COMPARISON OF MAIZE AND ALFALFA SILAGES ON MILK-PRODUCTION, MILK-COMPOSITION AND BLOOD COMPONENTS OF DAIRY-COWS

Twenty multiparous Friesian cows, 60 to 100 days postpartum, were allo tted to two groups of 10 cows according to calving date, lactation num ber, and daily milk production and were assigned randomly to one of tw o diets in a crossover design experiment. The control diet (maize diet ) was 55% maize silage (dry basis), 20% soybean meal, 22% ground maize , and 3% mineral and vitamin mix. The treatment diet (alfalfa diet) wa s 55% alfalfa silage, 10% soybean meal, 32% ground maize, and 3% miner al and vitamin mix. The two diets contained similar quantities of crud e protein and metabolizable energy. The diets were offered individuall y as total mixed rations in two equal portions at 09:00 and 20:00 h in amounts to achieve ad libitum intake. The two groups of cows were all owed exercise in an open lot without shade from 11:00 to 16:30 h and 2 2:00 to 05:30 h. The cows were milked daily at 06:00 and 17:00 h. The dry matter, metabolizable energy and crude protein intakes, milk produ ction, and milk fat, protein, lactose, total solids and solids not fat contents, as well as milk fat and protein yields and body condition s core, were not significantly affected when maize silage was given to l actating cows, compared with that of cows given alfalfa silage. No dif ferences were observed in blood serum concentrations of glucose, total protein, albumin, urea, triglycerides, cholesterol, Na, K, Ca, P and Mg between maize and alfalfa silages.