This study aimed to compare the effects of three different milk feeding methods on growth performance, health an‎d blood parameters of suckling Holstein calves. A total of 45 Holstein calves weighing 38 ± 3 kg were used in a ran‎domized complete block design. The experimental treatments based on the type of feeding were (1) pasteurized colostrum, pasteurized milk (2) pasteurized colostrum, acidified milk (3) acidified colostrum, acidified milk. Colostrum an‎d milk were adjusted to pH 4.2 with 85% formic acid. Body weight of calves was measured on days 1, 20, 40, 65, an‎d 80. Growth performance was measured on days 1, 40, an‎d 80, an‎d blood sampling was performed on days 15 an‎d 65. Health parameters an‎d forage intake were recorded daily. Milk samples were taken twice throughout the experiment to measure bacterial load. Statistical analysis of the measured parameters was performed for the entire experiment as repeated measures. Starter intake was higher in the treatment consuming acid colostrum an‎d acid milk than in the other two groups. Body weight did not differ between treatments. Daily weight gain in the post-weaning period was greater in the treatment consuming pasteurized colostrum, pasteurized milk. Pin width on day 40 was greater in the treatment consuming pasteurized colostrum, pasteurized milk. Body length on day 80 was greater in the treatment consuming acidified colostrum, acidified milk. Health data showed that calves fed acidified colostrum an‎d acidified milk had lower stool, ear, an‎d eye scores than the other two treatments, indicating improved health performance in calves fed acidified milk. The first day of diarrhea was also later in the pasteurized colostrum an‎d acidified milk treatment. Blood parameters data showed that glucose concentration on day 15 was higher in the treatment consuming acidified colostrum, acidified milk than in the other two treatments. Malonyldialdehyde concentration, as an indicator of stress, was higher on day 15 an‎d concomitantly with more diarrhea in the treatment consuming pasteurized colostrum, pasteurized milk. Feeding acidified milk reduced total antioxidant capacity in calves. Beta-hydroxybutyrate as an indicator of rumen development was highest in the treatment consuming acid colostrum, acid milk an‎d pasteurized colostrum, acid milk. Alkaline phosphatase was highest in the treatment consuming acid colostrum, acid milk. Globulin an‎d total blood protein were higher in the treatment consuming pasteurized colostrum, pasteurized milk due to the greater exposure of the calf to diarrhea. Blood cell count data showed an increase in white blood cells an‎d lymphocyte percentage in the treatment consuming pasteurized colostrum, pasteurized milk. Overall, the results of this study showed that calves that received acidified milk had the best performance an‎d health .Acidification of milk an‎d colostrum can be recommended as a low-cost an‎d practical alternative compared to pasteurization in small dairy farms, to reduce the bacterial load of milk an‎d reduce diarrhea in calves.

غلامرضا قرباني خراجي , فرزاد هاشمزاده

عباس رجائي راد , مهدي كديور