Table 2.

Effect of Bacillus subtilis PB6 and/or chromium propionate supplementation on clinical health outcomes of beef cattle during the feedlot receiving and finishing periods

	Treatmenta					P-value
Item	CON	CST	CHR	CST + CHR	SEMb	CST	CHR	CST × CHR
BRD1c, %	43.9	34.6	35.8	21.3	—	0.02	0.03	0.59
BRD2d, %	23.4	11.9	16.3	12.4	—	0.10	0.47	0.40
BRD3e, %	12.7	5.4	8.8	6.7	—	0.19	0.71	0.46
Respiratory mortality, %	4.2	1.1	3.3	2.2	—	0.34	0.95	0.65
Days to
First treatment	13.4	14.3	9.2	11.0	2.2	0.44	0.04	0.81
Second treatment	21.1	17.4	21.6	17.5	3.2	0.13	0.91	0.93
Third treatment	33.2	19.9	25.2	24.4	4.5	0.07	0.63	0.13
Rectal temperature, °C
First treatment	39.6	39.7	39.7	40.0	0.21	0.16	0.23	0.83
Second treatment	39.6	39.3	39.4	40.0	0.31	0.68	0.28	0.09
Third treatment	39.3	40.0	40.2	40.1	0.34	0.29	0.09	0.31
Antimicrobial treatment cost, $/hdf	12.45	8.50	9.62	6.15	1.66	0.03	0.13	0.87

^aCON = placebo control; CST = 13 g per animal daily DM inclusion of Bacillus subtilis PB6 (CLOSTAT, Kemin Industries, Des Moines, IA); CHR = 450 ppb DM chromium propionate (KemTRACE Chromium, Kemin Industries); CST + CHR = 13 g per animal daily DM inclusion of Bacillus subtilis PB6 + 450 ppb DM chromium propionate.

^bPooled standard error of least square mean.

^cPercentage of cattle treated for BRD at least once.

^dPercentage of cattle treated for BRD at least twice.

^ePercentage of cattle treated for BRD three times.

^fAntimicrobial treatment cost assumes the following: $0.59/mL for florfenicol (Nuflor, Merck Animal Health), $0.47/mL for enrofloxacin (Baytril, Bayer Animal Health), and $2.00/mL for ceftiofur crystalline free acid (Excede, Zoetis).