A strategy for simultaneous sire and cow evaluation of genetic merit was implemented. First lactation records of 1,074,971 Holstein cows in 20,065 herds were included. After inclusion of ancestors, there were 1,741,356 equations: 1,505,938 cow, 229,394 herd-year-season, 6000 sire, and 24 genetic group equations. All known genetic relationships among animals were considered. Genetic group coeffi...

BACKGROUND Research has indicated that a number of different factors affect whether an animal receives treatment or not when diseased. The aim of this paper was to evaluate if herd or individual animal characteristics influence whether cattle receives veterinary treatment for disease, and thereby also introduce misclassification in the disease recording system. METHODS The data consisted main...

Repeat breeding (RB), defined as cows failure to conceive from 3 or more regularly spaced services in the absence of detectable abnormalities, is a costly problem for the dairy producer. To elucidate the occurrence of RB in Swedish dairy herds and to identify risk factors of the syndrome totally 57,616 dairy cows in 1,541 herds were investigated based on data from the official Swedish productio...

Dairy cows may serve as asymptomatic carriers of Salmonella. The potential for herd carrier status increases with herd size, and Salmonella shedding may be triggered by stresses placed on the animals. The scope of the current study is to determine the effects lactation may have on Salmonella genotypic diversity among detected serotypes. Fecal samples were collected on two sampling dates from 60...

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 t...

The fertility of lactating Holstein cows is severely reduced during periods of heat stress. Despite this reduction in fertility, however, some inseminations conducted during heat stress result in successful pregnancies from which heifer calves are born. Many of these heifer calves are retained and raised to enter the milking herd as replacement animals. Heat stress experienced by these females ...

The objective of this study was to determine the dynamics and relative body weight (BW) changes after parturition and their relationships to milk yield in Holstein (H) and Czech Fleckvieh (F) cows, and also the relationships between their BW changes in the first 8 weeks of lactation and reproductive performance. A retrospective, observational study comprised analyses of individual cow records f...

Genetic relationships among lactation records are of interest because most selection of bulls is on first lactations. Selection also complicates estimation of genetic parameters. Techniques unbiased by selection should be used. Estimation of genetic and environmental (co)variances was done using restricted maximum likelihood with an expectation-maximization algorithm for an animal model. The al...

genetic parameters were estimated for somatic cell score (scs) in dairy cattle of iran using test day records. the records of first lactation were extracted from the database of national animal breeding center for cows calved between 2001 and 2010. data included 222923 test-day records, obtained from 29668 animals distributed in 100 different herds. estimates were carried out through gibbs samp...