123. Effect of Whole Cottonseed Delivery Frequency on Beef Cattle Performance in Warm-season Forage Systems

Abstract In the southeastern United States, whole cottonseed (WCS) is a widely available, nutritious, and cost-effective feed option for beef cattle. According to the NRC (2016), WCS consists of about 52% neutral detergent fiber (NDF), 24% crude protein (CP), and 18% crude fat. Feeding guidelines for WCS in beef cattle diets were originally developed in the 1980s, based on the seed quality at that time. However, changes in cotton varieties have altered nutritional composition in the Southeast. Recent research at Auburn University evaluated the level of whole cottonseed inclusion in the diet of lactating beef cows and demonstrated that cows could effectively be fed WCS up to ad libitum consumption without adverse effects. However, producers have raised questions about how these responses may change based on frequency of feed delivery. Thus, our study aimed to determine the optimum delivery frequency of WCS to support beef cow performance during gestation. This experiment was conducted as a completely randomized design with replicate pastures (n = 16; 0.8 ha) of sorghum-sudangrass (Sorghum × drummondii) and signal-grass (Urochloa spp.). Cows (n = 32) in the third trimester of gestation were randomly assigned to pastures, and pastures were assigned to one of four feeding treatments: pasture-only (CON) or supplemental WCS delivered two times weekly (2X), three times weekly (3X), or daily (7X). For the treatments receiving WCS, feed was offered to achieve a 4% crude fat intake. Cows in each treatment increased total BW over time (P < 0.01) However, there was no effect of treatment on BW (P = 0.27), BW gain (P = 0.19), or blood urea nitrogen concentration (P = 0.58). These findings suggest that gestating beef cows may consume WCS at varied frequencies to match management practices without negative effects, though this may not always align with economic production goals.