Evaluation of By-product Feedstuffs, Level of Concentrate, and Selenium and Vitamin E Injections on Performance and Health of Beef Calves in Backgrounding Systems
Weaning stress in young calves is often compounded with stress from transport, marketing, and commingling. The result is a weakened immune system, which can lead to increased incidence of diseases, especially bovine respiratory disease complex (BRDC). Backgrounding cattle post-weaning and prior to feedlot entry may alleviate some of the more common stresses and typically diminished feed intake. Five trials were conducted with a total of 228 weaned calves to evaluate different backgrounding systems. Drylot diets with 70:30 and 40:60 forage to concentrate total mixed rations with Se and vitamin E injections were studied. No differences were observed in daily gains or feed efficiency among treatments. Steers receiving Se injections had higher (P < 0.05) blood Se concentrations on d 7, 14, 28, and 42. Steers grazed four types of stockpiled pastures with previous pasture treatments: control, poultry litter fed to previous grazing cattle, poultry litter applied, and inorganic fertilizer. Supplements (16% CP) for each pasture treatment were none, soy hulls + SBM (0.5% BW), and corn + SBM (0.5% BW). On d 7, unsupplemented steers had higher (P < 0.05) daily gains than steers supplemented with corn + SBM. No differences were detected on any other day. Heifers grazed stockpiled fescue and were fed three 16% CP supplements: corn gluten feed + soy hulls (0.5% BW), corn gluten feed + soy hulls (1.0% BW), and soy hulls + SBM (0.5% BW). On d 14, heifers supplemented with soy hulls + SBM had higher (P < 0.05) cumulative daily gains. No other differences were detected in gains among treatments. Steers were allotted to four injection treatments: none, Se, vitamin E, and combination of Se and vitamin E. There were no differences in daily gain or blood Se concentrations on any day among all treatments. Steers grazed two pasture types: fescue and fescue + alfalfa, with the following injections: none, vitamin E, and Se. There were no differences in daily gains among all treatments. On d 7, 14, 28, and 42, steers receiving Se injections had higher (P < 0.05) blood Se concentrations. On d 7 and 14, steers grazing fescue pastures had higher serum alpha-tocopherol concentrations than steers grazing fescue + alfalfa pastures. There were no differences in serum alpha-tocopherol concentrations due to injection treatment on any day. No consistent differences were detected in forage and blood serum mineral concentrations in all trials. There were no differences in gains from by-product supplementation versus "traditional" corn-based supplementation, suggesting that by-product feedstuffs may be of value for backgrounding rations. Selenium and vitamin E supplementation did not have any significant effect on calf morbidity.