Production responses of multiparous dairy cattle with differing prepartum muscle reserves and supplementation of branched-chain volatile fatty acids

作者：Kyrstin M. Gouveia, Linda M. Beckett, Theresa Casey, Jacquelyn P. Boerman · 发表于：Journal of Dairy Science · 年份：2024 · DOI：10.3168/jds.2024-24915 · 被引用次数：12 · 研究领域：Reproductive Physiology in Livestock、Ruminant Nutrition and Digestive Physiology、Animal health and immunology

Periparturient dairy cattle undergo physiological adaptations to support fetal growth and colostrum synthesis in late gestation and milk production in early lactation. To support energy and protein demands, dairy cattle mobilize body tissue reserves. The objective of this study was to determine the effects of prepartum skeletal muscle reserves and supplementation of branched-chain volatile fatty acids (BCVFA) on body composition measurements, metabolic markers related to health, protein, and energy status, and subsequent milk yield in multiparous dairy cows. Skeletal muscle reserves were assessed by 3 ultrasounds of the longissimus dorsi muscle depth (LDD) measured 42 d before expected calving, and cows (n = 48) were assigned to either high muscle (HM; >4.6 cm) or low muscle (LM; ≤4.6 cm) groups. Cows were then randomly assigned to either control (CON) of soyhull pellets (80 g/d) or BCVFA treatment, which contained isobutyrate (40 g/d), isovalerate (20 g/d), and 2-methylbutyrate (20 g/d) calcium salt products. Treatments were top dressed from 42 d before expected calving until parturition, resulting in 4 combinations of muscle groups and treatments: HM-CON (n = 13), HM-BCVFA (n = 13), LM-CON (n = 11), and LM-BCVFA (n = 11). Measurements of the LDD, BW, and BCS were taken on the following days relative to calving: -42, -35, -21, -7, 0, 7, 14, 21, 28. Weekly blood samples were taken to measure glucose, BHB, and insulin concentrations, and 5 of the blood sample time points were ...