Collation of basic biological data on beef cattle production in North Australia.

Summary

The report provides summarised, basic biological data on growth, reproduction and mortality for beef herds in Queensland, Northern Territory and the northern part of Western Australia. In addition to data from research studies, data from producer demonstration sites are also included. The Holroyd and O'Rourke (1989) publication was the first overall collation and summary for production traits across north Australia. It served as an inventory of research carried out and provided reliable input data on growth, reproduction and survival for herd dynamics and simulation models. Since Holroyd and O'Rourke produced their collation, further research material has been published.

The results of this research have been collated and incorporated into those of Holroyd and O'Rourke thereby extending their work by another ten years. The methodology and means of presentation of collated data used by Holroyd and O'Rourke was adopted for this update. Collated data is presented in tables accompanied by reference lists for breeders and growing animals, respectively. Data collated was restricted to production traits for grazing beef cattle. Information from pen feeding or laboratory situations was not included. Neither was data from short term studies of less than a full season (6 months). Also, disease records, biochemical parameters, pasture attributes and carcase data were not part of their collation.

Holroyd and O'Rourke developed a set of rules to undertake the task and pointed out: In some cases, conflict situations had to be resolved in a manner that was decided as reasonable rather than by applying clear-cut rules. These rules indicate how the summaries should be used and what are their strengths and weaknesses. To make best use of the collated information, the reader should have an appreciation of the rules applied. Details of the methodology used (specification of regions, indices of quality and quantity of data, presentation of collated data and limits to interpretation) are given in the final report appendix.