ASPECTS OF REPRODUCTION IN FEMALE BOS-INDICUS CATTLE - A REVIEW

Differences occur between female Bos indicus and Bos Taurus cattle in various aspects of reproductive physiology and behaviour. These may be associated with different natural and human selection pressures, comp ounded by strong genotype-environment interactions. B indicus cattle a re better adapted for tropical environments (despite overall poor catt le reproductive rates in these regions) which tend to be more stressfu l for B taurus genotypes. Conversely, B taurus cattle generally show s uperior reproductive and productive traits under more favoured, temper ate conditions. Despite genotype-environment effects, B indicus female s are generally considered to take longer to achieve puberty and to ha ve longer gestation lengths, exhibit prolonged postpartum anoestrus, s how greater seasonality of reproductive traits (tending to be longday breeders), display a shorter, less overt oestrus as well as less tende ncy to allow riding behaviour by subordinate females. Some groups appe ar to have increased losses both during pregnancy and in the neonatal period. On the positive side, B indicus females respond well to manage rial and nutritional interventions, tend to have greater reproductive longevity and they generally exhibit strong maternal traits. Culling o f infertile females and selection for greater male scrotal circumferen ce and sex-drive, in conjunction with the use of target weights, body condition scoring and weaning stratagems can improve reproductive rate s in B indicus females.