[Preventive measures in the use of chicken bedding in lamb fattening]. / Izsledvane profilaktichnite problemi pri izkhranvane na pticha torova postelia na agneta za ugoiavane.

Investigations were carried out on the composition and some properties of the manure bedding from poultry-dressing combines as well as of the complete ration offered together with some beding. High variability of the indices was established so far as the nutrient value and the contamination with occasionally pathogenic bacteria (coli, proteus, and others) and moulds were concerned. No obligatorily pathogenic bacteria and mycotoxins were established. The reasons for illness and culling of lambs fattened with such feed were shown to be associated with the status of the urinary system in the first place. The presence of fungi and bacteria in meals of deep bedding from poultry houses and the occasional presence of chemical compounds in the meat of the fattened animals have made necessary further profound studies aimed at completely elucidating their effect on the health of ruminant animals and the quality of the meat obtained.

[Comparative pathomorphological studies of turkeys and hens experimentally infected with Newcastle disease virus]. / Sravnitelni patomorfologichni prouchvaniia pri puiki i kokoshki, eksperimentalno zarazeni s niukiasulski virus.

Comparative pathomorphologic studies were carried out with 40 birds (29 turkeys and 11 hens) infected per os with 0.5 cc embryonal fluid 10(5) ELD 50 each with two Newcastle disease virus strains (Texas -- standard and 7/5 isolated from dead hens and typed as viscerotropic). It was found that the pathoanatomical picture is negative for all birds experimentally infected with the Texas strain. Haemorrhagic necrotic modification of the glandular stomach and intestine were found in birds infected with strain 7/5. The pathoanatomical finding is better expressed in hens compared with that for turkeys. The histologic modification in birds infected with strain Texas were manifested mostly by nonsuppurative encephalitis. Haemorrhagic-diphtheroid inflammation of the alimentary tract, haemorrhages in the viscera and unreactive necrotic foci in the spleen as well as poorly manifested inflammatory changes in the central nervous system were found in birds infected with strain 7/5. No pathoanatomical modifications for Newcastle disease were found in turkeys, analogous to hens, infected with velogenic neurotropic virus. The velogenic viscerotropic strain is less pathogenic for turkeys than for hens. It causes slighter haemorrhagic necrotic modification in turkeys viscera than in hens. Nonsuppurative encephalitis established histologically in both turkeys and hens infected with neurotropic and viscerotropic Newcastle disease virus is a constant finding and may be used as a diagnostic sign of the disease.

[Impact on the state of health of lambs fed large amounts of concentrated fodder]. / Otrazhenie na zdravoslovnoto sustoianie pri shileta, khraneni s golemi kolichestva kontsentriran furazh.

Experiments were carried out with a total of 18 male lambs at the age of 5 months, included in three groups. The test period lasted 150 days during which the animals of the first group were fed daily 1200-1500 g each of pelleted concentrates, those of the second group--1200, 1300, and 3000 g of wheat straw, and the lambs of the third one--800 and 1050 g of pelleted concentrates as well as 540-720 g of pelleted whole maize plants. It was found that continuous feeding with high amounts of concentrates produced unfavourable effects on the general status of the experimental animals. Hematologically, there was increase in the hemoglobin level, the erythrocyte count, and the leukocyte count. Biochemically, the calcium-and-phosphorus metabolism was disturbed, there was a drop of the Ca level and a rise of the phosphorus level of the blood. Morphologically, dystrophic and necrotic changes were observed in the liver, kidneys, heart, and forestomach. It was concluded that higher amounts of concentrates in the diet may cause a disease status with severe, generalized symptoms due to their defective, unablanced, and physiologically inappropriate feeding.

[Evaluation of the immune state of poultry against Newcastle virus via various serological reactions]. / Otsenka imunnoto sustoianie na ptitsi sreshtu niukiasulskiia virus chrez razlichni serologichni reaktsii.

Studied were 336 sera of vaccinated and challenged chickens, 76 egg extracts, and 36 birds following challenge for the presence of serum antibodies against the Newcastle disease virus, using the hemagglutination-inhibition reaction, the agar gel diffusion precipitation reaction, and the virus-neutralizing test. The values of the antihemagglutinins, precipitins, and virus-neutralizing antibodies were investigated in relation to the immunobiologic resistance of birds to a velogenic Newcastle disease virus. A correlation was found between the antihemagglutinins and the neutralizing antibodies in broilers, aged 30-60 days, treated with an aerosol vaccine La Sota, and in henlayers treated muscularly with the Komarov vaccine. The presence of antihemagglutinin titers of 1:40 and higher values or positive neutralizing indices in the investigated birds were able to provide immunobiologic protection in challenging with a velogenic virus. Precipitins were detected in the blood sera of the challenged birds, which made reasonable their use as a sign pointing to the passage of a velogenic virus through the birds. The lower number of cases with positive precipitin reactions in the vaccinated birds speaks against using objectively this index for the evaluation of the immunologic status.

[Immune response of the chicks from immune layers vaccinated at 1 and 4 days of age against Newcastle disease]. / Imunen otgovor pri pileta, proizkhozhdashti ot imunni nosachki, vaksinirani na ednodnevna i chetirdnevna vuzrast sreshtu psevdochuma

The study of antihemagglutinins in day-old chicks revealed the presence of congenital antibodies against the Newcastle disease virus, having an average geometric titer of lg2 7.9. In the vaccinated 1,500 chicks on the first and fourth day with a La Sota vaccine there was four days later a drop in the antibody titer. Then again a rise in the antibody titer was noted that reached on the 14th day an average geometric value of lg2 7.6 which remained unchanged up to the 40th day. The antihemagglutination titers in the untreated chicks on the 40th day of age dropped to lg2 1.8. As many as 70 per cent of the control chicks died at challenging on the 24th day of age, while all of the treated birds (100 per cent) were given protection through vaccination by the spray method or ocularly and nasally, withstanding challenge on the 20th and 24th day following treatment.

[Effect of different amounts of carbamide on nitrogen digestibility and metabolism in broilers. II]. / Vliianie na razlichni kolichestva karbamid vurkhu smilaemostta i obmianaya na azota pri broileri. II suobshtenie

Experiments were carried out with one-hundred broiler birds of one and the same age group, breed, and origin, divided into five groups in order to follow up the effect of various amounts of urea on their physiologic state. A balance experiment was conducted to establish the effect of urea on the digestibility of nutrient matter and the metabolism of nitrogen with the use of nine birds per group, divided into three subgroups. Urea was added to a protein-balanced diet from the 20th to the 60th day in the following amounts by groups: I--2 percent; II--4 per cent; III--5 per cent; and IV--6 per cent. It was also found that with the increase of urea in the ration at the rates indicated above there was a progressive rise of both the amount of urea and the nonprotein nitrogen in the blood as well as the amount of nitrogen excreted with the urine. The intake of such amounts of urea lowered the assimilation of nitrogen by 4 to 9 per cent as against its initial level in the ration, and by 7 to 11 per cent--as against the level of digested nitrogen.

[Study of the effect of some of the vaccination plans applied in Bulgaria against Newcastle disease]. / Prouchvane efekta na niakoi ot prilaganite u nas skhemi na vaksinatsiia sreshtu psevdochumata po ptitsite

Comparative studies were carried out on the effect of the vaccination of broilers against Newcastle disease with La Sota strain through the single application in the drinking water on the 21st day and the newly introduced vaccination at the age of four days, using the spray method, as well as the combined method--spray vaccination on the fourth day and giving the vaccine twice on the 21st day. It was found that the last method confers better immunity and higher immunity against the disease as compared to offering the vaccine only once on the 21st day.

[Effect of different amounts of carbamide on the state of health of broilers. I]. / Vliianie na razlichni kolichestva karbamid vurkhu zdravoslovnoto sustaoianie na broileri. I suobshtenie

Three experiments were carried out with a total of 100 broilers each, divided into five groups of 20 birds. The effect was tested of urea on their health status, it being added to a ration that was balanced in terms of protein in progressively rising amounts of 0.3 to 6.0 per cent within the period of from the 20th to the 60th day. It was found that in amounts of 0.3 to 3.0 per cent urea does not lead to any clinical and morphological changes in the organism of the treated birds. At rates of 4.5 and 6.0 per cent, however, there appear disturbances in the alimentary tract, lack of appetite, thirst, diuresis, hyperemia and hypertrophy of the kidneys. The addition of urea in such amounts to the ration raises the content of urea in the organism from 2 to 5 times, and the amount of retained nitrogen (NPN)--as much as twice in the blood.

[Study of Vibrio strains isolated from swine]. / Prouchvane na shtamove vibrioni, izolirani ot svine

Antigen and biochemical studies were carried out of nine Vibrio strains isolated from pigs, testing their pathogenicity and toxicity for experimental animals. According to their biochemical behaviour six of the strains were shown to belong to type I, three--to subtype I, and on the grounds of their antigenic characteristics six belonged to type I and three--to type II. It was found that the strains producing hydrogen sulfide were more weakly pathogenic and toxic. No substantial differences were found between the strains isolated from miscarrying and normally farrowing sowa originating from pig breeding farms with a record of vibriosis.