Evaluation of prostaglandin F2 alpha treatment in dairy cows at risk for low fertility after parturition.

OBJECTIVE

To evaluate the effect of 2 postpartum prostaglandin F2 alpha (PGF 2 alpha) treatment protocols on reproductive performance of dairy cows at risk for low fertility. In addition, various medical conditions in cows that are recognized as having adverse effects on fertility were evaluated as criteria for fertility treatment.

DESIGN

Prospective study.

ANIMALS

291 cows with, and 271 cows without, risk factors for low fertility.

PROCEDURE

Cows at risk for low fertility were randomly assigned to 2 treatment groups. Group-1 cows received 3 i.m. injections of PGF2 alpha at weekly intervals after parturition, and group-2 cows received 1 i.m. injection of PGF2 alpha 17 to 24 days after parturition.

RESULTS

Compared with a single PGF2 alpha treatment 17 to 24 days after parturition, there was no added benefit of 3 treatments with PGF2 alpha 3 to 10, 10 to 17, and 17 to 24 days after parturition in cows at risk for low fertility. Cows without risk factors for low fertility had 20% higher pregnancy rates, compared with cows with risk factors for low fertility. Twinning had a negative effect on future fertility.

CLINICAL IMPLICATIONS

Results of this study indicate that further consideration should be given to the timing and intervals of PGF2 alpha administration after parturition. Risk factors for low fertility, such as retained placenta, twins, and assisted calvings, are valid criteria to evaluate different treatment options to improve fertility in dairy cows.