LAUSR

In the hot-weather regions, during the hottest hours of day, cattle experienced major difficulties dissipating excessive heat load to the environment. The main source of heat production of cattle is rumen fermentation process. Changing common feeding schedule from day to night hours could help cattle easily dissipate the heat from digestive process to surrounding and impact on its performance. With the objective of comparing once-per-night vs. traditional twice-a-day feed-delivering schedule on feedlot performance of back-growing cattle in hot climate, 80 bull-calves (244.9 kg BW) were involved in a 56 feedlot experiment, performed during summer of 2018 in Culiacan, Mexico. In a complete block design experiment in groups of five were placed in 16 ground pens (6 x 12 m), and inner each block pens were randomly assigned to two treatments: 1) Feeding twice a day at 0900 and 1530 hours (Control); and 2) Feeding once a day at 2000 hours (Night treatment). In animals fed ad libitum with a growing diet, body weight, dry matter intake, average daily gain, and feed efficiency were measured. Pen (five animals) was consider as the experimental unit (8 by treatment). Results were subject to ANOVA and P < 0.05 fitted to accept statistical difference. Across experiment, maximum and minimum temperature were 44.7 and 23.6 °C, respectively; and maximum and minimum THI were 95.99 and 73.07, respectively. Night feeding schedule increased (P < 0.01) in 5% final weight, 25% daily gain, 7% dry matter intake, and 17% feed efficiency (gain: feed ratio). Results suggest that feeding time has a strong influence on feedlot performance of cattle under hot weather. It is concludes that delivering feed during the night hours becomes as a viable feeding strategy to improve feedlot performance of cattle in hot climates.