The tests are in ....

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Joy of Texas

Well-known member
Nov 13, 2007
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As you all know we have a alot of problems this year with cows dying. Well,had alot of tests run and it came back. Not enough magnesium.
Even though we have extra mag out not counting lick tubs,salt , mineral blocks and loose minerals. We are not the only ones having this problem this year. A man stopped by yesterday ,while we were loading up the calves. He said he has lost 30 head now. The vet told him the same thing. Not enough magnesium. This is a county wide problem from what I understand.
In order to save what few cows I have left. I decided to pull all the calves off the cows. I'm not going to sell them yet. Some are just a couple of weeks old. So I wouldn't make nothing on them.
A question: How much mag does a cow need in a day ?
Article in March 21 Cattle Today says cattle need 13-15 grams Mg per day. They suggest 8-12% mg as a supplement or 2.5-3.5 year round. I use the same mineral year round with 4% mg and have not had a problem in years. Check the cattle today article for more info on grass tetany.
Wow, I am so sorry to hear this.
Did the vet give you what the level was and what it should be? This would help you to determine how much they need to get back upto par.
Once you get the info from the vet, go to a nutritonist, even the maker of your mineral and they would be able to help you out. They would be able to get the mag up to par then help you maintain it.

If you have gone this far in getting testing done, continue with the proffessionals to get your herd better as quick as possible.
did the vet tell you to pull the calves?
NOt to minimze what you are going through, but that might be premature. It might cause a whole lot of stress compounding the problem.
Joy.. that's a new one to me also! What part of Texas are you in? I've never heard of anyone losing cows or calves from low mag! We do use a high mag mineral in the spring, but don't start using it until the first green starts coming on, and then switch to a regular cow calf mineral the first part of June. I wouldn't think pulling the calves early would have any impact either way, but perhaps your vet can recommend on that.
I've never heard of anyone losing cows or calves from low mag!

Low mag is implicated with milk fever and I def. have lost cows on this farm to low blood magnesium! Usually a calving problem, but in high potash (effluent) paddocks I've found milk cows flat out without warning. Then autumn, late lactation, more cows going down ... blood test showed low mag.
Dairy cows more susceptible of course because greater stress/milk yield.

I use magnesium oxide, in an all-grass system. The dose per cow straight down the throat is 30 grams MgO per day. Dusted on the pasture or over feed, it's 100 g (4 oz) per cow pre-calving, probably only fifty at other times of the year.
MgChloride can be added to water at 60 g/cow/day but needs to be introduced gradually and this is only half the requirement pre-calving/early lactation so needs to be supplemented in another way as well (but for beef cows half dose is possibly enough).

I wouldn't be pulling calves. The magnesium needs to be given directly to the cow, not free-choice. High potash feeds/pastures can cause Mg deficiency - I've been told balancing the potash with salt can be effective, never done it myself. The salt is spread on the pasture as fertiliser.
Mag chloride can be dissolved in water and sprayed on pasture, but it's nasty on gear - corrosive.

I'm not too sure what the treatment rate is for grass tetany as opposed to straightforward milk fever. The injectible calcium bags with added mag I'm pretty sure contain 60 g MgCl, but I've also been told that's not enough if magnesium deficiency is the main problem. For a 'preventative' calving drench I start with double the reccomended rate - 60 g MgO, 100 g CaC04 (limeflour), 1 - 200 g molasses - and give them that once daily till the danger period is over. It is possible to overdose them on magnesium (they will scour and look very relaxed/dopey).
Well, I don't know that's what we are told what's wrong. See it doesn't make since because we have all their minerals plus out. I have been in the office when clients come in. They are having the same problems we are. I know it's not worms or liver flukes,they have been tested and treated.
We did pull all the calves. I brought them all home and will keep them a few months. So I guess I will see what happens.
So you're going to pull 2 - 3 week old calves off mama. Going to bottle feed them, sell them or what? You would probably be better off selling cow/calf pairs.
grannysoo":34ku4nre said:
You would probably be better off selling cow/calf pairs.

If you take your cow/calves to the sale barn, and they die, you will never sale another cow.
sorry to hear about all your bad luck say you have hi mag in the tubs an other minerals.but have you also got out the loose himag minerals in all pastures.if so then it sounds to me like your cows arnt consuming enough minerals.
Joy, we've had trouble over the years with grass tetany, which is what this sounds more like to me. We've only had trouble when the burr clover comes on lush however.. even with mag mineral out free choice. I've never lost more than one (which of course is enough) but I've never had a calf be affected.

What area of Texas? I'm curious because I don't know of anyone here that's had a problem.
You might try putting out a hi-mag mineral with at least 10% mag and add some cottonseed meal or dried molasses to it to make it more attractive to the cattle and increase intake a bit.

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