Constitution of Farm Animals

the aggregate of morphological, biological, and economic properties of an animal that characterize it as a whole. An animal’s constitution is expressed externally in its appearance or exterior. An animal’s constitution develops under the influence of heredity and environmental conditions, the most important being the way in which it was raised when young and the way it was fed and maintained. The teaching on constitution dates back to the fourth century B.C. (works of the ancient Greek historian Xenophon). It was further elaborated mainly as a result of advances in the biological sciences and zootechny.

The complex genetic factors and the many morphological, biochemical, and other indexes of the constitution of farm animals resulted in the creation of a great many classifications of constitutional types, the most significant being those devised by the Swiss scientist U. Duerst (1928) and the Soviet scientist P. N. Kuleshov (as perfected by E. A. Bogdanov and M. F. Ivanov). Duerst’s classification is based on the nature and intensity of the animal’s metabolism and on change in the appearance and structure of the body in relation to metabolism. It distinguishes two main constitutional types, respiratory and digestive, and two combined types, respiratory-digestive and digestive-respiratory. Animals of the respiratory type (for example, saddle horses, dairy cattle, and wool sheep) have a high rate of metabolism and do not tend to become fat. The feed eaten is converted mainly into muscular energy, milk, and wool. Animals of the digestive type (for example, beef cattle, mutton sheep, and heavy draft horses) have a low rate of metabolism because of their tendency to become fat. Based on Duerst’s classification, modern Soviet and foreign scientists have suggested identifying the following constitutional types: leptosome (slender body with long limbs), similar to Duerst’s respiratory type, and eurysome (wide body with short limbs), similar to the digestive type.

P. N. Kuleshov was the first zootechnician to view the constitution of farm animals as an organic relationship between body structure and vital activity, on the one hand, and productivity, on the other. He distinguished four main types of constitution: delicate, coarse, compact, and loose. But because these types generally do not occur in pure form, combinations of these types began to be distinguished: delicate compact (thin but solid skeleton and strong, compact muscles), delicate loose (thin skeleton and bulky, loose muscles covered with fat), coarse compact (strong, coarse skeleton and slim, strong muscles), and coarse loose (least desirable because animals with a coarse but loose skeleton have thick, flabby muscles and are unsuited for muscular work or for meat). E. A. Bogdanov supplemented this classification with the concepts of slim and fat constitutions. M. F. Ivanov emphasized the importance of a strong constitution, one reflecting health and usually associated with high productivity of the animal.

The evaluation of farm animals on the basis of their constitution is the most important part of the evaluation made of them from the aggregate of characteristics, especially in the case of pedigreed animals. Advances in biology make it possible to evaluate the constitution of farm animals not only from morphological characteristics but also from data on their metabolism and respiration, functioning of the digestive organs, nature of the nervous and muscular systems, and general physiological condition.