Periódicos Brasileiros em Medicina Veterinária e Zootecnia

p. 413-417

Efficiency of different methods of estrus synchronization followed by fixed time artificial insemination in Persian downy does

Hashemi, MajidSafdarian, Mazaher

For evaluating different methods of long term estrous synchronization followed by fixed time artificial insemination and to select the most efficient method, during the breeding season 160 Persian downy does were equally allocated to groups (n = 20/group). Estrus Was synchronized using controlled internal drug release devices alone (CIDR) or with equine chorionic gonadotropin (CIDR-eCG), intravaginal sponge impregnated with 45 mg fluorgestone acetate alone (Sponge) or with eCG (Sponge-eCG),subcutaneous auricular implant of 2 mg norgestomet alone (Implant) or with eCG (Implant-eCG) or two intramuscular injections of 10 mg prostaglandin F2α10 days apart alone (PGF) or accompany with eCG (PGF-eCG). The dose of eCG was 400 IU and injected intramuscularlly at the end of treatments. Heat detection and fixed time artificial insemination were done 12 and 4 hours after the end of the treatments, respectively. The estrus was detected in 94.7-100% of the does who received different forms of progestagens and estrus response was not affected by eCG. Estrus response in PGF-based groups was significantly lower (P <0.05) than progesterone-based groups. Injection of eCG did not affect fertility, fecundity and prolificacy rates in CIDR, Sponge and Implant groups. It also did not affectparturition rate in implant group. Finally, with respect to estrus response, fertility rate, costs and the simplicity of methods it can be concluded that the use of intravaginal CIDR For 16 days without administration of eCG may be a more efficient method for estrus synchronization in fixed-time artificial insemination programs in Persian downy does.(AU)

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