The study of fat and protein milk changes in relation to rumen pH in dairy cow

This study was done to investigate the relation between fat and protein milk with rumen pH changes and subacute ruminal acidosis in some dairy herds. For this purpose 7 dairy herds in Alborz and Tehran provinces of Iran were selected. In each herd 12 cows between 60-150 days of lactation were randomly selected. Milk samples were collected. Rumen fluid were collected by rumenocentesis and ruminal fluid pH was measured with portable pH meter. Data were statistically analysed for correlation. The results showed that there were no significant correlation between milk fat and ruminal pH. The correlation between milk protein and ruminal pH were statistically significant. The level of significance was showed with p< 0.05. The results show that the reduction in rumen pH and milk fat arise in situations where a high-concentrate ration with low fiber (nonbalanced ration) and it should be stated that SARA may develop in the same situations where low milk fat is likely to develop. It should be consider because of the short duration and severity of the diseases and short duration of rumen pH below cut off point in some instance (chronic SARA) which does not in accordance with clinical signs. In formulation of the ration all of the factors should be consider which include type of feed, method of feed process, feed additives, fibre and starch digestibility. These result in minimum changes in milk and protein and rumen pH should be in optimum producing of milk in the herd.