To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot. 21,743 high-risk calves from the southeastern United States. PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase-PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot. 15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal. This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.

To determine the suitability and estimate the sensitivity of an immunohistochemical (IHC) test for disease-associated prion protein (PrP(Sc)) in biopsy specimens of rectoanal mucosa-associated lymphoid tissue (RAMALT) for diagnosis of scrapie in sheep. 762 sheep at high risk for having scrapie and indemnified by the National Scrapie Eradication Program. The IHC test for PrP(Sc) was applied to 2 RAMALT and 2 third-eyelid biopsy specimens and a postmortem RAMALT specimen from each sheep. Results were compared with those of a reference test in which results for tissues from obex and retropharyngeal lymph nodes, tonsil, or both were considered in parallel. The reference test identified 139 sheep as having scrapie. Biopsy-related complications occurred in 3 sheep. Sensitivity of the IHC test in RAMALT ranged from 85.3% to 89.4%, depending on the anatomic location from which RAMALT was obtained. Results for the test applied to 1 RAMALT specimen were similar to results interpreted in parallel for 2 third-eyelid specimens (sensitivity, 87.0%). The proportion of inconclusive test results attributable to insufficient lymphoid follicles in biopsy specimens was lower when considering results for 2 RAMALT specimens in parallel (10.1%) than when considering results for 2 third-eyelid specimens in parallel (23.7%). Specimens of RAMALT that were inappropriately collected from an area caudal to the rectoanal interface yielded a high proportion of inconclusive results (33.3% to 50.0%). The IHC test for PrP(Sc) in RAMALT was an effective means of detecting subclinical scrapie in live, high-risk sheep.

In the conditions of the Republic of Belarus there was developed a concept for differentiation of eimeria and helminthes using a system of identification indexes as mathematical expressions of morphometric correlations of eimeria oocystae and helminth eggs morphology. There was developed a method for identification eimeria species on the basis of two-dimensional mathematical analysis of oocysts using a new identification index which represented a duplication proportion of contour perimeter to surface area of an oocyst.

Efficiency of cultivation of cow preimplantation embryos and support of pluripotent properties in different nutritive media was analyzed; a method of getting early embryos in vitro for the genetically engineered purposes was developed in the conditions of the Republic of Belarus. Oocyte separation was realized in 3; 3-6; 6-9; and 9-12 hours after ovariectomy for the studying of the influence of storage period of ovaries on the output qualitative embryos. Oocyte separation was realized by bisection with adding of 1% of fetal cattle serum, 10 units/ml of gentamicin and 1 unit/ml of heparin. Oocyte-cumulus complexes maturing took place in CO2-bath with 5% of CO2 in atmosphere of maximum humidity and temperature of 38 deg C in TS-199 (Sigma) media with entering of 25 mM/l of buffer Hepes, 10 unit/ml of gentamicin and biologically active substance (20 % of fetal calf serum, 10 mg/ml of bovine serum albumin and 5 % of estrous cow serum with 10 mg/ml of bovine serum albumin). Research result showed that application of 10 mg/ml of bovine serum albumin into TS-199 media made it possible to increase the yield of cattle embryos at the preimplantation stages in vitro conditions on 19,1%, as well as to increase the fetal calf serum in quantity 15% to the nutritive media volume up to 16,0 %. Application of sodium pyruvate and calcium lactate in the process of cultivation of early cattle embryos obtained in vitro conditions made it possible to increase the yield of preimplantation embryos on 5,4 %. Specifically, the level of transformation of morulas into blastocysts was 44,4 %

In the conditions of the Republic of Belarus there was developed a method of surgical treatment of servicing bulls with penial tumors including tumor removal by means of gas docker Tail Docker and intravenous 0,5% novocaini solution injection during postoperative stage makes it possible to reduce the duration of surgical operation in 3-4 times, completely remove probability of bleeding, reduce the healing period on the average on 6 days and lower the probability of relapse of tumor.

Development of highly efficient antigens for an early immunodiagnosis of cattle fascioliasis (Fasciola hepatica) and studying of its main properties was realized in the conditions of the Republic of Belarus. Received in result of the experiment antigens possessed high specificity and were suitable for use in fascioliasis immunodiagnostics. Research results showed that use of indirect fluorescent (IFA) test and immunodiffusion test for fasciolasis immunodiagnostics of cattle excludes false positive results caused by tuberculosis and hypodermotosis (p less than 0,001).

Analysis of data on distribution of clinicopathologic symptoms of rhinotracheitis, parainfluenza-3, bovine viral diarrhoea, clamidiosis, rhinosyncytial virus, adenovirus diseases, rotaviral diseases, coronavirus infections of cattle, viral transmissible gastroenteritis, and respiratory reproductive syndrome of swine, rinderpest, rabies and Aujesky disease of agricultural animals in the conditions of the Republic of Belarus was realized. There were given descriptions of diagnostic tests and vaccines for disease prevention used in Belarus and other countries. Treatment regimen and methods and other elements of prophylaxis were presented. There was given an analysis of prophylactic efficiency of produced medicine drugs

Data on development of an antigen on the basis of larvae of warble flies grubs (Hypodenna bovis) for diagnostic of spontaneous cattle hypodermosis by means of the indirect fluorescent (IFA) test and with application of blood serum and milk samples realized in the conditions of the Republic of Belarus were presented. Specificity and sensitivity of experimental sample of antigen for revealing of spontaneously infestated with larvae of warble flies with IFA test at hypodermotosis has made about 100%.

It was established that in blood serum of pigs vaccinated against leptospirosis there was an authentic increasing of alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase that made proved the presence of residual reactogenicity of biological preparations. In course of the experiment there were used 4 groups of swine which were administrated with 4 types of vaccines: 1. polyvalent vaccine produced in Belarus; 2. experimental thiosulfate vaccine in which there was used 30% sodium solution; 3. experimental emulsified vaccine; experimental emulsified + sodium + thiosulfate vaccine.

Comparative effectiveness of application of SV-1 and SV-2 sorbents for preventive treatment of abomazoenterite of 1-2 month old calves was studied in the conditions of the Republic of Belarus. Research results showed that application of SV-1 and SV-2 sorbents rendered a positive influence on hematological and biochemical blood indexes, in particular, there was an increasing of hemoglobin level, albumins content, alkaline reserve, calcium and phosphorous in blood serum. They also rendered the stimulatory effect on natural resistance. The prophylactic effectiveness in experimental group was 100%, in a control one – 60%.