Factors Affecting Conception Rate of Israeli Holstein Cattle

Factors Affecting Conception Rate

An analysis of dairy herd records to determine the cause of low reproductive efficiency usually leads to the conclusion that problems are centered in one of the following areas: breeding policy (intentionally waiting too long after calving for first service), estrous detection efficiency (missed heats), or conception rate. The challenge is to identify the factors responsible for the problem. On...

Insemination factors affecting the conception rate in seasonal calving Holstein-Friesian cows.

Differences in conception rate to first service between artificial inseminations (AI) carried out by commercial AI operators (CAI) or do-it-yourself operators (DIY), between natural service (NAT) and AI, between different AI sires, and between fresh and frozen-thawed semen, on Irish commercial dairy farms, were studied using logistic regression. The study comprised 12,933 potential first insemi...

Genetic analysis of the growth rate of Israeli Holstein calves.

Weight of male and female Israeli Holstein calves and yearling gain were analyzed on 285 800 records from 105 935 animals from 458 herds recorded between 1994 and 2007. The difference between the sexes increased until around 400 days, at which point the difference between males and females was 110 kg. Yearling gain, defined as 365 × (weight - 35)/age + 35, was greatest for males at approximatel...

Factors Affecting Twinning and Effects of Twinning in Holstein Dairy Cattle

Quantitative trait loci affecting calving traits in Danish Holstein cattle.

The objectives of this study were 1) to detect quantitative trait loci (QTL) affecting direct and maternal calving traits at first calving in the Danish Holstein population, 2) to distinguish between pleiotropic and linked QTL for chromosome regions affecting more than one trait, and 3) to detect QTL affecting stillbirth and calving difficulties but not calf size that could be used in selection...