Lasalocid Supplementation of Dairy Cow Diets in Early Lactation11Supported by the Illinois Agricultural Experiment Station (Hatch 35-397) and a gift from Hoffmann-LaRoche, Inc., Nutley, NJ 07110.

Abstract

<h2>Abstract</h2> A 36-cow study was conducted to evaluate the effects of lasalocid on feed intake, milk production and composition, and various blood metabolites in early lactation. Multiparous Holstein cows were assigned at parturition to a total mixed diet containing 33% corn silage, 17% chopped alfalfa hay, and 50% concentrate mix on a DM basis for 10 wk. An additional 2.3kg of alfalfa hay was fed during the first 7 d in milk (DIM). Diets were supplemented with 0, 180, or 360 mg/d of lasalocid in a completely randomized design. Covariant-adjusted mean (the covariate was mature equivalent milk production from the previous lactation) DMI; milk and fat-corrected milk (FCM) production; percentages of milk fat, protein, and solids-not-fat; milk somatic cell count; BW; body condition score; and concentrations of glucose, β-hydroxybutyrate, and non-esterified fatty acid (NEFA) in blood were unaffected by supplementation with lasalocid. A dose of 360 mg/d of lasalocid may not be enough to significantly affect high-producing cows consuming >20 kg/d of DM.