ISSUE FOCUS FEED & ADDITIVE MAGAZINE June 2022 31 For example, at Texas A & M AgriLife Research the implementation of GrowSafe Feed Intake bunks has allowed to show that under heat stress conditions, individual feed intake becomes very unstable. This drop in feed intake is sometimes more difficult to assess at the herd level, as it is very irregular in time from one animal to another. This leads to decreases in growth, which can even lead to negative growth (muscle loss due to low ingestion). Beef cattle weight loss could reach up to 10 kg carcass weight. In extreme situations, the quality of the meat may also deteriorate (higher pH at the slaughterhouse, which can impair meat ripening). Ultimately, if the animal fails to cool down, this may lead to sudden death (e. g. enterotoxemia and heart failure). Another, indirectly visible sign of heat stress is acidosis. Several trials performed by Lallemand Animal Nutrition using pH boluses in beef or dairy cows have shown a link between heat stress levels and rumen pH. In addition to performance and health, fertility is also affected. Bulls show a marked decrease in their fertility, linked to a decrease in the motility and quantity of their semen. LOOK OUT FOR SIGNS OF REDUCED RUMEN FUNCTION The following signs can indicate poor rumen function: decreased lying and rumination time, loss of saliva through panting, a reduction in meal frequency and a larger meal size, also known as “slug feeding.” The experts at Lallemand can also help producers measure rumen function on their operation by assessing signs such as manure color and consistency. The presence of undigested grain or cotton seeds, for example, are signs of sub-optimal rumen function, where precious (and expensive) nutrients are not being fully digested by the animal. STABILIZE THE RUMEN WITH LIVE YEAST A trial conducted at Texas A & M AgriLife Research Center in 2015 demonstrated that, in a situation of heat stress, the addition of rumen specific live yeast Saccharomyces cerevisiae CNCM I-1077 (LEVUCELL SC) to the diet allows the rumen pH to stabilize, with less daily individual changes, and the cattle to improve their intake. Feed intake was also more regular during the day, while animals not receiving LEVUCELL SC consumed more erratically during cooler periods.
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