Abstract

MODESTO, E.C. et al. Substitution of pasture by cassava foliage silage in the diet of dairy cows: production and quality of milk and milkfat. Arq. Bras. Med. Vet. Zootec. [online]. 2009, vol.61, n.1, pp. 174-181. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352009000100025.

The effect of a partial substitution of pasture for cassava foliage silage (CFS) on milk production and composition on fat quality of Holstein cow milk was studied using a replicated 4 X 4 Latin square design with four treatments. Regression was used for the comparison of nutrition levels. The control diet contained 50% pasture and 50% concentrate on a dry matter basis. The substitution levels of pasture for CFS were 0, 20, 40, or 60% of the forage dry matter. All diets were isonitrogenous. The analyzed parameters were: milk production (MP); 4% fat-corrected milk production (FCM); acidity; density; concentrations of fat, protein, lactose, urea, and total solids; somatic cell counts (SCC), and milk fatty acids profile. There was a linear decrease effect (P<0.05) in MP, FCM, and urea content with increasing levels of CFS in the diet. Concentrations of gamma linolenic and palmitic acids in milk fat linearly increased (P<0.05) with higher proportions of CFS in the diet. Other contents of milk fatty acids remained similar among treatments as well as acidity; density; concentrations of protein, fat, lactose, and total solids; and SCC.

Keywords : dairy cattle; by-product; milk production; fatty acid profile.