Reproductive parameters of Thoroughbred mares reared in the national stud farm "Kabiyuk" in Bulgaria (Retrospective analysis).

The reproductive parameters of 51 Thoroughbred mares were studied during the period 1997-2010. A total number of 270 oestrus and reproductive cycles were included in the analysis. Thoroughbred horses are only allowed to mate naturally by traditional hand method. As a source of information was used the zootechnical documentation of the national stud farm. It was established that the reproductive traits subject to the recent study varied in wide ranges - interval of foal heat (11.18±2.40-31.00±19.92 days) and foaling-to-conception (13.00±3.00-57.00±29.69 days), number of oestrus cycles (1.16±0.38-1.87±1.28), mating of mares (2.80±0.83-3.89±2.40) and total born foals (2-20) per year, duration of oestrus (21.00±2.51-26.00±7.07 days) and heat (3.00±2.22-5.09±1.95 days). The positive correlations were found between duration of oestrus cycle with number of matings per year and duration of heat, duration of heat and number of matings per year, foaling-to-conception interval with number of foals and foaling-to-conception interval and number of oestrus cycles per year. [ABSTRACT FROM AUTHOR]