Effects of Winter Grazing Stockpiled Cool-Season Grass Pastures and Method of Initiating Stockpiling on Fall-Calving Cow Production Costs in Comparison to Winter Drylot Hay Feeding Systems

To compare costs of grazing stockpiled forages, initiated by different methods, to winter hay feeding for fall-calving beef cows, nine 0.45-ha paddocks of cool-season grasses were blocked in triplicate and randomly assigned one of three treatments: spring strip-grazing (SPG), summer strip-grazing (SMR), or summer hay harvest (HAY). For SPG and SMR, live forage mass was estimated with a falling plate meter (4.8 kg/m²), allocated in daily strips (2.4% of BW/d) to ten fall-calving, Angus cows. Hay from HAY paddocks was harvested as large round bales, weighed, core-sampled, and stored outside. Paddocks were fertilized with 50.4 kg nitrogen/ha as urea. October through January, monthly forage samples were hand-clipped to 2.54 cm from six, 0.25-m² locations within each paddock. In November, bales were weighed, dissected, re-weighed, and cored to measure nutritional value and recovery of un-weathered hay. Forages were weighed, oven-dried for 48 h at 65 ᵒC, re-weighed to determine DM content and analyzed for IVDMD, NDF, ADF, ADL, and CP. The Cornell Net Carbohydrate and Protein System was used to meet ME requirements of lactating, beef cows (523 kg SBW) using monthly nutritional values of forage or hay with distillers dried grains (DDGS). Carrying capacity (CC) of stockpiled pastures was determined as total forage fed and initial stockpiled forage mass, adjusted for grazing efficiencies of 60% for SPG grazing and 70% for SMR and HAY. CC of a drylot system (DRY), comparable to HAY but without stockpile grazing, was calculated from HAY forage mass in October and amount of hay produced, adjusted for harvest, storage, and feeding losses. Gross feed costs (GROSS, $/hd/d) were calculated as the costs of land rental, DDGS, fencing, harvest, fertilizers, and labor on a fixed land base, divided by winter CC. Net feed costs (NET, $/hd/d) were calculated as total costs on the fixed land base less summer grazing or hay harvest income, divided by winter CC. Carrying capacity was greater for DRY when compared to all other systems (P < 0.05), but did not differ between stockpile systems (P > 0.10). Neither GROSS nor NET costs differed between systems (P > 0.10). DRY system incurred greater (P < 0.10) total costs/ha than stockpile systems. There was no significant difference in total cost ($/ha) between SPG, HAY, and SMR (P > 0.10). Although DRY systems had greater total costs, there were no differences in GROSS or NET with yields, costs, and returns utilized in this study.