Effectiveness of human recombinant FSH for enhancing reproductive performance of ewes in progesterone injection-based estrus synchronization program

Abstract

Exploring the safe, cheap, and efficient gonadotropin to enhance reproductive performance of ewe is of worldwide demand. The purpose of this study was to examine the possibility of using human recombinant FSH (hrFSH) at the end of a short progesterone injection-based estrus synchronization program during the breeding season in ewe. Shal ewes (n=184) were assigned randomly into 4 groups using 2 (hrFSH or No-hrFSH) by 2 (Mating or Laparoscopic artificial insemination; LapAI) factorial design during the breeding season. On Day 0 of the experiment, ewes received progesterone (37.5 mg; sc) and GnRH analogue (7.5 µg Alarelin acetate; im). On Days 3 and 6, ewes received 25 and 12.5 mg progesterone (sc), respectively. All ewes received prostaglandin F₂α analogue (250 µg Cloprostenol; im) on Day 6. On Day 7, ewes were divided into two equal groups and received hrFSH (75 IU Follitropin alfa; sc) or didn’t receive any further treatment. Ewes displaying estrus in each group were assigned for mating for 5 days or LapAI at either 4–10 or 20–24 h after estrous detection. Data were analyzed using GLM and Genmod procedures. The tightness of estrus synchrony within 24 h was greater in hrFSH (89.4 %) than No-hrFSH (63.9 %) group (P<0.0001). The respective prolificacy and fecundity were greater in hrFSH (1.81 and 0.96) than No-hrFSH (1.26 and 0.68) group (P<0.05). The respective lambing rate and fecundity rate were greater for ewes mated (61.9 % and 0.96) compared to LapAI (45.5 % and 0.68; P<0.05). Ewes inseminated between 4 and 10 hours after estrous expression had greater sex ratio toward male offspring (1.89) compared to those inseminated between 20 and 24 hours (0.64, P<0.05). In conclusion, hrFSH could be considered as an effective gonadotropin for enhancing the tightness of estrus synchrony, prolificacy and fecundity in the progesterone injection-based estrus synchronization program in ewe.