Inducing bovine parturition at 270 pregnancy days with early use of a long- acting glucocorticoid and passive immunity transfer/Inducao do parto de bovinos aos 270 dias de gestacao com a utilizacao previa de glicocorticoide de longa acao e a transferencia de imunidade passiva

This experiment had the objective of evaluating passive immunity transfer and placental retention rates with the early use of a long-acting glucocorticoid to induce bovine parturition at 270 pregnancy days, as well as comparing protocol efficacy regarding the timing of parturition induction. Forty-two pregnant cows were selected from a beef and dairy herd and randomly assigned into one of three groups: control (C) without drug injection, but with the same management; long-acting + induction group (LA), with one injection of 30 mg prednisolone methylacetate, subcutaneous, on pregnancy day 255 and another injection of 20 mg dexamethasone plus 0.5 mg cloprostenol, intramuscular, on pregnancy day 270; induction group (I), with 20 mg dexamethasone plus 0.5 mg cloprostenol on pregnancy day 270. The early administration of long-acting glucocorticoid did not have any difference on passive immunity transfer and placental retention. Cows from groups LA and I calved in 41.36 ± 1.89 hours post-injection of 20 mg dexamethasone plus 0.5 mg cloprostenol, regardless of previous long-acting glucocorticoid administration on the LA group. Induction of parturition using dexamethasone and cloprostenol was efficient in all cows, regardless of previous prednisolone methylacetate administration.