Effect of mineral Biochar feeding on growth performance, nutrient digestibility, blood ‎and fermentation parameters of weaned Holstein calves

‎‏ ‏Biochar is one of the carbon compounds that has been introduced ‎as a suitable substitute for some food additives, including antibiotics. The purpose of this study ‎was to investigate the effect of using different levels of a type of mineral Biochar from ‎Kohbanan Biochar mine in Kerman on growth performance, digestibility of nutrients, some ‎blood parameters and rumen fermentation of weaned Holstein calves.‎

‎‏ ‏In the present study,‎‏ ‏‎40 Holstein weaned calves (male and female) with ‎an average age of 128±7 days and an average weight of 99.4 ± 0.4 kg were used in a completely ‎randomized design with 4 treatments and 10 replications. Experimental treatments include: 1) ‎basic diet without mineral Biochar (control diet), 2) basic diet with 0.33% mineral Biochar, 3) ‎basic diet with 0.66% mineral Biochar, 4) The basic ration was with 1% mineral Biochar (all ‎based on the percentage of dry matter of the ration). A two-week habituation period was ‎considered. Weaned calves were weighed upon entering the design and weighing was repeated ‎every two weeks until the end of the experiment. Calves were kept in individual stalls and fed ‎experimental diets for three months. During the experiment, the feed consumed three times a ‎day was provided to the calves at the limit of optional consumption. The amount of feed ‎consumption was measured daily and average daily weight gain, average feed consumption and ‎feed conversion efficiency were calculated. At the end of the experiment, a blood sample was ‎taken from the jugular vein of the calves and blood parameters including urea nitrogen, glucose, ‎total protein and triglyceride, albumin , alanine aminotransferase, aspartate transaminase, very ‎low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein were determined. ‎Also, at the end of the test, the digestibility of dry matter, organic matter, protein Crude, ‎insoluble fiber in neutral detergent, pH and ammonia nitrogen concentration of rumen liquid ‎were measured.‎

The results showed that the use of mineral Biochar in feeding weaned calves had no ‎significant effect on dry matter consumption, daily weight gain, total weight gain and average ‎feed conversion efficiency. The highest apparent digestibility of dry matter, organic matter, ‎protein and insoluble fiber in neutral detergent was related to calves fed with a diet containing ‎‎1% Biochar (P< 0.05). The concentration of glucose, urea and high-density lipoproteins in the ‎blood of calves fed with a ration containing one percentage of Biochar was higher than that of ‎the calves of the control group (P<0.05). The concentration of cholesterol, triglyceride, aspartate ‎transaminase, alanine aminotransferase, albumin, total protein, very low density lipoproteins, ‎low density lipoproteins, gamma globulin did not differ significantly between the experimental ‎groups. Also, calves fed with a diet containing 1% Biochar had more ammonia nitrogen and ‎lower rumen pH than the control group (P< 0.05).‎

In general, the results of this experiment showed that the use of 1% mineral ‎Biochar in the ration of weaned calves can have positive effects on digestibility, some blood ‎parameters and rumen fermentation.‎