젖소에 있어서 요인별 후산정체 발생율과 번식효율 = Incidence of Retained Placenta and Subsequent Reproductive Performance in Holstein Dairy Cows

다국어 초록 (Multilingual Abstract)

A field experiment was performed to investigate the cause of retained placenta by season gestation length parity and sex of calf. and to determine the effect of placenta retention on the subsequent reproduction. days to first service days open and services per conception were evaluate in Holstein dairy cows. The cows which did not expell their placenta until 12 hours post-Parturient were termed as cow of Placenta retention. The time for placenta release was caleulated in the normal cows without retained placenta. The results obtained in these studies were summarized as follows; 1. The mean incidence of retained placenta was 24.4% in a total of 377 cows examined. Incidence of retained placenta was lowest in autumn calving cows(18.4%). in cows having longer than 286 days of gestation(20.0%), in 1st caking cows(14.7%) and in male calving but highest in summer calving(35.7%), in cows having shorter than 276 days of gestation(31.6%). in the 5th calving cows(28.2%) and in female calving although there were not significant differences between the respective groups. Birth weight of calves did not significantly affect the incidence of retained placenta Embryo transferred and artificial inseminated cows showed placenta retention of 33.3% and 23.9% respectively. with no significantly difference between both groups. 2. The times for placenta release in winter calving cows were significantly (P$lt; 0.05) longer than in spring and summer calving cows he 6.5±0.2 hours. but the gestation length, parity and sex of call were not found significant factors on incidence of placenta retention. 3. The period from calving to first service was significantly(p$lt; 0.01) longer in spring calving cows than autumn or winter calving ones. and also significantly(P$lt; 0.05) longer in the cows of 3rd parity than in tile cows of the 1st. 2nd, 6th and over parity. The results on days open and the services per conception showed significantly(p$lt; 0.111) lower reproductive performance in the cows of 4th parity but not significantly affected by gestation length or sex of calf. From these results. it seem to be no direct relationship between incidence of retained placenta and reproductive performance