Feeding of prohibited substances (swill) to pigs in Australia

Objective To assess current swill feeding legislation, swill feeding investigation practices by authorities and feeding practices of pig producers who trade via saleyards in eastern Australia in order to determine levels of understanding and conformance related to current swill feeding legislation. Method A three-tiered approach was undertaken to gather information on the feeding of prohibited substances (swill) to pigs in Australia. Firstly, a review of swill feeding legislation was undertaken to highlight the commonalities and inconsistencies between the various state and territory legislations in defining swill. Secondly, agricultural authorities were contacted in each state to gather information on swill feeding investigations undertaken in 2006. Finally, face-to-face interviews were conducted with 106 pig producers who traded pigs at one of six saleyards in eastern Australia to ascertain their knowledge of swill feeding and to determine the feeding practices of this sector of the industry. Results Areas of concern identified included (1) inconsistencies in the feedstuffs classed as ‘swill’ among states, (2) the number of producers who had been prosecuted for swill feeding in 2006 (n = 4 of 148 inspections), (3) the low knowledge base of producers who sell pigs at saleyards regarding swill feeding, and (4) the types of feedstuffs provided to pigs marketed at saleyards. Conclusion Our findings highlight the need for a consistent definition for ‘swill’ across Australian states and for improved awareness of swill feeding among producers, particularly those who market pigs at saleyards.     

Effect of acute haemorrhage on QRS amplitude of the lead II canine electrocardiogram

OBJECTIVE: To examine the effect of acute haemorrhage on the QRS amplitude of the canine lead II surface electrocardiograph (ECG). DESIGN: Ten adult racing Greyhounds were tranquilised, anaesthetised, positioned in right lateral recumbency and connected to recording electrodes of an ECG unit. Baseline six-lead ECG traces were recorded, and further traces were obtained after one unit (460 mL) of blood, and then a second unit, were collected from the femoral artery. RESULTS: There was a consistent and progressive reduction in amplitude of the QRS complex in all leads during acute haemorrhage. QRS amplitude in lead II after removal of two units of blood averaged 74% of the baseline voltage, with individual values of 61 to 91% (P < 0.0001). There were even greater reductions in QRS amplitudes in lead aVL during haemorrhage. In three additional dogs, reductions in QRS voltages were shown to be accompanied by reductions in end-diastolic left ventricular internal dimensions measured echocardiographically. Furthermore, the effects of haemorrhage on the QRS amplitude and echocardiographic measurements were reversed when circulating blood volume was restored by re-infusion of blood removed previously. CONCLUSION: Acute haemorrhage corresponding to an approximately one-third reduction in blood volume caused a substantial reduction in QRS voltage of the surface ECG. It is postulated that this resulted from diminished ventricular distension as a consequence of reduced venous return. A similar mechanism may account for the small-amplitude ECG complexes associated with pericardial effusion, severe dehydration and hypovolaemia.