The northern Australian beef industry, a snapshot. 3. Annual liveweight gains from pasture based systems

Abstract

The herd performance of 375 northern Australian beef producers during the 1991 and 1992 to 1995 and 1996 financial years was surveyed in 1996 and 1997. Estimates were made of annual liveweight gain from production systems based on native and improved pastures together with hormonal growth promotant use and supplementation practices. The most commonly used pasture communities for growing and finishing cattle were black speargrass and brigalow communities in Central Coastal Queensland and the Central Highlands; black speargrass in Northern Queensland; Mitchell grass and gidgee in Central Western and North-west Queensland; Mitchell grass in the Northern Territory and northern Western Australia regions and brigalow–softwood scrub in the Maranoa South West. There was considerable variation and overlap in the production ranges of the various pasture communities. The estimates and ranges of annual liveweight gains were comparable with measurements from scientific and commercial studies for 3 major pasture communities (black speargrass, brigalow and Mitchell grass). On this basis, the annual liveweight gain data are considered to represent sound estimates of performance from the pasture communities and husbandry systems in use in northern Australia. Mean annual gains for pasture communities in the more northern regions tended to be <150 kg/year. Half the survey group used hormonal growth promotants but use varied between regions with lowest levels in Central Coastal Queensland (30%) and highest usage in the Central Highlands (59%). Steers and bullocks were the most commonly implanted class of cattle. Supplementation periods tended to be longest in more northern regions. Nitrogen was a component of >90% of the supplements offered. The percentage of producers supplementing various classes of cattle varied widely (0–77%). Steers were often the least supplemented class and weaners were the most common. The highest percentage of producers (>68%) supplementing weaners was found in North-west and Northern Queensland, the Northern Territory and northern Western Australia. Significant correlations explaining 3–23% of the variance were found between annual liveweight gain and latitude and/or longitude for native black speargrass and Mitchell grass pasture communities and improved brigalow pastures. Generally, annual liveweight gain increased with increasing latitude and longitude. The results are discussed in relation to herd management practices and sources of variation in the northern Australian production environment.