Authors : Nihat Ozyurtlu , Yunus Cetin , Ibrahim Kucukaslan and Mesih Kocamuftuoglu
Abstract: The aim of this study, was to compare the efficacy of treatment with norgestomet implant and Progesterone Releasing Intravaginal Device (PRID) in combination with GnRH on estrus response and pregnancy rates in acyclic holstein heifers. A total of 64 heifers (14-24 months age) were randomly divided into 3 groups. Group Norgestomet (n = 25), Group PRID (n = 26) and Control group (n = 13). Group Norgestomet; ear implant implanted subcutaneous and solution containing 3 mg norgestomet and 5 mg oestradiol valerate were injected intramuscularly at the day of 0. The silicone implant removed after 11 days. Group PRID; PRID (1.55 g progesterone, 10 mg estradiol benzoate) was inserted into vagina and left in place for 11 days. Control group; saved as control group. GnRH (0.0042 mg buserelin acetate) was administered intramuscularly (2.5 mL) at implant removal or withdrawal of PRID in implant and PRID groups. The heifers were inseminated fix timed at 48 and 72 h after the removal of implant and PRID. The rate of induced estrus was 80 and 73.08% between norgestomet implant and PRID groups, respectively. No heifer of the control group showed estrus. The pregnancy rates were 44 and 53.85% in norgestomet and PRID groups, respectively. There was no significant difference in terms of estrus response and pregnancy rates between norgestomet and PRID groups. However, a significant difference between treatment groups and control group, with respect to estrus (p<0.001) and pregnancy rates (p<0.01) were observed. The average BCS were not different statistically between all groups. Results of the study showed that fertile estrus can be stimulated in acyclic heifers by norgestomet implant and PRID treatments combined with GnRH. Also, we concluded that norgestomet implant and PRID are equally effective for estrus induction and pregnancy rate in acyclic heifers.
Nihat Ozyurtlu , Yunus Cetin , Ibrahim Kucukaslan and Mesih Kocamuftuoglu , 2009. Induction of Oestrus with Norgestomet Ear Implant and PRID in Acyclic Holstein Heifers. Journal of Animal and Veterinary Advances, 8: 1035-1039.