BONUS SPRING SUMMER 2025

Factors affecting dressing percentage in feedlot animals George Schoonbee – Junior Product Manager: Extensive Ruminants Dressing percentage is a keymetric used in themeat production industry to assess the yield of marketablemeat froman animal after slaughter. It is calculated as the ratio of the animal’s carcass weight to its live weight, usually expressed as a percentage. For cattle raised in feedlots, understanding the factors that influence dressing percentage is crucial for producers and processors aiming to optimise their operations and profitability. Dressing percentage can vary significantly based on several variables, including genetics, diet, animal management practices, and environmental factors. Theoretically, dressing percentage is calculated by dividing the warm carcass weight by the shrunk live weight of the animal and expressing the result as a percentage. In practice, farmers use different weights to determine dressing percentage. The live weight is either measured at the feedlot before loading the animals to the abattoir or at the abattoir just before slaughter. The carcass weight used is mostly the cold carcass weight, as that is what the farmer is paid for. When comparing dressing percentages between different groups, it is essential to use consistent weight measurements. It is very rare to get dressing percentages of individual animals; we mostly calculate the dressing percentage of a group of animals slaughtered. We then compare the group average to other groups; however, forget that the variance between groups is much lower than the variance between individual animals. In 594 lambs that were slaughtered, the average dressing percentage calculated from the cold carcass weight (warm carcass weight minus 3%) divided by the final weight at the farm was 47,0%. In this group, we also calculated individual dressing percentages; the dressing percentages varied between a minimum dressing percentage of 37,7% and a maximum dressing percentage of 64,2%. In Graph 1, we can see how dressing percentages in individual animals vary – these differences in many cases have a large effect on the average dressing percentage calculated. Spring/Summer 2025 BONUS www.agribonus.co.za 74