Plasma prolactin variations and onset of ovarian activity in lactating anestrous goats given melatonin

Prandi, A.; Romagnoli, Giorgia; Chiesa, F.; Tamanini, Carlo

doi:10.1016/0378-4320(87)90066-2

Cited by 16 publications

(10 citation statements)

References 19 publications

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“…These variations suggest the presence of a seasonal rhythm of prolactin in the camel, which was proposed previously by other authors ( 42 , 50 , 51 ). Our results on camel prolactin patterns are close to those observed in goats, with a similar decrease of plasma concentrations in early summer followed by an increase in early Fall ( 15 , 52 ).…”

Section: Discussionsupporting

confidence: 86%

“…Melatonin implant treatment of female camels in the early anestrus season induced significant effects on the ovarian activity and plasma estradiol-17β concentrations and on the prolactin secretion from the adenohypophysis. Plasma prolactin concentrations measured in this study did not exceed 2.8 ng/ml and seem to be very low compared to other ruminants, such as goats ( 15 ), mouflon, and sheep ( 40 ). These results are consistent with those of previous studies that show low concentrations of plasma prolactin in camels ( 41 , 42 ).…”

Section: Discussioncontrasting

confidence: 60%

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Effect of Melatonin Implants during the Non-Breeding Season on the Onset of Ovarian Activity and the Plasma Prolactin in Dromedary Camel

et al. 2018

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To examine a possible control of reproductive seasonality by melatonin, continual-release subcutaneous melatonin implants were inserted 4.5 months before the natural breeding season (October–April) into female camels (Melatonin-treated group). The animals were exposed to an artificial long photoperiod (16L:8D) for 41 days prior to implant placement to facilitate receptivity to the short-day signal that is expected with melatonin implants. The treated and control groups (untreated females) were maintained separately under outdoor natural conditions. Ovarian follicular development was monitored in both groups by transrectal ultrasonography and by plasma estradiol-17β concentrations performed weekly for 8 weeks and then for 14 weeks following implant insertion. Plasma prolactin concentrations were determined at 45 and 15 days before and 0, 14, 28, 56, and 98 days after implant insertion. Plasma melatonin concentration was determined to validate response to the artificial long photoperiod and to verify the pattern of release from the implants. Results showed that the artificial long photoperiod induced a melatonin secretion peak of significantly (P < 0.05) shorter duration (about 2.5 h). Melatonin release from the implants resulted in higher circulating plasma melatonin levels during daytime and nighttime which persisted for more than 12 weeks following implants insertion. Treatment with melatonin implants advanced the onset of follicular growth activity by 3.5 months compared to untreated animals. Plasma estradiol-17β increased gradually from the second week after the beginning of treatment to reach significantly (P < 0.01) higher concentrations (39.2 ± 6.2 to 46.4 ± 4.5 pg/ml) between the third and the fifth week post insertion of melatonin implants. Treatment with melatonin implants also induced a moderate, but significant (P < 0.05) suppressive effect on plasma prolactin concentration on the 28th day. These results demonstrate that photoperiod appears to be involved in dromedary reproductive seasonality. Melatonin implants may be a useful tool to manipulate seasonality and to improve reproductive performance in this species. Administration of subcutaneous melatonin implants during the transition period to the breeding season following an artificial signal of long photoperiod have the potential to advance the breeding season in camels by about 2.5 months.

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Section: Discussionsupporting

confidence: 86%

Section: Discussioncontrasting

confidence: 60%

Effect of Melatonin Implants during the Non-Breeding Season on the Onset of Ovarian Activity and the Plasma Prolactin in Dromedary Camel

et al. 2018

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“…There are many reports about effects of melatonin on reproduction in the ewes (Bastan 1995) and goats (Prandi et al. 1987; Deveson et al.…”

Section: Introductionmentioning

confidence: 99%

Effects of CIDR‐G and Melatonin Implants, and their Combination on the Efficacy of Oestrus Induction and Fertility of Kilis Goats

Çetin

Sagcan²,

Güngör

et al. 2009

Reprod Domestic Animals

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The objective of this study was to compare the efficiency of oestrus induction protocols on Kilis dairy goats kept on a goat farm situated close to Kilis, Turkey. Eighty goats were assigned randomly into four groups of 20 animals each in a factorial arrangement: (i) untreated control (CON), (ii) melatonin implant (MEL), (iii) CIDR-G (CIDR) and (iv) melatonin implant plus CIDR-G (MC). Experiments were performed in mid-anoestrus season under natural photoperiod environment. The differences among treatment groups in oestrus response were significant. Oestrus response was higher in the MC group than in other groups (p < 0.05). A significant difference was observed in the time interval from cessation of treatment to the onset of oestrus among treatments. The CIDR-G treatment reduced intervals from buck introduction to oestrus. The time to onset of oestrus in both the MC and CIDR groups was significantly shorter, compared with the MEL and CON groups (p < 0.05). The number of does kidding and fertility were not different among treatment groups (p > 0.05). Fecundity was similar among goats in all groups. Prolificacy and twining rates showed similar trends as fecundity rates, with no differences (p > 0.05) between treatments. The results of this study showed that oestrus in Kilis does can be effectively induced by using melatonin and CIDR combined treatment, and fertility will not be adversely affected. However, this treatment did not improve fecundity, prolificacy and twining rates.

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“…Stimuli such as feeding, unfamiliar physical stimuli, teasing, and mating can cause acute changes in PRL levels (Buttle 1974). High PRL levels in goats during the non-breeding season do not prevent ovulation induced by administration of fluorogestone acetate and gonadotropins (Prandi et al 1987). Considerable individual variations in PRL levels and in the timing and pattern of PRL peaks during the estrous cycle were found in goats (Błaszczyk et al 2004) and sheep (Lamming et al 1974).…”

Section: Discussionmentioning

confidence: 96%

Effect of intravaginal fluorogestone acetate sponges on prolactin levels of Damascus-local cross breed goats

Talafha

Ababneh

Khalifeh

et al. 2014

Trop Anim Health Prod

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The effect of intravaginal fluorogestone acetate (FGA) sponges on prolactin levels (PRL) and correlations between PRL and milk somatic cell count (SCC) and steroid hormones levels of Damascus-local cross goats during transitional period to anestrous were investigated in this study. Fifty-six goats were assigned to three groups. Group 1 (FGA, n = 19) was treated with 40 mg FGA and equine chorionic gonadotropin (600 IU, i.m.) at time of sponge withdrawal (day 0). Group 2 (FGA-PGF; n = 19) was treated similar to group 1 but was also injected with dinoprost tromethamine (naturally occurring PGF2α) (10 mg, i.m.) on day 0. Control goats (n = 18) were left untreated. On day 0, five fertile bucks were turned in with all goats. Milk and blood samples were collected on days -13 (day of sponge insertion), -6, 0, 1, 2, 7, 13, and 20. Prolactin levels were at lowest values on day -13 of the study and increased (p < 0.05) from day -6 to day 20 in all groups. A significant positive correlation (p < 0.05) between PRL and progesterone and between PRL and estradiol levels was found in this study. No significant correlation was found between PRL and SCC of all groups during the study except on days 2 and 20 where PRL levels were correlated (p < 0.05) with SCC of left udder halves of FGA group. In conclusion, estrus induction with FGA resulted in significant increase in PRL. A positive correlation was found between PRL and steroid hormones, but there was no correlation between PRL and goat milk SCC.

show abstract

Plasma prolactin variations and onset of ovarian activity in lactating anestrous goats given melatonin

Cited by 16 publications

References 19 publications

Effect of Melatonin Implants during the Non-Breeding Season on the Onset of Ovarian Activity and the Plasma Prolactin in Dromedary Camel

Effect of Melatonin Implants during the Non-Breeding Season on the Onset of Ovarian Activity and the Plasma Prolactin in Dromedary Camel

Effects of CIDR‐G and Melatonin Implants, and their Combination on the Efficacy of Oestrus Induction and Fertility of Kilis Goats

Effect of intravaginal fluorogestone acetate sponges on prolactin levels of Damascus-local cross breed goats

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