The objective of this study was to estimate genetic correlations between calving difficulty score and carcass traits in Charolais and Hereford cattle, treating first and later parity calvings as different traits. Genetic correlations between birth weight and carcass traits were also estimated. Field data on 59,182 Charolais and 27,051 Hereford calvings, and carcass traits of 5,260 Charolais and...

than to calf birth weight alone. Percent calving difficulty is the percentage of births requiring assistance from the herdsman. Calving scores of3 or higher were classified as difficult births based on a scoring system ranging from I = no assistance to 5 = caesarian birth or abnormal presentation. Due to the substantially higher incidence of calving difficulty in 1978 over 1979 (11.3 percent vs...

Calving difficulty is a trait that greatly affects animal welfare, herd profitability, and the amount of labor required by cattle farmers. It is influenced by direct and maternal genetic components. Selection and breeding strategies can optimize the accuracy of genetic evaluations and correctly emphasize calving difficulty in multiple-trait indices provided there are accurate estimates of genet...

the financial losses, absolute and net economic values (evs) for direct (dcd) and maternal calving difficulty (mcd) were estimated using a bioeconomic model and taking into account the categorical nature of the trait. the effects of dystocia on other traits were estimated. but because of low reliability they were not considered for calculations in the base situation. in the base situation, the ...

This study compared the accuracy of several models for obtaining genetic evaluations of calving difficulty. The models were univariate threshold animal (TAM), threshold sire-maternal grandsire (TSM), linear animal (LAM), and linear sire-maternal grandsire (LSM) models and bivariate threshold-linear animal (TLAM), threshold-linear sire-maternal grandsire (TLSM), linear-linear animal (LLAM), and ...

The main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (BW), gestation length (GL) and calving difficulty (CD) in first-parity Iranian Holstein dairy cattle. The data included 29,950 calving records collected during 1995 to 2014 by the Animal Breeding and Improvement Center of Iran. A threshold-linear sire-maternal grandsire model was ...

Effects of selection for 2-yr-old heifer calving ease (reduced calving difficulty score) on phenotypic differences between select and control lines of cattle for birth, growth, yearling hip height, and pelvic measurements were estimated. The selection objective was to decrease calving difficulty score in 2-yr-old heifers, while either maintaining or increasing yearling weight. The control line ...

Calving difficulty, survival from birth to weaning, birth weight, and weaning weight of 167 calves and carcass traits of 88 cattle (63 for adjusted fat thickness) were compared for progeny of Red Poll and Longhorn bulls mated to crossbred cows that calved at 2 or 3 yr of age. Results indicated that Longhornsired calves required 28% less assistance at calving than Red Poll-sired calves when dams...

the main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (bw), gestation length (gl) and calving difficulty (cd) in first-parity iranian holstein dairy cattle. the data included 29,950 calving records collected during 1995 to 2014 by the animal breeding and improvement center of iran. a threshold-linear sire-maternal grandsire model was ...