Abstract

MARQUES, Lúcia Treptow et al. Supplementation of Holstein cows at an extended lactation stage. Cienc. Rural [online]. 2010, vol.40, n.6, pp. 1392-1398. ISSN 0103-8478.  http://dx.doi.org/10.1590/S0103-84782010000600024.

The trial aimed to verify the effects of two feeding supplements: low and high level supplementation given to cows at an extended lactation stage upon productive aspects, physical-chemical composition of milk and blood biochemical profile. Twelve lactating Holstein cows, with 514kg of body weight, body condition score of 3.5, yielding 13L milk cow^-1 day^-1 and approximately 349 days of lactation were used. Treatments were low or high level of supplementation for lactating cows grazing natural range pasture. Cow's body weight and body condition score, individual milk yield, physical and chemical characteristics and somatic cells count, besides biochemical blood profile were evaluated. Increased nutrient supply augmented body weight gain, body condition score, fat corrected milk, milk fat and total solids contents, but did not change the others milk components nor blood biochemical profile. Increasing nutrient supply for cows at an extended lactation might be a valuable option to match milk productivity and improved physical aspects of dairy cows kept on grazing systems, without adverse effects upon milk components yield.

Keywords : blood biochemical profile; milk physical-chemical composition; milk yield; non-acid unstable milk.