Document Type : Research Paper
Authors
Department of Animal Science, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran.
Abstract
Objective: One of the major challenges in the livestock industry is the health and proper growth of suckling calves, which are prone to digestive and respiratory diseases because of their immature immune system and are more susceptible to increased mortality. This study evaluated the nutritional strategy to improve performance by adding feed additives such as probiotic and biochar to the diet of Holstein suckling calves.
Methods: A total of 28 female newborn Holstein calves (41.2 ± 3.8 kg) were used as a 2×2 factorial arrangement within a completely randomized design over a 70‑day experimental period. The experimental treatments consisted of 1- basal diet without additive (control diet), 2- basal diet with 2 g/day of probiotic, 3- basal diet with 1% biochar and 4- basal diet with 2 g/day of probiotic plus 1% biochar. The basal diet was formulated with a forage-to-concentrate ratio of 10:90 to fulfill nutrient requirements. Water and starter feed were provided ad libitum during the experiment. Feed intake was recorded daily, while body weight and skeletal growth changes were assessed every two weeks. Blood samples were collected on days 0 (birth time), 35 and 70, and fecal samples were collected to evaluate diet digestibility in the last week of the experiment from all calves. All calves were observed for three days at the end of the experiment to record their feeding behaviors (standing, lying, eating, and ruminating) and non-feeding behaviors (licking, sucking, and chewing on environmental objects).
Results: The results indicated that calves receiving dietary biochar had significantly greater starter feed intake and weaning body weight compared with non‑biochar groups (P<0.05). Biochar supplementation also increased wither height, hip height and abdominal circumference of the calves (P<0.05). Moreover, concurrent supplementation with probiotic and biochar (treatment 4) further enhanced wither height and hip height (P<0.05). Dietary supplementation of probiotic and biochar improved the apparent digestibility of organic matter and crude protein, respectively (P<0.05), whereas the digestibility of other nutrients was not affected by experimental treatments. Blood glucose concentration was also increased by biochar supplementation (P<0.05). None of the feeding behaviors were significantly affected by dietary treatments. The interaction effect of probiotic and biochar was not significant on any of the parameters measured in this study.
Conclusions: Overall, dietary supplementation with biochar, alone or in combination with probiotic, positively enhanced performance, skeletal growth indices, and digestibility of nutrients in suckling calves, highlighting its potential as a functional feed additive to support early‑life health and productivity.
Keywords
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