A study was conducted with 23 Japanese Colliedale ewes. Each of them was administered with a dose of pregnant-mare serum gonadotropin (PMS) in her normal breeding season to determine the effect of the hormone on multiple pregnancy and to compare the rate of multiple pregnancy with untreated control ewes. Each experimental ewe was injected intramuscularly with a dose of 500 IU of PMS four days before the next expected estrus. On estrus they were inseminated and observed throughout the duration of pregnancy and at parturition. Eighteen of the 23 ewes treated lambed twins. The rate of twin-birth caused by the treatment was 78.3 per cent. So this figure coincides well with that given in the previous report; that is 76.9 per cent (G. Oita: this journal, 12, 146, 1959). The difference in the rate of twin-birth between the PMS treated and the untreated control was highly significant (significant level, 0.008). Then, ewes treated with PMS in two consecutive years were counted and the sum was compared with that given by the untreated control. The rate of twin-birth between the treated (sum in two consecutive years) and the untreated (sum in the late four consecutive years) was significant, the significant level being 0.001<P<0.05. It was demonstrated that PMS treatment was capable of increasing the rate of twin-birth in ewes when the treated were compared with the untreated control.
Anthelmintic effect on dog whipworms of phthalofyne, or 3-methyl 1-3-pentynyl acid phthalate, as administered by the oral route, was examined by using 39 dogs naturally infected. In the case of a single administration, a dose of 200mg/kg or below displayed only a low effect. When a dose of 250 or 300mg/kg was employed, 410 pairs out of 420 or 122 pairs out of 123, respectively, were removed, thus excellent results being obtained. In the case of two administrations as a course, two doses of 50 mg/kg each showed only a low effect. Two doses of 100 or 150mg/kg each were considerably effective, removing 633 out of 707 pairs harbored or 562 out of 611 pairs, respectively. It seemed that there were no differences in anthelmintic effect of the chemical between the enforcement and omission of starvation before medication and between the methods for medication. Vomiting was observed in no case. Softening of the feces of slight degree and inappetence was recovered before long. It can be concluded that this chemical is a safe, effective anthelmintic against whipworms. Administration of a single dose is more effective than that of two doses. Moreover, it is desirable to carry out fecal examination at least one week and more after medication.
An attempt was made to detect any additional substance from the milk by applying a method for the determination of electric conductivity to the conventional milk test. In basic experiments, various kinds of preservative at different concentrations were added to milk samples, which were examined for the presence or absence of any relationship between the preservative of a given kind and a given concentration and its resistance against electricity. Investigation was carried out also on the kind of electrode. As a result, the resistance against electricity varied with the kind and concentration of the preservative employed, indicating that the results might be available for practical purposes. Among different types of electrode examined, platinum and gold seemed to be excellent, as considered from their stability as well as their sensitivity. On the other hand, it is likely that the value of resistance against electricity varies with the quality of milk. Therefore, further study may be required to clarify any relationship of the resistance against electricity with specific gravity, fat, minerals, and freshness of the milk. Then, it may be possible to discuss the correlationship between the presence of prevervative in a milk sample and the value of resistance against electricity of it, taking the conditions to be elucidated from such study into consideration.
Recently swine toxoplasmosis has become very common in Japan. This paper presents comparative studies between DT and CF test, including the authors' complement fixation inhibition (CFI) test, on swine and cattle experimentally infected with toxoplasma. It also presents the results of a serological survey carried out by the application of CFI test, by means of which it was successful to detect naturally infected animals in some pig farms. The antigen was prepared in accordance with the method of Warren and Russ (1948). By adding the embryonal fluid to the CAM, such good results were obtained as to avoid the anti-complementary properties of antigens. Immune guinea-pig serum (IGPS) was prepared as follows. Guineapigs were injected intraperitoneally ten times, at one week's intervals, with 1: 100 dilution of the peritoneal exudate of a guineapig which had previously been infected with toxoplasma. Convalescent blood was taken 3 weeks later. Immunization was improved under the protection from death with the aid of a therapeutic medicament. Prior to the CFI test, appropriate amounts of IGPS and antigen to be used in the final test were determined by the direct CF method using boxtitration (table 2). Final CFI test was performed as was shown in table 1. Inactivation temperature and time are very important. The authors inactivated the sera at 60°C for 20 minutes according to the results obtained from the experiments. In the field screening test, the positive limit for this test is recommended by the authors as follows: over 1: 8 dilution of serum, positive; 1: 4 to 1: 2 dilution, suspected; and below 1: 2 dilution, negative.