The effect of different levels of alfalfa hay in the starter diet on performance, blood parameters and health of Holstein dairy calves fed with high amounts of milk

In this research, the effect of increasing the amount of alfalfa hay in the starter diet on the performance, blood parameters and health of Holstein dairy calves fed according to the milk feeding pattern by step down method using 24 female Holstein calves with 4±1 day of age and birth weight of 41.2 ±3 kg were studied in a completely randomized design with three treatments and eight calves in each treatment for 56-days (until weaning). Experimental treatments include: 1) feeding milk without alfalfa hay, 2) feeding milk with five percent of alfalfa hay (based on dry matter of the diet) and 3) feeding milk with 10 percent of alfalfa hay (based on dry matter of the diet). there was no difference between experimental treatments in terms of dry matter intake, feed conversion ratio, daily weight gain, fecal score, skeletal growth indices and ruminal pH. The concentration of propionate in the rumen of calves fed with milk and five percent alfalfa hay was significantly higher than the control and 10 percent forage treatments (P <0.05). The ratio of acetate to propionate in the rumen of calves fed milk and five percent alfalfa forage was significantly higher than of calves of other treatments. Plasma beta-hydroxybutyrate concentration was higher in calves fed the starter containing five percent of dry alfalfa than calves in other treatments (P <0.05). According to the results of this study, replacing part of the starter of dairy calves fed with high amounts of milk and alfalfa hay improves their rumen development.