Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter

Crocodile morphometric (head, snout‐vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (±SE) is 265.1 ± 0.4 days] and slaughter (average age is 1037.8 ± 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common‐sized skin sold having 35–45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (±SE) estimates for the traits hatchling snout‐vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (?0.81 ± 0.08) and phenotypic (?0.82 ± 0.02) correlations between age at slaughter and inventory head length.     

Evaluation of PCR,IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given. © 2001 Society of Chemical Industry     

Production and evaluation of monoclonal antibodies for the detection of beet mild yellowing luteovirus and related strains

A sugar-beet-infecting isolate of beet mild yellowing luteovirus (BMYV), and aBrassica-infecting isolate of beet western yellows luteovirus (BWYV) were used to produce monoclonal antibodies for epidemiological studies with BMYV and related field strains. Thirty-four monoclonal antibodies were tested for their reaction with 9 luteoviruses in triple-antibody-sandwich enzyme-linked immunosorbent assay. One (MAFF 24) is now routinely used in the UK for detecting BMYV and BWYV in plants and aphids, although it does not discriminate between them. Heterologous reactions were detected between some of the monoclonal antibodies and potato leafroll virus (PLRV), bean leafroll virus (BLRV) and barley yellow dwarf virus (BYDV-RPV). 38% of antibodies raised to BWYV reacted with PLRV compared with 4% of those raised to BMYV. Monoclonal antibodies were produced which distinguished a sugar-beet-infecting isolate of BMYV with differing host range and serological properties from the commonly-occurring field strain.     

Metal chelate molluscicides: The redistribution of iron diazaalkanolates from the gut lumen of the slug,Deroceras reticulatum (Müller) (Pulmonata: Limacidae)

Two related iron chelates, one toxic to slugs by ingestion, the other not, were introduced into the foregut of D. reticulatum. The subsequent movement and redistribution of the metal within the slug tissues was studied by labelling the chelates with the radioactive isotope ⁵⁵Fe. In slugs which survived treatment approximately half of the ⁵⁵Fe was voided in faeces. The iron retained became unevenly distributed, the highest concentration occurring in the digestive gland, irrespective of the chelate used. At high doses, slugs treated with tris(1-oxo-1,2-diazabutan-2-oxido)Fe(III) were fatally poisoned while those treated with the homologue, tris(1-oxo-1,2-diazaoctan-2-oxido)Fe(III) were not. Slugs killed by the toxic chelate consistently contained proportionally less iron in the digestive gland and proportionally more in the body wall and reproductive system. Dosing slugs already killed by carbon dioxide asphyxiation gave a similar pattern, suggesting that the greater mobility of the iron from the toxic chelate was not a function of the slugs' metabolism.     

The immune response and PBMC subsets in canine visceral leishmaniasis before, and after, chemotherapy

Peripheral blood mononuclear cell subsets, in vitro lymphoproliferative response to leishmanial antigen, and Leishmania-specific serum antibody levels were examined in 11 dogs, naturally infected with L. infantum, and 9 healthy control dogs. A decrease in the percentage of CD4+ T-cells and an increase in the proportion of gammadelta T-cells and sIgG+ B-cells were observed during canine visceral leishmaniasis (CVL). These changes may be responsible for the marked humoral response and the absence of in vitro lymphoproliferation to mitogen and specific parasite antigens. This possibility was supported by the analysis of these subsets after treatment with amphotericin B. One month after therapy, a significant increase in the percentage of CD4+ T-cells and a decrease of gammadelta T-cells and sIgG+ B-cells were observed. At the same time, the lymphocyte blastogenesis assay with leishmanial antigen was positive and the levels of specific antibodies to Leishmania were significantly lower than before the treatment. Five months after therapy, lymphocyte proliferative response to LSA disappeared, antibody and lymphocyte subsets levels returned to those observed during CVL. Therapeutic failure in CVL is associated with the inability of antileishmanial drugs to completely revert the profound immunodepression induced by the infection and prevent relapse.     

The effect of three types of rasps on the occlusal surface of equine cheek teeth: a scanning electron microscopic study

Two hand rasps (tungsten chip blade, solid carbide blade) and an electrically-driven solid carbide axial bur were used to treat the cheek teeth of 2 horses immediately postmortem. All teeth were normal and were rasped to a standard considered satisfactory in practice. Six teeth from each horse served as untreated controls. Following treatment, the teeth were extracted and the clinical crown removed and prepared for scanning electron microscopy. Teeth were also extracted and examined from a horse that had excessive dental treatment previously. Dental debris created by the procedures was collected and examined. All three rasp techniques resulted in amputation of odontoblast processes. The solid carbide blade cut deep gouges and grooves into the surface of the dentin, chipping the enamel and peripheral cement. No smear layer was created. Rasping with a tungsten chip blade created a partial smear layer and a smoother surface than the solid carbide blade. The electrically-driven bur produced a complete smear layer and removed all dental tissues to a smooth layer. The enamel had also been damaged by the electric bur. Crown particles collected after the procedures were larger following hand rasping compared with particles produced by the electric bur. The extent of damage to sensitive and vital dentin tissue was of concern. Further studies are required to establish the optimum technique for rasping equine cheek teeth.     

Regional risk of exporting cattle seropositive for bluetongue virus from the United States

OBJECTIVE: To create a stochastic model to quantify the risk that shipments of cattle from regions within the United States would contain animals seropositive for bluetongue virus and to determine shipment-level accuracy of serologic testing by use of a competitive ELISA (c-ELISA). SAMPLE POPULATION: 19,216 shipments containing 528,918 cattle and calves. PROCEDURE: Data were obtained on number of animals and state of origin of cattle in export shipments originating within the United States between January 1994 and March 2002. Probability distributions for size of export shipments were determined for all states within the United States, and distributions for agar gel immunodiffusion and c-ELISA accuracy (sensitivity and specificity) were determined from expert opinion and review of the literature. The model simulated selection of a shipment and then determined the probability that a threshold number or percentage of cattle within that shipment would have a positive c-ELISA result. Shipment-level sensitivity, specificity, positive-predictive value, and negative-predictive value were calculated. RESULTS: Substantial differences were evident in the regional probability of a shipment being declared positive, with shipments from northeastern states having the lowest probability and shipments from southwestern states having the highest probability. The c-ELISA had variable predictive values at the shipment level, depending on the threshold used and the prevalence of antibody-positive cattle within the region. CONCLUSIONS AND CLINICAL RELEVANCE: Results from this study will aid importers in making scientifically based decisions regarding risk of importing antibody-positive cattle.     

Insulin-secreting beta cell neoplasia in a 10-year-old dog

A 10-year-old collie-cross presented with intermittent episodes of pelvic limb weakness and collapse. Hypoglycemia, secondary to an insulin-secreting beta cell tumor, was suspected on the basis of clinical signs and serum biochemistry. Conservative dietary therapy consisted of multiple small meals, limited exercise, and avoidance of foods containing simple sugars.