Characteristics and variability of udder scores of simmental first calving heifers

Visual assessment and recognition of milk performance traits of cows are preliminary indicators of milk yield, longevity, as well as reproductive abilities of the animal, which is very important from the aspect of economy of milk production. Deficiencies in udder traits lead to poorer production, difficult milking and premature weaning of cows from the herd. The paper examines the frequency of desirable scores for a certain trait in first-calving heifers distinguished by way of keeping (heads reared by individual producers/holdings and heads reared on the farm) and by origin (domestic and imported animals), as well as the influence of these two factors on the observed traits. Five udder traits were analyzed: front udder length, rear udder length, rear udder height, central ligament, and udder depth on a total of 954 first-calving Simmental heifers. Observed by the way of rearing, higher frequency of desirable scores for all udder traits were achieved by cows reared on the farm, while according to the origin of cows, higher frequency of desirable scores for all udder traits was achieved by imported cows compared to domestic cows. The influence of factors of housing/keeping and origin, examined by χ2 test on all examined linear scores (frequency of scores) of udder traits was statistically very highly significant (p≤0.001), while the analysis of variance (F test) showed very high significance (p≤0.001) of interaction of origin and method of rearing on the traits of the central ligament and the udder depth, and significance (p≤0.05) on the height of the rear udder, however, no statistical significance (p>0.05) of this interaction was established on other linear scores of udder traits (length of the front and rear udder)