Effect of melatonin implants on sexual activity in Mediterranean goat females without separation from males

Zarazaga, L.A.; Gatica, M.C.; Celi, I.; Guzmán, José Luis; Malpaux, Benoît

doi:10.1016/j.theriogenology.2009.05.020

Cited by 37 publications

(34 citation statements)

References 32 publications

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“…Similar results have been observed by our group following the insertion of exogenous melatonin implant around the spring equinox, without a previous long-day treatment (Zarazaga et al, 2009a). However, it will be necessary to study the oestrus/ ovulatory response to the LD-M treatment in entire females isolated from males and in contact with males to confirm that the presence of males did not modify the response to the LD-M treatment in entire females.…”

Section: Discussionsupporting

confidence: 85%

“…Together with the data obtained by our group using a treatment with melatonin implants (Zarazaga et al, 2009a), our findings are, as far as we are aware, the first of this type observed in melatonin-implanted goats, because the male effect is a normal practice when melatonin implants are used. The only results in the bibliography, from a similar study of the effectiveness of melatonin implants without separation of the males, are those obtained in ewes (Forcada et al, 1995).…”

Section: Discussionsupporting

confidence: 77%

“…Exogenously administered melatonin from continuous slowrelease implants has been shown to advance the onset of the breeding season in goat males and females by mimicking the stimulatory effect of short days (Chemineau et al, 1992b;Zarazaga et al, 2009a). Traditionally, in Mediterranean latitudes, exogenous melatonin treatment is implanted around the spring equinox and accompanied by a prior separation of males and females for 45 days, inducing a male effect to optimise the response during the anoestrous period, obtaining a higher synchronisation at mount.…”

Section: Introductionmentioning

confidence: 99%

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Artificial long days in addition to exogenous melatonin and daily contact with bucks stimulate the ovarian and oestrous activity in Mediterranean goat females

Zarazaga

Gatica

Celi

et al. 2011

Animal

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One experiment was conducted to determine whether the treatment with artificial long days and exogenous melatonin can induce reproductive activity during spring (seasonal anoestrus) in Mediterranean goats that are in daily contact with bucks and whether this treatment causes a variation in the reactivation of the reproductive activity in the normal breeding season. The experiment started on 4 November 2005 and finished on 27 October 2006. Thirty-four adult and barren does were used, distributed into two groups balanced according to their live weight (LW) and body condition score (BCS). Seventeen females were exposed to long days (16 h of light/day) from 14 November 2005 to 20 February 2006. On 20 February, they received one s.c. melatonin implant (LD-M group) and were exposed to natural photoperiodic changes in an open shed. The other females during the experiment were placed in an open shed under natural photoperiod and remained as the control group (C group). The C and LD-M groups were keeping in contact with males during the whole experiment. During the experiment, the LW, BCS and plasma progesterone concentrations were measured weekly, oestrous activity was tested daily using entire aproned bucks, and ovulation rate was evaluated by laparoscopy 7 days after positive identification of the oestrus. A clear treatment–time interaction was observed for plasma progesterone concentrations ( P,0.001), with a period of high progesterone concentrations during the natural seasonal anoestrus in the LD-M group. Although 94.1% of females in the LD-M group presented ovarian activity during this period, no female in group C did. Resumption of ovarian activity in the subsequent natural breeding season was 2 weeks later in the LD-M group in comparison with group C ( P,0.05). We can conclude that in Mediterranean goat breeding systems, when females are in daily contact with bucks, the treatment with 3 months of long days and melatonin implant at the end of the light photoperiodic treatment can induce ovarian and oestrous activity during the seasonal anoestrus. Finally, this treatment causes a short delay in the subsequent reactivation of ovarian activity in the natural breeding season

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Section: Discussionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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Artificial long days in addition to exogenous melatonin and daily contact with bucks stimulate the ovarian and oestrous activity in Mediterranean goat females

Zarazaga

Gatica

Celi

et al. 2011

Animal

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“…The last suggests that goats might expend 2Á3 months to develop refractoriness. Male presence, have also induced reproductive activity in melatonin-implanted Mediterranean female goats causing a small retardation in the reactivation of reproductive activity during the natural breeding season (Zarazaga et al 2009). …”

Section: Resultsmentioning

confidence: 99%

“…However, it has been emphasised that male 'novelty' could be more important than male isolation ). Male presence has also induced reproductive activity in melatonin-implanted Mediterranean female goats causing a small retardation in the reactivation of reproductive activity during the natural breeding season (Zarazaga et al 2009). Also, it has been observed a 2Á3 months interval from summer solstice (21 June) to ovarian activity resumption in goats exposed to either natural photoperiod or controlled cycles of artificial photoperiod 6Á12 months long (Escobar et al 1997).…”

Section: Introductionmentioning

confidence: 99%

The male effect stimulus positively increased the ovarian and reproductive seasonality in Criollo goats irrespective of a controlled photoperiodic regime

Rincón

Aréchiga

Escobar

et al. 2011

Journal of Applied Animal Research

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Present study evaluated the presence of a sexually active male buck upon the onset of reproductive activity and estrous cycle progression in Criollo goats exposed to a 6-month long controlled photoperiod in a range of 13.4Á 10.6 light-hours per day. Mexican-native (Criollo) goats (n 010) were randomly assigned into 2 groups: (1) goats exposed to a male buck (n 05); (2) goats not exposed to a male buck (n 05). Blood samples were taken weekly to quantify serum-progesterone levels through radioimmunoanalysis. Male exposure increased luteal activity and estrous cycle progression reflected as a higher number of days in luteal activity (4499.05 vs. 32.3920.6); a reduced number of days in anestrous (4.094.8 vs. 51.9928) and a greater number of luteal phases (15.794.4 vs. 11.398.7) without compromising serum progesterone levels (6.890.8 vs. 7.390.5). In conclusion, presence of a sexually active male induced a greater ovarian activity in Criollo goats, shortening seasonal anestrous irrespective of the controlled photoperiodic regime.

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Influence of season and climatic variables on testicular cytology, semen quality and melatonin concentrations in crossbred bucks reared under subtropical climate

et al. 2018

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Seasonality in reproduction and effects of climatic variables on testicular cytology and semen quality in bucks reared under subtropical climatic conditions were not well understood. In the present study, using testicular cytology, semen evaluation and melatonin concentrations assessed over a period of 1 year, we report that bucks reared under subtropical climatic conditions did not show seasonality in reproduction. Climatic variables including temperature, relative humidity, temperature-humidity index (THI), sunshine hours and day length were recorded daily during the whole period of experimentation (one complete year). Ejaculates were collected from crossbred (Alpine X Beetal) males (n = 6) biweekly using artificial vagina, and semen quality (volume, mass activity, sperm concentration, motility, viability, membrane integrity and protamine deficiency) was assessed. To understand the seasonal influence at testicular level, using fine needle aspiration biopsy method, testicular cells were aspirated and different types of cells and testicular cytology indices were quantified. Blood was collected biweekly for estimation of melatonin concentrations. Mass activity was higher (P < 0.05) during rainy season while individual sperm motility and sperm concentration were higher (P < 0.05) during rainy and autumn seasons as compared to other seasons. Sperm functional parameters did not show any differences during different seasons. Sertoli cell count, spermatogenic cell count and testicular indices did not differ among the seasons. Melatonin concentrations also did not differ significantly among the four seasons studied. Among the climatic parameters, THI had significant (P < 0.05) influence on sperm quality. The proportion of Sertoli cell in the testicular cytology had a significant and positive relationship with RH, THI and day length. It was concluded that seasonal variations are less evident in terms of spermatogenesis and semen quality in Alpine X Beetal crossbred bucks reared under subtropical climatic conditions.

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Effect of melatonin implants on sexual activity in Mediterranean goat females without separation from males

Cited by 37 publications

References 32 publications

Artificial long days in addition to exogenous melatonin and daily contact with bucks stimulate the ovarian and oestrous activity in Mediterranean goat females

Artificial long days in addition to exogenous melatonin and daily contact with bucks stimulate the ovarian and oestrous activity in Mediterranean goat females

The male effect stimulus positively increased the ovarian and reproductive seasonality in Criollo goats irrespective of a controlled photoperiodic regime

Influence of season and climatic variables on testicular cytology, semen quality and melatonin concentrations in crossbred bucks reared under subtropical climate

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