steer calves, crude protein, limit feeding, ADG, feed conversion
One hundred ninety-two Angus x Limousin steer calves (560 lb) were used in an 85-day backgrounding trial. Dietary crude protein levels of 90, 100, 110 and 120% of the NRC factorial equation recommendation were used within ad libitum-fed corn silage diets (CS) arid limit-fed chopped high-moisture ear corn (HMEC) diets. The objective was to determine if optimum dietary crude protein levels differed between these two basal diets when fed at similar levels of a net energy of gain. By design of the experiment, daily dry matter intake of HMEC diets was lower than CS diets (P<.001). ADG was similar across basal diets and feed conversion was improved (P<.001) with HMEC diets. Dietary crude protein level did not affect ADG. Quadratic decreases in the protein efficiency ratio occurred as dietary crude protein Level increased (P<.01). Plasma urea N (PUN) levels were higher in calves fed HMEC diets (P<.05) arid increased quadratically with increasing dietary crude protein level on day 56 (P<.05). This study suggests the NRC factorial equation estimates the gram daily crude protein requirement and can be used without modification to predict dietary crude protein needs of limit-fed feeder calves.
Number of Pages
South Dakota State University
Copyright © 1988 South Dakota State University
Sip, M.L.; Pritchard, R.H.; and Robbins, M.A., "High-Moisture Ear Corn and Corn Silage in Backgrounding Cattle Diets" (1988). South Dakota Beef Report, 1988. 4.