Effetto del trattamento con impianti di melatonina sull’efficienza riproduttiva nella capra Sarda

Aim of the present study was to advance the reproductive activity in Sarda breed goats and to obtain lambing in Autumn, through melatonin administration in May. Two-hundred adult goats, aging between 3.8 and 7.6 years, with a BCS>2.5, were selected and subdivided into two groups (named M and C), each of 100 animals. Ten bucks were selected, and on April 25th they received 3 melatonin implants. On may 1st group M received 1 melatonin implant, while group C was untreated. On June 5th the male subjects were introduced in the female groups and removed 40 days after. From the 150° until to the 190° day after the introduction of the males, the kidding date and the number of new born were recorded. At the 150° day from the introduction of the males, group M showed a near double kidding rate compared to group C (P<0.05), while at the 190° day the two groups showed about the same kidding rate. The average in days from the introduction of the males to the parturition resulted lower in group M than in C. Data obtained, compared to data recorded in the previous two years, showed a shorter time (about 60 days) between the introduction of the males and kidding (P<0.01). In conclusion, melatonin administration produced an advance and a kidding concentration, compared to the previous two years. The lack of separation between treated and untreated animals produced a carry-over effect, reducing the differences among groups on fertility rate. This effect could be used to improve the reproductive efficiency in goats, with reduced costs of production.