Rumen-Undegradable Protein Supplementation Effects on Early Weaned Calves Grazing Annual Ryegrass

• Published in: Crop science Vol. 51; no. 1; pp. 381 - 386
• Main Authors: Vendramini, J.M.B, Arthington, J.D, Sollenberger, L.E, Saraiva, T
• Format: Journal Article
• Language: English
• Published: Madison, WI The Crop Science Society of America, Inc 2011; Crop Science Society of America; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; Beef; beef cattle; Biological and medical sciences; Body weight; calf feeding; calves; Cattle; Dry matter; dry matter accumulation; early weaning; feed intake; feed processing; feed supplements; feeding level; forage grasses; Fundamental and applied biological sciences. Psychology; Grazing; liveweight gain; Lolium multiflorum; Pasture; Pastures; protein supplements; soybean meal; Soybeans; stocking rate; Weaning; Florida; Monocotyledones; Farming animal; Bovine; Lolium; Calf; Ox; Rumen; Grazing; Young animal; Protein; Vertebrata; Mammalia; Weaned animal; Gramineae; Angiospermae; Herbaceous plant; Spermatophyta; Artiodactyla; Supplementation; Ungulata
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2010.04.0204

Early weaned beef calves (Bos spp.) can be raised on cool-season pastures in Florida but more information on protein supplementation is necessary to optimize the performance of those calves. The objective of this study was to evaluate the effects of three levels of rumen-undegradable protein (RUP) supplementation on performance of early weaned calves grazing annual ryegrass (Lolium multiflorum Lam.) pastures. The study was conducted in Ona, FL in 2007 and 2008. Treatments were 1.5 g kg−1 body weight (BW) supplementation of three levels of supplemental RUP, soybean meal (SBM, 350 g kg−1 RUP), Soyplus (SP, 600 g kg−1 RUP, modified expeller soybean meal, West Central, Ralston, IA), or a 50:50 mixture of soybean meal-Soyplus (SBMSP, 475 g kg−1 RUP). Pasture size was 0.3 ha and four early weaned calves were assigned to each pasture. There was a linear increase in herbage mass (HM, from 1.9–2.1 Mg ha−1) and herbage allowance (HA, from 1.1–1.4 kg dry matter [DM] kg−1 live weight, LW) with increasing levels of RUP. Increased RUP supplementation decreased forage dry matter intake (FDMI) and total dry matter intake (TDMI) in 2008 but there was no effect in 2007. There was no difference in average daily gain (ADG, 0.76 kg d−1) among treatments. Increasing the levels of RUP supplementation has potential to increase stocking rates of early weaned calves grazing annual ryegrass pastures.