Effects of intrauterine administration of a viscous gel-like substance on the estrous cycle in cattle. I. The estrous cycle length and the fertility following the treatment

Abstract

In our previous report, it has been demonstrated that the length of the estrous cycle of cattle can be shortened by inserting rubber tube into the uterine horn 1-3 days (early luteal phase) or 7-8 days (functional luteal phase) after ovulation. These results suggest that the uterus plays an important role in regulating estrous cycle length in cattle. The purpose of the work presented here is to investigate the effects of uterine distention by injecting a viscous gel-like substance into the uterus on the length of the estrous cycle in cattle. The fertility of the animal following the treatment was also investigated.The experiments were performed on a total of 34 cycles of 9 cows including 7 Japanese beef cows and 2 Jersey cows. When an animal was used successively, she was retreated by uterine distention after it was confirmed that the previous treated cycle had been followed by 1-3 cycles of a normal length. The viscous gel-like substance “Gelceptor F” G had been prepared originally for treating bovine endometritis. It contains 500mg of Fradiomycin sulfate, 280mg of Bithionol and 10, 000 IU of vitamin A palmitate per 100g. Each 75g of G is kept in a plastic tube for practical use. It was injected into the uterus through the cervix by using a special injector which composed of a metal catheter and a screw driver for rolling up the tube containing G. Dose of G was 42-137g per injection. The day on which ovulation occurred was considered as day 0 of the cycle. The results obtained were as follows.1) Experiment 1 (Preliminary experiment) : G was injected successively at intervals of 2-4 days. In all of 5 animals wich received 2 injections of G on day 2 and day 5 or 6 (early luteal phase), ovulation occurred 7-12 days after the first treatment. The mean length of the treated cycles was reduced to 11.9 days as shown in Fig. 1. Four animals were received 2-5 injection from day 12 to day 21 (functional luteal phase-late luteal phase). Two of the treated cycles were fairly lengthened, the cycle length being 28 days and 26 days respectively as shown in Fig. 2. The remaining 2 cycles were of a normal length. From these results, it was demonstrated that the estrous cycle could be modified by injecting this viscous gel-like substance into uterus.2) Experiment 2: Single or double intrauterine treatments were performed at various stages of the estrous cycle to clarify the relation between the time of the treatment and the cycle length. The results were shown in Table 1. In 4 cycles treated on day 1 (postestrus), 1 cycle was reduced to 8 days, and the remaining 3 were of a normal length. In 5 cycles treated on day 2(early luteal phase), 4 cycles were shortened and the remaining 1 was of a normal length, the mean cycle length being 12.0 days. In 4 cycles treated on day 6 (early luteal phase), all of them were shortened, the mean cycle length being 15.5 days. In 4 cycles treated on day 12 (functional luteal phase), the mean cycle length was 21.3 days. It was not different from those of the previous and following cycles in these animals. All of 3 cycles treated on days 14 and 16 (late luteal phase) were somewhat lengthened, the mean cycle length being 24.7 days. In 5 cycles treated on day 17 or 18 (late luteal phase or proestrus), 3 cycles treared at late luteal phase were lengthened (one of them was observed to be abnormally long), and the remaining 2 cycles treated at proestrus were of a normal length.