The Effect of Dam Breed on Calf Mortality in the First Month of Life in Slovenia

The aim of this study was to estimate the perinatal and neonatal mortality rates from day 2 to 30 in Slovenian calves and to evaluate risk factors for increased losses. We analysed data on 1,333,765 calves of different dam breeds, born in Slovenia in the period from January 1 to December 31st, 2012. Data were obtained from the Central register of bovine animals. The average perinatal calf mortality, including abortions and stillbirths, was 5.57% and 2.68% from day 2 to 30. The most significant effects on perinatal calf mortality rate were the number of calves at calving, age of the dam at calving, the herd size, while herd size and calving season were the most influential in the following neonatal period from day 2 to 30. Calves from Holstein Friesian dams showed much higher perinatal and neonatal mortality rates than calves from Simmental, Brown and other dam breeds. With increased herd size, the perinatal and neonatal mortality rate increased. This increase was more pronounced in Simmental, Brown and other dam breeds than in Holstein Friesian dams.