The effect of feeding soybean oil to mid-lactation dairy cows on milk production and composition and on diet digestion

Abstract

Mid-lactation Holstein cows were used to test the effect of feeding 3% soybean oil (SBO) on total mixed ration intake, apparent digestibility, milk production, and milk composition. Effect of SBO on rate and extent of rumen digestion was determined with nylon bags incubated in the rumen of fistulated cows. SBO reduced fibre digestion by 9% and degradability by 20%. Feeding of SBO caused a slight reduction in total mixed ration (TMR) intake, milk production, and milk protein production. However, these reductions were minor compared with the large reduction in fat production (0.2 kg d–1). Key words: Milk composition, soybean oil, digestibility, dairy cow