Table 4.

Effects of feeding an avian-derived polyclonal antibody preparation against Streptococcus bovis (PAP-Sb) or Fusobacterium necrophorum (PAP-Fn) for 12 d on ruminal fermentation variables, in steers fed a high-grain diet (Exp. 2)

	Main effect
	PAP-Fn		PAP-Sb
Item	0 mL/d	2.5 mL/d	0 mL/d	2.5 mL/d	SEM	PAP-Fn × PAP-Sb P-value
Mean daily ruminal pH1	5.76	6.04	5.82	5.98	0.08	0.07
Mean daily ruminal NH3-N, mM	4.0	2.1	3.4	2.8	0.79	0.74
Mean daily total VFA, mM	127	124	135	117	13	0.94
Mean daily VFA, mol/100 mol
Acetate	48.5	48.3	48.3	48.6	2.6	0.38
Propionate	29.8	32.3	30.6	31.5	2.7	0.12
Butyrate	14.1	12.0	13.7	12.4	1.1	0.14
2-Methyl butyrate	3.3	3.8	3.6	3.4	0.83	0.12
Isobutyrate	0.93	0.93	0.93	0.93	0.09	0.07
Valerate	2.42	1.90	1.97	2.36	0.59	0.07
Isovalerate	0.88	0.76	0.82	0.82	0.09	0.45
Lactate	ND2	ND	ND	ND
Acetate:propionate	1.73	1.68	1.69	1.72	0.29	0.32

¹PAP-Fn main effect, P = 0.03.

²ND = not determined.