For more than half a century, progeny testing has been the foundation of genetic selection programs in dairy cattle (Robertson and Rendel, 1950). Several factors make progeny testing especially advantageous in dairy cattle, most notably widespread use of artificial insemination (AI) with frozen semen and the fact that nearly all traits of economic importance, including milk production, milk com...

this study utilized daily records of 2000 egyptian holstein dairy cows. the productive, reproductive and economic data during a whole lactation season were recorded for healthy and mastitis cows. two risk factors for mastitis were included, parity and season of calving. mastitis cows had significant (p

Calving complications have an incidence on the economic profitability of dairy herds. In the Walloon Region of Belgium, calving ease data recording is being done on voluntary basis since 2000. This allows now the implementation of a genetic evaluation of Holstein dairy cattle addressing the need of dairy breeders to select bulls in order to reduce frequency of calving problems. Calving ease sco...

The BLRI Cattle Breed 1(BCB-1) is a native cattle breed developed by Bangladesh Livestock Research Institute (BLRI) through selective breeding among indigenous cattle of Bangladesh. Data asserted from record sheets of 529 animals maintained during 1992 to 2006 were analyzed to evaluate the reproductive efficiency of BCB-1 cattle in different generations, seasons and parities. The highest percen...

Genetic and environmental factors that might affect gestation length (GL) were investigated. Data included information from >11 million parturitions from 1999 through 2006 for 7 US dairy breeds. Effects examined were year, herd-year, month, and age within parity of conception; parturition code (sex and multiple-birth status); lactation length and standardized milk yield of cow; service sire; co...

This experiment was conducted to evaluate the association between risk factors and the risk of culling in Iranian Holstein cows. The data consisted of 329,772 lactation records obtained from the Animal Breeding Center of Iran (2003 - 2012) and logistic regression was applied to investigate the associations between the predictor and response variables. The response variable in this experiment wa...

stillbirth is defined as a calf death just prior to, during, or within 24 to 48 h of parturition. the exact cause of calf death in dairy cows in this period of time is unknown. the objective of this study was to investigate about the effective factors on stillbirth and also to estimate some of the genetic parameters in iranian dairy holsteins. data in the first and second lactation that have be...

Objective-To assess the effect of lameness on culling of dairy cows in Tehran province. Design- Historical cohort study. Study population and procedures- 7067 first- and second-parity Holstein dairy cows that calved from March, 21 2007 to March, 20 2008 were until next calving or culling. Logistic regression was conducted data. Results-The overall lactational culling rate for eligible cows i...

The objectives of the study were to assess colostrum quality and nutrients in dairy cows in Isfahan, Iran, and to determine the effects of calving season, parity, and volume of first colostrum on colostrum quality. Colostrum samples were collected over the period January-December, from 365 Holstein dairy cows from 12 dairy farms and analyzed for their IgG, IgM, total solids, fat, protein, lacto...

introduction cattle are a monotocous species meaning that, under most circumstances, a successful pregnancy results in the birth of one calf. twinning rate has been reported in dairy cows from 3 to 5 percent, which can be influenced by maternal age.the birth of twins is detrimental to the majority of beef and dairy cattle producer. financial loss arising from any of twinning has been reported i...