to study the effects of environmental factors on milk and fat yields (240day) traits of iranian buffaloes, 22596 and 22165 records were utilized for milk and fat yield traits, respectively. uni and bivariate analysis for estimation of (co)variation components of the traits were done in five lactations. milk yield in the 1st lactation had the highest number of records (4482), collected through c...

The objective of this research was to estimate genetic parameters of first-lactation body condition score (BCS), milk yield, fat percentage (Fat%), protein percentage (Prot%), somatic cell score (SCS), milk urea nitrogen (MUN), lactose percentage (Lact%), and fat to protein ratio (F:P) using multiple-trait random regression animal models. Changes in covariances between BCS and milk production t...

This study investigated the improvement in genetic evaluation of fertility traits by using production traits as secondary traits (MILK = 305-d milk yield, FAT = 305-d fat yield, and PROT = 305-d protein yield). Data including 471,742 records from first lactations of Denmark Holstein cows, covering the years of inseminations during first lactations from 1995 to 2004, were analyzed. Six fertility...

BACKGROUND Milkability is a complex trait that is characterized by milk flow traits including average milk flow rate, maximum milk flow rate and total milking time. Milkability has long been recognized as an economically important trait that can be improved through selection. By improving milkability, management costs of milking decrease through reduced labor and improved efficiency of the auto...

The objective of the present study was to investigate single nucleotide polymorphisms (SNPs) located in three candidate genes previously reported to have effects on fertility and milk production traits in a population of 123 Holstein cows. The milk production traits evaluated included lifetime averages of milk yield, protein concentration, and fat concentration. Fertility traits evaluated inclu...

OBJECTIVE This study estimated the genetic parameters for productive and reproductive traits. METHODS The data included production and reproduction records of animals that have calved between 1979 and 2013. The genetic parameters were estimated using multivariate mixed models (DMU) package, fitting univariate and multivariate mixed models with average information restricted maximum likelihood...

Genetic relationships between yield and type traits were investigated using multiple-trait REML procedures with an animal model. Computing strategies were developed to deal with large populations and numbers of traits. Data consisted of records for 3 production and 15 type traits for 20,836 primiparous cows from 1982 to 1988. The model included 2358 herd management effects, 28,749 animal effect...

This study provides estimates of genetic parameters for various diseases, fertility and 305-day milk production traits in dairy cattle using data from a UK national milk recording scheme. The data set consisted of 63891 multiple lactation records on diseases (mastitis, lameness, milk fever, ketosis and tetany), fertility traits (calving interval, conception to first service, number of services ...