WHOLE COTTONSEEDS OR A COMBINATION OF SOYBEANS AND SOYBEAN HULLS IN THE DIETS OF LACTATING DAIRY-COWS

Whole raw soybeans and soybean hulls were evaluated as a dietary repla cement for whole cottonseed as determined by rumination and total chew ing activity, milk fat percentage, and efficiency of 4% fat-corrected milk (FCM) production. Twenty-six Holstein dairy cows (14 multiparous; 35 +/- 12 d of lactation) were assigned randomly to one of two total mixed rations (TMR) for 15 wk. The whole cottonseed TMR and the soybea n plus soybean hull TMR contained 40% of a 45:55 mixture of alfalfa an d corn silages (dry matter basis) and either 15% cottonseed or 15% soy beans, 8% soybean hulls, and 0.7% sodium bicarbonate. Both TMR provide d 60% of dietary neutral detergent fiber from forage. The TMR, fed twi ce daily, were isonitrogenous (17.5% crude protein) and equal in neutr al detergent fiber (30%). The TMR had no effect on dry matter intake ( 24.8 kg/d). The cottonseed TMR stimulated greater rumination and total chewing activity. Although milk production was greater for cows fed t he cottonseed TMR (35.7 vs. 34.1 kg/d), milk fat production was unaffe cted by TMR (3.72%). The efficiency of 4% FCM production was similar f or cows fed the cottonseed and soybean plus soybean hull TMR (1.33), a nd both TMR resulted in a positive net energy balance (10.9 Mcal/d). A combination of soybeans, soybean hulls, and sodium bicarbonate was an effective alternative to whole cottonseed as measured by the efficien cy of FCM production.