Response of the Lactating Cow to Different Methods of Incorporating Casein and Coconut Oil in the Diet

Effects of diets containing 10% coconut oil in various physical forms on milk fat and protein secretion, rumen fermentation, and food intake of cows are reported. Coconut oil in unbound forms or as a spray-dried powder of oil and casein reduced total milk fat secretion. This was due to a decreased intramammary synthesis of fatty acids which exceeded the transfer to milk of fatty acids from the coconut oil. There were associated decreases in the ratios of acetic to propionie acid in rumen fluid. Coconut oil-casein powders treated with formaldehyde, however, did not affect volatile fatty acids in the tureen or the intramammary synthesis of fatty acids, and, therefore, the total output of milk fat was increased. Unbound coconut oil or untreated coeonut oil-casein powders reduced milk protein secretion. Untreated casein alone or treated coconut oil-casein powders did not affect milk protein, Food intake was lower on diets containing unbound coconut oil or untreated coconut oil-casein powder than on diets containing no coconut oil or formaldehyde treated powders of coconut oil and casein.