유우(乳牛)의 번식장해(繁殖障害) 조사(調査)

A Survey on Reproductive Disorders of Dairy Cattes

The status of artificial insemination was surveyed by investigating 20796 heads of adult dairy cattle out of 30464 heads at 1649 dairy farms located Seoul and Gyung-Gi and Chung-Cheong province area, and the results are as follows: 1. There were 286 small farms feeding less than 5 heads occupying 17.3% of total farm number, and 1083 medium sized dairy farms feeding between $6{\sim}20$ heads occupying 65.64% and also 280 large dairy farms feeding more than 21 heads occupying 17.06% of total. 2. Population of cow aging from 2 to 6 years were 87.26% and among 20907 heads of dairy cattles which had calved previously 13196 heads had histories of one to four calving 90.40%. 3. The successful conception rate with first A. I. occupied only 53.43% and 92.4% after third A. I. service. The average A. I. frequency for successful conception per/head was 1.8 times. 4. The breeding status was pregnancy 61.72%, uncertain pregnancy 19.39%, and as physiological vacancy 12.48% and reproductive disorders 10.62%. 5. Among 1264 heads of reproductive disorders 856 heads were clue to ovarian diseases and occupied 68.98% of total disorders and uterus diseases 10.64% and repeat breeders occupied 17.64%.