Institute of Mountain Stockbreeding and Agriculture, BG - 5600 Troyan, Bulgaria
ALEKSIEV, Y., 2007. Diurnal distribution of the time of parturition in the Danube fine wool breed of sheep. Bulg. J. Agric. Sci., 13: 723-728
Diurnal distribution of the time of natural spontaneous births was studied in the Danube fine wool breed of sheep kept under conventional management system. All sheep were at equal age and were served by one ram from the same breed. The time of parturition was recorded in 374 ewes round-the-clock. A unimodal distribution of births was observed with a peak between 12:00 and 15:00 h when 18.2% of the sheep gave birth, and the lowest incidence of lambing (8.8%) was recorded between 0300 and 0600 h. More ewes (56.7%) lambed between 06:00 and 1800 h and less (43.3%) during the nighttime between 18:00 and 06:00 h. Type of birth and sex of the lambs did not have any noticeable effect on birth distribution. Despite the established differences in birth distribution under the management practice employed the circadian rhythm was not clearly emphasized. The results suggest that round the clock observation of the flock at lambing time is necessary in order to prevent mismothering and other problems typical for this period of the year.