Predicting rump fat thickness and maturity type of tropically adapted cattle
by
Angela Reid
Qld Dept of Primary Industries
Coauthors: Brian McIntyre (Agriculture WA)

Knowledge of the relationship between carcase weight and fatness is critical in meeting market specifications for cattle. For an individual animal this relationship between weight and fatness is known as ‘maturity type’ (a high fat level for a given weight is considered as ‘early maturing’, a low level is considered as ‘late maturing’). If producers can predict the maturity type at an early age, they can manage their cattle to have carcase characteristics in the specific range the particular market requires (and thus avoid severe monetary penalties for being outside market requirements). The crucial element in predicting maturity type is being able to predict rump fat thickness. This paper investigates the ability to predict rump fat thickness using data from the CRC for the Cattle and Beef Industry. The CRC’s database includes records for a total of 3823 tropically adapted straight-bred animals (breeds Belmont Red, Santa Gertrudis and Brahman) and 865 tropically adapted crossbreds. Animals were finished on grain (in a feedlot) or at pasture, to different market endpoints and reared in temperate versus subtropical environments (Dundon, P., Sundstrom, B., Gaden, R. 2000). Data were collected over a 7-year period on approximately 220 animal traits. Regression analysis was used to develop predictive models for fat thickness at weaning, grow-out, pre-slaughter and slaughter. Explanatory variables in the models included animal characteristics such as weight, age, hip height, breed, management styles or nutrition treatments. References: Dundon, P., Sundstrom, B., Gaden, R. (2000). Producing and Processing Quality Beef from Australian Cattle Herds: Industry Outcomes of the Cooperative Research Centre for the Cattle and Beef Industry (Meat Quality): 1993-2000.

Date received: September 6, 2002