Effect of forage quality consumed in the diet of dairy cows on production and lactation performance

In this study alfalfa hay and corn silage were used in the diet of dairy cows as gross forage to investigate the effect of their quality on milk production. Fifteen Holstein cows (37 ±10 DIM) were used in completely random design during 9 weeks. Treatments included three levels of alfalfa hay and corn silage include: 1) 10% alfalfa -30% silage corn (CS), 2) 20% alfalfa -20% silage corn (CSAH) and 3) 30% alfalfa -10% silage corn (AH). Alfalfa hay was packed down second cutting in the mid-flowering. The ratio of forage: concentrate was 60:40 in all treatments. Cows were fed the total mixed rations (TMR) twice daily. Experimental diets were analyzed weekly. Individual dry matter intake was also measured daily. The results indicated that high dry matter intake was achieved when cows were fed by CSAH. Milk production was affected by all treatments (P = 0.014). Replacing corn silage with alfalfa hay increased the milk fat. There was not significant differences between total tract digestibility of dry matter, organic matter, crude protein and neutral detergent fiber in all treatments. Cows that received CS had higher apparent total tract digestibility of crude protein. There was significant difference in the total chewing time (minutes per day) and chewing activity decreased when alfalfa ratioin cow's diet were increased.