Postpartum reproductive activities and gestation length in Martina Franca jennies, an endangered Italian donkey breed

The donkey reproductive physiology is still partially known despite the increasing risk of extinction involving several breeds. The present study was designed to describe the postpartum (PP) reproductive performance of an Italian endangered breed: the Martina Franca donkey. To this aim, 52 jennies were monitored to define the foal-heat (FH) and the first and second PP estrus episodes (1st PPe and 2nd PPe). The data indicate that jennies spontaneously recovered reproduction in approximately 10 days after delivery. Then heats occur with a regular interval of approximately 23 days. Estrus length was 1 week in FH and the 2nd PPe and significantly shorter in the 1st PPe. Estrus–ovulation, and delivery– ovulation interval and follicle growth were similar in all animals tested. Pregnancy rate (PR) was lower when natural mating occurred during the FH and 2nd PPe (approximately 60%) than during the 1st PPe (approximately 70%; P 80%; P < 0.01) was recorded in jennies when the FH occurred after the first week PP and it dropped (<50%) in early FH animals. The PR was also affected by the season and by age: it significantly declined during the autumn–winter season and in subjects older than the sixth year of age. For the first time, the reproductive performance of PP donkeys were defined on a large number of Martina Franca jennies thus offering useful information to improve farm management with an immediate benefit to increase livestock production. This aspect of management improvement might be particularly important if applied to an endangered breed such as Martina Franca donkeys.