|Hogan, Robert -|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 28, 2011
Publication Date: January 25, 2012
Citation: Gunter, S.A., Hogan, R. 2012. Effects of stocking and supplementation rates on cattle performance and return when grazing mixed-grass prairie in Northwest Oklahoma [abstract]. p. 128. 65th Annual Society for Range Management Meeting. Spokane, Washington. Technical Abstract: Mixed grasslands with an over story of sand sagebrush (Artemisia filifolia) inhabits approximately 6 million ha of sandy soils along major rivers across the Southern and Central Plains. The objectives of this research were to determine the effects of stocking and supplementation rates on cattle performance and economic returns in northwest Oklahoma. The experimental treatments had a 3 x 2 factorial arrangement; the first factor was initial stocking rate (body weight [BW] = 221 ± 1.2 kg) at 30, 33, or 39 animal-unit-d (AUD)/ha annually. The second factor was supplementation rate. Steers were fed a 41% crude protein cottonseed meal-based feed at either 0.9 or 1.4 kg/d. Grazing was initiated in late-January and ended in late-April (89 d). As total cost, excluding supplementation cost, is constant for each factor, economic performance of supplementation will be evaluated on marginal value of gain versus marginal cost of gain. Economic performance of stocking rate will be analyzed on dollars of net revenue/ha. Standing herbage dry matter (kg/ha) forbs and graminoids at initial stocking (718 ± 206) and the end (716 ± 192) did not (P = 0.27) differ by either treatment. Average daily gain (ADG; kg) and ending BW (kg) interacted (P < 0.09) by treatments. At 0.9 kg/d, stocking rate had a quadratic (P < 0.01) effect on ADG and ending BW (0.43, 0.57, or 0.47 and 261, 269, or 261 for 30, 33, and 39 AUD, respectively). At 1.4 kg/d, stocking rate did not affect (P > 0.10) ADG or ending BW (0.56, 0.53, or 0.51 and 269, 269, or 267 for 30, 33, and 39 AUD, respectively). BW gain/ha (kg) at 0.9 kg/d had a quadratic (P < 0.01) effect (24, 32, or 32 for 30, 33, and 39 AUD, respectively). However, at 1.4 kg/d, stocking rate had a linear (P < 0.01) effect on BW gain/ha (29, 31, or 35 for 30, 33, and 39 AUD, respectively). On this prairie type, the effect of stocking rate was dependent on supplementation rate. At lower supplementation rates, cattle performance was more sensitive to stocking rate than at higher supplementation rates.