Effect of different level of corn silage and alfalfa hay on milk production and some biochemical blood parameters in early lactation dairy cows

To investigate the effect of different level of corn silage and alfalfa hay on milk production and some biochemical blood parameters in fresh cows, 42 dairy Holstein cows were used in a completely randomized block design and distributed among treatments randomly according to their parity. Treatments were: A- 5%0 corn silage and 5% % alfalfa dried hay as control, B- 8%0corn silage and 4% % alfalfa dried hay as high corn silage and C- 4%0 corn silage and 8% % alfalfa dried hay as high alfalfa portion. Also the forage to concentrate ratio was %%0 to 2%0. Diets were formulated by CNCPS software. The experimental period consisted of 41 d for adaptation to diets and 7 d for sampling. Milk yield data and milk samples for composition analysis (protein, fat, lactose, total solids, and solids non fat) and for somatic cell count were collected during sampling period. In addition, biochemical blood parameters such as glucose, triglyceride, cholesterol, calcium, phosphorus and insulin were determined. The results of this study showed that milk production in high corn silage treatment was higher compared with the others (p≤%0%5). As result relevant milk fat content in alfalfa hay treatment was higher than others but not significantly. Characteristics of blood biochemical showed that blood urea nitrogen (BUN) in cows that used higher alfalfa was less than others. Results showed that using of high corn silage diets led to an increase in lactose. Also data showed that glucose levels were decreased by using more alfalfa. Results of this study showed that increasing corn silage portion in high corn silage treatment could increase BUN, cholesterol, calcium, phosphorous and induce insulin compared to control and high alfalfa treatments. In conclusion we demonstrated that partial substitution of corn silage with alfalfa hay could improve milk yield, milk composition and some biochemical blood parameters in early lactation cows.

کلیدواژه ها:

Corn silage ، Alfalfa hay ، Milk production ، Blood parameters ، Dairy cows