LAUSR

Background and Aim: Ensuring the genetic potential of ruminants through nutrition studies using medicinal plants and trace element metals is an urgent task. This study aimed to study the effect of Artemisia absinthium L. (Asteraceae) herb plant separately and in combination with cobalt (II) chloride (CoCl2) chelate compounds on the course of metabolic processes in the rumen, methane concentration, and biochemical blood parameters in bulls. Materials and Methods: Control group (BD: Basal diet); experimental Group I – BD + A. absinthium herb at a dose of 2.0 g/kg dry matter (DM), experimental Group II – BD + A. absinthium herb at a dose of 2.0 g/kg DM + CoCl2 (1.5 mg/kg), and experimental Group III – BD + CoCl2 were set (1.5 mg/kg). The study was conducted on 16 beef bulls (Kazakh white-headed breed) aged 13–14 months, with an average live weight of 330–335 kg. Enzymatic processes in the rumen were studied, including the level of volatile fatty acids (using the gas chromatography method), nitrogen and its fractions (using the Kjeldahl method), methane concentration, and morphological and biochemical blood composition. Results: There was a decrease in the concentration of acetic acid in experimental group I (15.9%) (p < 0.05) and in the III group (60.3%) and propionic acid in all experimental groups by 5.6%–47.3% (p < 0.05). Feeding A. absinthium herb as part of the diet of experimental Group I contributed to a decrease in methane concentration by 17.8% (p = 0.05) and the lowest methane concentration was noted for experimental Group III. It was less than in control by 59.1% (p < 0.05). An increase in the concentration of glucose, total protein, and creatinine was found in the experimental groups (p < 0.05). The digestibility of organic matter (3.5%), crude fiber (3.6%), and hemicellulose (11.0%) increased with the feeding of A. absinthium herb. Conclusion: Thus, using biocomplexes based on A. absinthium herb and CoCl2 do not harm the rumen fermentation of cattle. Still, further microbiome studies are required to evaluate the effects of A. absinthium on cattle properly.