Needle Size for Cattle Blood Draw

There's something weirdly satisfying about pulling blood…

Or maybe it's just me.

Actually, it probably IS just me.

I guess it all started during my two years as a Vet Tech… I learned to pull blood from a lot of different critters, and got pretty proficient at it, if I do say so myself. My skills have gotten a little rusty, but they still have come in handy the last few years when we've drawn blood to pregnancy test our cattle.

Now, I know this post will be completely and utterly non-applicable to most of you, so feel free to click over and read about canning beef stew instead. However, when I mentioned this topic to my newsletter list I got a very positive response from folks who were interested in learning more, so I figured I'd write up a post just because my newsletter peeps are the BEST. 😉

First off, let's cover a few of the basics.

Why Would You Pregnancy Test Cattle in the First Place?

When I first brought up this topic to my readers, I got a whole lot of stories from disappointed homesteaders who had assumed their cows were bred, only to have the due date roll around and find out the cow was open (not pregnant) the whole time.

And that, my friends, is why preg-testing is awesome.

Preg-testing will give you a definitive answer so you can then either re-breed the cow, or potentially cull them. It's crucial for large producers to preg-check as it's extremely inefficient to feed hundreds of "hopefully pregnant" cows for months, only to find out they never got pregnant to begin with. And even if you're just small-potatoes cattle owners like we are, I still want the chance to re-breed my cow in the same window of time without waiting 10 months to find out if our artificial insemination efforts were successful.

(And no– you can't always expect to easily "see" the pregnancy in your cow. There have been many years where it was tough to tell our cattle were pregnant until their udders started really filling up– and that's usually not until late in pregnancy.)

Palpation vs. Blood Tests

Most large cattle operations around us simply schedule the local veterinarian to come out and preg-test big bunches of cattle at once.

A skilled vet can very accurately determine pregnancy via rectal palpation (yup– sticking an arm "up there"). It only takes a matter of seconds and it doesn't hurt the cow. It's fast and efficient.

Since we only have a small bunch of cattle, we generally haul our cattle to the vet office to be palpated. But we've also starting drawing blood and sending it to a lab to be analyzed. Why? Because blood tests can detect pregnancy a bit faster than palpation can. You can do a pregnancy blood test at 28 days post-breeding, while you must wait till around 40-days post breeding in order to have a cow palpated.

Sometimes that doesn't matter, but other times, detecting just a bit earlier can help you be ready to re-breed quicker, just in case.

Another advantage to using a blood test to determine pregnancy is that you don't have to haul any animals to the vet. This can be a big advantage for folks who don't have easy access to a trailer.

We'll personally continue to use both methods, but today I thought I'd show you how we draw blood from our cattle to send into the lab, just in case it might come in handy for you.

Supplies Needed

For each cow you are bleeding, you will need:

• 3 cc syringe (you can use one that's slightly larger, but this size is easy to handle.)
• Needle (I usually use an 18-gauge or 16-gauge needle– 3/4″ or 1″ in length is fine)
• Red-topped blood collection tube (get these at your local feed store or vet office)

(You can also use a Vacutainer set-up for drawing blood if you're more comfortable with that.)

How to Tail Bleed a Cow

(Note: You can also pull blood from the jugular vein of a cow, but I think the tail method is easier if you're a beginner.)

1.Restrain the cow.

If you have a squeeze chute or head catch, that's ideal. If not, hopefully your cow is quiet enough to be able to able to be tied with a halter while you draw the blood. If your cow is wild and you don't have a head catch or chute, you'll probably want to skip this method altogether. Oakley, our milk cow, will allow us to pull blood while she's just standing tied with a halter, but I definitely wouldn't try it with our other cattle. They go into the head catch to keep everyone safe.

2. Clean the underside of tail.

A swipe with a bit of rubbing alcohol is ideal.

3. Pull the tail straight up.

4. Find the midline groove about 3-5 inches from the base of the tail.

You'll be able to feel the "valley" with your fingers. The cap of the syringe is pointing to the groove in the above photo.

5. Insert the needle about 1/2″ into the groove, perpendicular to the tail.

6. Draw back on the syringe.

If it doesn't immediately fill with blood, carefully redirect your needle.

7. Once you have 2cc of blood, remove the needle and place your finger over the hole for a few seconds to stop the bleeding.

8. Place the blood in your red top tube.

Label the tube, and follow the instructions from the laboratory you're using for packaging and shipping.

And that's it! I usually have the results emailed to me, and then come only a day or two after I ship the blood off. Super easy.

The Lab We Use:

We've used local BioPYRN affiliated laboratory the last few years, and I've been super happy with them. BioPYRN also has great instructions on their website, and you can also use the lab locator on the main page to find a facility close to you.

(I'm not affiliated with BioPYRN, and I don't get a dime for recommending them. I just use them and like them.)

Your Garden's Best Kept Secret!

Cover crops are an incredibly underutilized, very affordable way to fertilize your soil, decrease erosion, and increase organic matter. Learn which crops are best for your garden, plus a step-by-step process so you know exactly WHEN and HOW to plant them! Grab the full-color cover crop PDF here (it includes my weekly Homestead Toolbox Newsletter, which gets rave reviews from busy homesteaders!)-->

Needle Size for Cattle Blood Draw

Source: https://www.theprairiehomestead.com/2017/03/draw-blood-cattle-tail.html#:~:text=For%20each%20cow%20you%20are,feed%20store%20or%20vet%20office)

Share this post