Effect of oestrus synchronization with different lengths of progesterone-impregnated sponges and equine chorionic gonadotropin on reproductive efficiency in Romanov ewes during the non-breeding season

Abstract

This study aimed to determine the effects of different lengths of progesterone and equine chorionic gonadotropin (eCG) treatment on reproductive performance during the non-breeding season in ewes. Progesterone-impregnated sponges were inserted intravaginally for 7 d in Group 1 (G1, n = 24), 9 d in Group 2 (G2, n = 25), and 11 d in Group 3 (G3, n = 24). On the day of sponge removal, eCG (350 IU) was injected and 24 h later the ewes were exposed to rams. Pregnancy was diagnosed by transrectal ultrasonography 30 ± 3 d after mating. Oestrus symptoms of G2 and G3 started earlier than G1, but there was only a significant difference between G1 and G3 (P = 0.013). In G1, G2, and G3, the oestrus responses were 100%, 100%, and 95.8%, pregnancy rates were 79.2%, 72%, and 75%, lambing rates were 79.8%, 72%, and 75%, litter sizes were 2.5, 2.2, and 2.4, and multiple birth rates were 86.7%, 80%, and 85.7%, respectively (P > 0.05). In conclusion, the short-term progesterone-impregnated sponge and eCG treatment provided excellent oestrus induction. The effects of different days (7, 9, or 11) of progesterone treatment on reproductive indicators were similar; therefore, the stress caused by the inserted sponge can be reduced by short-term use.

Effect of Bakofix® Treatment Prior to Estrus Synchronization on Some Fertility Parameters in Anatolian Merino Ewes During the Non-Breeding Season

“…However, in small ruminants, achieving pregnancy and lamb production during the non-breeding season can lead to additional economic benefits. In sheep, eCG plays a vital role in inducing estrus and follicular development outside of the breeding season (1,4,15,17). In our study, the use of eCG with progesterone-containing sponges during the non-breeding season in Anatolian Merino sheep resulted in excellent estrus induction, and this success was reflected in other fertility parameters, such as pregnancy rates.…”

Development and evaluation of an injectable slow‐release progesterone formulation for estrus synchronization in ewes out of the breeding season

“…In this study, all ewes in short‐term group came into estrus and short‐term group had the highest fertility rate (Eldomany et al, 2023). In the study of Kuru et al (2022), the effect of different lengths of progesterone treatment on reproductive performance of ewe during the non‐breeding season was investigated. The estrus response, pregnancy rate, lambing rates, litter sizes and multiple birth rate were excellent for short‐term progesterone treatment; they suggested it as an alternative to long‐term methods (Kuru et al, 2022).…”

“…In the study of Kuru et al (2022), the effect of different lengths of progesterone treatment on reproductive performance of ewe during the non-breeding season was investigated. The estrus response, pregnancy rate, lambing rates, litter sizes and multiple birth rate were excellent for short-term progesterone treatment; they suggested it as an alternative to long-term methods (Kuru et al, 2022). Several studies have shown that estradiol is a good marker of follicular function for both sheep and cattle, and healthy antral follicles contain high estradiol concentrations (Campbell et al, 1995;Ireland & Roche, 1983).…”