Optimum use of subcutaneous melatonin implants to enhance the reproductive performance of seasonal and non-seasonal sheep joined in spring and early summer

Williams, A.E.; McPhee, S. R.; Reeve, JL; Staples, L. D.

doi:10.1016/0378-4320(92)90012-3

Cited by 34 publications

(26 citation statements)

References 21 publications

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“…Indeed, when melatonin is administered to female sheep (ewes) during the time of year when they are not ovulating, it can actually promote the re‐initiation of ovulation and subsequent fertility. My group used these findings to develop a veterinary drug preparation of melatonin (Regulin; Ceva Animal Health Pty Ltd., Glenorie, NSW, Australia) that produces continuous levels of melatonin for more than 10 weeks in the night‐time physiological range and which is used to advance the start of the fertile period and increase their ovulation rate and offspring numbers . It is still available as a registered veterinary drug in Australia and elsewhere.…”

Section: What Does Melatonin Do?mentioning

confidence: 99%

Potential safety issues in the use of the hormone melatonin in paediatrics

Kennaway

2015

J Paediatrics Child Health

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Melatonin is a hormone produced by the pineal gland during the night in response to light/dark information received by the retina and its integration by the suprachiasmatic nucleus. When administered to selected populations of adults, in particular those displaying delayed sleep phase disorder, melatonin may advance the time of sleep onset. It is, however, being increasingly prescribed for children with sleep disorders despite the fact that (i) it is not registered for use in children anywhere in the world; (ii) it has not undergone the formal safety testing expected for a new drug, especially long-term safety in children; (iii) it is known to have profound effects on the reproductive systems of rodents, sheep and primates, as well as effects on the cardiovascular, immune and metabolic systems; and (iv) there is the potential for important interactions with drugs sometimes prescribed for children. In this review, I discuss properties of melatonin outside its ability to alter sleep timing that have been widely ignored but which raise questions about the safety of its use in infants and adolescents.

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Section: What Does Melatonin Do?mentioning

confidence: 99%

Potential safety issues in the use of the hormone melatonin in paediatrics

Kennaway

2015

J Paediatrics Child Health

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“…Information on the photoperiod is conveyed to the neuroendocrine system via the circadian secretion of melatonin from the pineal gland (Bittman et al, 1983). The administration of this hormone during the spring via the use of continuous, slow-release implants has been shown to advance the onset of the breeding season in goats (Chemineau et al, 1992;Williams et al, 1992). Usually, melatonin is provided following the separation of the sexes for 45 days (Zarazaga et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

The reproductive performance of female goats treated with melatonin is not improved after introduction to bucks displaying springtime sexual activity if these does are experiencing decreasing body weight/condition score

Zarazaga

Gatica

Gallego-Calvo

et al. 2017

Animal Reproduction Science

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Title: The reproductive performance of female goats treated with melatonin is not improved after introduction to bucks displaying springtime sexual activity if these does are experiencing decreasing body weight/condition score Authors: L.A. Zarazaga, M.C. Gatica, L. Gallego-Calvo, J.L. Guzmán PII:S0378-4320 (16) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Reproductive activity of bucks is reduced in spring when male effect is used.  The response to the male effect decreases when females have an inadequate food supply.  Melatonin might reduce the negative effect of decreasing body weight-condition score.  Greater fecundity, fertility and productivity were observed in gain-melatonin does.  Plasma glucose and IGF-1 concentrations could explain the better reproductive results.3 AbstractThe aim of the present work was to determine whether treatment with melatonin modifies the reproductive response of female goats experiencing increasing or decreasing body weight (BW)/body condition score (BCS) when introduced to bucks displaying springtime sexual activity. During natural anoestrus, 53 does were isolated from bucks for a period of 42 days and distributed into two groups: 1) low BW/low BCS animals (N=24) (LLg group), which were fed 1.9 times their maintenance requirements so they would experience increasing BW and BCS; and 2) high BW/high BCS animals (N=29) (HHl group), which were fed 0.4 times their maintenance requirements so they would experience decreasing BW and BCS. Half of each group was treated, or not, with melatonin (LLg+Mel N=12, HHl+Mel N=15, LLg-Mel N=12 and HHlMel N=14). On 6th May they were introduced to six males, showing natural sexual activity, fitted with marking harnesses (thus permitting the detection of oestrous activity). The ovulation rate was assessed by transrectal ultrasonography and confirmed via the plasma progesterone concentration (measured twice per week in blood samples). Plasma glucose, IGF-1 and non-esterified fatty acid concentrations were also determined, along with the conception rate, fertility, prolificacy and productivity of the does. LH concentrations and LH pulsatility were also recorded in the hours around introduction to the males. 'Oestrous plus ovulation' was observed only in does treated with melatonin. A higher conception rate and greater fertility and productivity were observed among the LLg+Mel does. These females showed higher glucose and IGF-1 concentrations after the introduction of the males. LH concentrations increased after male introduction independent of all other conditions. In conclusion, the present results show that treatment w...

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“…English et al (1986) reported that ovarian activity can commence 5-10 weeks earlier as a result of melatonin feeding or melatonin implants when compared to control ewes maintained in natural photoperiod where the treatment is begun in June. Williams et al (1992) pointed out that a single treatment with a subcutan melatonin implant, commencing 30-40 days prior to ram introduction in spring or early summer, maximizes the potential advantages of ram introduction.…”

Section: Discussionmentioning

confidence: 99%