THE INCIDENCE OF MULTIPLE OVULATIONS IN D UTCH WARMBLOOD MARES

In the period 1994 - 1996 1030 oestruses of Dutch Warmblood mares were evaluated on the incidence of multiple ovulations diagnosed by rectal palpation. Ultrasonography was not used. All follicles > 25 mm were n oted. The examination was repeated every 48 hours. The incidence of mu ltiple follicle development was 7,3%. In a group of 50 ultrasonographi cally diagnosed twin-pregnant mares only 14 (28%) had been detected by rectal palpation as a multiple ovulation. This suggests an incidence of multiple ovulations in Dutch Warmblood mares of 7,3 x 1/28 x 100 = 26%. Restrictions of rectal palpation are discussed. Ultrasonography i s essential for the diagnosis of multiple ovulations. The importance o f a good twin-prevention programme is emphasized.