Genetic and environmental relationship among udder conformation traits and mastitis incidence in Holstein Friesian into two different environments

Abstract. Type-performance of udder of Holstein-Friesian was analyzed using multi-trait animal model in two different environments (Hungary and Egypt). Udder traits were: udder height and depth. Teat traits were teat length, attachment and placement. Multi-trait animal model was used to compute estimates of additive variance and covariance components. 2507 records of 549 cows and 6011 records of 2018 cows were collected from Egypt and Hungary respectively. Heritability estimates of udder and teat characteristics ranged from 0.35 to 0.45 and from 0.32 to 0.59 in Hungarian and Egyptian cows, respectively. Heritability estimates of udder traits in both environments were higher than the corresponding estimates for teat traits. Udder characteristics of Egyptian Holstein-Friesian (EHF) had inheritance power higher than for Hungarian Holstein-Friesian (HHF). Mastitis was moderately correlated with udder height and teat traits in each environment. Additive genetic variance and heritability of the most studied traits increased with the advancing order of lactation in each environment. Heritabilities of mastitis were low. Sire and dam variance components of all studied traits were higher in EHF than HHF herds. Mastitis was strongly correlated negatively with udder depth of EHF than HHF. The genetic analysis results of the present study, indicate that udder characteristics should be taken into consideration during planning of selection strategies for improving dairy cattle performance. Enhancing management levels of Egyptian environmental conditions is very essential for improving general performance of the most exotic dairy cattle breeds. EHF has great chances for genetic improvement to mastitis resistance through selection, based on udder descriptive performance.