Melatonin Treatment in Rams and Their Replacement with Novel Treated Rams Advance First Lambing and Increase Fertility in Sarda Ewe Lambs

Abstract

This study aims to find reliable strategies for advancing first mating and shortening the period from weaning to first lambing in ewe lambs. Sarda ewe lambs (n = 400) were selected from two farms and allocated into four separated groups of 100, all of which were exposed to fertile, adult rams over the course of a 50-day breeding period. The first treatment group (RMR) was exposed to four melatonin-treated rams which were replaced every ten days, whilst the second treatment group (RM) was exposed to four melatonin-treated rams which were not replaced. Alternatively, the first control group (RCR) was exposed to four untreated rams which were replaced every ten days, whilst the second control group (RC) was exposed to four untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The highest fertility rate was recorded in the RMR group (p ≤ 0.05). Shorter DRIL (p ≤ 0.01) and higher lambing concentrations were recorded in the RM and RMR groups as compared to the controls. The findings indicate that melatonin treatment of rams and their replacement at 10-day intervals results in earlier onset of first mating, increased fertility rate in ewe lambs, and a higher number of ewes that lambs in a shorter time frame.

Efficacy of Melatonin Administration Via Different Route on Reproductive Performance and Blood Mineral Profile in Chhotanagpuri Ewe

“…The prolificacy or litter size and average birth weight of lamb did not differ among different treatment groups in the present study. A similar non-significant effect on litter size has also been reported in melatonin-treated Sarda dairy sheep (Cosso et al, 2021;Pulinas et al, 2021). On the contrary , significantly higher litter size was reported in melatonin-treated Kivircik and Charollais ewes by Cevik et al (2017).…”

Endocrine disorders and fertility and pregnancy: An update

“…Melatonin deficiency is correlated with decreased fertility (29, 30), lower levels of sex steroid hormones (30), and decreased survival of embryos after fertilization (31). At the same time, a positive correlation was observed between serum melatonin concentration and fertility (32)(33)(34)(35)(36). Administration of exogenous melatonin is associated with a higher percentage of maintained pregnancies (37).…”

Effects of melatonin implants on reproductive performance of dairy sheep and dairy goats

“…In small ruminants, where libido levels varies with depending on the season, reproductive performance can be increased in male animals with melatonin implants (Casao et al, 2010;Muir et al, 1993;Zarazaga et al, 2013). In addition, it can be used to induce oestrus in female animals by applying melatonin implants to male animals in the breeding season or out of breeding season (Cosso et al, 2021;Zarazaga et al, 2011Zarazaga et al, , 2019. Controversial reports exist on the effects of melatonin implantation in rams and bucks on oestrus and fertility of female animals (Muir et al, 1993;Palacin et al, 2008;Zarazaga et al, 2013).…”