effects of feeding different levels of alfalfa hay and corn silage on milk production and blood metabolites in holstein cows

the effect of different levels of alfalfa hay and corn silage, in early lactation diet, on milk production and on milk components in holstein cows was investigated. fifteen holstein cows (37 ±10 dim) were taken in a completely randomized design experiment, lasting for 9 weeks. three levels of hay and corn silage namely: 1) 10% alfalfa -30% silage corn (diet 1), 2) 20% alfalfa -20% silage corn (diet 2) and 3) 30% alfalfa -10% silage corn (diet 3) former the treatments. the ratio of forage to concentrate was taken as the same (40: 60) in all the treatments. cows were fed in total mixed rations (tmr) and twice daily. they were milked 3 times a day at 02:00, 10:00, and 18:00 h. milk production was recorded at each milking, but milk composition was weekly determined. dry matter intake for each cow was daily assessed. dry matter intake was higher (p0.05). blood parameters were not seriously affected by dietary treatments (p>0.05), although glucose content for diet 1 was higher than that for diet 2.