Lactobacillus plantarum GB LP-1 as a direct-fed microbial for neonatal calves

Direct-fed microbial feed additives with potential to enhance growth performance, gut health, and immunity have gained considerable popularity in neonatal calf production. Lactobacillus plantarum GB LP-1 (LP) produced by a proprietary fermentation process could be a viable direct-fed microbial feed for neonatal calves. The hypothesis was that feeding LP may ease transitioning from milk replacer (MR) to calf starter (CS) by improving gut health and appetite, while minimizing health challenges from pathogens and stress to improve growth performance. The experimental objective was to evaluate LP in an MR feeding program at 3 inclusion rates. Fifty-one 2- to 5-d-old Holstein bull calves were randomly assigned to 1 of 3 treatments using a randomized complete block design. Treatments were (1) Control (LP0): LP fed at 0 g/d; (2) LP4: LP fed at 4 g/d; and (3) LP8: LP fed at 8 g/d. Calves were fed MR at 0.57 kg/d for 14 d via bucket, which was increased to 0.85 kg/d until 35 d, and were then fed once daily at 0.425 kg/d with weaning after d 42 of the 56-d experiment. Calves were fed at 0630 and 1800 h in equal allotments, with access at all times to free-choice water and a pelleted CS with 25.5% crude protein. Calves demonstrated a linear growth response to increasing LP inclusion rate: calves fed LP8 gained more body weight (33.0, 36.9, and 37.7 kg for LP0, LP4, and LP8, respectively) than calves fed LP0, with calves fed LP4 being intermediate and similar. The 0-to-42-d (MR feeding phase) average daily gain (ADG; 562.9, 595.9, and 655.7 g/d) and 0-to-56-d ADG (588.6, 658.4, and 673.0 g/d) demonstrated linear responses, with calves fed LP8 having greater ADG than calves fed LP0, and calves fed LP4 being intermediate and similar. Total CS intake was similar among calves fed all treatments (66.3, 69.0, and 72.5 kg/56 d), which resulted in a quadratic response in feed efficiency (0.50, 0.53, and 0.52 kg of gain/kg of dry matter) for calves fed LP4 compared with calves fed LP0, with calves fed LP8 being intermediate and similar. Fecal scores improved linearly with increasing LP inclusion rate. These data demonstrate that feeding Lactobacillus plantarum GB LP-1 to neonatal calves improves gut health to increase growth performance at 4 and 8 g/d, while feed efficiency was greatest at 4 g/d.