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Department of Dairy Science, Michigan State University, East Lansing 48824
ABSTRACT
Seventy-five lactating Holstein cows were fed rations differing in the following additions of nitrogen to concentrate: none, 17% soybean meal, 2.5% urea, 9% and 18% fermented ammoniated condensed whey. The whey product contained 48% crude protein and was prepared by inoculating cheese whey with Lactobacillus bulgaricus, fermenting at 43 C for 24 h while infusing aqua ammonia (22% nitrogen) to maintain a pH of 5.5, and condensing to 54% solids. Treatments began about 130 days postpartum and lasted for 70 days. Corn silage was fed ad libitum and concentrate at .4 kg/kg milk. Dry-matter intakes of silage were lower for the negative control than supplemented rations. All nitrogen additions increased milk yields, particularly for high producing cows. Persistencies averaged .80, .89, .92, .86, and .89 for the respective treatments as compared to the pretreatment period. Milk yields increased linearly with increased whey. Liveweight gains were lower for negative controls than supplemented groups. Treatment did not affect content of milk fat, protein, or solids-not-fat, but production of these constituents was greater for supplemented groups. Rumen ammonia and urea nitrogen of plasma reflected nitrogen in rations. Fermented ammoniated condensed whey and urea equalled soybean meal in maintaining milk yields of cows when these sources furnished 27% of the total nitrogen for lactating cows fed rations containing about 13% crude protein.
1 Published with the approval of the Director of the Agricultural Experiment Station as Journal Article no. 7509.
2 Partially supported by Calor/American, Okemos, MI 48864.
3 Southern Piedmont Research and Continuing Education Center, Virginia Polytechnic Institute and State University, Blackstone 23824.
4 Cooperative Extension Service, Colorado State University, Fort Collins.
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