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Utilization of a Formaldehyde Treated Casein-Safflower Oil Complex by Growing and Finishing Steers

U.S. Department of Agriculture, Beltsville, Maryland 20705 and Berkeley, California 94710

Abstract

Sixteen 230 kg steers were fed a 65% ground hay-35% concentrate diet to which the following was added (expressed as a percent of total ration) resulting in six treatments: 5 or 10% casein, 10 or 20% unprotected casein-safflower oil (1/1), and 10 or 20% protected casein-oil. The casein-safflower oil complex was protected from ruminal fermentation by treating the emulsion with formaldehyde. There were no differences (P>.05) related to level of casein or to formaldehyde treatment of casein-oil in percentage of dry matter, energy or fiber digestibility nor in percentage of retained nitrogen. Crude protein digestibility was depressed (P<.05) by the presence of oil and tended to be lower as a result of formaldehyde treatment. The plasma concentration of total essential amino acids tended to be higher (P<.05) for steers fed formaldehyde treated casein-oil than for steers fed untreated material.

There were no differences (P > .05) related to level of casein or to formaldehyde treatment of casein-oil in percentage of dry matter, energy or fiber digestibility nor in percentage of retained nitrogen. Crude protein digestibility was depressed (P < .05) by the presence of oil and tended to be lower as a result of formaldehyde treatment. The plasma concentration of total essential amino acids tended to be higher (P < .05) for steers fed formaldehyde treated casein-oil than for steers fed untreated material.

The percentage of C14, C14:1, C16 and C16:1 tended to decrease as C18:1 increased in steers fed unprotected material or as C18:2 increased in steers fed protected material. At 42 days average C18:2 content of adipose tissue of protected and unprotected casein-oil treatments was 11.1 and 2.9% (P< .001), respectively, while that of casein treatments was 1.8%. There were no differences (P > .10) among treatments in the results of a taste panel evaluation for overall desirability of the meat. Within 14 days steers fed treatments with safflower oil had higher (P < .001) plasma cholesterol concentrations than steers fed no oil.

A second experiment was conducted with four 474 kg fistulated steers. The basal diet was supplemented with either 5.7% casein, 11.4% unprotected casein-oil or 11.4% protected casein-oil. Steers fed the formaldehyde treated casein-oil had markedly lower ruminal ammonia concentrations than the other steers. C18:2 did not increase in fat tissue of these steers to the extent of the lighter weight steers of the first experiment, being 5.4% of the fatty acids in longissimus muscle of two steers fed protected material for 48 days.

¹ Ruminant Nutrition Laboratory, Nutrition Institute, Agriculture Research Service, Beltsville, Maryland.

² Western Regional Research Laboratory, Agriculture Research Service, Berkeley, California.