Variability and heritability of type traits of Holstein-Friesian bull dams

Abstract

Objective of this study was to calculate the variability and heritability of type traits in the nucleus herd of bull dams by using the linear method of evaluation, and to determine their importance in selection of cattle. Study included 127 Holstein-Friesian cows selected as bull dams on cattle farms of PKB Korporacija, Belgrade. By applying the Least square method, main variationstatistical parameters were calculated: arithmeitc mean, standard deviation, variation coefficient, standard error and variation range. Bull dams of Holstein-Friesian breed had average milk production of 10245.98 kg, with variation range from 6514 kg to 13251 kg. Average milk fat yield was 361.95 kg, and milk fat content 3,53%. Average values for type scores of Holstein-Friesian bull dams were: rump height 5.40, chest width 7.09, body depth 7.38, rump position 5.39, rump width 6.55, dairy form 7.35, rear legs set (rear view) 5.22, rear legs set (side view) 5.28, hoof angle 5.27, fore udder 6.65, front teats placement 5.43, teat length 4.76, udder depth 6.96, rear udder height 7.13, suspensory ligament 7.08 and rear teats placement 5.89. Also, heritability coefficients and errors were calculated for all milk and type traits. Type and body development scores are very important indicators of production ability of cows, their potential to consume sufficient quantities of food, produce high quality milk from the technological aspect, reduce the use of energy in production and remain as long as possible in exploitation.

Genetic parameter estimates for body conformation traits using composite index, principal component, and factor analysis

“…This result revealed the importance of nonadditive genetic and environmental effects in the total variation of these traits. According to Pantelić et al (2011) and Campos et al (2012), care should be taken when comparing conformation traits with the result obtained from similar studies because different scoring system, breed, population size, classification system, and model are used in estimating these traits.…”

Evaluation of accuracies of genomic predictions for body conformation traits in Korean Holstein

“…The low h 2 observed for these traits suggests limited potential for significant response to selection and highlights the contribution of nonadditive genetic and environmental factors in explaining the observed variation [ 28 ]. Discrepancies in h 2 estimates can be attributed to factors such as population differences, scoring systems, estimation methods, sample sizes, measurement errors, and statistical models employed [ 21 , 29 , 30 ]. It is important to note that udder conformation traits, such as the shape, location, and strength of attachments, exhibit h 2 and significantly impact a dairy cow’s milk production capacity, consequently influencing culling decisions [ 31 ].…”