Susceptibility of dairy cows to subacute ruminal acidosis is reflected in both prepartum and postpartum bacteria as well as odd- and branched-chain fatty acids in feces

Table 6 Prepartum and postpartum fecal pH, dry matter content, volatile fatty acid (VFA) concentrations, and individual proportions as well as odd- and branched-chain fatty acid (OBCFA) concentrations of cows varying in SARA susceptibility over the first 3 postpartum weeks¹

Item	Prepartum			SEM²	P-value	Postpartum				SEM²	P-value
Item	SU	MO	UN	SEM²	P-value	SU	MS	MU	UN	SEM²	P-value
Fecal pH	6.89	6.90	6.86	0.042	0.934	6.47	6.57	6.38	6.41	0.032	0.252
Dry matter, g/kg	144	145	134	3.7	0.227	147	129	138	125	4.0	0.213
Total VFA, mmol/L	57.6	58.1	52.1	1.63	0.196	70.1	67.4	69.4	63.0	1.51	0.458
% of Total VFA
Acetate	75.0	75.2	75.5	0.23	0.614	75.1	74.3	75.2	74.6	0.19	0.717
Propionate	15.0	14.9	15.0	0.20	0.968	14.6	14.9	14.7	15.3	0.14	0.202
Butyrate	6.98	7.02	6.65	0.046	0.503	8.11	8.27	8.01	7.99	0.159	0.969
Isobutyrate	1.08	0.972	1.01	0.1574	0.607	0.768	0.822	0.593	0.653	0.0368	0.243
Isovalerate	0.821	0.81	0.657	0.0816	0.649	0.437	0.587	0.313	0.266	0.0542	0.311
Valerate	1.24	1.14	1.14	0.048	0.671	1.19	1.11	1.14	1.21	0.031	0.629
Odd- and branched-chain fatty acids, mg/100 g dry feces
anteiso-C15:0	37.6	39.6	35.7	1.99	0.299	41.6	47.5	41.3	42.3	1.30	0.395
anteiso-C17:0	22.9	24.9	22.2	1.37	0.117	21.1	24.9	21.8	21.3	1.13	0.662
iso-C14:0	9.12	10.1	9.90	0.473	0.392	8.80	10.1	9.16	9.60	0.252	0.378
iso-C15:0	16.5	17.6	15.9	0.86	0.343	15.0^b	19.6^a	16.7^ab	18.8^a	0.55	0.012
iso-C16:0	15.2	17.5	15.1	0.90	0.158	12.5	15.6	14.3	15.0	0.60	0.099
Iso-C17:0	28.6	29.1	25.7	2.01	0.469	29.1	33.2	28.8	29.2	1.53	0.778
C15:0	53.1	61.4	53.5	3.27	0.177	56.5	63.2	57.3	58.1	2.73	0.862
C17:0	60.0	63.6	58.8	2.66	0.524	56.1	60.2	55.1	53.9	2.79	0.905
Total odd-chain FA	113	125	112	6.03	0.284	112	123	112	112	5.4	0.264
Total BCFA	130	139	125	7.2	0.163	128	151	132	136	4.6	0.524
Total iso-BCFA	69.4	74.3	66.6	3.98	0.129	65.4	78.5	69.0	72.6	2.57	0.565
Total anteiso-BCFA	60.5	64.5	57.9	3.30	0.104	62.7	72.4	63.1	63.7	2.29	0.498
Total odd BCFA	106	113	99.5	5.8	0.485	108	125	109	112	4.0	0.534
Total even BCFA	24.2	27.7	25.0	1.34	0.123	21.3	25.7	23.5	24.6	0.81	0.556

¹Postpartum grouping: susceptible group (SU; n = 10): mean or median of time below pH 6 of at least 180 min/d; moderately susceptible group (MS; n = 7): 60 min/d < mean time of pH below 6 < 180 min/d and median time of pH below 6 < 180 min/d; moderately unsusceptible group (MU; n = 11): 10 min/d < mean time of pH below 6 < 60 min/d and median time of pH below 6 ≤ 30 min/d; unsusceptible group (UN; n = 10): median time pH below 6 = 0 min/d and mean time pH below 6 < 10 min/d. Due to early calving, 10 cows were from the SU group, the UN-group only contained nine animals in the prepartum period and MS (n = 3) and MU (n = 7) cows were merged into a single group (MO, n = 10)
²SEM = standard error of the mean
^a,bMeans within a row with different superscripts differ significantly (P ≤ 0.05)

ISSN: 2049-1891