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ORAL PRESENTATION / SÖZLÜ SUNUM

Comparison of the Effects of Melatonin and Tryptophan-Containing Feeds Added to the
Off-Season Ration and Regulin (Melatonin) Application on Estrus in Karacabey Merino
Sheep

Muharrem SATILMIŞ 1,* Murat ER
1

1 İzmir Bakırçay University, Menemen Vocational School, Department of of Veterinary, İzmir, TÜRKIYE

*Correspound Author: muharrem.satilmis@bakircay.edu.tr

In this study, the effects of dietary supplementation with melatonin- and tryptophan-
containing feeds and the administration of subcutaneous Regulin® (Melatonin) implants on
estrus induction and pregnancy rates were compared within the scope of the Karacabey
Merino sub-project of the National Small Ruminant Breeding Project conducted in Balıkesir
Province, Türkiye. Reproductive performance records of 60 Karacabey Merino ewes, aged 3–
7 years, raised within the framework of the project, were used. The study evaluated
interventions applied during the non-breeding season (February–April) prior to ram
introduction in order to induce estrus. Animals that received no treatment other than grazing
and routine feeding practices were designated as the control group (Group K). In addition to
routine feeding, animals whose diet was supplemented with oats, soybean meal, wheat,
maize, and grape pomace were assigned to experimental group 1 (Group Ç1). Animals that,
similar to the control group, did not receive additional dietary supplementation but were
treated with Regulin implants were designated as experimental group 2 (Group Ç2).
According to the farm records, ewes in Group Ç1 were fed a concentrate mixture (25% barley
+ 20% maize + 25% oats + 20% soybean meal + 10% grape pomace) at 150–200 g per
head daily beginning one month prior to ram introduction, increasing to 500 g per head one
week later. Ewes in Group E2 received a subcutaneous Regulin implant containing 18 mg
melatonin. Thirty days after treatment, rams were introduced freely into the groups for 40
days. One month after ram withdrawal, pregnancy was diagnosed by ultrasonography, and
pregnancy rates were analyzed using the Least Squares method. Pregnancy rates in Groups
K, E1, and E2 were found to be 77.8%, 95.0%, and 90.9%, respectively (P>0.05). In
conclusion, although the differences between groups were not statistically significant, the
higher estrus response achieved through the melatonin- and tryptophan-enriched feeding
program compared to Regulin treatment is considered noteworthy.

Keywords: Estrus, Karacabey Merino, melatonin, regulin, tryptophan.

Acknowledgement: This study was conducted in Balıkesir as part of the "Public Breeding of
the Karacabey Merino Sheep Breed Sub-Project" supported by the General Directorate of
Agricultural Research and Policies.

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