A portable ultrasonic fetal heart detector, Hearttone Model USD-I (Aloka Co., Ltd., Tokyo), with a 2.25 MHZ transducer was used for a study of pregnancy diagnosis in swine. An animal was placed on the pen's floor in the lying position, with out being restrained or anesthetized. The transducer was applied gently to the skin of the lower abdomen or the flank. Ultrasonic Doppler signals based on the fetal circulation were heard by the operator's ears and at the same time, recorded on magnetic tapes for the convenience of fetal heart rate caculation. The maternal circulation was distinguished easily from the fetal one for its markedly slow rhythm. Accuracy of pregnancy diagnosis was based on delivery. A total of 83 experiments were carried out on 70 sows of 4 different breeds over a period from 22 days post-coitum to the full term. The accuracy rate for pregnancy diagnosis was not satisfactory (58.3%) 30 days or more post-coitum, but became high between 30 to 39 days (81.8%). It reached 100% after 40 days of pregancy. Pregnancy could be detected by this method as early as 26 days postcoitum. A highly significant negative correlation was observed between fetal heart rate and fetal age. The orrelation coefficient was -0.87 (P <0.01). The fetal heart rate became low in a negative linear regression as gestation progressed: Y=252.6-0.572X (X=fetalage, Y=fetal heart rate).
A total of 118 strains of Pseudomonas aeruginosa were examined for sensitivity to antibacterial drugs by a plate dilution method. Of them, 97 had been isolated from bovine mastitis and 21 from clinical specimens of cattle, dogs, pigs, and snakes. All the strains showed high sensitivity to colistin, polymyxin-B, and gentamicin (MIC: 1.56×12.5μg/ml). More than 80% of them were rclativcly sensitive to fradiomycin, oxolinic acid, dihydrostreptomycin, streptomycin, oxytetracycline, tetracycline, and flavophospholipol (MIC: 12.5-50.0μg/ml). No strains were sensitive to aminobenzylpenicillin, Kanamycin, Kasugamycin, erythromycin, oleandomycin, spiramycin, tylosin, chloramphenicol, macarbomycin, nitrofurans, sulfa drugs, or nalidixic acid. Serological typing was carried out by the agglutination test with 14 antisera. Of. 93 strains of bovine mastitis origin, 83 were classified into 8 monoserotyps: 25 into Type 1, 18 into Type 8, 14 into Type 6, and 10 into Type 4. Of 17 strains isolated from clinical specimens, 16 were classified into 8 serotype: 5 into Type 1, 4 into Type6, 2 into Type 8, and one each into T·2×T·5 and T·10.
Eight Holstein steers 4.5 months, on the average, of age were divided equally into two groups. In each animal of one group, 2 pellets of a zeranol preparation were buried subcutaneously at the root of the ear. The other group served as an intact control. Each animal was placed in a metabolic cage for 3 consecutive days to collect all the feces and urine discharged, which were examined for the total nitrogen amount discharged by the micro-Kjeldahl method. As a result, average D.G. for the whole experimental period was 0.94kg for the medicated group and 0.84kg for the control group. The difference in average D.G. between the two group was the largest over a period from 10 to 20 days of experiment, when average D.G. aws 1.26 kg for the medicated group and 0.89kg for the control. When the total amount of nitrogen deposition was determined and expressed with an index which was regarded as 100 at the time of beginning of the experiment, it was 168.5 and 135.7 in the medicated and the control group, respectively, 20 days and 174.6 and 138.2, respectively, 40 days after the beginning of the experiment. These results lend support to a conclusion that the zeranol preparation has a proteinassimilating action.