Risk factors and mortality rate of calves in the first month of life in Slovenian Holstein Friesian population

The aim of this study was to estimate perinatal and neonatal mortality rates from day 2 to day 30 in Slovenian Holstein Friesian population and to assess risk factors for increased losses. Data from 420,556 calves of Holstein Friesian cows born in Slovenia in the period from January 2005 to December 2016 were analysed. Data were obtained from the Central register of bovine animals. The average perinatal calf mortality, including abortions and stillbirths, was 8.24% and neonatal mortality from day 2 to day 30 4.28%. The most important effects on perinatal calf mortality rate were the number of calves at calving and the age of dam at calving, while herd size and calving season were the most influential in the neonatal period from day 2 to day 30.