average age distribution and generation interval were investigated in four different selection pathways. i.e., sire of future sires (ss), sire of future dams (sd), dam of future sires (ds) and dam of future dams (dd). young bulls pathway (yb) is also considered as a path that affects the generation interval in sd pathway when using progeny testing program. data were collected from animal breedi...

Beef sire selection decisions have a major impact on future calf crops and ultimately on profitability. Using available selection tools can help make better bull buying choices. A critical place to start when beginning the herd sire selection decision process is to evaluate the cow herd(s) that the sires will service. From these herd assessments, profiles of desirable herd sires can be develope...

We assessed genetic factors on progeny dispersal due to sire color morph genotypes in a field pedigree and lab crosses, and we measured maternal effects by studying both natural and experimentally induced egg size variation. Progeny were released into nature upon hatching, but we recorded dispersal distance at maturity, which reflects effective dispersal after viability selection has run its co...

The genetic variance of inbred sires is increased and variance due to additive x additive effects proportionately more than that due to additive ones. In case of inbreeding by mating sire to daughters the time interval elite sire – son needs not to be elongated so that the genetic progress could be increased by this procedure. This pertains even more to the procedure where inbred sires are prod...

Estimating variances due sire × herd effects requires a large number of sires to be represented in multiple herds, otherwise too much variation between animals is ‘picked up’ as variance due to sire × herd effects, and heritability estimates are biased downwards. Such bias can be avoided by using only records for progeny of multiple-herd use sires to estimate the additive genetic variance. Esti...

In animal breeding, recording of correct pedigrees is essential to achieve genetic progress. Markers on DNA are useful to verify the on-farm pedigree records (parental verification) but can also be used to assign parents retrospectively (parental identification). This approach could reduce the costs of recording for traits with low incidence, such as those related to diseases or mortality. In t...

Data were weights of F1 calves and weaning weights of top-cross progeny from sires and maternal grandsires of 13 breeds. Three analyses were performed on each trait to obtain estimates and standard errors of breed effects needed to calculate across-breed EPD and accuracies. Model (R) for records of F1 progeny contained fixed effects for birth year and date of birth, sex, age and breed of dam, a...

First-parity Holstein (H), Normande-Holstein (NxH) crossbred, Montbeliarde-Holstein (MxH) crossbred and Scandinavian-Holstein (SxH) crossbred cows calving from June 2001 to December 2003 were compared for dystocia and stillbirths from seven California herds. Dystocia scores ranging from 1 (no assistance) to 5 (hard pull) and stillbirths (1 for alive and 0 for dead) were recorded for 1695 Holste...

Genetic correlations between purebred and crossbred performance and purebred and crossbred heritabilities were estimated for egg production traits of laying chickens using a multivariate sire model accounting for additive relationships between sires. Two sire lines, denoted lines 1 and 2, were crossed to one dam line to produce crossbred progeny. Records for egg weight, egg specific gravity, an...

An animal model and computer software were developed to conduct across-herd genetic evaluations using data from producers participating in the Sow Productivity Index program of the American Yorkshire Club. The final data set consisted of 61,596 litter records from 1986 to early 1990. The animal model included fixed contemporary group effects and random additive direct, service sire, permanent e...