Luteal regression and follicular dynamic after spontaneous or cloprostenol induced luteolysis in Gir cattle

J.H.M. Viana A.M. Ferreira W.F. Sá L.S.A. Camargo About the authors

The luteal regression and the follicular dynamic were evaluated during the natural luteal regression period (n=14) or after induction of luteolysis by the administration of 500 g of cloprostenol (n=13), using a portable ultrasound device. Luteolysis induction increased luteal regression over 24 (0.89±0.13×0.24±0.17cm²/day; P<0.05) and 48 hours period (0.78±0.15×0.36±0.07cm²/day; P<0.05), but the reduction of progesterone concentration was similar (P>0.05). There was no difference (P>0.05) in follicular dynamic between the two groups. Cows in which the largest follicle during luteolysis was the ovulatory follicle presented shorter periods of follicular growth (3.71±0.56×5.26±0.34 days; P<0.05) and luteolysis to estrous intervals (85.71±14.68×121.33±8.34 hours; P<0.05). This study shows that functional (but not morphological) regression of corpus luteum and follicular dynamics after spontaneous or induced luteolysis are similar in Gir cattle.

Cattle; Gir; follicular dynamic; luteolysis

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