Effects of different reproduction management protocols on the reproduction efficiency of three indigenous Greek sheep breeds

Abstract

<abstract> <p>The aim of this study was to evaluate the effects of two different methods of controlling ovine reproduction (ram effect and a combination of eco-friendly substances) in three Greek indigenous sheep breeds, namely Florina, Karagouniko, and Chios. 180 ewes, aged 2–3 years old, were used, equally divided between the three Greek sheep breeds. Each breed was divided in two equal experimental groups: In group ECO (combination of eco-friendly substances), a dose of Gonadotropin-releasing hormone (GnRH) was administered at day 0, followed by an intramuscular injection of prostaglandin seven days later and another dose of GnRH at day 9. In group ME, sexually active males were introduced to the females that have been isolated for 3 months. The experiment was conducted in three consecutive years: 2020, 2021, and 2022. Average estrus expression and fecundity in all three examined breeds was comparable, with the exemption of Florina ewes treated with the eco-friendly substances in the first year, a result that could be attributed to the strong seasonal pattern in estrus expression of the Florina breed. The average length to estrus expression in days was significantly lower in the eco-friendly method than the procedure using male effect and the prolificacy was higher for the Chios sheep than the Florina and the Karagouniko breeds. Overall, both methods for the induction and synchronization of estrus (male effect and PGF2a administration) could be used in sheep reproduction with promising results. Nevertheless, the male effect seems to be more efficient in indigenous breeds with long anestrus periods.</p> </abstract>