Abstract
Abstract. Data obtained from the evaluation of longevity in 118 646 dairy cows of the Slovak Simmental breed were analyzed. The average length of productive life reached 1 451 days (3.88 years). Based on the analysis of the length of productive life for the whole cattle population, we calculated the ratio of cows that reached more than 12, 24, 36, 48, 60, 72 and 84 months respectively. The most important effects were the sire (F=53.43, P<0.001) and the farm effect (F=26.32, P<0.001). The milk production at first lactation was an important factor, too. The effects of conformation traits on the length of productive life were analyzed in a group of 6 585 culled cows. From the main conformation traits the most important effects were recorded for body frame, udder, feet and legs. For a detailed evaluation, the level of the effects of a particular body conformation trait were tested. The most important effects were rump angle, croup height and body depth. The analysis of udder traits showed that the most important effects were udder depth, teats length, rear udder attachment and rear udder. From the feet and legs traits the most important effects were recorded for fetlock, foot and rear legs.
Highlights
IntroductionReproduction and total milk production in cows become the important traits among selection criteria criterions, which have tight connections to economic effectiveness of milk and beef production (MESZAROS et al 2008) for Pinzgau Cattle, (SZAJKO 1987, DISTL 2001, CUE and ONGE 2002, BERGFELD and KLUNKER 2002, SWALVE 2003).The fundamental problem of the selection for longevity is its low heritability. DUCROCQ (1987) calculated the heritability coefficient of longevity h2=0.09 in Holstein cattle. KARRAS et al (1985) calculated h2 from 0.05 to 0.09 for Simmental cattle in Germany and SÖLKNER et al (2000) h2=0.1 in Austria
The duration of the productive life was calculated in days for each dairy cow in the database of culled cows, the average of the length of productive life taken from the whole group and we analyzed the number and ratio of the dairy cows which survived the defined levels 12, 24, 36, 48, 60, 72 and 84 months after first calving, respectively
Using information from literature sources and stated hypotheses, we picked up effects, which can affect the length of productive life considerably: farm, milk production at 1st lactation, breeding group (S0, S1, S2), sire, year of culling and age at first calving
Summary
Reproduction and total milk production in cows become the important traits among selection criteria criterions, which have tight connections to economic effectiveness of milk and beef production (MESZAROS et al 2008) for Pinzgau Cattle, (SZAJKO 1987, DISTL 2001, CUE and ONGE 2002, BERGFELD and KLUNKER 2002, SWALVE 2003).The fundamental problem of the selection for longevity is its low heritability. DUCROCQ (1987) calculated the heritability coefficient of longevity h2=0.09 in Holstein cattle. KARRAS et al (1985) calculated h2 from 0.05 to 0.09 for Simmental cattle in Germany and SÖLKNER et al (2000) h2=0.1 in Austria. Reproduction and total milk production in cows become the important traits among selection criteria criterions, which have tight connections to economic effectiveness of milk and beef production (MESZAROS et al 2008) for Pinzgau Cattle, (SZAJKO 1987, DISTL 2001, CUE and ONGE 2002, BERGFELD and KLUNKER 2002, SWALVE 2003). The fundamental problem of the selection for longevity is its low heritability. DUCROCQ (1987) calculated the heritability coefficient of longevity h2=0.09 in Holstein cattle. One possibility is the selection based on the highly positive genetic and phenotype correlations between milk yield at first lactation and longevity traits. Several authors state the genetic correlation between 0.2 and 0.6 and the phenotype correlation between 0.2 and 0.4 (VAN RADEN and KLAASKATE 1993, SAWA and KREZEL-CZOPEK 2009, DAKAY et al 2006, TEKERLI and KOCAK 2009)
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