Risk factors for Merino ewe mortality on the Northern Tablelands of New South Wales, Australia

OBJECTIVE

To measure the association of worm egg count (WEC), body weight (BW) and fat score (FS) with mortality in Merino ewes.

METHODS

On six farms, Merino ewes (n = 1440) were yarded at approximately 3-month intervals for 2 years for a range of experimental measurements. Mortality was defined by failure to present at two consecutive measurement days and at next shearing. Survival analysis was conducted with phenotypic traits measured both as continuous variables and categorised appropriately for industry guidelines.

RESULTS

Overall mortality was 10%, with most deaths occurring in autumn followed by winter. Age class (2006 drop vs mature-age ewes) did not affect mortality. High WEC, low BW and low FS significantly increased the risk of mortality. WEC > 1200 epg significantly increased risk of mortality in summer (risk ratio 3.76) and autumn (risk ratio 3.61) compared with the reference group. Risk of mortality increased 1.1-fold for each kilogram unit decrease in BW and 7-fold for each unit decrease in FS.

CONCLUSIONS

Mortality of Merino ewes can be significantly reduced by management methods that reduce WEC, maintain BW and increase the FS. For Merino ewes on the Northern Tablelands of NSW, improved animal welfare and economic benefits may be achieved by maintaining sheep with WEC < 1200 epg, BW > 35 kg and FS > 2.5.

Imaging the spine for tumour and trauma--a national audit of practice in Irish hospitals

BACKGROUND AND PURPOSE

The provision of appropriate spinal imaging in cases of acute injury as a consequence of trauma or tumour is becoming ever more challenging. This study assessed the use of multimodal radiological investigations in the management of spinal cord compression as a result of trauma and metastatic cancer in all major Irish hospitals.

METHODS

We conducted a questionnaire of thirty four hospitals in an effort to assess the provision of these services to patients with possible spinal cord compromise. In all public hospitals the Emergency Department and/or the Orthopaedic Registrars were contacted and asked a series of questions relating to spinal clearance, spinal clearance protocols, CT and MRI scanning facilities and on site orthopaedic services.

RESULTS

All centres participated in the study. 67.64% of centres routinely used a protocol in spinal clearance. In 87% of hospitals the Emergency department were responsible for clearing the spine. 85.3% of hospitals had CT availability during normal working hours (9-5) dropping to 47% availability after hours. MRI was available in 50% of hospitals, with surprisingly just two centres providing out of hours MRI imaging services.

CONCLUSION

The provision of radiological services in the management of suspected spinal injuries in Irish hospitals is inadequate in comparison to international best practice. This is most marked in relation to CT and MRI.

Integrated parasite management for sheep reduces the effects of gastrointestinal nematodes on the Northern Tablelands of New South Wales

An experiment was conducted over 2 years on six commercial farms to quantify the costs of gastrointestinal nematode parasitism on grazing Merino ewes on the Northern Tablelands of New South Wales. To determine the effect of worm management practices, three farms implemented integrated parasite management (IPM) strategies and three farms continued to implement regionally typical industry practice (TYP). On each farm, 120 ewes born in 2006 and 120 mature age ewes were selected at shearing in 2007. Of these, 60 in each flock were serially treated with anthelmintics (CAP treatment) to suppress worm populations and the other 60 ewes were managed according to their respective farm management strategies (NOCAP treatment). Among NOCAP ewes, worm egg counts were significantly reduced over both years by IPM compared with TYP despite IPM farms requiring fewer anthelmintic treatments (3.5 vs 4.5 per year). In Year 1, mortality of sheep because of worms (CAP vs NOCAP) was significant on TYP farms (10.5%, P < 0.01) but was not apparent on IPM farms. Throughout the study, NOCAP ewes had significantly lower growth rates (–2.8 ± 0.1 kg/year, P < 0.01), produced less greasy wool (–170 ± 20 g, P < 0.01) and had reduced fibre diameter (–0.28 ± 0.05 μm, P < 0.01) when compared with CAP ewes. These effects were apparent for both TYP and IPM management. The results confirm the significant production loss caused by worms in a northern, summer rainfall region and show that IPM reduces the effect of worms and frequency of anthelmintic treatment compared with typical methods currently used by the industry.

A case of organic solvent exposure and temporal lobe demyelination

A 42-year-old, previously healthy man, developed dizziness and headaches. A CT scan revealed areas of demyelination in the left temporal lobe. He had been exposed to large amounts of organic solvents for most of his working life and as other possibilities could be excluded it was suspected that this was the cause.

Systemic, pulmonary, and coronary hemodynamic effects of labetalol in hypertensive subjects

Long-term therapy with oral labetalol, an alpha- and beta-blocking agent, has been shown to effectively lower blood pressure and heart rate without decreasing cardiac output. We examined the hemodynamic effects of the acute intravenous administration of labetalol in nine hypertensive patients. Labetalol (0.6 +/- 0.1 mg/kg) promptly reduced arterial pressure, heart rate, and systemic vascular resistance without change in stroke volume. Heart rate responses to passive tilt and the Valsalva maneuver were significantly blunted. With isometric exercise, heart rate and mean arterial pressure increased significantly during labetalol therapy but less than in the pre-labetalol phase. In eight patients oral labetalol therapy was continued for six weeks (mean dose 1,050 +/- 105 mg/day), and hemodynamic evaluation was repeated. During oral labetalol therapy, decreases in arterial pressure and heart rate were sustained. Systemic vascular resistance was reduced in five of the eight patients. Hemodynamic responses to tilt, Valsalva maneuver, and handgrip were similar to those during intravenous administration. Coronary blood flow decreased, but coronary as well as pulmonary vascular resistances were unchanged. These data show the efficacy of intravenously administered labetalol in lowering blood pressure and systemic vascular resistance promptly. With long-term oral therapy, decreases in blood pressure are sustained. Labetalol does not appear to have significant effects on pulmonary or coronary vascular resistances.

Acquired dysfibrinogenemia in a hemophiliac with hepatoma: resolution of fibrinogen dysfunction following chemotherapy

A 17-year-old male with previously undiagnosed congenital Factor IX deficiency (13%) presented with gastrointestinal bleeding and a hepatic mass. Prolonged thrombin and Reptilase times, which partially corrected with CaCl2 and a discrepancy between thrombin-clottable and immunoreactive plasma fibrinogen, suggested a dysfibrinogenemia. Laparotomy disclosed metastatic hepatoma. Adequate hemostasis was obtained with clotting factor replacement, but wound healing was delayed. Patient fibrinogen purified with 2.1 M glycine migrated normally on immunoelectrophoresis and 7.5% polyacrylamide-SDS gel electrophoresis. However, fibrin monomers prepared from purified patient fibrinogen displayed impaired aggregation at high and low ionic strengths when compared with fibrin monomers from normal and control Factor IX deficient subjects. Aggregation of normal monomers was delayed when mixed 1:1 with patient monomers. Fibrinopeptide release was normal, and total sialic acid content was similar to that of normal and control fibrinogens. Chemotherapy, consisting of 5-FU given via intra-arterial hepatic infusion, was accompanied by significant transient clinical improvement which coincided with correction of thrombin clotting times and fibrin monomer aggregation. Reappearance of fibrinogen dysfunction occurred with clinical deterioration prior to death from metastatic hepatoma and sepsis. This case is the first to corroborate the postulated tumor marker role of dysfibrinogenemia in a patient with hepatoma by documenting a direct relationship with response to chemotherapy.

Characteristics of inhibition of pancreatic secretion by isoproterenol

The effect of isoproterenol on pancreatic secretion stimulated by the octapeptide of cholecystokinin (OP-CCK) was studied in dogs with gastric and pancreatic fistulas. Special precautions were taken to prevent entry of gastric acid into the duodenum and reflux of duodenal content into the stomach. OP-CCK increased volume and the outputs of bicarbonate and protein from the pancreas. Isoproterenol inhibited these pancreatic responses to OP-CCK, and the degree of inhibition was dose related. Propranolol blocked the inhibitory action of isoproterenol completely. Analysis of data by Michaelis-Menten kinetics revealed that there was competitive inhibition of protein output with noncompetitive inhibition of bicarbonate output. The experiments show that isoproterenol inhibits OP-CCK--stimulated pancreatic secretion by a beta-adrenergic mechanism. The kinetic analysis suggests that the intimate mechanisms involved in inhibition of protein and bicarbonate output by isoproterenol are different.

Canine gut receptors mediating pancreatic responses to luminal L-amino acids

Pancreatic protein and bicarbonate outputs were measured in dogs with pancreatic fistulas receiving intravenous secretin while individual L-amino acids or mixtures of L-amino acids were perfused into proximal intestine, Both phenylalanine and tryptophan were potent stimuli of pancreatic secretion; alanine, leucine, and valine increased protein outputs but their effects were small and not statistically significant. Six other amino acids were ineffective. Tryptophan perfused together with phenylalanine augmented responses to phenylalanine; methionine, ineffective when perfused alone, did not alter responses to phenylalanine when perfused with the latter. Responses to phenylalanine perfused at concentrations above 8 mM were dependent on load and were mediated by lengths of proximal bowel greater than 10 cm.

Canine pancreatic responses to intestinally perfused proteins and protein digests

Pancreatic bicarbonate and protein secretory responses to intestinally perfused proteins or digests of proteins were measured in dogs with chronic gastric and pancreatic fistulas when luminalpancreatic protease concentrations were reduced to undetectable levels. Protein digests were analyzed for amino acid content, and various other indirect met-ods were used to assess the composition of the digest mixtures. Of five undigested proteins, none evoked more pancreatic secretion than a control perfusion with saline. Peptic digestion of these same proteins converted four of them to polypeptides that were poten stimuli of a pancreatic juice similar in HCO3-/protein ratios to that evoked by luminal amino acids. Dialyzed peptic digests of one of the proteins, bovine serum albumin (BSA), retained potency. Likewise, digestion of BSA with endogenous or exogenous pancreatic proteases converted the protein to a stimulus about equipotent with the peptic digest, though the composition of the pancreatic digests differed markedly from that of the peptic digests. We conclude that a) luminal peptides of four or more amino acids can stimulate the pancreas and b) during protein alimentation a wide array of luminal protein products may evoke pancreatic secretion.

Canine pancreatic response to intestinally perfused oligopeptides

Although older work indicated that luminal peptides are stimulants of pancreatic secretion, these earlier experiments were performed with crude peptide mixtures containing amino acids that are also known stimulants. Furthermore, no information was provided about size or composition of stimulating peptides. For this reason, the problem was reinvestigated with commercially synthesized oligopeptides in dogs equipped with chronic gastric and pancreatic fistulas. Synthetic peptides at 30 mM concentrations were perfused into the proximal bowel when luminal pancreatic proteases were reduced to undetectable concentrations and dogs were receiving intravenous exogenous secretin infusions. Increases in pancreatic outputs of protein and bicarbonate were measured. Of the peptides tested, only glycylphenylalanine, glycyltryptophan, and phenylalanylglycine stimulated, whereas both di- and triglycine were without effect. It was concluded that some, but not all, oligopeptides in the gut lumen are stimulants of pancreatic secretion.

Pancreatic secretion in response to an elemental diet and intravenous hyperalimentation

Pancreatic exocrine responses to oral and intraduodenal administration of an elemental diet and to an intravenously administered hyperalimentation solution were determined in dogs with fistulas of the stomach and pancreas. Administration of an intraduodenal elemental diet prevented the responses to water and bicarbonate seen with oral administration but did not prevent the protein response. Intravenously administered hyperalimentation solution produced only minor effects on pancreatic secretion when compared with the elemental diet.