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Excess dietary nitrogen (EDN) is commonly expected in dairy herds, but no data are available regarding its consequences on cattle immunity. In this study neutrophil functions were assessed during EDN in steers. In experiment 1, 4 one-month periods, 4 diets [16% crude protein (CP; DM basis), 20% CP based on soybean meal, 20% CP based on urea, and 24% CP based on urea and soybean meal], and 4 steers were included in a crossover design to determine the effects of a chronic excess. In experiment 2, the repercussions of an acute excess were assessed with 2 periods of 10 d, the same 4 steers, and 2 diets containing 14 and 20% CP. Sampling was done during the fourth week of each period in experiment 1, and on d 0, 1, 2, 3, 7, and 9 of each period in experiment 2. Individual blood biochemistry parameters were measured and neutrophil factors, such as counts, recovery after isolation, surface expression of CD11b and CD62L, phagocytosis, diapedesis, reactive oxygen species (ROS) production, and bacteria killing, were determined. Data were analyzed by general linear models of R, with period, diet or biochemical component, and animal as explanatory variables. The outcome variables were biochemical or immune variables. The variables diet, period, and animal were forced as fixed effects. Data collected over the entire period of experiment 2 were pooled. Several multiples linear regressions or ANOVA were performed and a Bonferroni correction was applied. In experiment 2 (acute EDN), neutrophil counts were negatively associated with nitrogen intake, conversely to CD62L expression. The observed relative neutropenia may be due to neutrophil margination because CD62L-expressing neutrophils are more likely to stick to endothelium. Interestingly, ROS production was changed by EDN: chronic EDN (experiment 1) was negatively associated with opsonized zymozan (OZ)-induced ROS production and acute EDN (experiment 2) with spontaneous ROS production. For chronic EDN, ROS production upon phorbol 12-myristate 13-acetate was not modified, in contrast to OZ stimulation. Decreased ROS production during chronic EDN probably involves the early events leading to ROS production, as OZ acts through membrane receptors and phorbol 12-myristate 13-acetate directly activates protein kinase C. This is the first study to provide evidence that the modifications of neutrophil functions produced by excess nitrogen depend on the intensity and duration of the excess. Further studies, including epidemiological studies during risk periods, are needed to resolve the issues linked to EDN. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the test characteristics of a blocking antibody ELISA applied to bulk-tank milk (BTM) samples for the detection of dairy sheep flocks positive for antibodies to border disease virus. In 161 flocks recruited in 2009 and 2010, the antibody inhibition percentage (AIP) in BTM was compared with the prevalence estimate of antibody-positive ewes obtained from an age-representative sample of 45 milking ewes. A strong negative exponential relationship (R² = 0.89) was found between AIP in BTM and seroprevalence level. Using receiver operating characteristic analysis, the best AIP decision threshold in BTM to discriminate between low (<10%) and high (≥10%) antibody-positive flocks was 65%. Diagnostic performance estimates based on observed seroprevalence levels and Monte Carlo simulations showed that this threshold value was associated with high sensitivity and specificity (91.9 ± 5.5% and 95.9 ± 1.6%, respectively), whereas the 80% decision threshold recommended in dairy cows yielded lower specificity (83.6 ± 2.0%). Results obtained from the same flocks during 2 subsequent milking campaigns showed that the 65% AIP cut-off value was associated with fewer false-positive results and is preferred. Testing of BTM samples could be a powerful tool in inferring border disease virus seroprevalence in a flock and in Pestivirus control schemes in dairy sheep flocks. [ABSTRACT FROM AUTHOR]

Background Cattle are commonly fed soybean meal ( SBM) and accidental intoxication sometimes occurs. Objectives To describe the biologic and clinical features of SBM intoxication. Animals Four steers with ruminal cannula. Methods Controlled experimental trial. SBM was administered once at 1 and 2% of body weight ( BW) via cannula at 2-month intervals. Results This study showed a 2-phase pathogenic course for 2% BW SBM intoxication. The 1st phase (until 10 hours post-administration) is restricted to ruminal modification with volatile fatty acid overproduction and moderate ruminal ammonia concentration. In the 2nd phase (12-22 hours post-administration), ruminal pH returned to initial values and marked ammonia accumulation occurred in blood, inducing severe metabolic alkalosis with hyperglycemia, hyperinsulinemia, and delayed aciduria (30-40 hours post-administration). Among the clinical signs, nervous signs were only observed during the period with increased plasma ammonia concentration. At 1% BW, ruminal and blood modifications were less pronounced than at 2% BW, and clinical signs were not observed. Conclusions and Clinical Relevance Ammonia accumulation in blood during the second phase is the consequence of continued ammonia production, decreased carbohydrate fermentation, and overwhelming of hepatic detoxifying capacity. Because ammonia accumulation is associated with the clinical signs, treatment of SBM intoxication could be similar to treatment of urea intoxication, including rumenotomy, oral administration of cold water and vinegar, and measurement of ruminal pH. [ABSTRACT FROM AUTHOR]

Bacteremia occurs frequently in newborn calves. The predictive value of clinical signs is low, suggesting the use of calf-side diagnostic tests. To investigate testing of urine catalase activity (Uriscreen test) for bacteriuria and bacteremia detection. Five colostrum-free calves and 3 colostrum-fed control calves. Controlled experimental trial. Colostrum-free calves were inoculated PO with Escherichia coli O78+. A clinical score was established to define the onset of the illness. Blood and urine (cystocentesis) samplings and cultures, and Uriscreen tests, were performed 4-6 times from inoculation to death. Three control calves received the same management as 3 inoculated calves, but with colostrum and without inoculation. Bacteremia was demonstrated in all of the inoculated colostrum-free calves and in none of the control calves. The E. coli O78+ strain, E. coli, and Klebsiella spp. were recovered from 4/5, 5/5, and 2/5 inoculated colostrum-free calves, respectively. Urine cultures were negative for the 2 groups at the start of the experiment; 5/5 colostrum-deprived inoculated calves were positive for E. coli thereafter whereas 3/3 controls remained negative. Concordance of Uriscreen tests with bacteremia and bacteriuria was 0.86 and 0.88, respectively. Kappa value of agreement between Uriscreen and bacteremia and bacteriuria was 0.73 and 0.76, respectively. Sensitivity of Uriscreen for bacteremia and bacteriuria was 80.0 and 86.6%, respectively, and specificity was 92.8 and 88.8%, respectively. The results suggest that Uriscreen can be used for detection of bacteremia in neonatal calves in connection with a constant bacteriuria. [ABSTRACT FROM AUTHOR]

Although susceptibility to scrapie is largely controlled by the PRNP gene, we have searched for additional genomic regions that affect scrapie incubation time in sheep, using two half-sib families with a susceptible PRNP genotype and naturally infected by scrapie. Quantitative trait loci were detected on OAR6 and OAR18. [ABSTRACT FROM AUTHOR]

Caprine-like Generalized Hypoplasia Syndrome (or SHGC) is a new hereditary disorder described in the Montbéliarde breed. We report here the characterization of this new disease, based on the visual examination of animals affected by SHGC, and on physiological and biochemical studies undertaken on samples of both SHGC and normal animals. Biological samples for more than 150 affected calves and their parents have been collected over the past 4 years within the framework of the Bovine Genetic Disease Observatory. First, pedigree analyses showed that the mode of inheritance is most probably autosomal recessive. Then, a genome scan with 113 animals and 140 microsatellite markers revealed a single locus within a 35-cM region on bovine chromosome 13. Genotypes of 261 animals for 18 new microsatellite markers from the region confirmed the localization of the disorder to a 6-cM interval. Finally, based on the analysis of haplotypes in 463 Montbéliarde sires, we estimated the frequency of the SHGC mutated allele in the population and could propose a strategy for the systematic eradication of this disorder in the near future. [ABSTRACT FROM AUTHOR]

Studies the immunohistochemistry of palatine and pharyngeal tonsils of young cattle. Similarity between the immunological cytoarchitecture between bovine and human tonsils; Development of lymphoid tissues in the first weeks of life; Condition of the tonsillar or mucosal epithelium.

The article discusses a study on the epidemiology, clinical signs and biochemical modifications observed during accidental soybean meal (SBM) intoxication in cattle. It notes that one tonne of SBM was accidentally poured on the straw area which housed 39 cows. Clinical signs (CS) such as hypersensitivity to noise and touch, blind gait, and severe dehydration were observed from the intoxicated cows. The study concluded that CS is an accurate way of diagnosing SBM intoxication in animals.

The first outbreak of trypanosomosis caused by Trypanosoma evansi in camels in France was reported on a farm in the Aveyron Department. Five camels were imported from the Canary Islands to the farm in early July 2006, and trypanosomes were observed on a stained blood smear from one of them, which died in October. On further investigations, trypanosomes were observed in the blood of five camels, three of them indigenous to the farm and two that had been imported. On the basis of microscopical examination (morphological criteria and measurements) and serological results based on the card agglutination Tevansitest and PCR typing, the parasites were identified as Tevansi. After treatment with melarsomine, the infected camels rapidly became negative by parasitological tests and were negative two to four months later by serological tests. The parasite was probably transmitted by tabanids and Stomoxys calcitrans, which were abundant in July to September 2006. No parasites were observed in other animals on the farm or on neighbouring farms, but some of the sheep on these farms were positive by PCR or serology. [ABSTRACT FROM AUTHOR]

Because variant Creutzfeldt-Jakob disease (vCJD) in humans probably results from consumption of products contaminated with tissue from animals with bovine spongiform encephalopathy, whether infectious prion protein is present in ruminant muscles is a crucial question. Here we show that experimentally and naturally scrapie-affected sheep accumulate the prion protein PrPSc in a myocyte subset. In naturally infected sheep, PrPSc is detectable in muscle several months before clinical disease onset. The relative amounts of PrPSc suggest a 5,000-fold lower infectivity for muscle as compared to brain. [ABSTRACT FROM AUTHOR]

The article focuses on a study conducted to detect Anaplasma phagocytophilum infection in the French izard Rupricapra pyrenaica. Anaplasma phagocytophilum is a bacterium that causes tick-borne fever, also called as granulocytic anaplasmosis, in domestic ruminants. The main carrier of this bacterium is hard tick Ixodes ricinus. Anaplasma DNA was present in one of the 120 izard spleens examined.