Betamethasone for the induction of parturition in dairy cows: a comparison of formulations

Abstract

Five hundred and fifty three dairy cows on 27 farms were treated with betamethasone formulations to induce premature parturition.

All cows received an initial subcutaneous injection of 20mg betamethasone alcohol as a 10mg/ml suspension. Cows not calved within 7 days received a subcutaneous injection of betamethasone either as a 2mg/ml suspension of the poorly soluble alcohol or as a 2mg/ml solution of the sodium phosphate ester. One hundred and three cows calved within 7 days of initial injection (Group I), 222 received an injection of the 2mg/ml suspension (Group II) and 223 were treated with the betamethasone solution (Group III). Cows in Group I were closer to term at time of treatment than cows in Group II + III (16.6 days compared to 29.9 days). Those cows which failed to calve within 10 days of the second injection were an average of 50.5 days away from term at time of treatment.

The mean response-time from first injection to calving was 9.6 and 9.1 days for Groups II and III, respectively (p<0.01). In Group II, 68.0% of cows had calved within 2 days of receiving the second injection compared to 76.7% in Group III (p<0.02). Twenty-eight cows (6.3%) failed to calve within the allocated time and differences between groups was not significant. Calf mortality for all treatments was high; 10.6% dead at birth and 27.3% by 4 days old. Calf mortality was clearly a function of prematurity. The overall incidence of metabolic disease was 5.2%, with a difference apparent between Group II (2.9%) and Group III (8.1%) (p<0.02). Retained foetal membranes were observed 24 hours after calving in 18.6% of cows. The incidence of dystocia, mastitis and otherillnesses was low (2.1%, 6.1% and 2.9% respectively) and no differences were detected between groups.