Supplementation to Compensate for Differing Stocking Rates for Steers Grazing Wheat Pasture

Throughout the southern Great Plains, the inability to predict optimum stocking rates for wheat (Triticum aestivum L.) pastures limits efficient use of wheat forage by stocker cattle. This is particularly true during the spring graze‐out period when forage production can vary greatly due to environmental conditions. The objectives of this study were to evaluate animal performance and economic returns for systems in which increased stocking rates on spring wheat pastures were accompanied by increasing supplementation levels. Steers averaging 671 lbgrazed wheat pastures from March through May in the spring of 1987 and 1992. As stocking rate increased, the amount of 11.6% crude protein (CP) supplement consumed increased from 0 to 1% of body weight (BW). Individual steer performance was similar across stocking rates, but beef production per acre increased (P < 0.05) with increasing stocking rate. As wheat matured, forage quality decreased (P < 0.05) and forage available for grazing became primarily stem (P < 0.05). As stocking rate increased, pasture cost per head decreased. At the highest stocking rate, return ($/acre) was $16.89 greater than at the lowest stocking rate. Grain‐based supplements can be fed at levels up to 1% BW daily to steers grazing spring wheat pastures to allow stocking rates to be increased to ensure maximum forage use. Research Question Wheat producers in the Southern Great Plains use winter wheat as pasture for young stocker animals from fall through spring. The fall‐winter phase is characterized by using accumulated forage, while the spring is dependent upon potential growth that can be described as very rapid over a short period with decreasing forage quality at the end of the grazing period. During the spring, the stocking rate and individual animal performance is greater than in the fall‐winter. The spring grazing season is less than half the length of the fall‐winter, compounding the problem of selecting the proper stocking rate to efficiently use the spring forage produced. The objective of this experiment was to evaluate animal performance and economic returns for systems in which increasing stocking rates on spring wheat pastures were accompanied by increasing supplementation level. Literature Summary A supplementation system has been developed for fall‐winter wheat grazing to compensate for variation in forage production from year to year without decreasing individual animal performance. In this system, animals have ad libitum access to silage allowing them to select the amount of supplemental feed. However, spring stocking rate is two to four times that observed in the fall‐winter and the potential animal gain per acre is greater in the spring than in the fall. Systems to compensate for different grazing pressures due to variation in spring forage production have not been developed. Study Description The study was conducted across two spring wheat grazing seasons. Steers, averaged 671 lb, were assigned to one of three stocking densities. As stocking density increased, the amount of 63% grain pellet provided was increased to compensate for decreased forage allowance. Based on previous observations, the dry matter intake of steers in this study was assumed to be 2.2% of body weight and the appropriate stocking rate to provide adequate forage to be 2 steedacre. As stocking rate was increased the amount of supplement fed as a percentage of body weight was increased (Table ). Wheat pasture (TAM 101) was produced under no‐till management and was grazed during the fall‐winter period prior to the spring grazing period. Applied Question If forage production is less than anticipated and as a result the grazing pressure is increased beyond the normal capacity of the pasture, can supplemental feed compensate for the increased grazing pressure without affecting animal performance and economic return? Stocking density, head/acre, was increaesd by 20 or 48% for the low and high supplemented groups, respectively. When the number of grazing days was applied to calculate the grazing day/acre, the stocking rate for a 46‐d grazing period was increased by 16 and 49% over the 2 yr period for the two supplemented groups (Table ). Individual animal performance was not different among the three groups, therefore beef production (lb/acre) was higher for pastures stocked at 2.98 AU/acre and fed supplemental feed at 1% of body weight than the other two treatment groups. As stocking rate increased pasture cost per head decreased, but the cost of additional feed increased the total inputs for pasture and feed above those of the control group (Table ). Because beef production per acre was increased as stocking rate increased, the return per acre was greatest for the high supplement group stocked at 2.98 head/acre. Recommendation A pelleted supplement can be limited‐fed to steers grazing spring wheat to compensate for increased grazing pressure without adversely affecting ADG. In the present study, increases in grazing pressure were intentional. Presumably, similar responses would occur in situations where increased grazing pressure results from less‐than‐expected forage production. Under either scenario, the goal is to allow the animal to consume as much wheat as possible and to meet the nutrient deficiencies through supplemental feed. Effect of stocking rate/supplementation treatment on stocking rate, supplementation intake, and animal performance. Treatment group Item Control Low supplementation High supplementation Stocking rate, head/acre 2.00 2.32 2.98 Supplement intake, % BW 0 0.58 1.02 ADG, lb/d 2.11 2.00 2.33 Beef uroduction. lb/acre 159 175 255 Economic analysis for each stocking rate/supplementation treatment. Treatment group Item Control Low supplementation High supplementation Pasture cost, $/head 30.05 25.74 20.20 Supplement cost, $/head 0 5.57 9.79 Return. $/head 23.17 19.91 21.23 Return. $/acre 46.38 46.19 63.27