Anesthetic waste gases in veterinary medicine: analysis of the problem and suggested guidelines for reducing personnel exposures

Anesthetic waste gases are a concern to veterinarians and their personnel. Investigations have shown that many of the anesthetic units used in veterinary medicine have leaks that contribute to operating room contamination. Many others do not have appropriate scavanging attachments to remove escaping gases. Personnel were frequently observed carelessly using equipment or handling anesthetic agents in a manner contributing to excessive exposure. Proper maintenance of equipment and careful use of gaseous anesthetic agents can significantly reduce waste gas levels and exposure of personnel.     

Behaviour and welfare of individual laying hens in a non-cage system

1. A leg band containing a transponder was fitted to 80 birds in a perchery containing 1,000 birds. 2. The transponder emitted a unique identification number when a bird walked on one of 8 flat antennae on the floor. The recording apparatus was used to measure the amount of time that each of the tagged birds spent on the slatted and littered areas in a 6-week period. 3. Some birds spent long periods of time on the slats, possibly as a means of avoiding repeated attacks. Duration on the slats was greatest in birds with the worst (as opposed to better) feather scores of the head, back and tail regions. 4. Birds that spent long periods on the slats were lighter than other birds at both 39 weeks of age and 72 weeks of age and had greater back, head and tail feather damage, consistent with these birds being victims of pecking. 5. Tagged birds received a social avoidance test outside the perchery at 39 weeks of age, which suggested that birds retreated to the slats in response to pecks rather than just to close proximity to other birds. 6. The failure to find that duration on the slats was related to anatomical indicators of stress (liver, spleen and bursa of Fabricius) suggests that retreating to the slats following pecking attenuates physiological stress responses. 7. We conclude that the provision of areas where birds in a large group can avoid pecking may improve the welfare of a minority of victimised birds.     

Interactions in postweaning production of F1 cattle from Hereford, Limousin, or Piedmontese sires

A 2-yr study was conducted to evaluate the interactions of castration, feeding length, and dietary CP on growth and carcass characteristics of male cattle (bulls and steers) that vary in expression of muscular hypertrophy. Crossbred cows were bred by AI to Hereford, Limousin, or Piedmontese bulls, which represented genotypes with normal, moderate, and hypermuscularity, respectively, but with similar mature weights. Male calves (131 in yr 1 and 120 in yr 2) were placed in pens with individual electronic feeding gates. Calves were fed growing diets until they reached 386 kg BW and then were individually switched to finishing diets for 90 or 132 d. Interactions were observed among sire breed, gender, and feeding length on carcass composition. Bulls were more efficient than steers in producing live weight gain. Length of finishing period accounted for a larger source of variation than gender for weight characteristics, whereas gender was the larger source of variation for carcass composition. Concentration or degradability of dietary CP influenced rate of gain from weaning to 386 kg. Interactions resulting from varying management on carcass characteristics among calves of different sire breeds indicate that unique strategies may be beneficial for the production of meat from these breeds.     

Renal pathology in working dogs in the South African National Defence Force

Urine analysis, serum biochemical profile and a cortical wedge biopsy for histopathological examination was performed on 42 South African National Defence Force (SANDF) dogs from around the country. The only significant finding on urine analysis and serum biochemistry was a relatively large number (16/42) of dogs with elevated serum inorganic phosphate levels. Histopathology revealed that only 9 of the animals had normal kidneys reflected in the wedge biopsy material, with over 50% of them showing signs of glomerular pathology (primarily mesangioproliferative glomerulonephritis). Other conditions detected histopathologically were haemosiderosis (47% of animals), focal nephrosis (2.4%), membranoproliferative glomerulonephritis (2.4%), focal interstitial nephritis (4.7%) and acute tubular nephrosis (4.7%). The lesions observed were of limited distribution and extent; this histopathological finding may account for the absence of significant abnormalities on urine analysis or serum biochemistry profiles. It appears from these results that a large percentage of the SANDF population would be expected to have mild renal lesions, but that these lesions are not severe enough to lead to clinical signs. The findings of this study are similar to those of randomly selected populations of non-military dogs performed in other areas of the world, which also demonstrated an unexpectedly high incidence of histopathological renal pathology in dogs considered healthy. These lesions may well, however, play a role in later life, and it is recommended that military veterinarians maintain an index of suspicion for renal disease, particularly glomerular disease. The aetiology of the histopathological lesions is unknown.     

Preanesthetic medications in ruminants and swine

The use of preanesthetic agents alone or in various combinations in food animals is complex. In addition to considering the pharmacokinetics and dynamics of the medications, one must give additional consideration to the animals's temperament, its physical condition, and its environment. Also, the potential of residues from meat and milk products of animals treated with preanesthetic agents must be considered.