Production Response of Lactating Dairy Cows to Whole Cottonseed with Elevated Concentrations of Free Fatty Acids in the Oil

Three hundred lactating Holstein cows were used in a 3 × 3 Latin square trial to determine the impact of feeding whole cottonseed with different concentrations of free fatty acids (FFA) in the oil. Treatments included whole cottonseed with low (10.7% FFA, LO), high (35.5% FFA, HI) or a 50:50 blend of LO and HI (23.1% FFA, MED). Whole cottonseed provided 8.5% of the total dietary DM in the experimental diets, which were fed to each pen of 100 cows. Cows were assigned to each pen by parity, days in milk, and milk yield. The DMI and milk yield were similar for all treatments and averaged 27.5 and 39.9 kg/d, respectively. Milk fat percentage and yield were lower for cows fed diets containing HI (2.87% and 1.14 kg/d) compared with LO (3.02% and 1.21 kg/d) and MED (3.13% and 1.26 kg/d). No differences were observed in percentage or yield of milk protein among treatments, which averaged 2.97% and 1.18 kg/d, respectively. Yield of energy corrected milk was lowest for HI, reflecting the reduced yield of milk fat. Concentrations of milk urea N were lower for LO compared with HI. Results of this trial indicated that feeding whole cottonseed with elevated FFA does not negatively impact DMI or milk yield of lactating dairy cows although reduced milk fat percentage and increased milk urea N concentrations are possible.