Peas and beans as a protein feed for dairy cows
Latvia University of Agriculture, Svetes street 18, LV-3001 Jelgava, Latvia
The need for alternative protein sources to soybean meal, partially or fully substituted in the diets of dairy cows, is an urgent problem in farming nowadays. Soybean meal is the most common protein source included in feed concentrate for dairy cows in Latvia and in other European countries as well. Among possible alternatives, grain legumes seem interesting for dairy cow diets because of their rapid degradation in the rumen and readily available energy. Peas and beans will be an important source of proteins in feed. Biochemical tests were done on eight samples of domestically grown dried peas of average size, 11 samples of dried beans of average size and some samples of soybean meal to examine the chemical composition of the peas and beans. Peas and beans were included in the feed ration during a feeding trial on dairy cows. Milk yields and milk quality parameters were examined in the trial. The digestibility of peas of most varieties and breeding lines examined was considerably higher than that of soybean meal, while the digestibility of beans of all the varieties and breeding lines examined and of soybean meal was the same. The peas contained more reducing sugars, starches and had a higher value of NEL than the tested beans, which meant the peas had a higher nutritional value. The diets comprising beans and peas fed to the dairy cows increased the fat and protein contents of milk, compared with the control group and the beginning of the trial. The total amount of amino acids increased in the bulk milk samples of all the trial groups during the feeding trial.