摘要
Fatty liver in dairy cows, which is associated with decreased metabolic function of the liver, develops during times of elevated non-esterified fatty acid （NEFA） concentrations in the blood when the hepatic uptake of lipids exceeds the oxidation and secretion of lipids by the liver and then it will cause hepatic accumulation of triglyceride （TG）. The condition is often related to decreased health status, well-being, productivity, and reproductive performance of cows. Prevention of fatty liver in the transition period is always better than any treatments. The nutritional preventative strategies mainly focus either on decreasing the supply of NEFA to liver, and it aims to improve liver function or optimize the capacity then to dispose of NEFA by exporting them as triglycerides in lipoproteins （VLDL）. Good dry cow nutritional programs, combined with excellent feeding management to achieve high levels of dry matter intake throughout the transition period should be the first priority for management. Several different compounds can promote these metabolic actions. The addition of glucose precursors such as glycerol, propyelene glycol, or propionate salts to the feed in the transition diet can modify metabolism in a manner to decrease fatty acid mobilization from adipose tissue and reduce the likelihood of liver TG accumulation. Supplying some other specific nutrients to dairy cows during the transition period may increase rates of NEFA disposal, with resulting effects on performance, though the hepatic capacities for export as triglycerides within VLDL are relatively limited in ruminants. Further studies examining nutritional and management strategies are required to develop new preventive or treatment options that are more practical to reduce the occurrence of fatty liver and its adverse metabolic effects.
Fatty liver in dairy cows, which is associated with decreased metabolic function of the liver, develops during times of elevated non-esterified fatty acid （NEFA） concentrations in the blood when the hepatic uptake of lipids exceeds the oxidation and secretion of lipids by the liver and then it will cause hepatic accumulation of triglyceride （TG）. The condition is often related to decreased health status, well-being, productivity, and reproductive performance of cows. Prevention of fatty liver in the transition period is always better than any treatments. The nutritional preventative strategies mainly focus either on decreasing the supply of NEFA to liver, and it aims to improve liver function or optimize the capacity then to dispose of NEFA by exporting them as triglycerides in lipoproteins （VLDL）. Good dry cow nutritional programs, combined with excellent feeding management to achieve high levels of dry matter intake throughout the transition period should be the first priority for management. Several different compounds can promote these metabolic actions. The addition of glucose precursors such as glycerol, propyelene glycol, or propionate salts to the feed in the transition diet can modify metabolism in a manner to decrease fatty acid mobilization from adipose tissue and reduce the likelihood of liver TG accumulation. Supplying some other specific nutrients to dairy cows during the transition period may increase rates of NEFA disposal, with resulting effects on performance, though the hepatic capacities for export as triglycerides within VLDL are relatively limited in ruminants. Further studies examining nutritional and management strategies are required to develop new preventive or treatment options that are more practical to reduce the occurrence of fatty liver and its adverse metabolic effects.
基金
Supported by National Natural Science Funds (30300259)
作者简介
XING Tao （1988-）, male, research assistant, engaged in the research of animal health.To whom correspondence should be addressed. E-mail： jgli@yzu.edu.cn
