Synchronization of parturition in beef cattle using delay as well as induction.
Two methods for synchronization of parturition in beef cattle were examined. In the first experiment, four groups of cows and heifers were used: untreated (C, n=9), 10 mg flumethasone on day 281 of gestation (F, n=9), 100 mg progesterone daily from days 276 through 283 and 50 mg progesterone on day 284 (P, n=6), and (P+F on day 284, n=7). Variances in gestation lengths (C, 26.01; F, 0.77; P, 11.97; P+F, 1.93) and proportions of cows and heifers with retained placentas (C, 0/9; F, 4/9; P, 1/6; P+E, 0/7) differed significantly among groups. Differences among groups in calving difficulty scores and proportions of dead calves were not significant. Four of the thirteen cows and heifers treated with progesterone required assistance in calving and all four delivered dead calves. Pulling of these calves was not accompanied by uterine contractions. Conversely, the difficult calvings in the control- and flumethasone-treated cows and heifers were accompanied by uterine contractions. In the second experiment, two groups of cows were used: 1) a single injection of 20 mg dexamethasone on either day 276, 277 or 278 followed by injections of saline every 12 h for 2.5 additional days (n=6), and 2) repeated injections of 20 mg dexamethasone every 12 h for 3 days beginning on day 276, 277 or 278 (n=8). The interval from time of first treatment to calving was not different between groups (43.6 and 43.0 h, respectively). Differences between calving difficulty scores, proportions of dead calves and incidence of retained placentas were not significant. Induction very close to the expected calving date could reduce the problems of retained placenta; however, methods must be identified to safely delay parturition.
Ottobre
J S
JS
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown, WV 26506, USA.
Inskeep
E K
EK