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Effects of different weaning strategies when feeding moderate and high milk replacer rates on fecal bacteria taxonomic profile, diversity, and community structure in Holstein calves.

A. Poulin

Events

06-23-2020

Abstract:

219
Effects of different weaning strategies when feeding moderate and high milk replacer rates on fecal bacteria taxonomic profile, diversity, and community structure in Holstein calves.
A. Poulin*2, J. Romero1, R. Klopp3, V. Richards4, F. Suarez-Mena5, T. Dennis5, T. Hill5, R. Causey1, R. Schlotterbeck5, G. Lascano3. 1Animal and Veterinary Sciences, SFA, University of Maine Orono, ME, 2Department of Molecular and Biomedical Sciences, University of Maine Orono, ME, 3Department of Animal and Veterinary Sciences, Clemson University Clemson, SC, 4Department of Biological Sciences, Clemson University Clemson, SC, 5Nurture Research Center, Provimi Brookville, OH.

Fecal bacteria profile can be greatly affected by pre-weaning diet and the strategy (STEP) used to wean calves. A 2 � 2 factorial design [moderate (MOD) or high (HI) milk replacer (MR) feeding rates and one step (ONE) or gradual (GR) weaning] was utilized to study how pre-weaning programs affect fecal bacteria diversity from 2 to 4 mo of age. Calves (n = 50, 56 d of age) were randomly assigned to 1 of the 4 pre-weaning treatments. The initial BW for HI and MOD calves was 78.9 and 74.3 � 1.92 (kg), respectively. Bacterial diversity was determined using the 16S rRNA gene (V4 region) for 0, 14, 28, 42, 56 d after weaning. The statistical model included the fixed effects of MR, STEP, DAY and their interactions and the random effect of calf nested within treatment. Differences were declared at P ≤ 0.05. At HI feeding, Ruminococcaceae relative abundance (rA, %) was reduced with ONE vs. GR weaning (15.8 vs. 18.5 � 1.0%); however, no differences were observed in MOD feeding (~16.9). For ONE weaning, HI feeding reduced Lachnospiraceae compared with MOD (6.8 vs. 9.4 � 0.83%) but no differences occurred within GR (~7.9). At d 0, ONE weaning increased Bacteroidaceae relative to GR (24.6 vs. 10.0 � 6.3%). As calves went from 0 to 56 d postweaning, the rA of Ruminococcaceae was lower for d 0 vs. 14 to 56 (11.9 vs. ~18.4 � 1.2%); unidentified Bacteroidales was lower at d 42 vs. 0 to 28 (5.6 vs. ~12.4 � 1.7); Lachnospiraceae was lower for d 0 vs. 14 to 56 (4.6 vs ~9.1 � 0.94); and Prevotellaceae was lower for d 28 vs. 0,14,42, and 56 d (4.0 vs ~8.0 � 1.2%). At HI feeding, ONE reduced phylogenetic diversity (richness) relative to GR (20 vs. 21.3 � 0.55%). A PERMANOVA analysis of weighted UNIFRAC distances indicated a difference in community structure across treatment and period combinations (P < 0.01). In conclusion, both MR feeding rate and weaning steps influenced bacterial rA independent of time, except for Bacteroidaceae; nonetheless both these factors had no effect on fecal bacteria richness.

Keywords: calves, post-weaning, fecal microbiome.