time to replace lost blood

[regolith]

Temperamental connection isn't letting me follow any links: https://www.google.co.nz/search?output= ... very&btnK= but the summaries look pretty bad.

Got a cow injured her tail on Christmas day, lost a lot of blood. The rest of the herd were chasing her around and riding her and since she was still seeing off the occasional bully yesterday morning, I pulled her out of the dairy herd to rest for a day or so, just milking her once a day she's not giving a lot of milk since this incident.

It's been four days since she lost that blood - I couldn't say how much but half the herd was thoroughly splashed in it. She looks okay just a little dull, milk isn't improving; she's ten years old. I'm presuming she's going to need to replace a lot of blood cells before she's really right again.
Any idea how long that might take? If it's more than a week or so I think I'd be better to dry her off and give her till next calving to recover.

 

[Nesikep]

http://www.ahc.umn.edu/rar/blood.html
Not exactly what you or I was looking for, but here's an excerpt. They are talking about taking blood from an animal deliberately, to a maximum of 1% of the weight of the animal.. so I'll say 5L for a cow? It sounds like she may have lost more, but it's pretty hard to tell when it gets spread all over

Single Blood Draw, Not Repetitive

As a one time large volume blood draw with concomitant IV fluid replacement, a maximum 2% of the body weight of a healthy adult animal can be removed, as long as fluid replacement consists of warmed, isotonic fluids and both the fluid replacement and blood withdrawal are slow and steady.
Single Blood Draw Repeated Multiple Times

For multiple blood draws separated by a period of weeks, a maximum of 1% of the animal's body weight can be removed, i.e., 0.15 ml from a 15 gram mouse; 50 ml from a 5 kg cat; 400 ml from a 40 kg dog. A 14 day recovery period is needed for the average healthy adult animal to recover from this blood loss. Although the blood volume is restored within 24 hours after blood withdrawal, two weeks Is needed for all constituents of the blood to return to normal. If less than the maximum amount of blood is withdrawn the animal will replace blood constituents at the rate of 1 ml/kg/day.
Multiple Blood Draws
If blood must be drawn more frequently than once every two weeks, a total of 0.5% of the animal's body weight can be removed each week with this total volume being spread out over the entire week if needed.
Monitoring
By monitoring the hematocrit (or packed cell volume-PCV) and/or hemoglobin of the animal, it is possible to evaluate whether the patient has sufficiently recovered from a single blood draw or multiple blood draws. After a sudden or acute blood loss, it takes up to 24 hours for the hematocrit and hemoglobin to reflect this loss. This means that after a 1% of body weight blood loss without fluid replacement, an animal's hematocrit will not show a measurable drop for several hours, and will not stabilize for 24 hours. After 24 hours although the blood volume will normalize, the number of red blood cells (hematocrit) will be measurably reduced. In general, if the animal's hematocrit is less than 35% or hemoglobin concentration is less than 10 g/dl it is not safe to remove the volume of blood listed above.

 

[regolith]

Thanks. So about two weeks *with* fluid replacement.

I had another cow do this last year and she was fine, though the pasture was scarlet. In this instance it's really hard to tell how much she lost, nothing on the ground just all over her and a lot of the other cows.

 

[Nesikep]

I think the fluid replacement is mostly important to maintain blood pressure, and since she's gotten over the initial trouble, I think she's fine on that front as they say the blood *volume* is usually restored within 24 hours. They say the contents of the blood take longer, and may require iron supplementation... another site suggested higher dietary protein as well.

It sounds like she went through a fair bit of stress.. I'd probably give her a week before making a decision on drying her up, and see if her milk improves over that time.

Good luck with her :)

 

[regolith]

Her milk was up this morning and she was keen to avoid being drafted back out on her own
looks like she's on the right track now.

 

[Putangitangi]

How on earth did she injure her tail that badly and why do your cows have a tendency to do that, since this is the second one?

 

[wbvs58]

Regolith, many years ago I used to bleed a lot of racehorses usually at the request of trainers. I would take out a 10 litre plastic bucket full, some I would monitor the pcv afterwards and it was surprising how little it affected it usually only dropping about 3 %age points a day or two after and would be back up within 2 weeks and usually go higher than it was before. they have a big reserve in the spleen and can mobilise areas to build blood that have been lying dormant. The horses would stay in work afterwards and their performances would usually improve especially older geldings that may have trained off a bit. It was a usefull technique though frowned upon by modern medicine.
I have heard of old stockman that would pull out their penknife and sever an artery below the knee on their horses before turning them loose in a paddock for a spell.
Ken

 

[regolith]

I have no idea.
Sometimes you see a ring close to the bottom of the tail that grows no hair. The first cow to lose the tip of her tail, it snapped there. I never saw one on this cow. Neither have ever been injured from dag build-up that I can recall... and not trimming the dags frequently enough certainly *will* set up some pretty nasty infections.
Had one in the spring catch up her switch and yank it out, didn't cause heavy bleeding but that was enough to make the blood run.

 

[Nesikep]

Our cows trim their switches by having one step on it while they get up... I've never seen any of them lose blood from it.

 

[Quigly]

If she is starting to improve, she will probably do alright, but monitor her closely for the next couple days, as I'm sure you are planning on anyway. I have seen steers that were cut poorly, lost a large volume of blood in the next 24 hours, had the bleeding stop, but then died up to 4 days after bleeding ended. Stress/activity can exacerbate your problems with these animals as it increases oxygen demand in an animal that already has poor oxygen transport.

Her blood volume is likely improved at this point but she will have somewhat thin blood. The spleen and bone marrow can kick out a lot of blood cells during these events but not as quickly as the body can add fluid to the blood. In future bleeding events, I would consider doing a blood transfusion any time an animal is acting depressed following blood loss. Have you vet evaluate them and they may get by with just additional IV fluids, but a transfusion can really help some of these animals, and it is not that challenging to do.

 

[milkmaid]

Horses have a tremendous splenic reserve of red blood cells. Cattle do not.

Blood loss in either horses or cattle >25% indicates a transfusion should be seriously considered. >30% and it's required. PCV (% of red blood cells in blood) typically doesn't change in horses with acute blood loss due to splenic contraction. It may or may not in cattle. Any PCV changes are typically not noted until >24 hours after the bleeding event.

I would not recommend deliberately bleeding horses or cattle.

In regards to the original question - I can't find an exact number but a 1-2 week regeneration time sounds reasonable to me.