Isolation of Chlamydia psittaci from an aborted bovine fetus

One strain of Chl. psittaci was isolated from two aborted foetuses of two cows coming from the same locality. Tissue from the lungs of the aborted foetuses was used for the isolation tests; after sample preparation this tissue was inoculated into the yolk sacs of chick embryos. It was found on the basis of serological examination (RVK) that both aborting cows had positive levels of antibodies against the Chl. psittaci antigen at a serum dilution ratio of 1 : 64. The serological examination for brucellosis (BAB) and coxiellosis was negative. The bacteriological examination (aerobic and anaerobic cultivation, salmonellae, mycoplasms and moulds) also gave negative results.     

The effect of blood-sucking diptera on the weight of grazing heifers

It was demonstrated experimentally that bloodsucking dipterans (gad-flies, gnats, midges, black flies) influenced negatively weight increments of grazing heifers and that it was suitable to treat the heifers with repellents; 10% water emulsion of the repellent diethyltoluamide was used for heifer spraying in the intervals of 48 hours. Over the 66 days of the experiment, the total live weight of one heifer from the test group increased by 5.00 kg, in comparison with the controls. The coefficient of loss per untreated animal was 105.00 Kcs., the returns of investments per 1.00 Kcs of investment costs were 1.90 Kcs. Owing to worse climatic conditions in the experimental years which significantly differed from meteorological conditions in the previous four years, which ensued from mathematico-statistical evaluation, differences in weight increments over the period of study were statistically insignificant.     

The effect of colostral immunity on the active formation of antibodies in pigs after the administration of inactivated vaccine against Aujeszky's disease

In a large herd of pigs where a trial was performed to cure the animals from Aujeszky's disease (AD) by applying to all animals an inactivated vaccine, a post-vaccination antibody response was studied in piglets coming from the sows that were vaccinated several times. When the piglets were vaccinated at the age of eight weeks (the average virus-neutralizing titer (VNT) of colostral antibodies was 1:11.4) and revaccinated at the age of 11 weeks, 73% of the forty-five animals (examined at the age of 17 weeks) did not have any virus-neutralizing (VN) antibodies in the blood serum. After the third vaccination dose (at the age of 17 weeks), 11% of piglets did not have any VN antibodies if they were examined at the age of 22 weeks (the average antibody VNT was 1:15.3). Applying the ELISA procedure, the antibodies were demonstrated in the sera of all piglets after three vaccination doses. Shifting the time intervals of vaccination (at the age of 8, 13 and 19 weeks), the VN antibodies were found out after three vaccination doses in the sera of all piglets examined at the age of 23 weeks (the average VNT was 1:56.4). After three vaccination doses at the age of 12, 17 and 23 weeks, the VN antibodies were also demonstrated in all piglets at the age of 27 weeks (the average VNT was 1:208).     

Experimental infection of calves with an adenovirus isolated from sheep and related to bovine Adenovirus type 2 I. Clinical and virological studies.

Colostrum deprived calves were experimentally infected with an adenovirus isolated from sheep and related to bovine adenovirus type 2. The calves showed respiratory symptoms and mild diarrhoea from the third day after infection. Laboratory tests revealed the development of leucopenia, lymphopenia, a drop of the pH of the urine and the appearance of pathological changes in the urine. The animals shed the virus in their nasal discharge, faeces and urine. Comparing the clinical and virological findings with the previous experimental infection of lambs it is concluded, that this type of adenovirus is similarly pathogenic for the two ruminant species.     

Circadian rhythmicity of urea concentration in the liver and blood serum of cockerels]

The circadian rhythmicity of urea concentration was studied in 70 12-day-old cockerels (the Primant commercial hybrid). Urea in the liver homogenate supernatant and in the blood serum was determined by means of diacetylmonoxim (Homolka, 1971). The cockerels were killed in four-hour intervals. Urea concentration in the liver reached its peak at 15.30 o'clock (123.36 +/- 6.32 in conversion to wet tissue or 0.308 +/- 0.01 mg of nitrogen per 100 mg). The circadian rhythmicity of uremia generally coincided with the rhythmicity of urea in the liver.     

Seasonal changes in spermatozoas and fertility of stallions in the tropics]

An attempt was made to express the relationship of spermiological characteristics with the fertility on the basis of seasonal variability of the fertility of stallions and of the ejaculate quality. A positive correlation between the activity of spermatozoa and the fertility ensues from the values of correlation coefficients. There is a negative correlation between the fertility and the concentration of citric acid. In the other characteristics, i.e. in the production of spermatozoa, volume of gel substance, pH, ergothioneine concentration, polarographic and hemolytic activity, the correlation coefficients were very low. It is assumed that these characteristics may influence the livability and preservation of the sperm, but they do not affect its fertilizing ability.