With cotton production in the southwestern U.S. increasing, the availability of cotton byproducts for use in cattle diets has also increased, according to Oklahoma State University's Andrea Warner, who presented a late-breaking research abstract during the American Society of Animal Science-Canadian Society of Animal Science annual meeting.
Warner said there is extensive research on the use of cotton byproducts in grazing beef cattle and dairy cattle but limited research in feedlot cattle.
Along with Oklahoma State researchers Paul Beck, Andrew Foote, Colton Robison, Kaitlyn Pierce and Blake Wilson, Warner conducted an experiment to evaluate the inclusion of cotton byproducts in feedlot finishing rations on the performance, carcass characteristics and fecal characteristics of steers.
In the study, 64 crossbred beef steers were assigned to one of two experimental treatments in a randomized complete block design with eight pens per treatment and four steers per pen.
Warner said treatments included either a control diet -- composed of 7% hay, 15% wet corn gluten feed, 67% rolled corn and 5% liquid supplement -- or a cotton byproduct diet, which contained 7% gin trash, 15% whole cottonseed, 72% rolled corn and 5% water. Both diets included 0.75% urea and 5% dry supplement.
According to Warner, cotton-fed steers tended to have a heavier final bodyweights (P = 0.09) and greater average daily gains (P = 0.08) than control steers. Over the entire feeding period, dry matter intake was also greater for cotton-fed steers than the control steers (P = 0.04), Warner reported; however, there was no difference in gain:feed between treatments (P = 0.89).
For carcass traits, cotton-fed steers had heavier hot carcass weights (P = 0.02) and greater fat thickness (P = 0.03) than control steers, but marbling score and rib-eye area did not differ between treatments (P > 0.64), Warner said.
She reported that fecal scores were lower for cotton-fed steers on day 56 (P = 0.03) and that fecal pH tended to be higher for the cotton-fed steers on day 28 (P = 0.09), but neither differed during other periods (P > 0.18).
Warner concluded that cotton byproducts can be used in feedlot rations without adverse effects on performance or carcass characteristics.