Influence of feeding chromium-enriched enzymatically hydrolyzed yeast on growth performance, dietary energetics and carcass characteristics in feedlot cattle under conditions of high ambient temperature

Forty crossbred steers (245 ± 0.95 kg) were used in a 222-day feeding trial to assess the effects of a supplementation of chelated chromium-enhanced extract of enzymatically hydrolyzed yeast (Cr-EHY) on growth performance, dietary energetics and carcass characteristics in feedlot cattle finishing during high ambient temperatures. Treatments consisted of a steam-flaked corn-based diets supplemented with 0 or 0.4 g/kg of diet with Cr-EHY (0.3 g/kg of TruMax plus 0.1 g/kg of chelated Cr). Both dry matter intake (DMI) and climatic variables were measured weekly and the temperature humidity index (THI) was estimated. Daily maximal THI that exceeding a THI value of 72 was reached in 213 of the 222-day study (avg. THI = 75.24). During the initial 112-day period (including the receiving and diet transition phases), Cr-EHY increased average daily gain (ADG) (7%, P = 0.03). This effect was due to a tendency (P = 0.07) for increased DMI. There were no treatment effects on gain efficiency and dietary net energy (NE). Overall, however, there were no treatment effects on growth performance or dietary NE. Nevertheless, Cr-EHY supplementation had a modulating effect on carcass quality, decreasing carcass fat thickness (10%, P = 0.09, and increasing longissimus muscle area (7%, P < 0.01) and retail yield of boneless closely trimmed primal cuts (2%, P = 0.07). Results indicate that supplementation with a chelated chromium-enhanced extract of enzymatically hydrolyzed yeast can have beneficial effects on feed intake and daily weight gain, particularly during the initial receiving growing phase. It also appears to have a modulating effect on carcass quality, enhancing muscularity and reducing external fat. These results indicate that Cr supplementation has a modulating effect on carcass quality and may enhance DMI and corresponding ADG of feedlot cattle during periods of high ambient temperature.