176 Performance, digestion, and passage of whole cottonseed offered either as libitum or under restriction to beef cows nursing calves

Abstract

In the southeastern U.S., whole cottonseed (WCS) is a readily available, nutritious, and cost-effective feedstuff for beef cattle. The NCR (2016) estimates that whole cottonseed contains approximately 52% neutral detergent fiber (NDF), 24% crude protein (CP), and 18% crude fat. Feeding recommendations on feeding WCS in beef cattle systems were developed in the 1980’s based on the whole cottonseed quality of that time. Based on recent studies, we have demonstrated changes in seed quality in the Southeast due to the development of new varieties. Therefore, the purpose of this study was to determine WCS supplementation rates in beef cow diets based on industry changes in cottonseed quality, especially in the Southeast. The experiment was conducted as a generalized complete block design with two feeding pens (blocks) of eight cow-calf pairs each. Cow-calf pairs were then randomly allocated into four treatments: a negative control receiving bermudagrass (BG) hay (CON), BG plus supplemental WCS at 15% targeted dry matter intake (DMI), BG plus WCS to achieve a crude fat allowance of 4% dry matter intake (FAT), and BG plus ad libitum supplemental WCS (LIB). Cows offered LIB consumed the most WCS (P < 0.01; 7.9 kg/d), followed by FAT (3.3 kg/d), then DMI (1.8 kg/d). However, total daily intake was greatest (P = 0.03) from CON (14.9 kg/d) and LIB (13.7 kg/d) and least from DMI (10.3 kg/d), with FAT intermediate (12.4 kg/d). There was no effect of treatment on dam milk production (P = 0.60) nor calf ADG (P = 0.47). Results are interpreted to mean that WCS may be offered beef cows nursing calves at levels approaching ad libitum consumption without adverse responses, though this may not achieve economic production goals.