Title:Nagy létszámú hazai tejelő szarvas marhatelepek teheneinek főbb szaporasági mutatói és szaporodás biológiai menedzsmentje
SUMMARY Background: The reproductive performance of the Hungarian dairy cattle popu lation has been continuously declining since the early ’80s. Objectives: The aim of our study was to survey the reproductive management prac tices and performance in Hungarian dairy herds in order to assess the current situation. Materials and Methods: A survey was carried out in 34 large-scale dairy herds from all the statistical regions in Hungary between 22 May and 6 November 2015. Altogether 25,672 cows were surveyed in these herds, which cover 14.6% of the total Hungarian milk recorded Holstein-Friesian cow population. The average herd size was 755 dairy cows (291–2,502) and the average 305-day milk yield was 10,014 kg (8,330–12,541). In each herd a questionnaire was used to collect the data. Firstly, the farm manager and/or the veterinarian were personally interviewed about the reproductive management practices in their herd, and secondly, the relevant data were gathered from the farm management computer programs. Results and Discussion: The average calving interval was 435 days (392–490), average first service conception rate was 26.52% (11.26–51.40%), and average services per conception (cows only) was 4.04 (2.56–6.16), respectively. The breed ing interval was 31.38 days (22.00–56.03), and the proportion of reproductive culling was 31.68% out of all premature disposals (7.57–69.70%), on average. A voluntary waiting period after calving was applied in 26 herds (76.47%), with an average length of 50.23 days (30–80). Visual oestrus detection (30 herds; 88.24%) was the predominant method of searching for cows in heat, activity monitoring devices were used in 23 herds (67.65%). In 27 farms (79.41%) oestrus synchronization was performed, mostly OvSynch (20 herds; 58.82%). The aver age time of the first pregnancy check was 35.06 days (27–60) after insemination, which was performed via ultrasound in 23 herds (67.65%) and by laboratory PAG test in 2 herds (5.88%). Daily milk production was the most prevalent criterion in reproductive culling decisions (32 herds; 94.12%).