Abstract The objective of this study was to determine genetic parameter estimates for age at first calving (AFC) in Red Angus and Simmental heifers. ability a heifer calve earlier has implications on calf performance the heifer's successive re-breeding. Heifer pregnancy data were obtained from International Genetic Solutions, where females with exposure records included population. Females subs...

Data from 528 male and 645 female progeny of 63 sires were used to estimate genetic correlations between female and male reproductive traits. Data were from two Hereford herds involved in a long-term selection program of the North Carolina Agricultural Experiment Service. Testicular measurements of circumference, diameter, length and volume were obtained on bulls at 205 and 365 d. Testicular gr...

Two trials were conducted to evaluate one trial, pregnancy first 21 d and total pregnancy in effects of Synovex C@ implants on replacement heifers, 63-d breeding season were decreased ( P = . 0 5 ) by given at two different ages. Crossbred heifer calves ( n implanting at 6 mo. At subsequent calving, an = 370) were allotted to four treatments: 1) noninteraction existed between the effects of the...

The aims of this study were to determine some major biochemical alterations observed in first calving cows with udder edema during the periparturient period and to detect some associations between dietary factors and the disease. For that, the concentrations of some electrolytes (Na+, K+, Cl, Ca2+, P and Mg2+), lipid (triglycerides and cholesterol) markers and lipoproteins (HDL, LDL and VLDL) a...

Clinical mastitis was analyzed with mixed linear models (LM) and survival analysis (SA) using data from the first 3 lactations of >200,000 Swedish Holstein cows having their first calving between 1995 and 2000. The model for both methods included fixed effects of year-month and age at calving, fixed regressions of proportions of heterosis and North American Holstein genes, and random effects of...