The objective was to study the effect of the monensin on milk yield and milk composition, somatic cell count, body condition score, serum parameters and reproductive aspects high producing Holstein cows in early lactation. Fourty-four cows with daily milk yield of the 33.44 ± 4.93 liter of milk were assigned to a completely randomized design with two treatments: control (C) and other with controlled released monesin capsule with eficacy of 100 days (300 mg/cow/day). The individual administration of the monensin capsule was made 30 day before the probable calving time. Monensin did not affect the milk yield and milk composition, somatic cell count, body condition score and glucose and BHBA (beta-hidroxibutirate) concentration in the cow blood serum. However, decreased concentration of NEFA (Non esterified fatty acid) in blood serum of cow with 60 days in milk. Service period and number of services per conception was not affected by treatments, however, the administration monensin decreased the number of the cows that showed retained placenta and laminitis. The administration monensin for high producing Holstein cows in early lactation did not change the milk production and composition. However, decrease the concentration of NEFA 60 days post calving and the incidence of laminitis and retained placenta in the post calving cows.
NEFA; glucose; ionosphor; milk composition and yield; reproductive aspects
