Assessment of lactoferrin supplementation in milk replacer on calf growth, feed efficiency and scouring incidence preweaning and postweaning.

We investigated the hypothesis that supplementing milk replacer (MR) with exogenous lactoferrin (LF) would improve average daily gain (ADG) and feed efficiency and decrease scouring incidence in dairy calves. Lactoferrin is an antimicrobial and anti-inflammatory glycoprotein naturally found in bovine colostrum and milk that is low in MR. Previous studies suggest that supplementing LF to MR enhances ADG and feed efficiency while reducing disease occurrence in pre-weaning dairy calves. In our experiment, 103 Holstein heifer calves were randomly assigned to 1 of 4 treatments in a randomized complete block design from birth to d56 of age. Each calf received 340.1 g/d of 24% protein, 20% fat basal MR fed twice daily from d1 to 42 and once daily from d43 to 49, supplemented with 0 (L0), 1 (L1), 2 (L2) or 4 (L4) g/hd/d of LF treatment (45% purity). Calves were weaned at 49d of age. Body weight was measured at d1, 14, 28, 42, 49 and 56 of age. Faecal scores were measured weekly. Milk replacer and calf starter intake was measured daily and calculated biweekly. Data were analyzed using a linear mixed model with fixed effects of LF inclusion, and random effects of source herd and nursery room. In the first two weeks of life, ADG and gain-to-feed ratio (G:F) were numerically (non-statistically) increased in L4 tended compared with L1 and L2, but this effect was not maintained throughout the rest of the pre-weaning period or entire experiment. Average faecal score during the entire 56d experiment was greater in L2 compared with L0, L1 and L4, although faecal scores of all treatment groups were generally low. Under the conditions of the present study, LF supplementation at the inclusion levels provided showed minimal effects on feed intake, growth rate or calf health.