The effect of am versus
pm feeding on the feeding patterns, internal temperature and performance
of feedlot cattle
during winter
K.S. Schwartzkopf-Genswein1,
S. Atwood2, R. Silasi2, A. Kennedy3 and T.A. McAllister2
1Alberta Agriculture,
Food and Rural Development, Lethbridge, Canada, 2Agriculture and Agri-Food
Canada, Lethbridge, Canada,
3University of Manitoba,
Brandon, Canada
Growth performance, feeding behavior and internal temperature of feedlot cattle were assessed in a 204-d trial using 240 crossbred steers fed once daily at either 0900 h (early-fed) or at 2000 h (late-fed). The steers (300 ± 19 kg) were blocked by weight and assigned to 16 pens randomly allotted to the early-fed or late-fed feeding schedule (n = 8) for the duration of the study. All steers were weighed every 21 d and received barley silage/barley grain-based backgrounding and finishing rations ad libitum. Two pens per treatment were equipped with a radio frequency identification system (Growsafe Systems Ltd) that continually monitored bunk attendance patterns (animal identification, and time, duration and location of bunk visits). Five steers in each of the bunk-monitored pens were outfitted with radio transponders that logged internal body temperatures at 20-min intervals for the duration of the 204 d. Average ambient temperature was -4.36 C during the backgrounding phase, and 4.79 C during finishing. Early vs late feeding did not affect DM intake (7.65 vs 7.87 kg/d, respectively), growth rate (1.26 vs 1.31 kg/d) or feed conversion (6.06 vs 6.00 kg feed/kg gain). Overall, time spent at the bunk was approximately equal (P = 0.5) between groups (102.48 min/d for early-fed vs 111.84 min/d for late-fed), but during the backgrounding period, which was cooler, steers fed in the morning spent more (P = 0.008) time at the bunk (108.96 min/d) than did those fed in the evening (99.36 min/d). Internal body temperatures did not differ between the two groups (38.71 vs 38.73 C; P = 0.60). Within the bunk-monitored pens, steers with the highest rates of gain spent more time at the bunk during backgrounding, and less time at the bunk during finishing, than did their slower-gaining counterparts (P <.05). Lack of treatment effects may have been due to mild winter conditions (mean temperature -2.98 C) and the fact that late-fed steers (fed to ad libitum) did not significantly alter their feeding time in response to evening feed delivery. Multiple year testing and moderate feed restriction would enable more accurate assessment of the effects of feeding time during winter months.