Summary
Low weaning rates are common in beef herds in northern Australia. A large breeding project was established to quantify the contribution of genetics to various measures of female reproduction in two diverse tropical genotypes. Specifically the project aimed to identify early-in-life indicator traits that could be used in selection to improve lifetime reproduction rates. Weaning rates in the project were low, particularly in Brahmans, and results showed it can be improved through selection by focusing recording on early-in-life female reproduction traits. Traits associated with age at puberty and lactation anoestrus in first-lactation cows were highly variable and moderately to highly heritable in both genotypes. Several male traits were identified, including semen quality traits, that could also be used as indirect selection criteria to improve female reproduction rates. The project established that it is possible to select for improved female reproduction simultaneously with selection for steer traits (growth, carcass, meat quality and feed efficiency), however improvement in both will require recording and appropriate multiple-trait selection strategies.
