Veterinarno-meditsinski nauki最新文献

Identified were various species of Mycoplasma organisms isolated from three continuous cell lines--BHK-21, SPZF, and TT. On the base of cultural, biochemical, and serological investigations the isolates were defined as M. bovirhinis, M. arginini, and A. laidlawii. The bovine sera, used to culture the cell lines were shown to be the basic source of contamination with Mycoplasma organisms. This made it necessary to carry out a preliminary study on each batch of serum for Mycoplasma contamination prior to its use for laboratory and productional needs.

Studied was the dynamics of antibody production and Salmonella shedding in a flock of year-old female sheep affected with a mixed form of infection of Salmonella abortus ovis and Chlamydia psittaci var. ovis. It was established that in the presence of a mixed infection dominating was the part played by Chlamydia organisms. The apparent epizootic process with these agents usually ran its course in the later period of pregnancy, while Salmonella organisms acted by the end of the first half of pregnancy. The carrying out of a tentative serologic study during estrus contributes to revealing the state of Salmonella harbouring.

Comparative investigations were carried out with the gas composition of air and the productivity of broilers raised in cells and on deep litter in the region of Northeast Bulgaria. The buildings were sized 75 X 15 X 3.8 m. The air exchange in them was effected through mechanical ventilation at lowered pressure, after the pattern 'from above--sideways'. As many as 17.3 birds/m2, when deep litter was used, and 28.6 birds/m2, when cells were used, were housed in the buildings for raising up to the age of 56 days. The content of harmful gases, such as ammonia, hydrogen sulfide, and carbon dioxide was determined at 14-day intervals at 3 sites in the buildings. The body mass of broilers, raised after the two methods, was followed up on the 14th, 28th, 42nd, and 56th day of age. The number of birds and the live mass produced per square meter of floor area in the various seasons of the year were calculated at the end of the fattening periods. It was found that by the end of fattening on deep litter the concentration of ammonia varied around the upper admissible threshold, while with fattening in cells it was within the standard range. With cell raising of broilers the live mass produced per 1 m2 of flooring was 50.5 to 83.6 per cent more as compared with the live mass produced on deep litter. The total broiler produce with cell raising over the 4 seasons was 63.3 per cent, on an average, more than that with the use of deep litter.

Methods have been worked out for the electron-microscopic diagnosis of Q-fever. A characteristic feature with them is the use of clinical, pathological, and experimental material that is investigated through negative contrast and ultra thin sections for the detection of rickettsial cells and inclusions. It is underlined that the methods referred to are readily applicable, economic, highly effective, and hazardless. They are described for the first time and could be adopted into the diagnostic and epizootiologic practice as well as in experimental investigations.

Investigated were 16 pregnant merino sheep, 5-7 years old with active weight 50 kg, divided into two groups--control and experimental. The experimental group was fed with forage, containing 0.65 nitrates from the dry substance of the ration. It was established that the elimination of part of the taken with the forage nitrates is realized through the milk. Traced were the periods of substitution of the fetal haemoglobin with adult in new-born lambs, and the influence of the liberated with the milk nitrates, taken by the sucking lambs, on the quantity of the methemoglobin.

An experiment was carried out to define the stimulating effect of Tribestan on rams that were intended for breeding as well as on rams that exhibited sexual impotence and deteriorated semen qualities. The oral application of the preparation, following the pattern suggested by the authors, led to extending the period of sexual activity and to improvement of the semen production of the rams over the service period. The results of Tribestan therapy with rams having affected libido sexualis showed that the animals could recover up to the 7th-8th day with no essential morphologic changes in the structure of both testes and epididymides. The use of the preparation led to considerably influencing the endocrine activity of the testis, raising the testosterone level, and normalizing the sexual activity of rams affected with coital impotence.

Tested were the embryotoxic and teratogenic effects of some organic solvents (dioxane, propylene glycol, ethylene glycol, ethyl alcohol, and tween-80). The solvents were introduced into 3-day-old chick embryos at the rate of 0.1 cm3 in the yolk sac. With the exception of the 5th group (20 per cent ethylene glycol) in all other test groups mortality rate reached 100 per cent, manifested up to the 14th day. No teratogenic effects with expressed malformations were observed.

A live vaccine against coli enteritis in pigs, CA-80, with a protection medium of 5 per cent hemodex, was successfully freeze-dried in ampoules or vials at the rate of 5 to 10 vaccinal doses each, the titer ranging from 10(9) to 10(10) live bacteria per cu. cm, of a 12-month shelf-life period. The vaccine was found to be innocuous for pigs, and was intended for active immunoprophylaxis on both infected and menaced farms and complexes, applying it to sows in the last third of the gestation period.

Studies were carried out to ascertain the effect of a preparation produced from yeasts of the Saccharomyces cerevisiae species on some indices characterizing the quality of pork. Studied was the chemical composition, the pH values at the 45th minute and the 24th hour post mortem, the content of tryptophane and oxiproline as well as the colour of meat obtained from musculus longissimus dorsi. It was found that the preparation had no negative effect on the indices, characterizing the quality of meat.