Comparative reproductive performance of Brahman and Santa Gertrudis cattle in a hot humid environment 1. Fertility and descriptive statistics

Abstract

SUMMARYIn a 15-year period (1956-1970) data were available from 192 Brahman cows exposed to bulls on 1409 occasions (1199 calvings) and from 155 Santa Gertrudis cows exposed 907 times (847 calvings). All were mated by natural service in the same herd in Cuba. Calving percentage and net calf crop significantly favoured the Santa Gertrudis with overall means of 92·7 and 85·3% for the two traits respectively. Parity, lactation status and year of calving significantly affected calving percentage with significant year × breed and status × parity interactions. Lactation status, year of calving, breed × year and status × parity interactions also affected net calf crop. Calf mortality was 6·41% in Brahmans and 5·64% in Santa Gertrudis but more of the latter breed were stillborn (41·7 v. 16·9% of all deaths). There were no breed effects on age at first or last calving, age at culling or calves per cow which were 38·5 months, 117·1 months, 130·1 months and 6·62 calves in Brahmans and 39·3, 111·5, 123·2 and 6·58 respectively in Santa Gertrudis. Twinning percentage was low (under 0·4%) and male births high (53·54%) in both breeds. Some 30% of cows lost at least one calf prior to weaning during their lifetime.