Effect of intrauterine administration of a viscous gel-like substance on the estrous cycle in cattle. II. Irritating effects of the treatments on the uterus

Abstract

In the previous report, we investigated the effects of intrauteine injection of a viscous gel-like substance on the life span of the corpus luteum in the cow. The intrauterine treatment at early luteal phase caused an early regression of the corpus luteum and shortened the cycle length significantly. On the contrary, the treatment at late luteal phase delayed the regression of the corpus luteum and lengthened the cycle. The purpose of the present experiments is to investigate the relation between the irritating effects of the intrauterine injection of the viscous gel-like substance on the endometrium and the modification of the cycle length in the cow. The viscous gel-like substance was “Gelceptor F” (G) which was same as in the previous report.Three experiments were performed to determine 1) the retention of G in the uterus of the treated cow, 2) the irritating effects of the treatment on the bovine endometrium and 3) the effective period of the uterine irritation for modifying the cycle length of the cow.The cows used in the present experiments were almost same as in the previous report. Dose of G was 42-137 gm. per injection. The day on which ovulation occured was considered as day 0 of the cycle. The results obtained were as follows.1) The retention of G in the uterus of the treated cow. The retention of in G the uterus was verified by rectal palpation on 32 cycles of 9 cows in which intrauterine injections of G had been performed 1 to 5 times. The results are shown in Table 1. In only 3 of 16 cases treated during postestrus and in early luteal phase, liquid contents in the uterus were palpable for a few days after the treatment. After treatment during functional luteal phase and late luteal phase, uterine contents were palpable for 2 to 3 days in 10 of 16 cases. In 5 of the latter cases the uterus was swollen as in the case of pyometra or pregnancy. However, the swollen uterus involuted rapidly as the corpus luteum began to degenerate. From these results it was concluded that the retention of G in the uterus depended upon the stage at which the intrauterine injection was performed, the retention period being longer in animals treated at postestrus-early luteal phase.2) The irritating effects of the treatment on the bovine endometrium.A. Responses of cervical mucus following the treatment.: On 20 estrous cycles included in experiment 1, cervical mucus samples collected before and after the treatment were examined macroscopically and microscopically. The microscopical examination was performed on the mucus smear stained with Giemsa. The results are shown in Table 2. For 1 to 3 days after the treatment, the cervical mucus became cloudy or greyish white and a large number of neutrophil leucocytes and epithelial cells and a small number of eosinophil leucocytes appeared in most of the cases. However, cervical mucus became clear again in the following estrous period.B. Effects of the treatment on the endometrium.: The endometrium of seven beef cows slaughtered 1 to 9 days after the intrauterine treatment was examined macroscopically. In an additional 5 cases, the endometrium at the first post-treatment estrus was also examined histologically by endometrial biopsy. The results are shown in Table 3. In five of the seven animals, 105 to 330 gm. of brownish liquid were recovered from the uterine cavity. The volume of the uterine contents recovered was greater than the quantity of G injected. The surface of the endometrium was rough and brownish in colour in six of the animals. Marked edema was also observed in the endometrium of five animals. Endometritis was found four of the seven animals. However, the endometritis was limited to the surface area of the endometrium only. The uterine glands appeared normal in all cases. In five animals in which endometrial biopsies were carried out at the post-treatment estrous period, endometritis was not found in any of them.