Background

Once again PICA has been reported on several farms in the last two weeks. I was on one of those farms watching the cows rummaging in the ditches, with one lady out after milking chewing on black plastic she picked up.

We often hear about this condition where cows are eating stones, briars, and chewing on anything they can get.

It is an interesting condition often difficult to find research on.

If we think about the condition the cow herself is telling us something when she is doing this. In simple terms, this behavior to me indicates a deficiency.

We often hear about dogs eating grass and the old wife’s tail “they must have worms when eating grass”. My experience in dogs is not always worms but may indicate the dog is purging and has an underlying issue with the digestive system.

Just like dogs eating grass, when cows are eating soil, stones, and ditches they are trying to tell us something. Again their normal homeostasis is out, she is trying to correct whatever deficiency is occurring.

When this happens at herd level we must take action.

I may be oversimplifying the condition but my mind will always focus on three areas when I see this. Before I go into these specifics we always need to be mindful of underlying stressors that affect rumen health. Just like every animal the gut is central to good production and health. Any animal displaying PICA we need to ensure nothing has affected gut health.

Always look and start with the diet. Look at cows and look at dung.

 

The main reasons for PICA in the dairy herd?

  1. Salt (Sodium)

Low sodium is certainly a factor for this behavior in cows. With high potassium (slurry, fertilizer) creating a risk also by locking up sodium. Low sodium can also be a factor where we see cows licking urine or licking walls. Pasture in the early summer can have lower sodium so we need to have this high up our list of differentials.

Salt (Sodium) is a very interesting mineral in the ruminant. They self-regulate and will only generally consume it if they need it. So my first course of action would be to give them salt licks in a barrel to see what their reaction is.

I find with these herds I tend to review overall mineral status. The best way to do this at pasture is grass samples and blood.

  1. Low fibre

We all know how important fibre is in the ruminant diet. It is the building block for good rumen health and function. As we hit peak grass growth in early summer, we can see that leafy grass being low in fibre. This can affect rumen health and function on some farms. We can often have other issues with this, with butter fats dropping and cows getting very loose dungs. They are loose at grass anyway I hear you say, but my experience is the dungs get very loose. They will often appear bubbly in nature, another old wife’s tail on this one is “bubbles in the dung is a sign of fluke”. I think again “bubbly dung”  is just telling us primarily rumen health and digestive function isn’t right.

The next logical step in herds where this is suspected would give cows access to some fibre. Ring feeders with straw and watch cows. This can be enhanced by chopping the straw and maybe mixing some molasses through it to help palatability.

A simple tool could also be a little bit of buffering after milking with silage in the morning. Where BF and dungs are ok in herds I find that low fibre is lower down the differential list.

  1. Low phosphorous

This is the last of the three underlying factors or potential causes  I see with this condition. I found blood tests useful for this where the salt didn’t make a difference or fibre wasn’t thought to be an issue. P can be low in the grass on some farms at this time of year.

It can be difficult to supplement but one word of warning is again my experience is that it takes time to lift P in blood and usually will take 10-14 days before you see a response to supplementation.

If you’re going to blood test go after the animals you have seen displaying the symptoms for testing.

 

Why are we seeing more of this?

The first question is are we seeing more of this PCIA condition? My opinion is yes and others can disagree after that. If we understand why it happens then the increased cases can be explained.

It is a condition we see in lush grass that is low in fibre. On some farms, this grass can be lower in P and also sodium. Where we have higher levels of K (potassium) we also will get sodium locked up.

So in very simple terms it can be a grazing issue very much seen during peak growth periods on some farms.

 

The solutions

I am currently running a trial with one such farm. I think we are going to supplement salt and minerals. I feel where these cows are displaying PICA it takes a little bit of time to get minerals and good rumen health back where it should be,

Our approach on this farm will be energy, rumen health, and minerals for the next 6-8 weeks.

 

As always we must understand normal biology and physiology. When we see issues we must act fast and always ask the question why? It is not normal for cows to be chewing sticks, stuck in ditches, and chewing stones. Act early to stop impacts on rumen health and performance. Investigate these problems and take action.

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Mark Gillanders

Maybe many farmers and indeed advisors are a little too paranoid about having pure grass manicured pasture. I heard a very reputable highly respected vet say once a cow should not have more than 70% of its diet to be one constituant (even grass). Herd health seems to be vastly improved in multi-species pasture. Even grazed docks have a benefit to animals. The benefits of chicory and plaintain are well known to Organic farmers. What’s it going to take for knowledge extension to change to a more holistic approach to pasture?