Lost 3 to blackleg

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I used to think that cows that had been properly vaccinated as calves were good for life. But... I've seen cows with good calfhood vaccination histories die with classic blackleg lesions ... and almost all were in an estrus synch program. Seen enough of them, that we started boostering adult cows in our herd every 3 years or so... it's cheap insurance.

Not all cases will have crepitance (bubbles) that you can feel under skin or in deep muscle tissues. I've posted a bunch that had lesions only in the heart or diaphragm. Even if you cut into big muscle masses in the limbs, you could miss the diagnosis... most will have lesions in big muscle masses - with the characteristic dry, red-black appearance and separation of muscle fibers by gas bubbles, with a characteristic 'rancid butter' smell... but not all... if you don't look at heart, diaphragm, tongue, on those, you may miss it.
Most cases of blackleg I've seen started with a prostaglandin injection. I still recommend annual boosters for cows; the vaccine is so cheap I don't see a reason to cut corners with it.
 
Why do you think we see black leg in some, but not all, animals in the same program and the same environment ?

Since it is in the dirt - - can they ingest the BL bacteria in both water and forage ?
They can get it from just about anywhere. I've seen blackleg in dairy cows that have never had dirt under their feet, presumably from dust in the feed.

The bacteria that cause blackleg can remain dormant in the muscle of the animal for a long time. It will not replicate in the presence of oxygen, so it generally needs some form of tissue damage to get started. This can be an injection site, bruises from injuries, etc. If you have one animal with clinical disease, it's safe to say that all of the rest of your cattle have been exposed to the spores.
 
The bacteria that cause blackleg can remain dormant in the muscle of the animal for a long time. It will not replicate in the presence of oxygen, so it generally needs some form of tissue damage to get started. This can be an injection site, bruises from injuries, etc. If you have one animal with clinical disease, it's safe to say that all of the rest of your cattle have been exposed to the spores.
So vaccination can trigger black leg ?
 
Back when i was 15, i saw my first dead calf. I had just started dating my now husband. When i got to his house, they had just found a big dead steer.. My husband worked for a vet and said it was blackleg. He showed me how to feel bubbles under the skin. I still remember that like it was yesterday.
Feels like bubble wrap once you feel it you can't forget!
 
They can get it from just about anywhere. I've seen blackleg in dairy cows that have never had dirt under their feet, presumably from dust in the feed.

The bacteria that cause blackleg can remain dormant in the muscle of the animal for a long time. It will not replicate in the presence of oxygen, so it generally needs some form of tissue damage to get started. This can be an injection site, bruises from injuries, etc. If you have one animal with clinical disease, it's safe to say that all of the rest of your cattle have been exposed to the spores.
That is food for thought. A spot of new dirt will cause a lot of pushing and butting of cattle. Spring calves not vaccinated will often get it late summer here, about the time they start getting decent horn nubs and the fight for pecking order gets stronger. All situations that could lead to bruising.
 
Well, now I'm going to talk to my vet about vaccinating the cows, bulls & retained heifers. Cows & retained heifers were all born & raised on this ranch but haven't had clostridial vaccinations since they were calves. Generally, just an autogenous (custom) pinkeye and Vira Shield 6+VL5 HB. That said, we usually work them around end of May & early Oct, so passive immunity wouldn't help their newborn calves the following Spring. Very informative - and somewhat scary thread. BTW, calves get everything but the kitchen sink but only Inforce 3 prior to appx 3 months.
 
FYI, anything you're giving to cows hoping to pass antibodies along in colostrum needs to be given not less than 8 weeks or so prior to calving... maximum colostral antibodies are 'set' by 5 weeks pre-calving... anything given after that point won't be in the mix, for all intents & purposes.

We've been giving cows annual booster shots when we castrate bull calves (about 1-2 months old) in December, but sounds like for the benefit of the calves, we may be better off giving cows booster vaccines 2 months prior to calving, for the calves to get the most benefit from their mamas colostral antibodies. Thanks Lucky_P.
 
Well, now I'm going to talk to my vet about vaccinating the cows, bulls & retained heifers. Cows & retained heifers were all born & raised on this ranch but haven't had clostridial vaccinations since they were calves. Generally, just an autogenous (custom) pinkeye and Vira Shield 6+VL5 HB. That said, we usually work them around end of May & early Oct, so passive immunity wouldn't help their newborn calves the following Spring. Very informative - and somewhat scary thread. BTW, calves get everything but the kitchen sink but only Inforce 3 prior to appx 3 months.
Why do you say that passive immunity won't help the following spring? They should be vaccinated no LESS that 8 weeks or MORE from calving. We do it about 4-6 months before calving.... they go out to pasture and get bred, and get brought through the chute about 4-6 months after being out there... so preg anywhere from 2 to 6 months....
Oct would be perfect to give the cows a blackleg shot.... plenty of antibodies by the time they calve in March....
 
Why do you say that passive immunity won't help the following spring? They should be vaccinated no LESS that 8 weeks or MORE from calving. We do it about 4-6 months before calving.... they go out to pasture and get bred, and get brought through the chute about 4-6 months after being out there... so preg anywhere from 2 to 6 months....
Oct would be perfect to give the cows a blackleg shot.... plenty of antibodies by the time they calve in March....
Circulating antibody levels peak 2-4 weeks after vaccination and slowly taper off from there. How long they last is variable depending on the vaccine and individual cow. You're probably providing adequate colostral antibodies by vaccinating six months before calving, but doing it a little closer would have those numbers higher at a time when you really want them.
 
Why do you say that passive immunity won't help the following spring? They should be vaccinated no LESS that 8 weeks or MORE from calving. We do it about 4-6 months before calving.... they go out to pasture and get bred, and get brought through the chute about 4-6 months after being out there... so preg anywhere from 2 to 6 months....
Oct would be perfect to give the cows a blackleg shot.... plenty of antibodies by the time they calve in March....
What Buck said. Also why I stopped vaccinating with Scour Bos. I used to vaccinate 6 weeks prior to calving, but bad/unpredictable weather & rounding 'em up yet again was a PITA. Plus, I got off track from a tight calving window for a few years and ended up with Spring through Fall. I'm back to45 days (with maybe a couple stragglers), so it's a good time to revisit my vaccination protocol.
 

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