Risposta dell’attività riproduttiva al trattamento con melatonina in pecore di razza Sarda con differenti BCS

The aim of this research was to investigate the influence of BCS (Body Condition Score) on the
reproductive response to the male effect in Sarda ewes treated with melatonin implants. For the research 80
adult ewes at an average age of 4,2 ± 1,3 years giving birth to lambs in November, were used. The animals
were divided into four groups (n = 20 per group) as follows: group A, animals with BCS > 2.5 treated on
April 20th with a subcutaneous implant (at the base of the left ear) of 18 mg of melatonin (Melovine®, Ceva
Vetem); group B, animals with BCS > 2.5 untreated; group C, animals with BCS <2.5 treated on April 20th
with the same implant used in group A; group D, animals with BCS <2.5 untreated. On May 25th two males
of proved fertility were introduced in each group. From May 25th to July 7th, blood samples were collected
weekly from each animal for plasma progesterone dosage. Moreover their delivery dates were recorded. All
the animals of the group A (100%), the 55% of the B group, the 60% of the C group and the 35% of the D
group were cyclic within the first 28 days after male introduction. At the end of the experiment all the
animals of the A and C groups were cyclic, vs the 90% of the B group and the 75% of the D group. In
conclusion, BCS influences considerably the reproductive response to male effect and melatonin improves
reproductive efficiency.