Disposal and disease rates in British dairy herds between April 1998 and March 2002

Data derived over four years from 434 dairy herds in 1998/99 to 244 in 2001/02 revealed average disposal rates of 22.6 per cent per year, half of which were for poor fertility, mastitis and lameness. The quartile of herds with the lowest disposal rates sold an average of 11.5 per cent annually and the quartile with the highest rates sold 35.5 per cent. Average annual disease rates over the four years were as follows: for assisted calving 7.8 per cent, for digestive disease 1.2 per cent, for ketosis 0.5 per cent, for hypomagnesaemia 0.5 per cent, for hypocalcaemia 5.0 per cent and for injuries 0.8 per cent. The incidence of mastitis increased from 36.0 to 43.3 per cent of cows per year. The incidence of lameness decreased from 23.3 per cent in 1998/99 to 20.7 per cent in 2000/01 but increased to 21.9 per cent in 2001/02. Data received from the same 219 farms during the first three years showed no effective differences from the full set of data for each of the three years. The lowest annual incidences of mastitis and lameness on individual farms were below 7 per cent and 2.5 per cent, respectively. In general, housing cows in cubicles was associated with a greater risk of lameness, and housing them in straw yards with a greater risk of mastitis. However, some of the lowest rates of lameness were recorded in cubicle-housed cows and some of the lowest rates of mastitis were recorded in cows housed in yards. Larger herds were not associated, in general, with higher rates of mastitis.     

Mitogen-induced lymphocyte proliferation in loggerhead sea turtles: comparison of methods and effects of gender, plasma testosterone concentration, and body condition on immunity

A fully functioning immune system is vital to the survival of threatened and endangered sea turtles. Immunological protection against diseases in any organism can be reduced by a number of natural and anthropogenic factors, such as seasonal changes, malnutrition, disease states, and contaminant exposure. These factors are even more critical when they occur in endangered species or populations. To identify alterations in the immunological health of loggerhead sea turtles (Caretta caretta), the mitogen-induced lymphocyte proliferation (LP) assay was developed using peripheral blood leukocytes (PBLs). Collection and culture conditions were optimized for this assay using non-lethal blood samples collected from free-ranging turtles along the southeastern US coast. During the collection, two anticoagulants (sodium heparin and lithium heparin) were compared to determine effects of different ions on assay results. Optimal culture conditions were established for loggerhead PBLs while two different methods of measuring LP were compared: (1) the traditional radioactive (3)H-thymidine assay and (2) a non-radioactive, colorimetric method utilizing 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium (MTT). The results indicate that the (3)H-thymidine and the non-radioactive MTT methods did not correlate with each other and that the use of heparin type did not influence the results of the LP assay. Lastly, using these optimized methods, we investigated the effect of gender, plasma testosterone concentration, and body condition on LP in loggerhead turtles and found that none of the parameters largely influenced LP.     

The use of polymerase chain reaction assay to diagnose proliferative gill disease in channel catfish (Ictalurus punctatus).

To assess the potential of a polymerase chain reaction (PCR) assay as a diagnostic tool in the detection of proliferative gill disease (PGD) in channel catfish (Ictalurus punctatus), PCR assays were compared with the traditional diagnostic methods of gill wet mounts and histology. A PCR assay using primers for Aurantiactinomyxon ictaluri, the actinospore associated with PGD, was performed with tissues from fish from commercial ponds. Using histology as the "gold standard," the sensitivity, specificity, and accuracy of the PCR assay were all >90%. In comparison, the wet mount examinations had a lower sensitivity and specificity. Using the chi-square test and a test for strength of association, there was a significant, strong association between results obtained by PCR and those obtained by the other 2 methods. These results demonstrate that the PCR assay is a good diagnostic tool for the detection of PGD.     

Effects of ozonation on the speciation of dissolved iodine in artificial seawater.

Iodine in the form of iodide is required for synthesis of tri-iodothyronine and thyroxine in fish. Iodine chemical speciation in aliquots of raw artificial seawater mix was measured before, during, and after exposure for fixed time periods to air only and to concentrations of ozone required to achieve oxidation-reduction potentials typical of a protein skimmer (400 mV) and an ozone contact chamber (800 mV). Chemical species of iodine were also measured in tank water from a large, recirculating, ozonated aquarium system that has a low-grade incidence of thyroid lesions (e.g., thyroiditis, hyperplasia, adenoma, and adenocarcinoma) in its fish. With increasing exposure to ozone, concentrations of iodide and dissolved organic iodine (DOI) decreased, whereas iodate levels increased. As a result of exposure to 400 mV, iodide concentration dropped to less than half the amount found in raw artificial seawater mix. After exposure to 800 mV, initial iodide levels decreased by 67%, and DOI became undetectable, whereas iodate concentration increased by 155%, with no remarkable change in total iodine concentration. These results indicate ozone-induced conversions from iodide to iodate, and DOI to iodide or iodate (or both). Iodide and DOI were not detectable in the aquarium system's water samples. Ozonation of artificial seawater may alter the relative concentrations of iodine species in a closed tank system, so that iodide supplementation of the diet or tank water of captive teleosts and elasmobranchs living in ozonated seawater is advisable.     

Differential induction of redox sensitive extracellular phenolic amides in potato

This study focuses on the differential induction of extracellular phenolic amides that accumulate in potato cell suspensions during the first few hours of the interaction between these plant cells and either bacterial pathogens or pathogen-related elicitors. Using suspension cells of Solanum tuberosum we identified 4 hydroxycinnamic acid amides that accumulate in the extracellular environment. Treatment of the suspension cells with pathovars of the plant pathogens Pseudomonas syringae or Ralstonia solanacearum or with pathogen-related elicitors changed the composition of the extracellular phenolic amides within hours and the composition differed for each treatment. Some of the phenolic amides were sensitive to oxidative stress; when suspension cells were treated with bacterial strains or elicitors that triggered an oxidative burst, the phenolics were oxidized and depleted for the duration of the burst. Other critical parameters that affected the qualitative and quantitative makeup of these phenolic amides were plant cell age and density.     

Effects of N‐acetyl‐cysteine and N‐acetyl‐cysteine‐amide Supplementation on In Vitro Matured Porcine Oocytes

This study was conducted to evaluate the effects of different concentrations of the antioxidant N‐acetyl‐cysteine (NAC) supplemented to the maturation medium on porcine embryo development. Concentrations of NAC and its synthetic derivative, NAC‐amide (NACA) were evaluated for effects on nuclear maturation, fertilization success and embryo development. Concentrations of NAC (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 5.0 mm ) were supplemented to maturing oocytes, and embryo development was analysed at 48 and 144 h post‐fertilization. There were no differences among cleavage rates for any of the treatment groups. Blastocyst formation for 1.5 mm NAC (56.5 ± 9.2%) was higher (p < 0.05) than all other supplementations. There were no differences in nuclear maturation or fertilization or in cleavage rates when comparing 1.5 mm NAC and 1.5 mm NACA supplementation to the control. Blastocyst formation for 1.5 mm NAC (44.4 ± 4.7%) and 1.5 mm NACA (46.2 ± 3.4%) supplementation were higher (p < 0.05) than the control (32.1 ± 6.2%) oocytes. These results indicate that supplementing 1.5 mm of NAC or NACA to the oocyte maturation medium increased the percentage of viable embryos reaching the blastocyst stage of development.