Associations between body condition, rumen fill, diarrhoea and lameness and ruminal acidosis in Australian dairy herds.

AIMS: To investigate associations between ruminal acidosis and body condition score (BCS), prevalence of poor rumen fill, diarrhoea and lameness in dairy cows in New South Wales and Victoria, Australia. METHODS: This was a cross-sectional study conducted in 100 dairy herds in five regions of Australia. Feeding practices, diets and management practices of herds were assessed. Lactating cows within herds were sampled for rumen biochemistry (n = 8 per herd) and scored for body condition, rumen fill and locomotion (n = 15 per herd). The consistency of faecal pats (n = 20 per herd) from the lactating herd was also scored. A perineal faecal staining score was given to each herd. Herds were classified as subclinically acidotic (ACID), suboptimal (SO) and non-acidotic (Normal) when ≥3/8 cows per herd were allocated to previously defined categories based on rumen biochemical measures. Multivariate logistic regression models were used to examine associations between the prevalence of conditions within a herd and explanatory variables. RESULTS: Median BCS and perineal staining score were not associated with herd category (p >0.05). In the multivariate models, herds with a high prevalence of low rumen fill scores (≤2/5) were more likely to be categorised Normal than SO with an associated increased risk of 69% (p = 0.05). Herds that had a greater prevalence of lame cows (locomotion scores ≥3/5), had 103% higher risk of being categorised as ACID than SO (p = 0.034). In a multivariate logistic regression model, with herd modelled as a random effect, an increase of 1% of pasture in the diet was associated with a 5.5% increase in risk of high faecal scores (≥4/5) indicating diarrhoea (p = 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: This study confirmed that herd categories based on rumen function are associated with biological outcomes consistent with acidosis. Herds that had a higher risk of lameness also had a much higher risk of being categorised ACID than SO. Herds with a high prevalence of low rumen scores were more likely to be categorised Normal than SO. The findings indicate that differences in rumen metabolism identified for herd categories ACID, SO and Normal were associated with differences in disease risk and physiology. The study also identified an association between pasture feeding and higher faecal scores. This study suggests that there is a challenge for farmers seeking to increase milk production of cows on pasture to maintain the health of cattle.

Rural veterinary services in Western Australia: Part A. Government veterinary services.

OBJECTIVE: To determine the status of rural veterinary services in Western Australia. PROCEDURE: Two questionnaires were mailed to eligible, registered veterinary surgeons in Western Australia in 2006. The first was mailed to government veterinarians and the second to private practitioners in rural practice. Part A presents the replies from government veterinary officers and Part B the replies from rural practitioners. Replies were transferred to Microsoft Excel for analysis. RESULTS: Sixty-seven per cent of government veterinary officers responded to the questionnaire. Eighty per cent of these had been in the service for 20 years or more and their average age was 54. Work with sheep and beef cattle occupied 75% of their time, with dairy cattle receiving 10% and pigs and poultry less than 10%. The majority of respondents reported changes in the attitude of farmers to the service as a result of rural recessions and the decision to make a direct charge for government veterinary services. Although most respondents thought that the government veterinary service would continue in the future there were differences of opinion as to what form that would take. CONCLUSION: Government veterinary services in Western Australia are undergoing major changes, with the service decreasing in size and scope. Recently the Department of Agriculture has been renamed the Department of Agriculture and Food and it is likely that the role of its veterinary officers will change accordingly.

Rural veterinary services in Western Australia: Part B. Rural practice.

OBJECTIVE: To determine the current status of rural veterinary services in Western Australia. PROCEDURE: A questionnaire was sent to all eligible rural practitioners registered in 2006 and the replies were transferred to Microsoft Excel for analysis. RESULTS: Of the rural practitioners invited to participate in the survey replies were received from 67%. There were equal numbers of females and males. Their mean age was 44 years. Ninety per cent of respondents considered knowledge gained as an undergraduate was sufficient to equip them for practice, but only 60% considered their practical skills adequate. Thirteen per cent of those in rural practices in 2005 had left by 2006. Eighty-nine per cent of respondents were in mixed practice, the balance in specific species practice, such as equine, large animal and production animal consultancy. The majority of rural practitioners relied on servicing companion animals for their viability; 7% earned their income from servicing production animals only. Seventy per cent utilised merchandising and the sale of pet foods to supplement the income received from the traditional veterinary services and 34% found it necessary to earn an independent income. A quarter considered that rural practice did not have a future. CONCLUSION: The majority of rural practitioners in Western Australia depend on companion animals, not production animals, to remain viable, with very few operating production animal services. Poor remuneration is a major reason why veterinarians leave rural practice, and many find it necessary to supplement their income or develop an independent income.

The definition of acidosis in dairy herds predominantly fed on pasture and concentrates.

This cross-sectional survey examined the prevalence of ruminal acidosis and the effects of acidosis on the production of dairy cattle. Eight fresh cows, 3 primiparous and 5 multiparous (< 100 d in milk), were selected randomly from each of 100 dairy herds in 5 regions of Australia. Rumen fluid was obtained from each cow by rumenocentesis and a stomach tube, and samples were tested for pH. Stomach tube rumen fluid samples were analyzed for volatile fatty acid, ammonia, and D-lactate concentrations. On the basis of the results of all assays, cows were categorized into 3 distinct categories (categories 1, 2, and 3) by cluster analysis. The percentages of cattle in categories 1, 2, and 3 were 10.2, 29.9, and 59.9%, respectively. Mean rumen pH for categories 1, 2, and 3 were 5.74 +/- 0.47, 6.18 +/- 0.44, and 6.33 +/- 0.43, respectively. Biochemically, categories 1, 2, and 3 were characterized, respectively, as follows: mean total VFA concentration (mM), 100.74 +/- 23.22, 94.79 +/- 18.13, and 62.81 +/- 15.65; mean ammonia concentration (mM), 2.46 +/- 2.02, 7.79 +/- 3.75, and 3.64 +/- 2.03; and mean D-lactate concentration (mM), 0.34 +/- 0.86, 0.28 +/- 0.97, and 0.12 +/- 0.51. Category 1 cows had higher propionate, valerate, isovalerate, and caproate concentrations and were of lower parity than cows in other categories. Cows in category 1 had higher milk production but lower milk fat content than category 2 cows. Herds were assigned to 1 of 3 groups according to the numbers of cows assigned to each category. Herds with > or = 3 of the 8 cows in category 1 were classified as acidotic. Herds with > or = 3 of the 8 cows in category 2 were classified as having suboptimal rumen function, and herds with > or = 3 of the 8 cows in category 3 were classified as normal. Herds that had 3 or more of the 8 cows in category 1 (acidotic herds) had diets with higher energy and nonfiber carbohydrate contents and a lower neutral detergent fiber content than herds with a high prevalence of category 2 or 3 cows. The lack of significance of a herd effect in the statistical models developed suggests that the categories were robust across production systems, in which diets varied from all pasture to total mixed rations. A point prevalence of 10% (95% credible interval, 8 to 12%) of cows with an acidotic profile indicates a high risk for acidosis in the cattle sampled. The higher nonfiber carbohydrate and lower neutral detergent fiber contents of diets for herds with a high prevalence of category 1 cows (acidotic herds) indicates that there may be opportunities to reduce the risk of acidosis by dietary manipulation.

Clinical acidosis in a Gippsland dairy herd.

OBJECTIVE: To report on spontaneous clinical and subclinical acidosis in a large dairy herd, to evaluate the diets and feeding strategies involved, and to report on measures of rumen function in the cows affected. DESIGN: A Gippsland dairy herd was sampled as part of a wider randomised cross-sectional study that examined the prevalence, risk factors for, and effects of, acidosis on rumen function of dairy cattle. Three herds on the farm were involved in the study: the transition herd (cows 3 weeks prior to calving), the very fresh lactating herd (1 < days in milk < 10, herd 1) and the fresh lactating herd (10 < days in milk < 120, herd 2) including a small lame herd fed separately. The transition cows were fed 2 kg dry matter triticale per cow per day and hay with an estimated total dry matter intake of 4.8 kg per cow per day. The lactating cow diet included 6.75 kg dry matter triticale per cow per day with total concentrate fed being 8.1 kg dry matter per cow per day in the milking parlour. Silage, lucerne cubes, hay and pasture (herd 2 only) was also fed to the lactating cows with the estimated total dry matter intake for cows in herds 1 and 2 being 13.7 kg and 20.8 kg per cow per day respectively. Three primiparous and five multiparous cows in early lactation (< 100 days in milk) were randomly selected from each of two lactating herds: herds 1 and 2. Rumen fluid was sampled from each cow by both rumenocentesis and stomach tube. The rumenocentesis samples were tested for pH at the time of sampling. Stomach tube samples were frozen and subsequently tested for volatile fatty acid, ammonia, and D- and L-lactate concentration. RESULTS: In the very fresh herd, there was a high prevalence of severe lameness and scouring, coupled with a mean rumen pH 5.67, low mean total volatile fatty acid concentration 71.0 mM and high mean concentrations of L- and D-lactate, (7.71 mM and 7.31 mM), respectively. Cows in the fresh herd had moderate signs of scouring and lameness. A lame herd comprising approximately 50 cows separated from the fresh herd was also present on the farm. The mean rumen pH of the fresh herd was 5.74 and mean rumen concentrations of volatile fatty acids, ammonia, L- and D-lactate were within ranges considered normal. CONCLUSIONS: The transition diet failed to supply sufficient energy and protein for maintenance of cows of this live weight in late gestation. The diet fed to the very fresh herd was low in effective fibre and contained an excessive content of non-structural carbohydrate in the form of processed, rapidly fermentable grain. The sudden change from the transition diet to the diet fed to the very fresh herd probably also precipitated the outbreak of acidosis. This case report provides unique detail, including information on diets and rumen parameters, of an outbreak of acidosis in a pasture-fed herd.

Effect of copper, zinc and cadmium on the promoter of selenoprotein W in glial and myoblast cells.

Rat selenoprotein W (SeW) promoter activity was investigated using different concentrations of cadmium, copper, and zinc. Two fragments (404 and 1265 bp) of the SeW promoter, containing a single metal response element (MRE), were ligated into the multiple cloning site of a pGL3-Basic reporter plasmid. The constructs were transfected into cultured C6 (rat glial) and L8 (myoblast) cells and promoter activity measured by means of luciferase reporter gene fused to the SeW promoter fragments in the reporter plasmid. With post-transfection exposure of these cell lines to these metals, copper and zinc, but not cadmium, significantly increased promoter activity of the unmutated 1265 bp (not 404 bp) construct (p<0.05) only in the C6 cells. Mutation of the MRE sequence abolished promoter response to metal exposure but did not eliminate promoter activity. The results suggest that SeW expression in glial cells can be increased on exposure to copper and zinc and that this response is dependent on the MRE sequence present in the SeW promoter.

Bleeding reflux esophagitis: a prospective 1-year study in a university hospital.

OBJECTIVES: The prevalence of bleeding from reflux esophagitis has not been studied. The aim of the study was to evaluate the 1-yr prevalence of bleeding from reflux esophagitis, as well as the independent factors associated with bleeding. METHODS: All patients with reflux esophagitis diagnosed with upper digestive tract endoscopy in Reims Hospital in 1996 were included. Studied parameters were prospectively recorded and compared between patients with bleeding and nonbleeding reflux esophagitis. RESULTS: Endoscopy was performed in 1983 patients of whom 219 (11.0%) had overt upper digestive tract hemorrhage. Reflux esophagitis was the cause of bleeding in 32 patients (14.6%). Reflux esophagitis was diagnosed in 391 patients during the same period of time. Bleeding reflux esophagitis accounted for 8.2% of them. Independent factors associated with bleeding were grade 3 or 4 (Savary-Miller) esophagitis (odds ratio [OR]: 25.5, 95% confidence interval [CI]: 9.6-67.9), cirrhosis (OR: 5.7, 95% CI: 1.7-18.9), Eastern Cooperative Oncology Group performance status > or = 3 (OR: 4.6, 95% CI: 1.5-14.2), and anticoagulant therapy (OR: 3.9, 95% CI: 1.2-12.5). A history of reflux esophagitis or heartburn was noted in only 28.1% or 37.5% of the patients with bleeding reflux esophagitis, respectively. CONCLUSIONS: In this population of patients with reflux esophagitis, the prevalence of bleeding esophagitis was high (8.2%). Bleeding esophagitis occurred primarily in patients with severe esophagitis and was the revealing clinical form of gastroesophageal reflux disease in the majority of cases, suggesting that bleeding prevention would hardly be effective.

Post-traumatic intraventricular hemorrhage: analyssis of 19 cases

Post-Traumatic Intraventricular Haemorrhage (IVH) occurs after a traumatic head injury and is usually associated with an adjacent intracerebral hemorrhage or brain contusion. Post-traumatic IVH was associated with other brain lesion in most cases. In fact, thepethogenetic mechanism that governs the formation of a post-traumatic IVH is not clear. Computed tomography represents the first reliable and nonsurgical tool for identifying IVH, where the sites of ventricular haemorrhage have been analysed. Ventricular drainage is used to made a good recovery in pacients with IVH. Prognostic in traumatic IVH, in general, is poor. In our study, we had 19 pacients with IVH, with 76 per cent male and 24 per cent female. Age average's were 30,3. As for the causes we had hit by a car, car collision, gunshot accident, fall and fight. CT was very important to detect IVH in our cases. The surgery was more frequent in our study when additional intracranial lesions were present. There were 8 death and 11 pacients had good recovery

Molybdenum poisoning in feedlot cattle.

OBJECTIVE: To describe a case of acute, fatal molybdenum poisoning in feedlot cattle. DESCRIPTION OF THE HERD: In total, 831 Hereford, Hereford x Angus, and Hereford x Simmental steers, aged 8 to 10 months, with an average body weight of 310 kg were fed a diet, to which sodium molybdate at a rate of 1.9% of the total ration had been accidently added. INVESTIGATION: The steers lost appetite within 3 days and deaths commenced within 6 days of the diet being first offered. The error was rectified when deaths started to occur, but steers continued to die for up to 7 months afterwards. Of the 831 steers on the feedlot, 90 died and a further 5 remained in poor condition. The cause of death was periacinar to massive hepatic necrosis and acute renal tubular necrosis. Blood and tissue samples were taken from surviving steers for 76 days, by which time plasma molybdenum concentrations had returned to normal concentrations. CONCLUSION: Sodium molybdate when fed at a rate of 1.9% of the diet results in acute renal tubular necrosis and periacinar to massive hepatic necrosis.

Chromosomal aberrations induced by defined DNA double-strand breaks: the origin of achromatic lesions.

The mechanisms of formation of chromosomal aberrations are poorly understood, despite the common use of aberrations as a measure of the genetic effects of physical and chemical agents. We have used restriction endonucleases to introduce defined DNA double-strand breaks into mammalian cells, and measured chromosomal aberration formation relative to the activity of the endonuclease. The endonucleases AluI and Sau3AI remain active for a relatively short time under simulated cellular conditions and induce achromatic lesions ('gaps') in chromatids only within the first hour or two following treatment. In contrast, the endonuclease MboI (an isoschizomer of Sau3AI) is active for an extremely long time and continues to produce chromatid gaps during the whole 12 hr sampling period. This observation strongly suggests that the aberrations classified as gaps are a manifestation of unrejoined DNA double-strand breaks. The formation of gaps may relate to the opportunities for repair of DNA breaks in relation to cell-cycle position. It is more difficult to relate the formation of structural chromatid aberrations to the endonuclease activity, although at relatively low concentrations all 3 endonucleases gave similar levels of structural aberrations.

Mutations induced by DNA double-strand breaks: the influence of genomic site.

The transgenic CHO cell line PL61, carrying a recombinant SV40-gpt gene, was treated with restriction endonucleases to assess mutagenesis from defined DNA double-strand breaks. Mutations in gpt were measured under two conditions: a stringent condition where selection ensured that the closely-linked neo gene was retained functionally intact, or a relaxed condition without the requirement for neo gene function. Despite testing 18 different restriction endonucleases with various numbers of potential break-sites within the transgene, mutations were only found under relaxed selection conditions. These mutations commonly led to complete loss of the transgene, suggesting that large deletions predominate when selection is relaxed. It is argued, in comparison to mutation data for other genomic sites in CHO cells, that variations in the 'effective target size' for mutagenesis may explain the response of the transgene under different conditions.

Case report: efficacy of oral carnitine therapy for dilated cardiomyopathy in boxer dogs.

This paper investigates the role of carnitine in the etiology and treatment of dilated cardiomyopathy in boxers. Two boxers were diagnosed as having dilated cardiomyopathy on the basis of clinical presentation, chest radiographs, electrocardiography and echocardiography. In one dog, carnitine was administered at 6.0 g (or approximately 250 mg/kg live weight (LW) daily per os, and this dog remained asymptomatic for 4 mo until it presented for anorexia, coughing and weakness. Necropsy and histologic findings were consistent with boxer cardiomyopathy in both dogs. Cardiac carnitine concentration was 567 nmol/g wet weight in the unsupplemented dog, which is below the normal mean +/- SD concentration of 1493 +/- 141 nmol/g wet weight. Low cardiac carnitine concentrations appear to be a consistent finding for dilated cardiomyopathy in boxers. However, in the dog that received carnitine therapy, cardiac carnitine was 2802 nmol/g wet weight, and all tissues assayed in the supplemented dog had higher carnitine concentrations than normal dogs. Elevation of tissue carnitine failed to ameliorate dilated cardiomyopathy in this dog. Oral carnitine supplementation in these therapeutic doses appears not to resolve dilated cardiomyopathy in all boxers.

Electroporation and streptolysin O--a comparison of poration techniques.

CHO (Chinese hamster ovary), xrs5 (X-ray sensitive Chinese hamster) and HF19 (untransformed human fibroblast) cells, were exposed to a lethal dose of the restriction enzyme Pvu II during electroporation or poration with the bacterial toxin streptolysin O. The uptake of the exclusion dye trypan blue was used as a measure of poration and compared with survival as measured by subsequent colony formation. It was assumed that any surviving cells had not been permeabilized and therefore did not receive any restriction enzyme. Electroporation alone proved to be more cytotoxic to the cells, whilst streptolysin O was more efficient at permeabilizing both hamster and human cells.

Plasma indicators of muscle damage in a model of nutritional myopathy in weaner sheep.

Subclinical nutritional myopathy was induced in 5-month-old sheep by feeding them a diet low in vitamin E and selenium. Subsequently clinical myopathy was induced by dosing with protected polyunsaturated fatty acids. Plasma activities of creatine kinase (CK), pyruvate kinase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase and aldolase, enzymes of muscle origin, all remained above their reference ranges in clinically affected sheep, but fluctuated widely. Similar fluctuations occurred in subclinically affected animals, resulting in some activities being within the reference ranges and some above, at different times. Plasma malondialdehyde, an indicator of lipid peroxidation, proved of no diagnostic value. Terminal plasma CK activities were significantly correlated with microscopic damage in the vastus lateralis (VL), but not the vastus intermedius (VI) or the tensor fascia lata (TFL) muscles. AST was the most highly correlated with damage in VI and VL. In two clinically affected sheep successfully treated with an oral dose of alpha-tocopherol acetate all enzymes decreased steadily to within their reference ranges, at rates probably related to their plasma half-lives. These results suggest that measurement of plasma CK activity would be useful in monitoring recovery of treated sheep.

Response of radiation-sensitive human cells to defined DNA breaks.

We have investigated the response of four human cell lines, representing a range of sensitivities to ionizing radiation, to enzymes which induce defined DNA double-strand breaks (dsbs). Cell lines were derived from a normal individual, from the cancer-prone disorders ataxia-telangiectasia (AT) and Bloom's syndrome (BS), and from an immunodeficient individual (46BR). The molecular defects in AT and BS are unknown, while 46BR is known to be DNA ligase I deficient. We assayed the clonogenic survival of the cell lines following in vivo scission of the DNA by the restriction endonucleases PvuII and BanI. These two enzymes differ in their action; PvuII gives rise to dsbs with blunt termini, while BanI generates staggered ends with a 4 bp overhang. We found a correlation between the sensitivity of the cell lines to X-rays and to the blunt-end cutter PvuII, but not to the cohesive-end cutter BanI.

Age-related changes in plasma biochemical values of farmed emus (Dromaius novaehollandiae).

Blood samples were collected from 40 emus (Dromaius novaehollandiae) of 4 different age groups ranging from 1 week to 14 months. Plasma values of glucose, cholesterol, uric acid, total protein, albumin, creatine kinase, aspartate amino transferase, alkaline phosphatase, calcium, phosphorus and magnesium were measured. Fourteen-month-old birds had lower plasma glucose values and enzyme activities and higher plasma protein values than younger birds. One-week-old birds had higher cholesterol and uric acid values than other age groups. Plasma calcium, phosphorus and magnesium values did not differ across the age profiles sampled.

The effectiveness of restriction endonucleases in cell killing and mutation.

The use of restriction endonucleases (RE) to study the importance of DNA break end structures in differential cellular response has proved controversial. The number of DNA cut sites and the accessibility of RE are recognized examples of confounding factors. We have eliminated these factors by comparing the effectiveness of isoschizomers. Additionally, we considered for the first time the tolerance of the enzymes to cellular conditions. Cell killing and mutation were compared to the overall cutting ability of the enzymes in an "intracellular" buffer. We found that the activity of each RE combined with its lifetime, under simulated cellular conditions, were the overriding factors in determining effectiveness.

Elevated levels of DNA double-strand breaks (dsb) in restriction endonuclease-treated xrs5 cells correlate with the reduced capacity to repair dsb.

Recently we have reported the kinetics of DNA double-strand breaks (dsb) induced in electroporated mammalian (CHO) cells that had been treated with the restriction endonuclease PvuII, as measured by the filter elution assay at the non-denaturing pH of 9.6. A gradual accumulation of dsb was observed over a 24-h incubation period following the restriction endonuclease (RE) treatment and this was attributed to a competition between incision of the DNA by PvuII and dsb repair. In order to test this 'competition' hypothesis we have carried out similar experiments in the radiosensitive xrs5 mutant cell line, which has been shown to be deficient in dsb repair. The levels of dsb monitored by the non-denaturing filter elution assay in the xrs5 cell line treated with PvuII was found to be 3-4 times higher than that found for the wild-type CHO K1 cell line. Levels of dsb were also significantly raised in xrs5 cells treated with BamHI, as compared with the background levels observed in the CHO line. These data lend strong support to the competition hypothesis of simultaneous incision and repair of RE-induced dsb.