DETERMINATION OF ALTERED RUMEN FERMENTATION BY REAL-TIME RUMINATION OBSERVATION

In an effort to meet the high energy and protein demands of lactation the modern dairy cow is fed a highly fermentable diet. However, these diets reduce rumen pH and result in a condition called sub-acute rumen acidosis. This condition reduces feed efficiency, reduces milk fat because of synthesis of bioactive trans fatty acids, and increase incidence of numerous diseases. This results in reduced animal welfare and farm profitability and sub-clinical rumen acidosis has been estimated to cost the US dairy industry between 500 million and 1 billion dollars per year.Rumination is a key process required by dairy cows for optimal digestive function and health. Rumination reduces digesta particle size, adds salivary buffers to stabilize rumen pH, and assists in mixing rumen contents. Reduced rumination has a number of negative consequences for the cow including decreased rumen pH and altered rumen fermentation resulting in poor performance and depressed milk fat. Recently, automated systems have been developed for observation of rumination on commercial dairy farms and are being used to manage reproduction and identify clinically sick animals. The rumination observation systems have the potential for determination of subacute rumen acidosis, but a lack of research data and benchmarks are limiting their usefulness.This research component of the project will collect milk samples from individual cows on 6 commercial dairies with rumination observation systems. Milk fatty acid profile will be used as an indication of rumen fermentation. Relationships between milk fatty acids and rumination behavior will be determined and benchmarks and prediction equations will be developed that can be used on farms. This information will be used to identify and reduce sub-acute rumen acidosis on farms. The extension component will deliver this information to field nutritionists and herd managers. This project meets a critical need to fully utilize a new technology that is being rapidly adopted on farms to reduce an issue that has major impacts on farm profitability and animal welfare.