Intrauterine bacterial findings and hormonal profiles in post-partum cows with normal puerperium.

The post-partum intrauterine bacterial flora, prostaglandin release, uterine involution and resumption of ovarian activity were studied in 9 Swedish dairy cows during the first 8-week period. Uterine involution was monitored by transrectal examinations of the reproductive tract 3 times weekly. Bacteriological examination was performed from twice weekly uterine biopsies. The main PGF2 alpha metabolite (15-ketodihydro-PGF2 alpha) was monitored from twice daily blood plasma samples, while morning samples were used for progesterone determinations. The cows were assigned to 2 groups: Group I (n = 7) with an uncomplicated puerperal period and Group II (n = 2) with signs of intrauterine infections. A total of 143 biopsies were collected, of which 129 (90.2%) were found to be bacteriologically negative. Thirteen (9.1%) of the remaining 14 biopsies were bacteriologically positive, while one (0.7%) was probably a contamination on a single occasion. The 13 bacteriologically positive biopsies belonged to the Group II cows from which 31 isolates contained 6 different genera of facultative and obligate anaerobic bacteria. Actinomyces pyogenes along with Bacteroides sp. and Fusobacterium necrophorum were found to predominate in a mixed flora. The bacteria were rapidly eliminated and disappeared completely from the uteri towards the end of the third week post-partum. The average number of days required for completion of uterine involution was 21.8 +/- 3.0 for all animals. The plasma levels of the PGF2 alpha metabolite were significantly elevated for the first 12-18, and 18 and 27 days in Group I and Group II, respectively. There was no significant relationship between the duration of PGF2 alpha release and the time required for completion of uterine involution (p > 0.05). Progesterone analysis showed resumption of ovarian activity and subsequent ovulation in 4 of the 9 cows 44-55 days post-partum. Thus, intrauterine infections are not commonly seen in cows with normal calving and comparison between the duration of PGF2 alpha release and the time required for completion of uterine involution showed insignificant correlation. However, the longer duration of PGF2 alpha release recorded in the 2 cows with intrauterine infections are related to the increased frequency of infections.