Evaluation of amitraz against ticks and mites infestation in cattle and sheep in comparison with diazinon and deltamethrin was performed. Amitraz showed over 95 % inhibition of oviposition and hatching of laid eggs at dilution of 1:500 while diazinon and deltamethrin produced around 90 % inhibition of oviposition at the same dilution. Fed ticks were more susceptible for all tested acaricides than the unfed ticks, where amitraz reached its full effectiveness (100 % kill of fed and unfed) 2 weeks after application while diazinon and deltamethrin produced over 90 % at the same dilution. Spraying application of amitraz 12.5 % resulted in 100 % tick control by day 5 and the effect was maintained for further 28 days whereas diazinon and deltamethrin were fully effective by days 9 and 13, respectively and their efficacy were maintained for 16 and 20 days, respectively. Spraying application of amitraz 12.5 % produced 100 % efficacy as no live mites were found on day 17 and maintained in full effectiveness till day 33 where respraying was needed. In conclusion, amitraz produced rapid detachment of ticks from animals; its residual effect was long and protected animals from re-infestation for 29 days and was able to eradicate psoroptes mite infestation in sheep.

Lymph nodes (Ln) are the preferred samples for virus isolation and detection. Inthe present study, carcass and visceral Ln of apparently healthy cattle were screened for the presence of bovine herpes virus type 1 (BHV-1) and bovine ephemeral fever virus (BEFV) antigens. A total of 198 Ln (114 carcasses Ln and 84 visceral Ln) were collected. Lymph node homogenates were assayed by agar gel precipitation test (AGPT), rapid Staphyloccocal protein A (SPA) agglutination test and Dot-ELISA. The overall results revealed that BHV-1 antigens were detected in 43.9%, 56.1% and in 68.4% of carcass Ln, and in 29.8%, 47.6% and 57.1% of visceral Ln collected from slaughtered cattle by AGPT, SPA agglutination test and Dot-ELISA respectively. On the other hand, BEFV antigens were detected in 5.3%, 38.6% and 52.6% of carcass Ln, and in 6%, 41.7% and 54.8 % of visceral Ln collected from slaughtered animals by AGPT, rapid SPA agglutination test and Dot-ELISA respectively. The results showed high percentage of positive samples with SPA agglutination test and Dot- ELISA in comparison to AGPT for both BHV-1 and BEF.

In the present study, the humoral immune response developed following vaccinationwith the live-attenuated (Smithburn) Rift Valley fever (RVF) vaccine in sheep, goats,cattle, buffaloes and camels was investigated. Results showed that, serum neutralizing antibody titers of RVF virus started to appear in the sera of all vaccinated animals with live-attenuated Rift valley fever vaccine after the first week post-vaccination and reached its peak after the third month of vaccination. It persisted to be higher than the acceptable limit of protection (>40) in the sera of sheep and goats in more than 6 months post-vaccination while it declined in the sera of cattle, buffaloes and camels to become lower than the acceptable limit of protection (<40) after the sixth month post-vaccination. On the other hand, the serum neutralizing antibody titers remained negative in the sera of non-vaccinated (control) animals throughout the study. It could be concluded that, the neutralizing antibodies following vaccination of cattle, buffaloes and camels with live attenuated RVF (Smithburn) vaccine was low and of a short duration compared with those in sheep and goats. Hence, it is important to prepare a new vaccine which is safe and gives a high immune response for long period in cattle, buffaloes and camels instead of live attenuated (Smithburn) RVF vaccine to protect these animals species against this disease.

During summer 2004, an outbreak of bovine ephemeral fever (BEF) had beenspread among cattle as well as buffaloes in Egypt. The most striking clinical signs incattle were fever of short duration, depression, stiffness, lameness and sometimerecumbency. Young calves, unfattened bulls and dry, lean non-pregnant cows showed only mild signs while fattened calves, mature heavy bulls and high-producing dairy cows and cows at the late stages of pregnancy were severely affected and signs persisted longer. Deaths and other complications accompanied the disease such as subcutaneous emphysema was not recorded in these outbreaks. In buffaloes, the clinical signs were mild and less severe compared with that of cattle. Serological examination of paired serum samples collected from the diseased animals using serum neutralization test revealed rising of the neutralizing antibody titers for BEF virus after 3 weeks from the onset of clinical signs. Blood picture and biochemical analysis of sera of 6 diseased animals, showed anemia represented by significant decrease in RBCS, PCV% and Hb content. The leukogram showed neutrophihia and lymphopenia with normal leukocytic count. There was rise in plasma fibrinogen with drop in calcium and phosphorus values. All of these parameters were more or less improved three weeks post-recovery. Good nursing care with early treatment with non-steroid anti-inflammatory drug (Phenylbutazone) or administration of calcium borogluconate of lame or recumbent animals lead to rapid and prompt recovery.

In this study field application of RB51 vaccine combined with the policy of test and slaughter as well as application of hygienic measures for control of bovine brucellosis were carried out and evaluated in a dairy herd of cattle for two years. Serological examination of 1280 cattle using tube agglutination, buffered acidified plate antigen, Rose Bengal plate antigen and Rivanol tests revealed 240 (18.75%) positive animals with a previous history of abortion of 12 cows. Brucella melitensis biovar 3 could be isolated from tissue specimens of slaughtered cows. Animals that tested negative in the first examination were vaccinated with RB 51 vaccine with periodical examination every three weeks and slaughtering of positive cases. New positive cows continued to develop up to the 5th examination then three successive sero-negative tests were obtained with release of the farm from quarantine. Examination of animals 6,12,18 and 24 months post release of quarantine revealed 2, 3, 0 and one positive cases respectively the matter which clarified that the control of the outbreak using RB51 vaccine associated with policy of test and slaughter and application of hygienic measures showed some limitations.

To evaluate site-to-site variation within fecal pats from cattle with regard to detection of Escherichia coli O157 and determine the effect on the accuracy of prevalence estimates of assay of multiple samples collected from the same fecal pat. 120 freshly voided fecal pats collected from 2 beef feedlots. Procedures-5 samples were systematically collected from each fecal pat and analyzed for E coli O157 via selective preenrichment techniques, immunomagnetic separation, and biochemical tests. Presumptive isolates were definitively identified via agglutination assays and polymerase chain reaction techniques. Best estimators of prevalence were calculated from the distribution of E coli O157-positive samples per pat. Of the 120 fecal pats, 96, 13, 4, 2, 3, and 2 fecal pats had 0, 1, 2, 3, 4, and 5 E coli O157-positive samples, respectively. The greatest estimate of E coli O157 prevalence (20%) was achieved when all 5 samples were assessed; this estimate represented a 2.4- fold increase in prevalence, compared with that provided via analysis of 1 sample/pat (8.2%). Compared with assessment of 5 sites/pat, the relative sensitivity of detecting an E coli O157-positive fecal pat via analysis of 1 site/pat was 40.1%. Results suggest that estimates of E coli O157 prevalence derived from sampling of 1 location/pat are likely underestimates of the true prevalence of this pathogen in fecal pats (and by extension, cattle). Additional research is warranted to confirm these results in situations of high and low prevalence and across different feedlots.

The effect of a novel bovine mastitis trivalent vaccine, containing Staphylococcus aureus capsular polysaccharide type 5 (T5), 8 (T8), and 336 (T336), on lymphocyte subpopulations, antibody production, and neutrophil phagocytosis was evaluated. Twenty pregnant heifers were immunized with either the trivalent alone, trivalent emulsified in Freund's incomplete adjuvant (FICA), trivalent in aluminum hydroxide, or adjuvant only (FICA). Immunization was done 30 d before the expected calving date followed by 2 boosts in a 2-week interval. Compared to FICA, serum antigen-specific immunoglobulin (Ig)G1 and IgG2 were significantly increased in all the vaccinated groups before parturition and sustained until 3 wk postpartum. In comparison with the trivalent alone, formulation with either adjuvant enhanced production of IgG2, but not IgG1. Immune sera, which contained the highest amount of antibodies, slightly increased neutrophil phagocytosis to the 3 serotypes of killed S. aureus, but most of the differences were not significant due to large variation between the cows. The percentage of CD4+ lymphocyte was significantly higher in vaccinated groups than that of FICA 4 wk after the primary immunization. In comparison with FICA, cows inoculated with trivalent vaccine and adjuvants had an increased percentage of CD8+ lymphocytes at 2 time points, 2 wk before and after calving. Our results indicated that the whole cell trivalent vaccine, with or without adjuvants, is able to elicit antibody responses specific to the 3 capsular polysaccharide antigens. The increase of T8-specific IgG2 was more noticeable when the vaccine was emulsified with adjuvants.

An abattoir study on the abdominal fat necrosis in adult cattle was performed pathologically. Grossly, masses of fat necrosis were leekgreen in colour, lobulated on the cut surface, and saponificated in the texture. These necrotic adipose tissues infiltrated usually into neighboring parenchymal organs including intestines and pancreas, leading to fibrosis or atrophy of them. Histopathologically, necrotic fat cells contained acidophilic, opaque, amorphous substance or basophilic fibrillar or granular minerals in their cytoplasms. The lesions of fat necrosis were divided by fibroconnective tissue. With increase of the severity, necrotic fat cells fused each other and then formed fat cysts.

To evaluate herd-level risk factors for seropositive status of cattle to 1 or more bluetongue viruses. 110 herds of cattle in Nebraska, North Dakota, and South Dakota. Blood samples were collected before and after the vector season. Samples were tested for antibodies against bluetongue virus by use of a commercially available competitive ELISA. Factors evaluated included descriptors of geographic location and management practices. Trapping of insect vectors was conducted to evaluate vector status on a subset of 57 operations. A multivariable logistic regression model was constructed to evaluate associations. For the full data set, altitude and latitude were associated with risk of having seropositive cattle (an increase in altitude was associated with an increase in risk, and a more northerly location was associated with a decrease in risk of a premise having seropositive cattle). Import of cattle from selected states was associated with an increase in risk of having seropositive cattle. From the subset of herds with data on vector trapping, altitude and latitude were associated with risk of having seropositive cattle, similar to that for the full model. However, commingling with cattle from other herds was associated with a decrease in risk of seropositivity. Findings reported here may be useful in generating additional hypotheses regarding the ecologic characteristics of bluetongue viruses and other vector-borne diseases of livestock. Sentinel surveillance programs are useful for documenting regionalization zones for diseases, which can be beneficial when securing international markets for animals and animal products.

A cDNA clone encoding a prohibitin-like protein (Toprh) was isolated from a piroplasm cDNA library of Theileria orientalis and its nucleotide sequence was determined. An open reading frame, encoding a polypeptide of 278 amino acid residues, was found in Toprh cDNA sequence. An intron of 89 bp was identified when this cDNA clone was compared with the Toprh gene in the genome of T. orientalis. The deduced amino acid sequence of Toprh shares 93.8, 93.1 and 69.1% identities with the prohibitins of T. parva (from chromosome 1), T. annulata (from chromosome 1), and Plasmodium falciparum, (from chromosome 10), respectively. By Western blot analysis, Toprh was found to be expressed in the piroplasm stage of the parasites.