The most stressful time for your cows is around calving with over 50% of dairy cow metabolic problems occurring within three weeks of calving.

Within the transition period all we are really trying to do is to stop cows getting milk fever or sub-clinical milk fever. Milk fever or sub-clinical milk fever is a gateway disorder, with a cow that suffers from milk fever or sub-clinical milk fever being twice as likely to get metritis, 3 times more likely to have a retained afterbirth and 8 times more likely to get mastitis and ketosis in early lactation.  A farm that suffers from 5% clinical milk fever could be suffering from up to 33% subclinical milk fever.

To help prevent milk fever we are concerned about 2 areas:

1: The BCS of the cow and the

2: Calcium status of the cow

A cow that calves down fat is 4 times more likely to suffer from a milk fever than a cow that calves down in the correct condition score.  We had a very mild backend, lots of grass and concentrates were eaten and cows in general are in good condition.  Once the cow gets within 3 weeks of calving, it’s very difficult to adjust cow BCS.  Limiting her energy intake or feeding more will only affect the calf.  If you have cows that are over or under condition and need individual treatment, you’ll need to group your cows.  Cows that are within 3 weeks will need feeding irrespective of BCS as their intakes will drop and a silage only diet won’t meet their energy needs, in fact fat cows within 3 weeks of calving need the most feeding as their intakes drop the most.  Cows that are further from calving can be fed accordingly with thin cows getting concentrates and the fat cows getting straw to limit silage intakes.

Secondly on calcium status, a milk fever occurs when blood calcium levels drop.  It can happen at any stage of lactation if we don’t feed your cows enough calcium but generally it happens around calving for a very specific reason.

Your far-off dry cow has a very low Ca requirement, and our silages generally over supply you cows with Ca.  When this is happening, your cows deposit the excess Ca into the bones.

When your cows start to bag up, to produce milk her Ca requirement increases, and her Ca requirement can be 3 to 5 times higher at calving than in the far-off dry period.  Now her diet isn’t supplying sufficient Ca, and she needs to draw Ca from her skeleton.

This switch from depositing Ca to drawing is slow and if it doesn’t meet your cows Ca requirement, she gets a milk fever or a sub-clinical milk fever.

This switch is controlled by mainly Magnesium and Vitamin D.  To control your cow’s calcium status, ensure your feeding sufficient magnesium and vitamin D.

There is one further complicating factor.  That’s the potassium level in your cows’ diets.  Potassium is an antagonist for Magnesium basically stopping the magnesium from fulfilling its function.

So, it’s very important that you know the level of potassium in relation to the level of magnesium in your cow’s diet.  A ratio of 10 to 1 is ideal, a level of 20:1 or greater is a real milk fever risk and a level in the mid to high teens is a big risk especially if your cows are heavily conditioned or if they bag up strong.    With a ratio of concern again we must increase our magnesium feeding and a pinch of calcium may be required for the last 10 days.

Within Dairygold we can help you to make sense of these complicated mineral interactions.

Firstly, we have a lab that can analyse your silage for nutritive and mineral content.

Secondly, we have a team of dedicated Area Sales Managers that can condition score your cows and advice you on a feeding to a desired outcome.  These area sales managers can also interpret your silage mineral analysis and advice on what product best suits your needs.

And finally, we have a suite of products that are designed to overcome these complicated mineral interaction.