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5. Gender effects Gender is another significant factor that impacts dressing percentages, with differences observed between male and female animals. In beef cattle, heifers usually have a 1,5 to 2,0 percent lower dressing percentage than steers at a similar fat level. As a whole, heifers tend to carry more waste fat in the udder, around the internal organs and on the carcass than steers. The difference in dressing percentages narrows as heifers become fatter than steers. Since heifers mature earlier, they are usually marketed as lighter than steers. In sheep, we tend to see that rams have a lower dressing percentage than ewes at the same slaughter weight. In a trial done on merino crossbred lambs that were 5 months of age, on average, the ewes had a 3% better dressing percentage than rams. The main contributing factor to the lower dressing percentage in the rams was the higher frequency of animals with horns. 6. Diet effects Nutrition is one of the most influential factors in dressing percentage. A well-balanced diet that promotes muscle growth rather than excessive fat deposition will result in a higher dressing percentage. The density of the ration can have a large effect on the dressing percentage. Cattle on a high roughage diet, such as hay, silage, or pasture, have a lower dressing percentage than cattle on a high proportion of grain diet, even if the cattle are marketed at similar fat levels. In a trial done by the Lethbridge Research Station in Canada, the entire digestive tract of slaughtered steers was weighed. Gut fill, as a percentage of live weight, was higher in steers on a roughage diet than in steers on a grain diet. In this trial, steers on the grain diet had an 8% higher dressing percentage than steers on the roughage diet. Cattle in feedlots are often fed a high-energy diet rich in grains, which encourages muscle growth and fat deposition. The balance of proteins, carbohydrates, fats, and fibre in the diet, as well as the timing of the feeding programme, can have a significant impact on how efficiently the animal gains weight. Animals with higher muscle mass and appropriate fat cover (not excessive) tend to have higher dressing percentages. Additionally, animals that have been fed a consistent and high-quality diet throughout the finishing period will typically have better dressing outcomes than those that experience feed fluctuations or poor-quality rations. The use of beta antagonists as a feed additive, such as Zilmax or Growfactor, in the finishing phase of the feedlot can improve the dressing percentage. In both lambs and calves we expect an improvement in dressing percentage of 2% on average. The benefit of the improved dressing percentage outweighs the cost of adding a beta antagonist to the ration. 7. Distance and time from the feedlot to the abattoir The distance and time from loading animals on the farm to getting them to the abattoir play an important role in maximising dressing percentage. This effect of a lower dressing percentage is primarily related to stress, dehydration, and weight loss during transportation, all of which can alter the final yield of meat. It is therefore important to shorten the time from the feedlot to the abattoir as much as possible and reduce stress on the animals. Transporting animals from the feedlot to the abattoir is a stressful process that can result in weight loss and reduced dressing percentages. Stress can cause several physiological changes in animals, such as an increase in heart rate, muscle tension, and the release of stress hormones like cortisol and adrenaline. The time and distance involved in transportation can lead to weight loss, particularly from dehydration, sweating, and exhaustion. The further the distance from the feedlot to the abattoir, the more pronounced this effect can be. A trial done on the effect of time without feed and water on the carcass weight of bull calves Spring/Summer 2025 BONUS www.agribonus.co.za 76