the objective of the present study was to estimate the lactation curve parameters through incomplete gamma function and to genetically evaluate the relationship of these parameters and udder traits in holstein population of iran. two data sets' including 117583 [(for lactation curve parameters) and 7351 (for determining genetic and phenotypic relationship between lactation curve parameters...

The purposes of this study were to estimate the effects of risk factors on stillbirth parturition and evaluatethe effects of stillbirth on lactation performance in Holstein dairy cows. Data were obtained from a dairycattle herd located in Isfahan province, Iran. The logit of the probability of stillbirth was modeled usinglogistic regression and the effect of stillbirth on lactation performance ...

the purposes of this study were to estimate the effects of risk factors on stillbirth parturition and evaluatethe effects of stillbirth on lactation performance in holstein dairy cows. data were obtained from a dairycattle herd located in isfahan province, iran. the logit of the probability of stillbirth was modeled usinglogistic regression and the effect of stillbirth on lactation performance ...

Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estimate genetic parameters for milk production trait, test day records (TDR) were collected from the first lactation of Holstein co...

random regression models (rrm) are used for genetic estimations of milk traits in dairy cows. rrm utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. in this study, to estimate genetic parameters for milk production trait, test day records (tdr) were collected from the first lactation of holstein co...

Using monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. The model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) ...

The objectives were to estimate (co)variance components and genetic parameters for lactation curve traits in Holstein dairy cows in Iran. The used data were records on Holstein cows collected during January 2003 to December 2012 by the Animal Breeding Center of Iran (Karaj, Iran). In order to describe the lactation curve, an incomplete gamma function was fitted to 691200 test-day records on 962...

the objective of this study was to determine the optimum replacement strategy using dynamic programming for dairy herds in fars province. a dairy cow is kept several lactations for milk production in the herd. after spending several lactations, milk production gradually begins to decline, while animal health problems rises simultaneously. so one of the most important management decisions of dai...