POTENTIAL PASTURE PRODUCTION IN THE UPLANDS OF WALES

The DM and N contribution of S184 white clover in mixed ryegrass/clover swards was recorded at Pant-y-dwr Hill Centre (305 m) for 4 years, 1967–70. By direct comparison with fertilized grass swards it was estimated that the clover N contribution on peaty gley soil averaged 100 kg N/ha per year (89 Ib N/ac) under cutting and 98 kg N/ha (87 ib/ac) under grazing with faecal return. On more fertile acid brown earth the corresponding contributions were 81 and 90 kg N/ha (72 and 80 Ib/ac). Full replacement of clover by N fertilizer would require average annual applications of 268, 229, 156 and 128 kg fertilizer N/ha, respectively (239, 204, 139 and 114 Ib N/ac).     

Distribution of infectious pancreatic necrosis virus (IPNV) in wild marine fish from Scottish waters with respect to clinically infected aquaculture sites producing Atlantic salmon, Salmo salar L

This study represents the first large-scale investigation of IPNV in Scottish wild marine fish. Kidney samples were taken from 30 627 fish comprising 37 species and 45 isolations were made from nine different species, illustrating these as reservoirs of IPNV in Scottish waters. The estimated prevalence of IPNV in the Scottish marine environment was low at 0.15% (90% confidence intervals, (CI) of 0.11-0.19%). This was significantly greater in fish caught less than 5.0 km from IPN-positive fish farms in Shetland, at 0.58% (90% CI of 0.45-0.77%). This prevalence persisted and did not significantly decrease over the 16-month period of study. The estimated prevalence of IPNV for each positive species was less than 1% with the statistically non-significant exceptions of flounder, Platichthys flesus (L.), at 12.5% (90% CI of 0.64-47.06%) and saithe, Pollachius virens (L.), at 1.11% (90% CI of 0.49-2.19%). The 45 isolates were titrated and all but two were below the detection limit of the test (<55 PFU g(-1)). Titres of 3.8 x 10(2) PFU g(-1) and 2.8 x 10(1) PFU g(-1) were calculated from common dab, Limanda limanda (L.), and saithe, respectively. This study provides evidence that clinical outbreaks of IPN in farmed Atlantic salmon may cause a localized small increase in the prevalence of IPNV in wild marine fish.     

Brain natriuretic peptide concentration in dogs with heart disease and congestive heart failure

Plasma brain natriuretic peptide concentration ([BNP]) is high in humans with cardiac disease and is further increased with congestive heart failure (CHF). The hypotheses of this study were that dogs with moderate to severe mitral regurgitation due to myxomatous mitral valve disease (MVD) would have increased plasma [BNP] compared to normal dogs, that plasma [BNP] would be higher in dogs with CHP, and that plasma [BNP] would predict premature death from cardiovascular disease. The study population consisted of 34 dogs: 9 normal dogs and 25 dogs with MVD. Patients were divided into 4 groups: group 1-10 dogs with moderate to severe MVD and no radiographic evidence of CHF; group II--6 dogs with severe MVD and mild CHF; group III--7 dogs with severe MVD and moderate CHF; and group IV--2 dogs with severe MVD and severe CHF. Diagnostic tests included thoracic radiographs, an echocardiogram, a serum chemistry profile, and the measurement of plasma [BNP] by a canine-specific radioimmunoassay. There was a significant positive correlation between the plasma [BNP] and heart disease/failure groups (P = .0036). Plasma [BNP] increased with progressively increasing severity of MVD and CHE Group I dogs had higher plasma [BNP] than did control dogs (P < .0001), and plasma [BNP] was higher in dogs with CHF (groups II-IV versus group I; P = .012). Plasma [BNP] was also weakly positively correlated with left atrial size (r = 0.43, P = .04). For every 10-pg/mL increase in plasma [BNP], the mortality rate over 4 months' time increased approximately 44%.     

A comparison between non-destructive and destructive testing of Atlantic salmon, Salmo salar L., broodfish for IPNV--destructive testing is still the best at time of maturation.

Two populations of Atlantic salmon broodstock, previously identified as infectious pancreatic necrosis virus (IPNV) carriers, were screened for IPNV at the time of stripping. Four hundred and ten broodfish were individually sampled of which 91 were detected as IPNV positive by virus culture of sonicated kidney homogenates combined with gonadal fluid, but none tested positive by the blood leucocyte assay. Thirty fish identified as IPNV carriers prior to maturation by the blood leucocyte assay were used in a separate study to compare non-destructive vs. destructive testing methods at stripping. IPNV was not detected using the blood leucocyte method at the time of stripping. RT-PCR and real-time PCR assays failed to detect IPNV from 13 blood samples, the virus was not isolated from milt (0/14) or sonicated ovarian fluid cell pellets (0/16) and only three fish tested positive by the standard culture of kidney homogenates. A third study of Atlantic salmon broodfish compared the IPNV isolation rates prior to maturation with the isolation rates at spawning during 1999-2001. In each year the percentage of IPNV-positive broodfish was significantly lower than in the pre-broodstock sample. While in pre-broodfish samples IPNV was detected by the blood leucocyte assay, no culture isolations or PCR positives were detected from non-destructive samples of the same individual broodfish at stripping. A consistent finding was that even for the kidney assay, the percentage of IPNV-positive fish in carrier populations was higher in pre-broodstock than in broodfish at stripping. These results indicate that destructive kidney sampling is still the most sensitive method for detecting IPNV carrier Atlantic salmon broodfish and that a change in IPNV carrier-status occurs during the maturation period.     

Relationship between diet and liver carcinomas in roe deer in Kielder Forest and Galloway Forest

The winter diets of roe deer culled from Kielder Forest, in north-east England, where the incidence of liver carcinomas in roe deer is high, and Galloway Forest, in south-west Scotland, where the incidence of liver carcinomas is low, were compared by microhistological analysis of faeces. Both areas are planted with spruce forests but the diets of the deer from Kielder Forest were less varied and contained more spruce and heather than the diets of the deer from Galloway Forest.     

Myasthenia gravis associated with cutaneous lymphoma in a dog

A middle-aged golden retriever presenting with exercise intolerance and multifocal cutaneous nodules was diagnosed as having non-epitheliotropic cutaneous lymphoma with concurrent myasthenia gravis. Treatment with corticosteroids induced short-term remission of the lymphoma and alleviation of myasthenic signs.     

A Retrospective Analysis of 2,253 Cases Submitted for Endocrine Diagnosis of Possible Granulosa Cell Tumors in Mares

Endocrine diagnoses of granulosa cell tumors (GCTs) in the mare are frequently based upon determination of serum concentrations of inhibin, testosterone, and progesterone (GCT panel). In the present study, we examined results from 2,253 samples submitted for determination of GCT panel. In an additional subset of samples (n = 75), diagnosis of GCT was confirmed based upon surgery or necropsy. The objective of the current study was to examine the agreement between serum inhibin and testosterone concentrations in mares with serum progesterone concentrations less than or ≥1 ng/mL. Across all samples, elevations in serum inhibin or testosterone were noted in 15.2% or 17.3% of samples, respectively. For samples with progesterone <1 ng/mL, more (P = .001) samples had elevated inhibin than elevated testosterone, whereas for samples with progesterone ≥1 ng/mL, more (P < .0001) samples had elevated testosterone than elevated inhibin. For samples with progesterone <1 ng/mL, the agreement between elevated inhibin and testosterone was greater than that for samples with progesterone ≥1 ng/mL. In a subset of 53 samples with progesterone ≥1 ng/mL, 28 samples had endocrine evidence of a granulosa cell tumors based upon elevations of serum anti-Müllerian hormone, and 4 of these samples had endocrine evidence of pregnancy based upon estrone sulfate concentrations. For samples from mares with confirmed GCTs, 85% and 55% had elevated inhibin or testosterone, respectively. Based upon endocrine diagnosis, GCTs occur in mares with elevated progesterone and/or estrone sulfate, albeit at a low rate.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.