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The Comparative Value of Urea and Linseed Meal for Milk Production*

Journal of Dairy Science
American Dairy Science Association
DOI: 10.3168/jds.s0022-0302(43)92766-3
  • Biology


Summary 1. Twenty-four Holstein cows were involved in a study of the possibility of substituting urea nitrogen for linseed oil meal nitrogen in milk production. Fifteen of the cows completed a lactation on each of the basal, urea, and the linseed meal rations. Six of the cows were involved in a study of the effect of corn molasses on urea utilization. Each completed a lactation on a urea, a urea-molasses, and a urea ration. 2. On the basal ration the protein level in the concentrate mixture was about 10 per cent. With the added urea or linseed meal it was 18 per cent protein equivalent. Timothy hay and corn silage constituted the roughage. 3. In milk production some cows led on the linseed meal ration while others led on urea with average differences favoring linseed meal in too small a degree to be statistically significant. On the basal ration, with its lower protein content, less milk was generally produced than on either of the other two rations and the cows failed to keep up their live weight as well as on either the linseed meal or urea rations. It appears that with this species and a suitable ration in respect to carbohydrate content, urea can function as a source of nitrogen as effectively as can oil meal. 4. In respect to weight of calves and breeding history, one ration appeared as efficient as the other. 5. The composition of the milk, the flavor of the milk, and the composition of the blood were not different on the two rations. 6. There was no sustained and positive evidence that molasses feeding on a grain ration improved the utilization of urea. With the starches of the grains available, sugar is rapidly produced in the rumen and serves as a suitable substrate for the organisms. 7. Urea (46 per cent nitrogen) should not be fed at a rate greater than about 1 per cent of the dry matter of the ration or 3 per cent of the concentrate mixture. In dairy sections where hay, silage, and home grown grains are available, a suitable nitrogen level in the concentrate mixture can be secured by the addition of 3 pounds of urea to 97 pounds of the grain mixture.

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