Title:Holstein-fríz tenyészüszők szaporodásbiológiai menedzsmentje és mutatói nagy létszámú hazai tehenészetekben
SUMMARY Background: Heifer raising represents 15-20% of the total milk production costs, but the management of replacement heifers is often neglected. The goal of replacement heifer programmes is to reduce raising costs, while maximizing future profitability.Objectives: The aim of our study was to survey the reproductive management practices and the reproductive performance of replacement heifers in large commercial dairy herds in Hungary.Materials and Methods: Reproductive management practices were surveyed using a questionnaire between 22 May and 6 November 2015, and altogether 34 large-scale Hungarian dairy herds were involved. Individual heifer data from the participating farms were gathered for 50,396 heifers first inseminated between 1 January 2011 and 31 December 2014.Results and Discussion: Mean (± standard deviation) age at first service, age at first calving and mean first-service conception risk were 15.53 ± 1.59 months, 25.61 ± 2.22 months and 47.10%, respectively. 8.6% of the inseminated heifers were culled prior to first calving, 246.25 ± 107.10 days after first insemination, at 23.94 ± 3.95 months of age, on average. Heifers grazed on 35.3% of the surveyed farms. Body weight was regularly measured on 47.1%, body condition was regularly scored on 8.8% and oestrus detection aids were used on 14.7% of the farms. Sexed semen was used in 94.1% of the herds. Early pregnancy diagnosis was performed in 38.2% of the herds. Most commonly, pregnancy diagnosis was performed weekly (34.4%) or monthly (25.0%). The use of labour-intensive and costly management measures was infrequent, therefore, there is room for the uptake of intensive management practices in the reproductive management of heifers. In order to minimize losses stemming from the prolonged non-productive period, farm managers and veterinarians should dig deeper than monitoring average age at first calving and conception risk only.