Effects of Feeding Stockpiled Tall Fescue Versus Tall Fescue Hay to Late Gestation Beef Cows on Steer Offspring Carcass Quality and Yield

We hypothesized that cows grazing stockpiled tall fescue (STF) during late gestation would have greater nutrient intake than cows fed summer-baled hay, which would result in increased prenatal nutrient supply and ultimately improved fetal development and subsequent carcass quality and yield. Multiparous, spring-calving crossbred beef cows (yr 1: n = 48; yr 2: n = 56) either strip-grazed STF (n = 4 pastures/yr, 12.3% CP, 63.9% NDF; DM basis), or received ad libitum tall fescue hay (6.9% CP, 66.6% NDF; DM basis) fed in uncovered drylots (n = 4 pens/yr) from d 188 ± 2 (SEM) until calving. Treatments were terminated within a week post-calving, and all cow-calf pairs were managed as a single group until weaning in each year. Post-weaning, steer offspring (yr 1: n = 17; yr 2: n = 25) were placed under common management and fed growing and finishing diets in each year. Steers were slaughtered in groups (yr 1: 4 slaughter groups; yr 2 = 3 slaughter groups) based on degree of finish. At slaughter, samples were collected from the longissimus dorsi (LD) for determination of Warner Bratzler shear force, cooking loss, fat content, and moisture content. Data were analyzed with maternal forage system, year, and their interaction as fixed effects in the model. Dam pasture or pen was considered the experimental unit. It has been previously reported that birth weight was reduced in calves born to cows fed hay during late gestation (main effect of treatment only), suggesting impaired fetal growth due to low forage nutrient availability. Despite this, there was no effect (P > 0.10) of maternal forage system on final BW at slaughter, carcass weight, yield grade, marbling score, backfat thickness, ribeye area, KPH, or dressing percent. Additionally, Warner Bratzler shear force, cooking loss, percent moisture, and percent fat of LD were not impacted by maternal forage system (P > 0.14). In conclusion, maternal nutrition during late gestation did not impact steer offspring carcass quality or yield, nor did it affect tenderness or cooking loss of the LD, despite the differences observed in cow performance and calf birth weight. This suggests that late gestational forage systems used in the current study did not impair fetal muscle or adipose development enough to cause long-term negative impacts on product quality or yield.