GENETIC-PARAMETERS FOR TYPE TRAITS IN THE FRENCH HOLSTEIN BREED BASEDON A MULTIPLE-TRAIT ANIMAL-MODEL

Genetic parameters for 15 linear type traits and milking ease score in the French Holstein breed were estimated by Restricted Maximum Likeli hood using a multiple-trait animal model. The analysis was based on 28 738 cows, daughters of at least 3 generations of Al Holstein sires and distributed over 16 samples of about 1800 observations (i.e., 6000 an imals when nonrecorded relatives are included) The fixed effects consi dered in the model included age at calving, stage of lactation, herd-r ound-classifier and group of unknown parents. The genetic value of bas e sires were either treated as random, or fixed for sires with at leas t 10 daughters. Treating sires as fixed increased the heritabilities f or udder traits while heritabilities of size traits and most genetic c orrelations were stable or slightly decreased. Most udder traits were rather highly correlated and exhibited heritabilities varying from 0.2 3 (Teat direction rear) to 0.35 (Udder-hocks distance). All size trait s were very highly correlated (0.69 to 0.97) with heritabilities from 0.25 (Chest width) to 0.47 (Height at sacrum). The heritability of Rea r legs side was found to be very low (0.07). These parameters are used in the multiple-trait animal model evaluation of type traits in the F rench Holstein breed.