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 ...

One hundred sixteen spring-calving Polled Hereford x Angus cows were milked using milking machines after receiving 20 IU of oxytocin. Sires of the cows had been divergently selected on yearling weight (YW) and total maternal (MAT) EPD to form four groups: high YW, high MAT EPD; high YW, low MAT EPD; low YW, high MAT EPD; and low YW, low MAT EPD. Average milk production after 12-h calf separatio...

SUMMARY four-generation crossbreeding experiment with Hereford, Angus a from a tt1e were analyzed. Individual, maternal, and grand-maternal rthorn c: rotic effects on the composite trait of calf weight weaned per I e and h\~eeding and its component traits were evaluated. The parameter e."osed to then used to project performance at equ i 1 i bri urn under rotat i on teS ~ere The average of two-b...

Simultaneous genetic evaluations for bulls and cows obtained by mixed model procedures with an animal model incorporating all numerator relationships for artificially sired Holstein cows in northeastern United States were compared with separate (Northeast) mixed model evaluations of cows and sires for predicting genetic evaluations of progeny from dam, sire, and maternal grandsire evaluations. ...

Steer progeny (n = 80) produced by mating British crossbred females to one of three terminal (Charolais) sires or one of five maternal (Angus or Red Angus-Composite) sires were evaluated from birth to harvest to compare the effects of sire type (terminal vs. maternal) on growth performance, carcass characteristics, and net return per head. Steers sired by terminal bulls were heavier (P < 0.05) ...

Intrabreed additive genetic, environmental, and phenotypic variances and covariances for Romosinuano (R) and Zebu (Z), as well as interbreed nonadditive genetic variances and covariances (sire x breed-group-of-dam interactions), for birth weight (BWT), weaning weight (WW), and postweaning gain (GW) were computed using a Romosinuano-Zebu multibreed data set from the Turipaná Experiment Station i...

Evaluations that analyze first and later parities as correlated traits were developed separately for calving ease (CE) from over 15 million calving records of Holsteins, Brown Swiss, and Holstein-Brown Swiss crossbreds and for stillbirth (SB) from 7.4 million of the Holstein CE records. Calving ease was measured on a scale of 1 (no difficulty) to 5 (difficult birth); SB status was designated as...

A method used to approximate reliabilities for animal models was modified to estimate reliabilities for sire-maternal grandsire (MGS) models. Accuracy of the approximation was tested on a calving-ease data set for 2,968 bulls for which the inverse of the coefficient matrix could be obtained. Correlations between estimated and true reliabilities ranged from 0.984 to 0.998 for first- and later-pa...

the aims of this research were to estimate of genetic parameters for pre-weaning traits and lamb survival in iran-black sheep. for this purpose 6344 records for birth weight (bw) and lamb survival (ls) and 5264 records for weaning weight (ww), average daily gain (adg) and kleiber ratio (kr) were available, which collected by abbasabad animal breeding and rearing station, over the period from 19...