Effect of level of cow nutrition and calf creep feeding on fall calving system productivity, feedlot performance and carcass traits

Effects of cow nutrition and calf creep were evaluated in a two-year experiment. One hundred and seven fall calving Angus and Angus x Hereford cows calved during September and October and grazed abundant tall grass prairie throughout the experiment. Treatments were initiated in early January, after the breeding season had ended, and continued through mid April. Pairs were assigned to one of four treatments based on cow body condition and age. Treatments were: LN) .91 kg of 40% crude protein supplement with no creep feed; LC) .91 kg 40% crude protein supplement with calves having ad libitum access to creep feed; HC) 2.72 kg 20% crude protein supplement with creep feed and HN) 2.72 kg of 20% crude protein supplement with no creep feed. Creep feeding calves did not influence cow weight or body condition score change during winter or spring. Cows fed the higher level of winter supplement tended to lose less weight during winter and gained significantly more weight during spring and early summer grazing. Creep feeding resulted in increased calf weight gain from January to April (43.6 and 31.3 kg for calves nursing cows receiving the restricted and high level of winter supplement, respectively). Seventy nine percent of the additional weight gain from winter creep feeding was retained through weaning. Calves were weaned in early July and steer calves were placed directly on feed. Non-creep fed steers gained at a faster rate in the finishing phase compared with steers that had received creep feed, regardless of the dam's supplement treatment during late winter. Finishing phase DMI was greater when cows received the higher level of winter supplement. When steers were not fed creep during the treatment period, feed efficiency was improved by 7.2%, regardless of the level of cow nutrition. Creep feeding during late winter resulted in increased dressing percentage, although marbling was not significantly influenced. Creep feeding increased hot carcass weights 5.3%. Neither level of cow supplement nor creep feeding treatment influenced ribeye area, 12th rib fat depth, marbling, or yield grade. Creep feeding during late winter increases dressing percent although finishing phase rate of gain and feed efficiency are compromised.;Key words: Beef, Creep feeding, Fall calving, level of nutrition.