Evaluating efficacy and limitations of winter grazing systems for beef cattle on animal production and soil properties

Two studies were conducted to address concerns confronting the beef industry in regards to the application of winter feeding programs. The first experiment was designed to determine if \u27Fawn\u27 endophyte-free tall fescue (Festuca arundinacea L.) and red clover (T. pratense L.) pasture stockpiled for winter grazing was of adequate nutritional value to maintain growth of mid to late gestation Angus and Angus x Simmental heifers. Experimental treatments included high (1.17 heifers/ha) and low (0.84 heifers/ha) stocking rates, high (heifer body weight and conceptus growth) and low (conceptus growth only) corn gluten feed supplementation rates, and feeding of hay with the high corn gluten feed supplementation rate as a control comparison. Mean seasonal concentrations of IVDMD were greater (P\u3c0.05) and NDF, ADF, and ADIN were lower (P\u3c0.05) in the stockpiled forage than hay. Average daily gain and body condition score increases were greater (P\u3c0.05) for heifers grazing stockpiled forage at either stocking rate than heifers fed hay in both years. Mean production costs were 0.86, 0.87, 0.64, 0.65, and 1.17 $/d for heifers grazing stockpiled forage at the low stocking rate without and with corn gluten feed, grazing stockpiled forage at the high stocking rate without or with corn gluten feed, and fed hay and corn gluten feed. The second experiment compared changes in soil physical properties and subsequent soybean yields of corn crop residue fields grazed by mature pregnant Angus cows compared to nongrazed control paddocks. Each paddock was stocked at a rate of 3.7 cows/ha and was grazed in five consecutive 28-day periods over the winter season. Grazing corn crop residue did not affect soil bulk density, but increased penetration resistance to a depth of 10.5 cm in paddocks grazed in October and November. Cattle grazing had no effect on subsequent soybean plant population, but soybean yields decreased with increased soil penetration resistance (r2=0.36). Soybean yields also increased as the proportion of the time soil temperature was below 00 C increased (r2=0.72)