Abstract This study investigated the effects of rumen-protected B and fat-soluble vitamins on the growth and health performance of receiving calves at the feedlot. Two hundred newly weaned Angus-cross steers (BW = 222 ± 20 kg SD) from one ranch were transported for 1,010 km, acclimated for 2 days and then were randomly assigned to 36 pens (5 or 6 steers/pen). The basal diet was corn silage-based, supplemented with NASEM (2016) minerals and vitamins. Treatments were arranged in a 2x2 factorial: 0 or 6 g/steer/d of rumen-protected formula of vitamins for receiving cattle (VIT1; Jefo, Quebec, Canada; containing B vitamins and minimal vitamins A, D3, E ); and 0 or 10 g/steer/d of rumen-protected formula of vitamins and fermentation extracts (VIT2; Jefo; containing vitamins A, D3, E, B vitamins, and fermentation extracts). Diets were fed for 56 days. Vaccinations (Bovilis Vista 5, Bovilis Vision 7, and Bovilis Nasalgen; Merck Animal Health, Rahway, NJ) were given on d 0 and boosted (Bovilis Vista 5) on d 28. Pen-based DMI was calculated weekly. All steers were weighed on d 0, 28, and either 56 or 57. Blood was collected from a single sampler per pen for TLR-antagonist assays on d 28 and 56. Data were analyzed using the Mixed and PHREG procedures of SAS with the fixed effects of VIT1, VIT2, and the interaction. Weekly pen DMI was analyzed as repeated measures. Pen was the experimental unit (n = 9 per simple effect). Weekly DMI tended to be increased by VIT1 (P = 0.07), but there was a decrease in G:F (P = 0.02; d28-56 and overall) and a tendency for decreased ADG (P = 0.07; d28-56) when VIT1 was supplemented. There was a tendency to increase ADG (P = 0.08) and G:F (P = 0.096) with VIT2 from d 28-56. No other growth differences were noted (P ≥ 0.18). From d 1 to 14, there was a main effect of VIT1 and VIT2, with both reducing morbidity (P ≤ 0.04) and VIT1 delayed days to pull for medical treatment by 42% (P = 0.046). From d 1 to 56 there tended to be an interaction between VIT1 and VIT2 (P = 0.098) for medical treatments, driven by numerically lesser treated steers getting only VIT1 (P 0.12). VIT1 also reduced blood IL-1 β and IL-6 when induced by LPS (P ≤ 0.06), both on d 28 and 56, with no impact of VIT2 alone on these agonist responses (P ≥ 0.18) and minimal interactions. Under the conditions of this study, VIT1 modulated the activity of pro-inflammatory cytokines in response to TLR agonists. This may explain the observed delay in medical treatment needs and decreased incidence of medical treatment.
Hirano et al. (Wed,) studied this question.