Video-assisted thoracoscopy.

Thoracoscopy is a minimally invasive operative endoscopic procedure designed for visual inspection of the thoracic cavity. The use of small, highly maneuverable, rigid telescopes allows visualization beyond what is possible by standard operative techniques. The use of a small video camera attached to a standard rigid telescope allows the operator and assistants to view a simultaneous, enlarged, and clear image. This article focuses on the basic diagnostic and surgical techniques used in veterinary video-assisted thoracoscopy.     

Cytokine gene expression in ileal tissues of cattle infected with Mycobacterium paratuberculosis

Cytokine gene expression in ileal tissues of cattle infected with Mycobacterium paratuberculosis was evaluated. The effects of infection with M. paratuberculosis on cytokine production may influence immune regulation at the site of colonization, resulting in the chronic inflammatory state associated with the latter stages of this disease. Ileal samples were obtained at necropsy from noninfected control cows (n=8) and clinically infected cows (n=7) and processed for immunohistochemistry and in situ hybridization. Cows infected with M. paratuberculosis were in the latter stages of disease with clinical signs such as weight loss, watery diarrhea, and inappetence. Among cytokines we studied, interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, and interferon-gamma (IFN-gamma) were expressed significantly more in infected animals than in noninfected control animals. The expression of tumor necrosis factor-alpha (TNF-alpha), however, was not different between the two groups of cattle. In addition, immunohistochemical staining demonstrated that the number of resident macrophages in the ileum of infected animals was three times greater than that of noninfected cows. In contrast to this, ileal tissues from noninfected control animals contained 1.5 times more neutrophils than the ileal tissues from cows infected with M. paratuberculosis. These data demonstrate that localized ileal cytokine production is different between cows chronically infected with M. paratuberculosis and noninfected control cows.     

Influence of long-time transportation stress on re-activation of Salmonella typhimurium DT104 in experimentally infected pigs

In this study a Salmonella Typhimurium infection model in swine was used in order to investigate the influence of pre-mortal stress induced by long time period transportation on the re-activation of Salmonella in experimentally infected pigs. Salmonella free pigs were exposed to a highly virulent strain of Salmonella Typhimurium DT104 by direct intragastrical administration. Clinical parameters were monitored and the shedding rate in faeces was qualitatively and quantitatively determined by standard bacteriological procedures for 21 days. The distribution of the challenge organism in 14 different internal organs of transported and nontransported animals was determined. All infected animals developed clinical signs of salmonellosis 12 to 24 hours post infection. About 88 to 100% of the fecal samples were culture-positive up to post exposure day 6, and then varied from 71 to 92% until slaughter, respectively. At necropsy S. Typhimurium was recovered most frequently from caecum and ileocolic lymph nodes (83%), colon (79%), palatine tonsils (71%) and mandibular lymph nodes (62.5%). A negative impact of transportation stress on the shedding rate and the general condition of the animals was observed.     

Body and intestinal growth of broiler chicks on a commercial starter diet. 2. Development and characteristics of intestinal enzymes

1. Investigations were conducted into the development of intestinal enzyme function in broiler chickens on a commercial starter diet. The differences between intestinal regions and localisation of enzymes on the villus were assessed. 2. The specific activity of maltase, sucrase, aminopeptidase N (APN) and alkaline phosphatase (AP) at all intestinal sites decreased with age. There were also variations between intestinal sites although this variation depended on age. The specific activity of maltase was higher than that of the other enzymes examined, regardless of age and intestinal site. The total activities of the enzymes also increased with age at all intestinal sites. 3. Results of the localisation of enzymes on the crypt: villus axis showed that activity was expressed over a large proportion of the villus. There was an increase in the total villus activity of alpha-glucosidase (AG), APN and AP with age. Activity per unit villus surface area was similar between ages, except for jejunal AP. At hatch enzyme activity was expressed over 44.1, 55.8 and 63.3% of villus height in the duodenum, jejunum and ileum, respectively. At 21 d of age, corresponding values were 68.7, 65.6 and 77.2%. The point of peak activity from the crypt: villus junction increased with age. In the jejunum, most enterocytes were capable of secreting active enzymes within 1 h of formation. Cells maintained their secretory capabilities until they were more than 60 h old in the case of AG. 4. Although the specific activities of the enzymes were maximal at hatch, the digestive capacity of older birds may be sustained by an increase in total enzyme activity brought about by increased surface area. The pattern of enzyme activity along the gastrointestional tract (GIT) and crypt: villus axis is similar to that reported for some mammalian species.     

Detection of Pasteurella multocida in pigs with porcine dermatitis and nephropathy syndrome.

Comprehensive bacterial cultures were made on samples from 20 pigs that had died of porcine dermatitis and nephropathy syndrome after a short clinical illness. Eleven species of porcine bacterial pathogens and a range of commensal organisms were isolated. Pasteurella multocida was isolated from 16 of the 20 cases but the other pathogens occurred much less commonly. P. multocida was isolated from between one and five sites per case and from the tonsils, retropharyngeal lymph node or lungs in 14 of the 16 cases. Immunohistochemical investigations of kidneys from 30 cases of the syndrome (including the 20 cases in the bacteriological study) revealed P. multocida-specific staining in 26 of the cases, primarily in the renal tubular epithelial cells of the proximal convoluted tubules, but also in the glomeruli, in lesions of renal vasculitis and in the cytoplasm of interstitial mononuclear cells.     

Seasonal Variations in the Abundance of Gasterophilus spp. Larvae in Donkeys in Northern Jordan

One hundred and five donkeys were examined over a 12-month period for the presence of Gasterophilus spp. larvae in their stomachs. G. intestinalis and G. nasalis were found, but there was a distinct seasonal variation in their abundance. The numbers of second-stage larvae (L₂) peaked during the early winter and early summer, but they were absent or at low levels during the early spring and early autumn. This suggests that there are two periods of adult fly activity (late autumn and late spring) for both G. nasalis and G. intestinalis. Third-stage larvae (L₃) were found throughout the year, but the lowest levels were seen in the late summer and autumn. The parasites also had an aggregated distribution, which may be due to host selection by the fly. The numbers of larvae did not vary significantly with age, which may be due to a lack of acquired protective immunity or to tolerance after repeated exposure.     

Diagnostic imaging of lameness in small animals.

The demand for advanced diagnostic imaging procedures such as nuclear scintigraphy, ultrasonography, computed tomography, and magnetic resonance imaging has increased dramatically over the past 10 years. Veterinarians, seeking to improve their diagnostic capabilities and clients willing to pursue "best medicine" have driven this demand, resulting in installation of advanced imaging facilities at most academic and private referral practices. Knowledge of potential benefits of various modalities will allow the veterinarian to optimize his or her use of diagnostic imaging in his or her own practice or in a referral practice.     

Genetic parameters for ultrasound and carcass measures of yield and quality among replacement and slaughter beef cattle.

Real time ultrasound (RTU) measures of longissimus muscle area and fat depth were taken at 12 and 14 mo of age on composite bulls (n = 404) and heifers (n = 514). Carcass longissimus muscle area and fat depth, hot carcass weight, estimated percentage lean yield, marbling score, Warner-Bratzler shear force, and 7-rib dissectable seam fat and lean percentages were measured on steers (n = 235). Additive genetic variances for longissimus muscle area were 76 and 77% larger in bulls at 12 and 14 mo than the corresponding estimates for heifers. Heritability estimates for longissimus muscle area were 0.61 and 0.52 in bulls and 0.49 and 0.47 in heifers at 12 and 14 mo, respectively. The genetic correlations of longissimus muscle area of bulls vs heifers were 0.61 and 0.84 at 12 and 14 mo, respectively. Genetic correlations of longissimus muscle area measured in steer carcasses were 0.71 and 0.67 with the longissimus muscle areas in bulls and heifers at 12 mo and 0.73 and 0.79 at 14 mo. Heritability estimates for fat depth were 0.50 and 0.35 in bulls and 0.44 and 0.49 in heifers at 12 and 14 mo, respectively. The genetic correlation of fat depth in bulls vs heifers at 12 mo was 0.65 and was 0.49 at 14 mo. Genetic correlations of fat depth measured in bulls at 12 and 14 mo with fat depth measured in steers at slaughter were 0.23 and 0.21, and the corresponding correlations of between heifers and steers were 0.66 and 0.86, respectively. Live weights at 12 and 14 mo were genetically equivalent (r(g) = 0.98). Genetic correlations between live weights of bulls and heifers with hot carcass weight of the steers were also high (r(g) > 0.80). Longissimus muscle area measured using RTU was positively correlated with carcass measures of longissimus muscle area, estimated percentage lean yield, and percentage lean in a 7-rib section from steers. Measures of backfat obtained using RTU were positively correlated with fat depth and dissectable seam fat from the 7-rib section of steer carcasses. Genetic correlations between measures of backfat obtained using RTU and marbling were negative but low. These results indicate that longissimus muscle area and backfat may be under sufficiently different genetic control in bulls vs heifers to warrant being treated as separate traits in genetic evaluation models. Further, traits measured using RTU in potential replacement bulls and heifers at 12 and 14 mo of age may be considered different from the corresponding carcass traits of steers.