There is limited genetic information relating calving difficulty and body weights to other productive and reproductive traits. Such information is useful for specifying selection criteria and for predicting economic consequences of selection. Genetic, maternal, and environmental covariances of six productive and reproductive measurements with calving difficulty, birth weight, 200-d weight, and ...

The use of genomic selection for changing the growth curve shape of animals, acting simultaneously on the 3 parameters of a Gompertz growth curve, was studied using computer simulation. Results showed that genomic selection modified the growth curve. Responses to all selection criteria were accompanied with a correlated response in mature weight due to the high genetic correlations between matu...

Data from seven generations of a divergent selection experiment designed for environmental variability of birth weight were analysed to estimate genetic parameters and to explore signs of selection response. A total of 10 783 birth weight records from 638 females and 1127 litters in combination with 10 007 pedigree records were used. Each record of birth weight was assigned to the mother of the...

An experiment was conducted comparing multilevel selection in Japanese quail for 43 days weight and survival with birds housed in either kin (K) or random (R) groups. Multilevel selection significantly reduced mortality (6.6% K vs. 8.5% R) and increased weight (1.30 g/MG K vs. 0.13 g/MG R) resulting in response an order of magnitude greater with Kin than Random. Thus, multilevel selection was e...

a selection program is being implemented to improve meat production in makooei sheep. increasing litter size per ewe is the main objective, but possible repercussions on weight traits of lambs should be considered. the aim of this study was to estimate heritability along with genetic and phenotypic correlations between ewe's reproductive vs. weight traits in makooei ewes. data were comprised of...

HE first seven generations of a selection experiment designed to allow exTperimental evaluation of a restricted selection index were reported by OKADA and HARDIN (1967). The index was computed to produce maximum response in 14-day larval weight of Tribolium castaneum while preventing a correlated increase in 30-day adult weight. Not only was the index effective for restricting the change of 30-...