Document Type : Research Articles
Department of animal science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashad, Iran
Animal Nutrition and Physiology Research Department, Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
Introduction: Biochar is a solid product obtained from the thermal conversion of biomass under oxygen-free conditions, which can be used as an additive in animal feed in addition to agricultural applications.
The purpose of this study was to use a natural mineral biochar in the diet of Holstein dairy cows and investigate its effect on functional characteristics, blood parameters, milk production and composition.
Materials and Methods: This research was conducted using 24 lactating Holstein cows, whose average weight at the beginning of the experiment was 618. 25 ± 79. 27 kg, average daily milk production was 41. 08 ± 3. 06 kg, and the number of lactation days was 89. 1 ± 19. 1 days. On average, they were in their second-lactation. The experiment was conducted in the form of a completely random design with three treatments, so that there were eight cows in each group. The length of the experiment was 40 days, the first 21 days were adaptation and the next 19 days was sample collection.
Experimental treatments included 1) control group (base diet) 2) base diet with 0. 5% mineral biochar 3) base diet with 1% mineral biochar (all based on dry matter).
Food consumption and milk production were measured daily. Sampling was done on the 17th and 18th day to determine the composition of milk. On the last day of the experiment, two blood samples 1) containing anticoagulant and 2) without anticoagulant were drawn from the tail vein of the cows to analyze biochemical parameters and count blood cells.
Results and Discussion: Adding 0. 5% and 1% mineral biochar to the diet had no significant effect on dry matter consumption, body weight change and metabolic weight change, which showed that biochar did not have an adverse effect on the palatability of the diet.
The effect of experimental diets on the biochemical parameters of the blood of cows showed that there is no significant difference between the treatments.
The result showed that the use of 0. 5% mineral biochar in the cow’s ration, decreased the ratio of non-fibrinogen proteins to fibrinogen and platelets. Also, when 1% of mineral biochar was used in the ration, the average volume of platelets increased (P<0. 05), but other parameters of blood cell count in cows were not affected by adding biochar.
Therefore, the antibacterial, anti-inflammatory and anti-stress properties of biochar may have caused the reduction of platelets and the ratio of non-fibrinogen proteins to fibrinogen or increase the average volume of platelets.
The evaluation of the effect of experimental diets on milk production and milk composition of lactating Holstein cows showed that there is no significant difference between the treatments in the amount of milk production, but the use of 0. 5% mineral biochar increased the milk protein percentage, although other milk composition was not affected by adding biochar.
Considering that the origin of the metabolic biosynthesis process of the protein in milk is due to the amino acids available in the blood reaching the mammary tissue, and on the other hand, the source of energy needed for this metabolic pathway is provided from glucose (glucose which absorbed from the small intestine or derived from propionic acid produced in the rumen). Also, since the amount of milk protein obtained from the total amount of casein protein, albumins and blood immunoglobulins secreted in milk, so as the evaluation of the amounts and ratios of glucose, protein and blood albumin showed, almost the highest amounts Glucose, protein and albumin in blood plasma in the treatment fed with basic diet with 0. 5% biochar. As a result, it has caused the process of protein production in mammary tissue to be more than other treatments. As a result, due to the mentioned reasons, it is possible to justify the increase of milk protein in the treatment fed with ration containing 0. 5% biochar.
Conclusion: The results of this research showed that the addition of 0. 5% and 1% of biochar from Kohbanan mine to the lactating Holstein cows diet, did not have a significant effect on the performance, blood biochemical parameters. However, when 1% of mineral biochar was used in the diet, it caused an increase in the average volume of platelets, and the use of 0. 5% mineral biochar increased milk protein and decreased platelets and the ratio of non-fibrinogenic proteins to fibrinogen. . It seems that the use of 0. 5% mineral biochar as a feed additive in the diet of lactating Holstein cows can improve the milk protein.