Abstract
The objective of the present study was to investigate relationships between Caslick's index and fertility for different age groups of Cheju mares. Ninety-one Cheju mares were used for this study. Caslick's index was measured the effective length and angle of declination of the vulva in the mare. They were mated naturally by stallions from February to October during the years $2002{\sim}2005$. The classification used in the present study was : Group I - good conception every years, Group II - conception every other year and Group III - Barren. Younger aged group ($3{\sim}7$ years) had a lower Caslick's index (<50) compared with $8{\sim}14$ aged group and older aged group (> 15 years). In this study, Caslick's index was increasing by increasing age of Cheju horse like Thoroughbred. However, fertility was decreasing by increasing Caslick's index. Hence, there was significant association between the different Caslick's index and fertility. Further research is needed to determine relationship between different Caslick's index and endometritis.
본 연구에서는 제주마의 연령에 따라 Caslick's index와 번식률의 관계를 조사하고자 수행하였다. 제주마의 연령이 증가할수록 Caslick's index 역시 증가됨을 알 수 있었다. 연령이 어린 암말($3{\sim}7$세)에서는 평균 Caslick index가 45.4, $8{\sim}14$세에서는 72.5, 15세 이상은 72.5로 나타났다. Caslick's index에 따른 암말의 평균 연령은 Caslick's index 50 이하에서는 10.9세이고, 50이상 150 이하에서는 13세, 150 이상에서는 15.1세로 나타났다. 제주마의 번식률과 Caslick's index와의 관계 에서도 Caslick's index가 증가함에 따라 번식률은 감소하는 것으로 나타났다.