Male Instructor: The procedure is very, very straightforward. I always just come
to the back of the animal and I come about a third of the way down, that way
I can count the ribs without catching that extra rib if they happen to have one.
Boy, you did get me a fat one, didn't you? [Students laughing.]
And the more obese they are, the more difficult it is as far as being able to
count your ribs. Okay. There's the third rib space. You're gonna come a third of
the way down the back, so about right here, I'm gonna clip about a 4 inch wide
square right at that space.
[Razor buzzing.]
Okay. First rib, second rib. [Razor buzzing.]
It's not gonna hurt him to lose a bit of extra hair. Make it a little bit wider
open and easier to see. Do a quick Betadine scrub.
I'll actually go down into the muscles between the ribs and deposit about
a CC and then as I pull the needle out, I'll leave myself a bleb under the skin
and that's exactly where I wanna go with the scalpel blade.
I'll give it a couple minutes to numb.
--Right here, because you've got the point the point that you stuck the needle in.
You'll have just a trickle of blood there. When you get ready to go in, just a
straight punch through the skin. That's all it takes. That leaves you a very, very
small hole in the skin that you don't have to close. There's no suturing,
nothing that you have to do at that point.
The biopsy needle has a notch in it, which is where your biopsy's gonna actually come
from. When you're going into the animal, you want the stylus slid all the way back.
That way, you've got a full, solid needle pushing through the intercostal muscles
and down into the liver. Once you get into the liver, then you push the stylus
forward, which opens up your notch.
I generally wiggle the needle a little bit to get the liver to kind of settle down
into that notch. Then you want to hold the stylus itself solid and you actually
advance the outer sleeve by pushing it forward towards the animal.
That has a cutting surface on this outside sleeve, so as you push it forward, it cuts
the liver down into that notch. Then when you pull it out and open it up, you've got
a piece of liver sitting in that notch.
Did everybody see that? Okay.
When you actually do the biopsy, you'll come in--I actually will touch
both sides of the ribs because I want to go halfway between the two ribs.
I'll actually aim at about fifteen degrees down and fifteen degrees forward and
just push into the intercostal muscles.
I actually will feel a little bit of resistance as it goes into the liver.
And then I just push the stylus forward and when I come out, I've got a piece of
liver. It is a very small piece of liver. I can actually reach down and grab
this biopsy. It comes up. That's not very much liver.
I can do a mineral profile on two of these true cuts, which gives me about thirty to
forty milligrams of liver tissue is all I get.
But I can do the full mineral profile on two to three of those very small pieces
of liver.
I generally ask that everybody tries to get me two true cuts.
I don't need to do any further prep. Everything is still clean.
Everything is still sterile. I have touched nothing with the needle that
wasn't sterile, so I'll just come right back to this same spot, come right
back between the ribs. Since I know that this animal's liver is in that position
because I got a good biopsy the first time, I remember how I went in the
first time.
It is a very, very simple procedure.
As soon as I have finished with that biopsy, then I will come back over to my
tray, I'll rinse my forceps, I'll put my biopsy needle into the tray, rinse it
back and forth both closed and opened.
At that time, I'll take my scalpel and put it into the alcohol because then
I'm ready to drop this animal out of the chute and load the next animal.
Every once in a while, they will do exactly as he's doing and decide to lay
down in the front end. If they do, or if you attempt to do the biopsy on an animal
that's laying lateral, you will have trouble.
The positioning of the liver because of the rumen--[Cow slamming chute.]
Because of the rumen and the fill of the rumen will actually shift.
Depending upon how much gas is in the rumen, when they lay down like that, it
may pull the rumen back if there's a lot of gas, in which case the liver will drop
a little bit. If there's not a lot of fill, then as they drop down like that
then the weight of the rumen actually pushes forward and actually pushes the
liver up and out of the way even more, and so because the rumen positioning is key
in the positioning of the liver, you want the animal standing as square as possible.
So if you have animals that keep laying down on you, unless you have to test
that specific animal, it's better to go to a different animal than to try to do
it. I've done enough of them at this point if I have an animal who lays down on me,
I very commonly will go ahead and do the biopsy and 90% of the time, I'm able to do
it without any complications, but every once in a while, if it shifts the
position of the liver enough, I don't like going in and probing just to see if I can
find a liver because then you have the potential of cutting vasculature, you have
the potential of cutting into the intestinal tract or into the rumen.
And, you know, why add the additional stress and additional risk to the patient?
Do not attempt it on the left side because the rumen pushes the liver to
the right. If you attempt to go in on the left side, if you get a liver biopsy,
you'll be extremely lucky because, if you've ever looked at the animals,
opened 'em up on a postmortem, the liver very rarely will cross mid-line to the
left side. It's almost always from mid- line over on the right side.
And it also has that cup in the side of the liver where the rumen's pushing on it,
and so you're shooting at a target that not only doesn't cross mid-line, so you're
going to be at the very end of your needle, you're shooting at a target that
may be this wide. Where the liver on this side, you're shooting at a target that may
have that kind of a size to it.
So it would be very difficult and very risky doing a biopsy on the left side.