It’s all about calcium!

It’s all about calcium!
By Katrina Roberts, Herd Health Veterinarian, Anexa Vets

“What if the basics don’t work on my farm? If despite doing the basics right you are still get >2-3% clinical down cows, then you may need to consider some other options. One option, which Anexa has developed is a special transition mix; which is a DCAD mineral mix with plenty of magnesium at a reasonable price. If you want to know if this mix will fit for your herd then please give us a call.”


Just because you don’t have cows sitting down with milk fever, doesn’t mean that low calcium isn’t limiting your herd’s potential.

On the day of calving a cow has to find a truckload of calcium to dump into the colostrum that she is producing. There is no way we can feed her enough calcium (and even if we could her gut couldn’t make use of it anyway), so she mobilises calcium from her bone stores. Even with
well-managed mature cows, we still have a large proportion of animals (about 50%) with low calcium levels (subclinical hypocalcaemia) on the day of calving.

Most of the time if a cow hasn’t had any other issues (for example a difficult calving or mastitis) on the day of calving, she will cope with this normal short-lived drop in blood calcium levels. But if the drop in calcium is too low (she’ll sit down) or for too long (2-3 days), then her lactation will be negatively affected. Cows that have subclinical hypocalcaemia may look normal, however their low blood calcium levels will be reducing their dry matter intakes and their ability to fight infection. Therefore, low calcium around calving maybe an underlying issue on your farm.

Do you know whether you have a problem? The only way you can know is if you measure (take some bloods from the colostrum cows) and, record ALL your down cows.

So what can I do - do I have to buy all that fancy stuff?

In most herds, the basics work:
  • Get magnesium intakes right (not too much nor too little) in the springing and dry mob. Springing cows need about 40 g of elemental magnesium. They will get about 20 g from their diet and therefore need to be supplemented with a further 20 g. If you need any help working out how much elemental magnesium is provided by the different magnesium products (i.e. chloride, sulphate or oxide) give us a call.

  • Get the dry matter intakes right for the springing cows (not too much nor too little). This is especially important if you have skinny cows (less than BCS 4.5) or fat cows (BCS 5.5 or more).

  • Avoid pastures with high potassium levels.

  • Feed and mineral supplement the freshly calved cows as soon as practical after calving (to help prevent the drop in calcium).

  • Colostrum cows need lots of food and calcium - feed them ad lib high quality feed and do not skimp on calcium.

  • Give the high-risk cows (6+ year olds, cows with BCS >5, cows that have had assisted calvings, Jerseys and cows that sit down every year) oral calcium on the day of calving.
One of the options to prevent clinical disease in the high-risk cows at calving time is the Calpro Bolus. Cognosco undertook the New Zealand registration research for this bolus a few years ago in a local herd. The bolus was extremely effective at lifting calcium levels within 1h of administration (this is related to the calcium chloride in the bolus), and then sustaining that higher calcium level for up to 8h (this is related to the calcium sulphate). Boluses similar in composition to the Calpro bolus are used widely in the Northern hemisphere. We recommend that one bolus is given as soon as practical after calving in these high risk cows and then if needed repeat 12-15h later. These boluses are also useful for follow up treatment for down cows. IV calcium causes a rapid spike in blood calcium, which is followed by a drop a few hours later. Therefore, all IV calcium treatments should be followed up with an oral calcium product when the cow can swallow. Boluses are easier to administer in these situations than the oral calcium starter drenches.

Date Added: Tuesday, 2nd June 2020


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