REARING DAIRY HERD REPLACEMENTS

Abstract

A reduction in the age of calving of heifers should give a quicker return on capital; reduce the number of dairy heifer replacements being reared at any one time; and allow the assessment of the genetic value of a heifer at a younger age. Target weights for first calving at different ages are suggested. The desired age of first calving may not be achieved because of late puberty. Age at puberty is affected both by growth rate and season of birth. The greatest deterrent to a reduced age at calving is the increased risk of dystokia.