Submitted to: Journal of Animal Science Supplement
Publication Type: Proceedings
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Interpretive Summary: Diversifying an operation to include summer grazing of yearling cat in addition to cow-calf production can aid in decreasing economic r Using yearling cattle to match forage demand to supply can be of considerable benefit in an environment of widely fluctuating precipitation patterns. The challenge in managing stocker cattle on n Northern Great Plains rangelands is in meeting the nutrient needs growth when forage quality or quantity begin to decline in late sum Options are to remove cattle from rangeland or to supplement cattle the nutrients that have become limiting. The objective of this stud to evaluate different sources of protein for their ability to alter forage intake and weight gain compared with a nonsupplemented contr group of steers. This study was conducted during two summers. Yearl steers were assigned to one of four treatments in three pastures. Treatments were a nonsupplemented control or steers fed a protein supplements with safflower meal, soybean meal or a combination as t protein source. Protein supplementation was started after forage qu began to decline in late summer. There was no effect of supplementa on weight gain or intake of yearling steers. Rate of gain did decli grazing season progressed. Protein supplements, fed every third day were not beneficial to weight gain of yearling cattle grazing forag the quality and quantity observed in this study.
Technical Abstract: Summer grazing trials were conducted during two years to test the value of supplementation with two protein sources for yearling steers grazing late season native range compared to unsupplemented controls. Each year, 56 yearling steers (288 kg) were allotted to one of four treatments in three pastures. Each treatment was represented within each pasture. Once each month forage intake was estimated using total collection of feces from two steers from each treatment-pasture combination (24 steers per year). Diet quality was determined monthly using esophageally cannulated yearling heifers. Treatments were control, 1.5 kg safflower-based supplement (22.0% CP), 1.2 kg soybean meal-based supplement (25.8% CP), and 1.2 kg safflower and soybean meal based supplement (25.8% CP). Steers were individually fed supplement once every third day. Grazing began in mid-May. Dates of supplementation were 16 August to 4 October, 1993 and 18 July to 8 September 1994. Forage IVOMD declined from 72 to 56% and CP declined from 16.6 to 7.8% between the beginning and end of the grazing season. No differences were observed in weight gains, forage intake or digestibility among the treatments (P > .10). Weight gain averaged 1.19 kg/d before and .74 kg/d during the supplementation period. Forage intake differed by year for the late summer supplementation period (P < .01) but not during the early summer grazing period (P > .10). Forage intake averaged 19.0 g/kg BW before supplementation. During supplementation, forage intake averaged 21.2 g/kg BW in 1993 and 18.7 g/kg BW in 1994. Supplementation was not beneficial to weight gain of yearling cattle grazing forage of the quality and quantity observed in this study.