Comparison of two methods of induction and synchronization of estrus and the ovulation in cows in post-partum anoestrus
Oliveira, K.P.L.; Araujo, A.A.; Montezuma, P.A.J.; Moura, A.A.A.; Nunes, J.F.
Revista Brasileira de Reproducao Animal 27(3): 453-454
2003
Accession: 034624739
It was evaluated the efficiency of two protocols of Estrus synchronization and ovulation response (CRESTAR and OVSYNCH) in 50 crossbred dairy cows in post-partum anoestrus. The animals were allocated in two groups, the first one (n=24) was submitted to the CRESTAR treatment receiving ears implants containing 3mg of Norgestomet plus an intramuscular injection of 6mg of Norgestomet and 10mg of estradiol valerate. In the ninth day, the ear implant was removed and a dose of 500 Ul of eCG was performed. The artificial insemination was performed 40 hours later. The second group (n=26) was submitted to the Ovsynch protocol that consisted in the use on first day of 2,5ml of GnRH and seven days later an intramuscular injection of 2ml of Prostaglandin and on the ninth day a second dose of GnRH with the artificial insemination performed 14 hours later. The pregnant diagnosis was accomplished 50 days after the first and second insemination. All the females were observed in estrus in both protocols (100%). The treatment Crestar showed more efficient concerning to the pregnancy rate in the first insemination (P <0,05), but, when the results were evaluated including the second insemination, no statistical difference was observed among treatments. The results allow concluding that the Crestar protocol is more efficient for obtaining better pregnancy rates with just one insemination.