REPRODUCTIVE PERFORMANCE OF SIMMENTAL COWS IN SERBIA IN RELATION TO PROVENIENCE AND MANAGEMENT SYSTEMS

The enhancement of Simmental cattle productivity in Serbia has predominantly relied on pure breeding. Effective selection remains essential for substantial progress in improving the genetic foundation and increasing the overall efficiency of livestock production. In an effort to accelerate genetic improvement and expand herd size, Serbian farmers are increasingly importing Simmental cattle from countries with highly developed breeding programs-particularly Austria and Germany-where average milk yields reach 6,500–7,000 kg with over 4% milk fat. This study aimed to evaluate the influence of animal provenience on four key reproductive indicators: calf birth weight, age at first calving, calving interval, and service period length, comparing domestic versus imported Simmental populations. A total of 954 cows were observed, encompassing 3,641 completed lactations. Animals were raised either by individual farmers (tied housing system) or on commercial farms (loose/free housing system). Based on provenience and housing method, cows were categorized into four groups: group 1: domestic provenience, smallholder tied housing; group 2: imported provenience, smallholder tied housing; group 3: domestic provenience, commercial farm free housing; group 4: imported provenience, commercial farm free housing. The highest performance values across the studied traits were found in Group 4. All reproductive parameters varied highly significantly (p ≤ 0.001) depending on the combined effects of housing system and animal provenience, except for age at first calving, which showed no statistically significant difference (p > 0.05).