Linear assessment of Hereford cow exterior in the Republic of Tyva

Abstract

The research findings on comparative evaluation of the exterior features and the results of linear assessment of the exterior of Hereford cows of different lactations in the Republic of Tyva are discussed. The exterior was assessed by the following methods: measurements, calculation of body indices, and using the System A for linear assessment. The first group consisted of cows in their first and second lactations, while the second group consisted of mature cows with three or more lactations. The animals under study were imported from another region. The animals with high genetic potential brought to the harsh climate of Tyva should be resistant to extreme temperatures, diseases, and roughage. To determine cow adaptability to year-round pasture conditions in a sharply continental climate, a linear body conformation assessment was made. The measurement results showed that mature cows were by 5.1 cm taller in withers; by 14.4 cm wider in chest girth; by 7.9 cm longer in oblique body length; by 6.3 cm higher in rump; by 5.7 cm longer in back length; and by 2 cm wider in the cannon bone than those of young cows. The measurements of the animals in both groups were below the minimum values of the standard with the exception of cannon bone girth in adult cows. It was found that adult cows had a significantly higher long-leg index (5.4 abs. %), while the massiveness index was lower (6.6 abs. %). When comparing the body indices of cows of different lactations with the standard indices, it was found that all indices except for the indices of lengthiness and massiveness were higher than the standard for beef cattle. For the first time, a linear assessment of cows of different lactations was made, and as a result, the chest depth was assigned 7 score points which was by +2 points higher than the average; the rump was assigned 6 score points, and the strength of the body regardless of age was assigned 6 score points which was higher than the average, and the position of the front limbs assigned 6 score points. The back length (5 score points) and pelvis position (5 score points) were both rated as satisfactory.