An improved ferritin assay for canine sera

An improved serum ferritin assay for canine serum has been developed. It uses two monoclonal antibodies in a sandwich arrangement. Serum ferritin can be determined on undiluted canine sera with this assay. The recovery of ferritin added to canine serum ranged from 98 to 106%, the within-assay coefficient of variability was 3.3 to 4.5%, and the assay-to-assay variability was 9.8 to 10.2%. Serum ferritin from 61 apparently healthy dogs had a geometric mean of 252 ng/ml, with a range of 80 ng/ml to 800 ng/ml.     

A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.     

Quality of tissue specimens obtained endoscopically from the duodenum of dogs and cats

OBJECTIVE: To evaluate quality of duodenal tissue specimens obtained endoscopically from dogs and cats and submitted to 1 of 2 diagnostic laboratories for evaluation. DESIGN: Case series. SAMPLE POPULATION: Slides from 50 consecutive canine and 50 consecutive feline endoscopically obtained duodenal tissue specimens submitted to laboratory 1 and 49 consecutive canine and 46 consecutive feline specimens submitted to laboratory 2. PROCEDURE: Slides were examined independently by 3 investigators, and each tissue piece on each slide was classified as clearly inadequate, questionable, or clearly adequate on the basis of 4 criteria. An overall score was then assigned to the slide. RESULTS: Slides from laboratory 1 were more likely to be scored as clearly adequate and less likely to be scored as clearly inadequate than slides from laboratory 2. Clearly adequate slides from laboratory 1 had a higher number of clearly adequate pieces of tissue than did clearly adequate slides from laboratory 2. Slides scored as clearly adequate had a higher number of individual tissue pieces than did slides scored as clearly inadequate. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the quality of endoscopically obtained duodenal tissue specimens submitted to laboratories can vary, possibly because of differences in experience of individuals collecting biopsy specimens. Results suggest that at least 8 individual tissue pieces should be submitted when performing endoscopic biopsy of the duodenum in dogs and cats.     

Influence of the design of facilities at auction markets and animal handling procedures on bruising in cattle

The movements of cattle at 12 livestock auction markets were observed to determine the possible causes of trauma leading to carcase bruising. Design faults included right-angled bends in races, dead ends, flooring with insufficient slope or grip, and steps. Sliding gates were often misused for goading cattle. Projecting fittings and square-edged corners were potentially injurious; conversely, rounded posts and curved races assisted the flow of cattle with minimal impacts. At all the markets, some cattle were hit directly and poked with wooden sticks, and the variations in their use could partially explain the differences between the markets in the prevalence of carcase bruising. Most harder hits were directed at less valuable parts of the body, such as the spine, hips and shoulders, and a survey of bruising at the abattoir showed that these were the areas with most bruising. In this survey of 48,926 carcases, the overall level of commercially significant bruising of 4.1 per cent was lower than the 6.5 per cent found in a previous survey. Carcases of cattle from markets had a greater incidence and severity of bruising (P<0.001) than those arriving directly from farms or dealers. Carcase bruising in young bulls was less (P<0.001) than in heifers and steers.     

Self-selection of the analgesic drug carprofen by lame broiler chickens

Lame and sound broilers, selected from commercial flocks, were trained to discriminate between different coloured feeds, one of which contained carprofen. The two feeds were then offered simultaneously and the birds were allowed to select their own diet from the two feeds. In an initial study to assess the most appropriate concentration of drug, the plasma concentrations of carprofen were linearly related to the birds' dietary intake. The walking ability of lame birds was also significantly improved in a dose-dependent manner and lame birds tended to consume more analgesic than sound birds. In a second study, in which only one concentration of analgesic was used, lame birds selected significantly more drugged feed than sound birds, and that as the severity of the lameness increased, lame birds consumed a significantly higher proportion of the drugged feed.     

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound

Objective To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.
Design A physiological study with controls.
Procedure There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.
Results Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.
Conclusions If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.     

Functional evaluation of macrophages in fish from a polluted estuary

The chemotactic and phagocytic efficiencies of macrophages from spot, Leiostomus xanthurus and hogchoker, Trinectes maculatus are reported here. Fish were captured from the York and Ware Rivers, two relatively nonpolluted rivers, and from a reach of the Elizabeth River, known to be contaminated with high concentrations of polynuclear aromatic hydrocarbons (PAHs). Kidney cell types were separated by density gradient centrifugation and single cell suspensions of macrophages were used for in vitro studies. Chemotactic activity was measured in Boyden chambers using Escherichia coli as the chemotactic stimulus. The percentage of macrophages migrating was maximal at 90 min but was markedly reduced in Elizabeth River fish (spot, 33%; hogchoker, 56%) as compared to clean water controls (spot, 55%; hogchoker, 85%). Macrophage phagocytosis of bacteria was quantified by the microscopic enumeration of the proportion of phagocytes which contained intracellular bacteria. Phagocytic activity reached maximum values within 120 min and remained relatively constant for the remainder of the experiment. Phagocytic activity was reduced significantly in the fish obtained from the Elizabeth River. Values at 120 min were 74% and 19% for spot from the control and PAH-contaminated sites, respectively. Comparable values for hogchoker were 88% and 32%. The results suggest that defective macrophage function is related to exposure to PAH-contaminated sediments.