2023 Volume 14 Issue 2 Pages 53-62
The peripartal negative energy balance in dairy cows results in mobilization of triacylglycerols （TG） from the adipose tissue and increase in circulating non-esterified fatty acids （NEFA）. Fatty liver （FL） develops when the hepatic uptake of NEFA exceeds the oxidation and secretion of TG by the liver. FL is associated with decreased health status in the perinatal period and reproductive performance. Therefore, a practical prevention or an efficacious treatment of FL is important. TG in the liver is converted to very low-density lipoproteins （VLDL） and secreted into the blood. The synthesis of VLDL requires methionine and choline as methyl donors as well as vitamins as a coenzyme. Thus, supplementation of these nutrients may be useful for prevention of FL. The purpose of this study was to evaluate the effects of a new supplement containing methyl donors and vitamins （MCV-J） and developed for use in Japan on hepatic lipid accumulation, dry matter intake （DMI）, body weight （BW）, body condition score （BCS）, ruminal fermentation, blood metabolites and milk production in peripartum dairy cows. Twelve multiparous （except one in the treatment group） cows were divided into two groups: a control group fed a standard diet （n = 6） and a MCV-J group fed a standard diet supplemented with 50 g/d of MCV-J; n = 5） from 3 weeks （wk） before anticipated time of calving to 3 wk after calving. DMI and milk yield were recorded every day during the study period from 3 wk before anticipated calving to 12 wk after calving. Liver tissue was biopsied at 1, 2 and 5 wk after calving. The degree of adipose accumulation （FL score） and the content of TG in the liver were determined by histological examination. Furthermore, the measurement of BW and BCS, blood sampling and rumen fluid collection were performed at 3, 2 and 1 wk before anticipated calving and 1, 2, 3, 5, 8 and 12 wk after calving. As a result, the FL score was lower in the MCV-J group than in the control group at all wk at which biopsy was performed. The level of TG in the liver was lower in the MCV-J group than in the control group at 1 and 2 wk after calving. Among blood metabolites, β-hydroxybutyric acid and NEFA were significantly lower, and aspartate aminotransferase and γ-glutamyl transpeptidase were significantly higher in the MCV-J group than in the control group at 1 wk after calving. There were no significant differences in DMI, BW, BCS, ruminal fermentation and and milk production between the two groups. These results suggest that MCV-J supplementation to peripartal dairy cows can alleviate liver lipid accumulation without ill effects on DMI, BW, BCS, rumen fermentation or milk production.
