Lactation and Growth of Dairy Cows and Steers from Large Amounts of Dried Whey

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Abstract
Large amounts of dried whole whey (65% of concentrate mix) were fed to 10 lactating cows during 16 wk. Dried whole whey replaced all of corn, dicalcium phosphate, trace mineralized salt and portions of oats and soybean meal which were included in the concentrate mix fed to 10 control cows. All received the respective concentrate mix at 1 kg/3 kg milk produced, 4 kg alfalfa hay daily, and corn silage ad lib. Milk production tended to be less for dried whole whey diet (22.8 and 24.5 kg/day), although 4% fat-corrected milk and solids-corrected milk were similar because of a higher percent fat (3.77 and 3.46) and percent protein (3.08 and 2.99) in the milk. In a 2nd trial, 12 Holstein steers weighing about 300 kg were in a 2 .times. 2 factorial experiment of 16 wk evaluating dried whole whey (65% of concentrate mix, 45% of total dry matter intake) and limestone (2.8% of dry matter intake). The control diet contained corn, soybean meal, vitamins A and D, minerals and corn silage. Diets consisted of 70% of dry matter as concentrate mix and 30% as corn silage fed ad lib as a total mixed ration. Weight gains and dry matter intakes were similar for steers fed dried whole whey and control diets but tended to be less with limestone diets. Samples of rumen contents from cows and steers fed dried whole whey contained more butyrate and less propionate than from animals fed control diets. Rumen ammonia concentrations were lower in steers fed dried whole whey and limestone additions had no effect on rumen volatile fatty acids, ammonia or fecal starch.