21/10/2024
Liver Biopsy
This is one of those procedures that seems more difficult than it proves to be.
Site placement is crucial, the second large intercostal space cranial from the paralumbar fossa and a large hands breath down from the top of the ribs. I say large intercostal space as some cows have a vestigial or floating rib, which you can ignore.
Clip, scrub, and freeze a square roughly 15cm x 15cm. Photo 1 and 2. I have actually gone a bit too low in this one. Then, with a scalpel, nick a small 1cm hole through the skin only.
The video in 3 shows the biopsy needle being pushed through the different layers. Three muscle layers and then peritoneum. After peritoneum, you will actually be in thorax as the diaphragm reflects back at this point, so don't remove stylet yet, or you can cause pneumothorax. Feel the distinct pop as the point goes through the diaphragm. At the end of the video, you can see the needle moving up and down with the cows' breathing, which shows placement is correct.
Your needle is now hovering over the causal liver. Remove stylet, attach a syringe, and take several cores of the liver. Use syringe to apply negative pressure and remove needle with liver sample hopefully inside.
It's more straightforward than it seems, though it is weird to stand on a farm and wave a big f # off metal rod about inside of a cows abdomen.
We send these samples to the lab for a general profile, selenium, manganese, copper and cobalt. Liver biopsy is the only reliable way to assess copper status.
Top tip, make sure cows have had chance to fill up with food as much as possible, a full rumen will push the liver up against body wall.