LIVE BODY MEASUREMENTS FROM FIRST-CROSS AND BACKCROSS FEMALES

Abstract

Live body measurements were evaluated in F1 and backcross females ranging in age from 1 to 5 yr, inclusive, maintained at Manyberries, Alberta (extensive range management) and Brandon, Manitoba (semi-intensive management). The objectives of this study were to examine measures of size, weight, and subcutaneous fat cover to determine: (1) their relationship with age of cow; (2) the impact of varying proportions of Simmental and Charolais breeding; (3) the similarity between generalized and specific contrasts involving 1/4 and 3/4 European continental and British breeding; and (4) differences between four consecutive lactations and three out of four possible lactations. Body length, height at the hips and withers, and cow weight at weaning reached or approached their mature levels by 5 yr of age and subcutaneous fat cover was more dependent upon environmental factors than age. Incremental increases in Simmental and Charolais breeding in the cow crosses resulted in corresponding increases in body size and weight. The generalized comparisons between 1/4 and 3/4 Simmental, Charolais, Angus, Hereford, and Shorthorn breeding provided useful information regarding generic comparisons but there was a need for evaluating specific backcross comparisons. Cows experiencing four consecutive lactations, compared to those that had three lactations out of a possible four, had decreased physical dimensions in addition to weight and subcutaneous fat cover. Key words: Beef cattle, body measurements, backcrosses, heifers, cows