Northern Australia beef fertility project: Cash Cow

Abstract

The causes of poor reproductive performance in northern Australian beef herds are multi-factorial and uantification of the impact of individual factors on performance of breeding mobs is lacking. The reproductive performance of ~78,000 cows managed in 142 breeding mobs located on 72 commercial beef cattle properties was measured over three to four consecutive years (2008-11) using a crush-side electronic data capture system. Percentage of lactating cows pregnant within four months of calving, annual pregnancy rate, percentage foetal/calf loss between pregnancy diagnosis and weaning, and annual percentage of pregnant cows missing (mortality) were used to define performance, with the commercially achievable level of performance proposed as the performance of the 75th percentile mob or cow for each measure. Also, methods of estimating liveweight production from breeding herds were developed, and an achievable level determined for each country type. The impacts of 83 property, environmental, nutritional, management, and infectious disease factors on performance were investigated. The major factors affecting performance included country type, time of previous calving, wet season phosphorous status, cow body condition, hip-height, cow age class, cow reproductive history, severity of environmental conditions, and occurrence of mustering events around the time of calving. Producer/manager opinion that wild dogs were a problem, evidence of recent pestivirus infection and vibriosis were factors that did not contribute to the final model, but did significantly affect animal performance when present. A framework was developed for conducting economic analyses to assess the impact of factors affecting performance.