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Treatment with an intravaginal progestagen and estradiol to prevent prolonged anestrus in crossbred zebu cows under tropical conditions

Abstract:

To study the effectiveness of a treatment with an intravaginal progestagen in combination with estradiol-17β (E-17β) on estrus induction, prevention of prolonged anestrus and fertility in noncycling crossbred zebu cows, a trial was conducted in a farm in Zulia state, Venezuela. Fifty noncycling suckled crossbred cows (B. taurus x B. indicus) with 60 dpp were randomly allotted to one of the following treatments: MAP+E-17β (n=22), intravaginal device (250 mg of MAP) during 7 days + 50 mg of MAP and 5 mg of E-17β im (day 0) and 1.5 mg of E-17β im (day 8) (Pregnaheat-E®; VIATECA-Venezuela); CG (n=28), control group without hormonal treatment. The MAP+E-17β group showed higher (P<0.05) estrus and synchronization rates (59.1 and 36.4 %) than CG (25.0 and 3.5 %). Cows receiving MAP had higher (P<0.05) overall pregnancy rate than CG (45.5 and 17.8 %, respectively). A decreased (P<0.05) anestrus rate was observed in MAP+E-17β (31.8%) compared to CG (57.1%). Calving-conception interval was shorter (P<0.05) in MAP+E-17β (132.5±16.8 days) than in CG (178.9±14.7 days). In conclusion, treatment with MAP+E-17β at 60 days postpartum was effective to induce estrus, prevent prolonged anestrus, and reduce the calving-conception interval, improving reproductive performance in dual purpose crossbred Zebu cows. © 2007 Springer Science + Business Media B.V.