|Short, Robert - RETIRED ARS|
Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2003
Publication Date: March 1, 2004
Citation: Grings, E.E., Short, R.E., Haferkamp, M.R., Heitschmidt, R.K. 2004. Late summer protein supplementation for yearling cattle in the northern great plains. Journal of Range Management 57:358-364. Interpretive Summary: Diversifying an operation to include summer grazing of yearling cattle in addition to cow-calf production can aid in decreasing economic risk. 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 Northern Great Plains rangelands is in meeting the nutrient needs for growth when forage quality or quantity begin to decline in late summer. Options are to remove cattle from rangeland or to supplement cattle with the nutrients that have become limiting. The objective of this study was to evaluate late summer protein supplementation to improve forage intake and weight gain compared with a nonsupplemented control group of steers. Studies were conducted over three summers. A soybean meal-based supplement was compared to a nonsupplemented control in Study 1. For Study 2, treatments were a nonsupplemented control or protein supplements with safflower meal, soybean meal or a combination as the protein source. Protein supplementation was started after forage quality began to decline in late summer. There was no effect of supplementation on weight gain or intake of yearling steers. Rate of gain did decline as grazing season progressed. Protein supplements, fed every third day, were not beneficial to weight gain of yearling cattle grazing forage of the quality and quantity observed in this study.
Technical Abstract: Two studies were conducted to evaluate late summer protein supplementation for growing steers on Northern Great Plains rangeland. In one study, crossbred yearling steers (N = 84 per year, avg initial weight = 275 kg) were allotted to 1 of 2 treatments replicated in 3 pastures in each of 3 years. Treatments were summer-long grazing with or without protein supplementation in late summer. Protein supplement (25.8% crude protein) was fed at a rate of 1.68 kg (dry matter basis) every third day. In 1995, a third treatment was added to additional pastures consisting 1.62 kg dry matter of a 40% crude protein supplement fed every third day. There was no weight gain response to protein supplementation. In the second study, grazing yearling steers were fed either no supplement, 1.5 kg of a 22.0% crude protein safflower meal-based supplement, 1.2 kg of 25.8% soybean meal-based supplement or 1.2 kg of a 25.8% safflower and soybean meal-based supplement every third day in late summer. Forage intake and digestibility were measured monthly. Weight gain, forage intake, and digestibility were not affected by supplementation. A third study using ruminally cannulated steers fed grass hay and the protein supplements showed an increase in ruminal ammonia concentrations but no other appreciable change in ruminal fermentation with protein supplementation. Supplementation with 310 to 648 grams of protein every third day was not a viable means to increase gains of steers grazing Northern Great Plains rangelands during late summer under the conditions of this study.