Authors: A. I. Denkin, V. O. Lemeshevsky
All-Russian Research Institute of Physiology, Biochemistry and Animal Nutrition – a branch of the Federal Scientific Center for Animal Husbandry – All-Russian Research Institute of Livestock named after Academician L. K. Ernst, Borovsk, Russia E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Abstract. The nature of biosynthetic processes and the productive qualities of ruminants depend on the level and ratio of substrates absorbed in the digestive tract. The maximum efficiency of the biosynthesis of meat components in the body is ensured if the amino acids enter the metabolic pool in sufficient quantity and in the optimal ratio. The purpose of the work is to study the needs of Aberdeen Angus meat bulls calves for metabolizable protein for the optimal use of amino acids and metabolizable energy of the diet for the increase in live weight of bulls-calves during the growing period. Research materials. Consecutively, 3 series of studies were carried out on bulls calves of the Aberdeen Angus breed with a live weight of 277 kg, 317 kg and 363 kg. The animals of the 1st experiment were fed according to the RAAS (Russian Academy of Agricultural Sciences) standards, where the ratio of the exchange protein to the exchange energy was 8.2 g/MJ, in the 2nd and 3rd experiments they increased the level of the exchange protein to 8.6 and 9.1 g/MJ due to the introduction of 0.5 kg and 0.6 kg of soybean meal in the diet, respectively. At the end of each period, physiological experiments were performed. Results. The studied parameter did not have a significant effect on the dry matter intake of the feed, and an increase in the diet of hard-to-break down protein contributed to an increase in the concentration of metabolizable energy and digestibility of dry matter. It was found that metabolizable energy and amino acids are effectively used to increase the live weight of bulls calves during the growing period on a diet in which the ratio of metabolizable protein to metabolizable energy is 8.6 g/MJ. A further increase in metabolic protein in the diet leads to an increase in heat production, which in turn increases the use of amino acids and metabolic energy in energy metabolism and reduces their contribution to the increase in live weight.
Keywords: metabolizable energy, metabolizable protein, energy balance, substrates, bull calves, gain, growth.
For citation: Denkin A. I., Lemeshevsky V. O. Energeticheskiy obmen u bychkov porody aberdin-angus v period vyrashchivaniya pri raznom urovne obmennogo proteina v ratsionakh [Energy metabolism in aberdeen-angus bulls during the growing period with different levels of metabolizable protein in the diets] // Agrarian Bulletin of the Urals. 2020. No. 08 (199). Pp. 34‒42. DOI: 10.32417/1997-4868-2020-199-8-34-42. (In Russian.)
