Duration of estrus and estrous cycles in mares from Haflinger breed

Abstract

A study of the duration of oestrus and estrous cycles in mares from Haflinger breed (HB) and the influence of some factors was conducted. The records used for this study were from the breeding registers of the mares from the State Stud farm Kabiuk near Shumen, covering a period of 11 years (2009 to 2020). In the study were included 15 mares with 110 estruses and 22 estrous cycles. With the mares from Haflinger breed, the average duration of oestrus is 5.52 ± 0.26 days and the length of the estrous cycle is 24.21 ± 1.13 days. The year (P<0.001), month (P<0.001), season (P<0.05), and length of the estrous cycle - the year of fertilization (P<0.05) had reliable influence on the duration of oestrus. In Haflinger mares, the shortest estrus is in the middle and at the end of the breeding season (March: 4.39 ± 0.46 days, July: 3.33 ± 0.82 days). Its duration increases during the winter season and reaches its peak in the middle of spring (February: 5.96 ± 0.51 days, April: 8.37 ± 0.72 days).

Keywords

• estrous cycles
• estrus
• haflinger breed
• mares
• reproduction