A longitudinal Bayesian threshold analysis of insemination events during the first 250 d after calving of first-parity Holsteins was carried out. The outcome of an insemination event was treated as a binary response of either a success (1) or a failure (0). Thus, all breeding information for a cow, including all service sires, was included, thereby allowing for a joint evaluation of male and fe...

this study was carried out to investigate the relationship between early lactation curve parameters andcalving interval in holstein cows of iran. in order to describe the lactation curve, the incomplete gammafunction was fitted to 5,754,428 test-day milk records corresponding to 766,108 lactations on 315,634 cowsin 2,448 herds. cows with higher milk yield during early lactation had shorter calv...

Estimated transmitting ability for milk production calculated from only first lactation records was regressed on milk proofs of the sire and maternal grandsire and either estimated transmitting ability of the dam calculated from only first lactations or estimated transmitting ability of the dam calculated from all lactations of a data set in which all cows were required to have milk records of ...

A modification of the evaluation method for cows in the northeast United States allowed simultaneous evaluation of cows in pairs of herds and computation of variances of prediction errors of differences of genetic potential between pairs of cows within and across herds. These variances were examined for 20 pairs of herds in Holstein, Jersey, and Brown Swiss breeds. Current evaluations of cows a...

Piecewise Weibull proportional hazard models were used to investigate the effect of genetic and nongenetic factors on functional and true longevity traits of the Slovenian Brown cattle breed. Records of 37 908 Brown cows from 2401 Slovenian herds were used. As these herds were characterised by a relatively small average herd size starting from 6.7 in 1999 and increasing to 8.7 Brown cows per he...

Early lactation parameters are difficult to estimate from commercial dairy records due to the small number of records available before the peak of production. A biological model of lactation was used with weekly milk records from a single Holstein herd to estimate these early lactation parameters and the secretion rate of milk from the average cell throughout lactation. A genetic analysis of th...

Random regression models have been widely used to estimate genetic parameters that influence milk production in Bos taurus breeds, and more recently in B. indicus breeds. With the aim of finding appropriate random regression model to analyze milk yield, different parametric functions were compared, applied to 20,524 test-day milk yield records of 2816 first-lactation Guzerat (B. indicus) c...