Calculating a winter ration for a dairy cow is relatively straight forward. Our understanding of her nutritional needs is fairly well defined. But the diet we plan is often not exactly the diet that gets fed. That in turn is not always the diet that gets eaten.
The diet’s physical and chemical properties can change throughout the day due to sorting, and heating up or drying down. Light levels also need to be consistent throughout the day and sufficient to extend day length.
Managing all these variables can be tricky in practice. For the cow, she loves consistency and will be at her best when the diet and the environment are correct and consistent.
Below is what might be a cow’s ode to the PMR (Partial Mixed Ration):
What have you done to my dinner?
It’s not what it was yesterday.
It’s lacking in effective fibre;
You’ve forgotten to put in the hay!
You know I love lots of molasses,
It’s tasty and makes me eat more.
But this diet’s all bitter and taseless,
So I’ll just leave it sat on the floor.
And what have you done with the water?
This diet’s too dry for my taste.
I’m just going to pick out the grain now;
The rest of it can go to waste.
Now I can’t really see what I’m eating;
The lightbulb went pop in the night.
It’s time you put up new lighting,
So my day is perpetually bright.
And it’s time you bought a new mixer;
This ration was mixed for an hour.
One mouthful is silage and PK;
The next is all maize and limeflour.
So please just fulfill my requirements;
They have to be met everyday;
I’ll milk better if dinner’s consistent,
So keep all variation at bay.