Enhancement of postpartum cow health and calf performance through maternal‒offspring interactions: effects on the immunity, antioxidants, and bacterial flora induced by Guiqi Yimu Powder.

This study evaluated the effects of dietary supplementation with Guiqi Yimu powder (GYP) on the postpartum health of beef cows and the growth performance of their calves, with an emphasis on immune function, antioxidant capacity, and the bacterial flora. Twenty-two postpartum cows were randomly assigned on the day of calving to either the control group (CON) or the GYP group. The control group was fed a basal diet, and the GYP group was fed the basal diet supplemented with 300 g/day of GYP starting on the day of calving. After 7 days of supplementation, serum samples from the cows and calves were collected, and antioxidant indices [superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH)] as well as immunoglobulins (IgA, IgM, and IgG) were analyzed. Fecal samples from cows were assessed for gut microbiota diversity and short-chain fatty acids (SCFAs) content; milk samples were analyzed for microbial composition and immunoglobulins. GYP was administered to the cows, and calves were exposed to GYP solely through suckling. Compared with those in the CON group, calves in the GYP group presented significantly greater weaning weights and average daily gains. The calf survival rate tended to increase, whereas the incidence of diarrhea tended to decrease in the GYP group. Among cows in the GYP group, both postpartum conception rates and estrus rates tended to increase; conversely, return-to-estrus rates and semen doses per conception tended to decrease. Serum levels of superoxide dismutase (SOD) and glutathione (GSH) were elevated, whereas malondialdehyde (MDA) levels were reduced (p < 0.05) in GYP cows. Moreover, supplementation with GYP significantly increased the serum IgG levels (p < 0.05), the milk IgM, IgA, and IgG levels (p < 0.05), and the serum IgG levels in calves (p < 0.05). Analysis of the gut microbiota of these cows revealed that, compared with CON, GYP improved the gut bacterial diversity and increased the relative abundances of UCG-002, Faecalibacterium, norank_f_F082, and Oscillibacter. Furthermore, examination of the milk microbiota revealed that GYP increased the relative abundances of Acetobacter, Lactobacillus, and Prevotellaceae_UCG-003. In addition, compared with CON, GYP significantly increased the contents of short-chain fatty acids (SCFAs), including acetic acid, propionic acid, isobutyric acid, n-butyric acid, isovaleric acid, and n-valeric acid, in the feces of postpartum cows (p < 0.05). GYP improves postpartum cow health and calf performance via (1) direct antioxidant and immunomodulatory effects, (2) gut microbiota remodeling and SCFAs promotion, and (3) vertical transfer of immunoglobulins and probiotics through milk. These findings support the use of GYP as a functional feed additive for optimizing postpartum management in beef cattle.