waves per estrous cycle increased (P < 0.001). The duration of the interwave interval (time between the day of onset of two consecutive waves) was longer when the second wave was ovulatory. The length of the growth phase (2.4 ± 0.9 days) and size (5.9 ± 0.7 mm) of the dominant follicle in the second wave were lower (P < 0.01) than for the first wave (3.3 ± 1.2 days and 6.6 ± 0.9 mm, respectively) and the fifth wave (4.1 ± 1.2 days and 7.5 ± 1.0 mm, respectively). Within pairs of ovaries, the onset of the last wave occurred later (P < 0.05) and was less variable in ovulatory ovaries (day 16.8 ± 1.4, n = 20) than in anovulatory ovaries (day 15.1 ± 3.7, n = 20). The length of the growing phase was longer (P < 0.001) in the last waves of ovulatory ovaries (3.1 ± 0.9 days) than in the last waves of anovulatory ovaries (1.7 ± 0.8 days). These results support the hypothesis that the day of onset of the ovulatory wave is related to or, at least, conditioned by the luteolysis and the decrease in plasma progesterone. * Corresponding author. Tel.: +35 1259350417; fax: +35 1259350480. J. Simões et al. / Animal Reproduction Science 95 (2006) 16-26 17 In summary, the estrous cycle of Serrana goats is characterized by sequential follicular wave growth with a great variability in their onset and duration, with the exception of the ovulatory wave. The temporal and morphological differences observed in the last wave of estrous cycle provide strong evidence for the role of progesterone in their regulation.

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Section: Discussionsupporting

confidence: 88%

Follicular dynamics in Serrana goats

Simões

Almeida

Valentim

et al. 2006

Animal Reproduction Science

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“…In all cases, kids attained puberty during the first breeding season after birth. This result indicates a strong seasonal effect on the onset of reproductive activity in this species, with photoperiod apparently playing a key role, since in sheep and goats the effects of photoperiod on reproduction are mediated by similar physiological mechanisms (Chemineau et al, 1988).…”

Section: Discussionmentioning

confidence: 73%

Nutrition level and season of birth do not modify puberty of Payoya goat kids

Zarazaga

Guzmán

Domínguez

et al. 2009

Animal

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This study analysed the effect of level of nutrition and date of birth (age) on the onset of puberty in Payoya she-kids born in autumn (November) or in winter (February). Two experiments were conducted to examine pubertal events at the onset of puberty. For each date of birth (age), two experimental groups were used, differing on the level of nutrition. Groups were balanced for live weight (LW) and body condition score (BCS). For the first experiment (goat kids born in autumn), 27 Payoya she-kids were used: high-nutrition group (H1, n513) and control group (C1, n514). For the second experiment (goat kids born in winter), 25 Payoya she-kids were used: high-nutrition group (H2, n513) and control group (C2, n512). In both experiments, the level of feeding was adjusted weekly according to LW so that the animals would gain about 50 and 100 g per day for C and H groups, respectively. Oestrus was tested daily using young aproned bucks. Ovulation rate was assessed by laparoscopy 7 days after identification of oestrus. Plasma samples were obtained weekly for progesterone assay. LW and BCS were recorded weekly. No effect of nutrition level or birth date (Experiment 1 v. 2) on the date of the first ovarian activity or the first detected oestrus was observed. No effect of nutrition on LW or BCS at the first detected oestrus was observed. Birth date influenced significantly the LW of the animals at the onset of ovarian activity or first oestrus (P,0.001). Irregular sexual activity was frequently observed before the first oestrus (74.7% and 48.0% of the first reproductive activity was irregular for Experiments 1 and 2, respectively). No effect of nutrition level or birth date on ovulation rate was observed. Ovulation rate at first oestrus was influenced by LW in November-born goat kids (1.0660.06 v. 1.6760.21 corpora lutea for LW,30 and >30 kg, respectively, P,0.01). These results demonstrate that the age at puberty was very dependent upon the season of birth in Payoya goat kids, and that there could be some benefit in breeding November-born goat kids at a higher LW to obtain a higher prolificacy at the first kidding as a consequence of a higher ovulation rate at puberty

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“…In Australian and Mexican bucks adapted to subtropical latitudes, the breeding season starts in late spring and ends in late autumn (Walkden-Brown et al, 1994;Delgadillo et al, 1999), while the breeding season of does of such breeds lasts from early autumn to late winter (Restall, 1992;Duarte et al, 2008). In the temperate and subtropical breeds mentioned above, photoperiod is the main environmental factor responsible for reproductive seasonality (Chemineau et al, 1988;Delgadillo et al, 2004). Therefore, artificial photoperiod treatments could be used to modify the reproductive seasonality in males and females.…”

Section: Introductionmentioning

confidence: 99%

Stimulation of reproductive activity in anovulatory Alpine goats exposed to bucks treated only with artificially long days

Delgadillo

Vélez

2010

Animal

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Two experiments were conducted in a subtropical latitude to determine the response of Alpine male goats to a treatment with artificially long days (experiment 1), and the response of anovulatory lactating Alpine does exposed to males treated only with artificially long days (experiment 2). In experiment 1, one group of males was kept under natural photoperiod ( n 5 4) while another was exposed to 2.5 months of artificially long days (16 h of light/day) from 1 December ( n 5 4). Plasma testosterone concentrations were determined weekly. Intensity of odor of males was determined every 2 weeks. Sexual behavior of bucks was observed during 3 days about 90 days after the end of the long day treatment. A treatment-by-time interaction was detected for testosterone secretion ( P , 0.001). In control males, low plasma concentrations of testosterone were observed from March to June. In contrast, in long-day treated males, high levels of testosterone were observed from March to June ( P , 0.05). A treatment-by-time interaction was detected for the intensity of male odor ( P , 0.01). The male odor was stronger in long-day treated bucks than in untreated ones from March to June ( P , 0.05). The number of ano-genital sniffing, nudging and flehmen was greater in long-day treated males than in untreated ones when exposed to anestrous does ( P , 0.05). In experiment 2, one group of males was left under natural photoperiod variations ( n 5 5) and the other ( n 5 5) was submitted to the same photoperiodic treatment described in experiment 1. On 3 May, three untreated and three long-day treated males were put in contact with anestrous Alpine does left under natural photoperiod. Fertility was higher in does exposed to light-treated males (36/45, 80%) than those in contact with untreated ones (3/45, 7%; P , 0.05). Prolificacy was similar ( P . 0.05) in does exposed to treated (1.8 6 0.1) and untreated males (1.7 6 0.3). These results indicate that the sexual activity of Alpine male goats raised in subtropical latitudes can be induced using only artificially long days and that such males are effective in stimulating reproductive activity in anovulatory females in late spring.Keywords: seasonal anestrous, photoperiod, male effect, sexual behavior, ovulation ImplicationsThese results demonstrated that, in lactating Alpine female goats raised in subtropical latitudes, sexual activity can be induced during the anestrous season by exposure to males rendered sexually active by a long-day treatment. These results have an important practical application because they show that in subtropical latitudes the photoperiodic treatment of females is not necessary to stimulate their reproductive activity by the male effect, in contrast to that reported for the same breed under temperate latitudes.

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Seasonal and hormonal control of pulsatile LH secretion in the dairy goat (Capra hircus)

Cited by 43 publications

References 20 publications

Follicular dynamics in Serrana goats

Follicular dynamics in Serrana goats

Nutrition level and season of birth do not modify puberty of Payoya goat kids

Stimulation of reproductive activity in anovulatory Alpine goats exposed to bucks treated only with artificially long days

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