The Effects of Supplementing Growing Purebred Angus Heifers with Bacillus Coagulans during Dietary Transitions on Performance and Acute Phase Proteins

The use of direct-fed microbials in animal nutrition is a growing practice to improve animal health and performance. To investigate the effects of supplementing growing beef heifers with a direct fed microbial (Bacillus coagulans; Provia 6086™, Phibro Animal Health Corporation, Quincy IL, USA), sixteen purebred Angus heifers were trained to eat behind Broadbent Calan gates (American Calan, Northwood, NH, USA) during a 28 day acclimation period. Acclimation diet contained a 20:80 concentrate to forage (C:F) ratio. Heifers were assigned to one of two treatment groups; Control (CNTL, n=8) or direct fed microbial (Provia 6086™, PV, n=8). Three basal diets (40:60, 55:45 and 70:30 C:F) were used in this study; diet 1 (40:60 C:F) was offered on days 1-7, diet 2 (55:45 C:F) was offered on days 8-14, and diet 3 (70:30 C:F) was offered on days 15-28 (of supplementation). Cattle enrolled in the PV group were fed product at the rate of 2billion CFU/hd/d, hand mixed in the top 1/3 of the presented diet. DMI was collected three times for diet 1 and 2 and six times for diet 3. Body weights (BW) were collected at baseline and weekly thereafter; BW were used to calculate ADG, and feed efficiency was calculated as gain:feed (G:F). Serum was collected on days 0, 14 and 28 of supplementation and samples were assayed for lipopolysaccharide binding protein (LBP), haptoglobin (Hp) and serum amyloid A (SAA). LBP, Hp and SAA were analyzed as change from baseline and log transformed prior to analysis. All data were analyzed using PROC GLIMMIX of SAS; P≤0.05 was considered significant 0.05<P≤0.10 was considered trending toward significance. Provia 6086™ supplementation improved average daily gain (P=0.007 CNTL 0.73, PV 1.16± 0.10 kg) and feed efficiency (G:F; P=0.008 CNTL 0.08 and PV 0.13 ± 0.03) compared to control counterparts. Basal diet influenced BW, DMI, G:F and ADG (P<0.0001). During diet 1, ADG decreased in all cattle ( -0.45 kg/d ±0.21 P<0.0001), as a result, compensatory gain was seen during diets 2 and 3. PV supplementation had no effect on BW and DMI and had a tendency to increase SAA (P=0.10) and LBP concentrations (P=0.05; relative to baseline) when compared to control cattle. This data indicates providing Provia 6086™ during dietary transitions may improve ADG and G:F and modulate the acute phase protein response in growing Angus heifers.