Snake Bites?

Well this Texas heat and drought as yall know have been the toughest yet. 
To make matters worse we lost our 2nd cow today in less than a month.  Now she didn't starve, although its been very dry we are still one of the more fortunate ones that do still have some grass, and still good water.  Both well and tanks.

The first cow we lost was a bred older cow bred about 5 months.  The one today was a heifer we held back (last clubby types).

Wanted to get some of you guys ideas of what you think the causes.  We can't figure it out.  They've all been vaccinated properly and all.  We feed some syrup with the grass they have in the pastures.  They all seem pretty fat still and we check em daily. 
Our only guess is they got snake bit?  Maybe by a cotton mouth in the tanks?  They love to get out in the water and wade around?  I really didn't think a snake bite would kill a cow but that's all we can figure??  No signs on the body, but this heifer still had mud on her legs and was laying out in the wide open up a bit from the water.

Drought sucks... but this really does.  Are any of you out there losing any in this heat?

I've seen several cows and horses with snakebites, but they usually just swell ALOT and maybe abcess and drain.  I've got a cool picture of a horse that was bit.  His head is almost twice the normal size.I'll post it if I can find it.  I guess snake bites could kill them though.  Especially cottonmouths and possibly multiple bites.

i have seen a cootonmouth bite a good hog dog we had as a kid when we lived in texas and killed him as they will bite sevral times. we lost a heifer 2 years ago to a copper head bite. Will that is what the vet said

What if they just got really hot and drank too much water, is this a possibility?  I heard a story about a trailer load of cattle that came out of a drought area and they got to their destination and went and drank alot, which they weren't used to and several died.  The reason given was the water, too much at once, kind of like bloating I guess.

I wouldn't jump to a snake bite.  You generally should see significant swelling and often puncture wounds.  Also, most snakes in Texas aren't as toxic as those on the west coast.  Death can occur, but it is not nearly as likely.  

If any others die, I would recommend having them necropsied by your vet as soon as you find them.  Otherwise you are just playing the guessing game.  You can convince yourself of anything, but this won't help you or your other cattle.  

Snake bite is huge swelling, puncture holes, and drainage. Last summer we had a young weaning heifer get bit, and it was bad. Ended up messing up her hoof from the sloughing of hide and extreme swelling. Lots of antibiotics in her, and lots of drainage.

Well IDK, what does 'necrospsied' mean ccmmercial cow man?  I didn't see either one... husband did it makes me sick to see.
The over watering isn't a issue either since the girls all have water in places they know...no new hauls or anything like that.

Can they eat a bad weed or something in this drought?   

Necropsy is an autopsy for animals.

We had the same thing happen to two fully grown cows.
The first one died when we were at our county fair, someone came home every night to check the cows. One day, about the middle of fair, my mom went home to check them. Found one of our best cows, she just dropped dead. Fairly young cow. Just died.
The other just died last year, half sister to the first one. I checked them at about 4 one afternoon. She was perfectly fine. I walked up to her, rubbed on her like I usually do. About 9 I went to feed the show calves one last time. Found the cow about 30 feet from where I seen her earlier that day. She too just appeared to drop dead.
Still to this day we don't know what killed them

I'm from southern Ohio, and I've never heard of snakes getting animals that often if ever here.

One of our friends lost a 9 month old calf earlier this year, again no obvious reason the calf died. It was fine in the morning, then when they went out in the middle of the day it was laying dead. They had the vet necropsy it, and found out it had a massive heart attack. One of the atrium's had blown out. They would have never known the cause without the necropsy.

We get cows and calves snakebit every year and as someone said, they just swell up bad. Never have had one die.

Most likely it was anaplasmosis in this part of the world if it wasnt some type of respiratory disease.