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Protecting your equipment
Sheath knives in a plastic scabbard to p rotect the edges; don’t just keep them loose in a
toolbox. Dry steels thoroughly after use to prevent rust. Store whetstones in a thick woolen sock to prevent dents and chips.
Choosing a knife and steel
When choosing knives, get a skinning knife for the rough work involved in dismembering the carcass and a boning knife for the finer dissection of viscera and tissues samples
Figure 7.7. Shorter knives with blades 12.5 to 15 cm are better – easier to sharpen,
store, and less fatiguing on the wrist. They should have solid plastic handles so that they are easy to disinfect.
Choose a steel with a plastic handle, an “O” ring, a hand guard and with the steel section being 25 to 30 cm long. Smooth steels are fine if a good job has been done with the
whetstone. They are used to realign microserrations bent during cutting. Fine to medium grooved steels are good for all round use. Used gently, they realign bent microserrations;
used forcefully they remove metal and may sharpen a dull edge but may set back a honed edge. Coarsely grooved and diamond steels can remove a lot of metal and wear
out a blade very quickly.
L R
Figure 7.7: A short, plastic handled skinning L and boning R knife
7.2 Taking necropsy photographs on cattle ships
7.2.1 Digital camera specifications
The following minimum specifications are desirable: 1-2 megapixel resolution or higher
Higher resolution photographs are generally better but also take up more memory. 1 to 2 MB JPEGs will generally be adequate.
minimum 128 MB memory card and at least one spare card in case of mishap. robust and splash-proof
51 Macro capacity close up shots is desirable but not essential
7.2.2 Photograph requirements
The photographic shots required are as follows: 1. Dead cattle in situ before they are relocated or dismembered
with the case number
on a small placard or the NLIS tag number captured in the photograph.
2. Each of the major body cavities i.e. oral, thorax, abdomen at end of display stage see necropsy protocol even if no lesions are evident.
3. Organs and tissues where there are gross changes suspected to be caused by disease
Where there are gross changes suspicious of disease, take initial photos of the organ showing surrounding tissues for context, then take a close up showing the lesions in more
detail.
The camera can be protected in a zip lock plastic bag. Photographs are taken through the zip lock opening as required.
It is desirable to have someone other than the operator take the photographs during the necropsy
– to save time.
7.2.3 Tips for good photographs of suspect lesions
Remove blood to increase contrast. Use props to position the lesion e.g. drape the opened abomasum over a bucket to
photograph an ulcer or ostertagia nodules, or raise the liver with a hidden specimen container or wad of paper to emphasise a thickened edge.
Demonstrate size with a coin or key rulers tend to be obtrusive Minimise reflections from wet shiny surfaces by drying with a paper towel and having
torch or port hole light directed so that any reflection is away from the photographic axis. Use a clean, dry, light-coloured background whenever possible
7.2.4 Saving and making copies of photographs
