2015 Pan Pacific Veterinary Conference

Reproduction rate is a major factor influencing enterprise profitability in the Bos indicus and Bos indicus infused herds of northern Australia. Prior to the commencement of the recently concluded Cooperative Research Centre for Beef Genetic Technologies (Beef CRC), little genetic information was available for male and female reproductive traits and their associations between these traits in tropical beef cattle genotypes. This Beef CRC clearly demonstrated that key component traits of fertility (age of puberty and post-partum reconception interval) in two tropical breeds (Brahman and Tropical Composite) are at least moderately heritable and that substantial improvements in reproductive performance can be achieved. In addition, key reproductive traits in males have been shown to be genetically correlated with key reproductive traits in females. However, while these heritability and genetic correlation estimates for and between traits can be readily identified in Brahman and Tropical Composite sires used in the Beef CRC, this information is not currently available to the general industry. This paper discusses a project that was designed to measure and evaluate these recently reported Beef CRC male and female reproductive performance traits, modifications of these ‘new’ traits, and preliminary results, in key/leading Brahman Droughtmaster and Santa Gertrudis GROUP BREEDPLAN seedstock herds in northern Australia.