Effects of Postpartal Relative Body Weight Change on Production Performance, Serum Biomarkers, and Fecal Microbiota in Multiparous Holstein Cows.

This study aimed to determine effects of postpartal relative body weight change (PRBWC) on production performance, serum biomarkers, and the relation between PRBWC and gastrointestinal microbiota. A total of 59 multiparous cows participated in this research. Every cow's PRBWC was calculated by the following equation: PRBWC = (BW₂₁ - BW₀)/BW₀ × 100%, in which BW₂₁ refers to body weight on Day 21 post-calving and BW₀ refers to body weight on the day of parturition. Among the 59 enrolled cows, cows with the top 21 ranked PRBWC values were categorized into the high PRBWC (H-PRBWC) group; cows with the bottom 21 ranked PRBWC values were categorized into the low PRBWC (L-PRBWC) group. PRBWC did not have significant influences on average daily milk yield (ADMY). However, on Day 21, cows in the H-PRBWC group displayed significantly higher body weight (BW) and body condition scores (BCS) (BW, p = 0.02; BCS, p < 0.01). Additionally, levels of serum glucose (GLU) and albumin (ALB) were significantly higher in the H-PRBWC group on Day 21 (GLU, p = 0.05; ALB, p < 0.01), while the lipopolysaccharide-binding protein (LBP) level was significant lower (p = 0.03). Moreover, the microbiota of fecal samples on Day 0 (FE0) differed notably between groups, as evidenced by various alpha diversity indices, including Shannon (p = 0.02), Simpson (p = 0.03), Pielou_e (p = 0.02), and principal coordinate analysis (p = 0.002). The relative abundances of Monoglobus, norank_f__UCG-010, and Christensenellaceae_R-7_group were significantly higher in the H-PRBWC group (p < 0.05), while the relative abundances of Clostridium_sensu_stricto_1, Turicibacter, and Romboutsia were significantly lower (p < 0.05). Pathways related to amino acid biosynthesis were significantly enriched in the FE0 of the H-PRBWC group, while pathways involved in carbohydrate metabolism were significantly upregulated in the FE0 of the L-PRBWC group. This study argues the potential of PRBWC to describe alteration of energy status in the postpartum, evidenced by production performance, serum biomarkers, and the fecal microbiota.