I was gonna let this thread go by, but now I have to say something. (anyone at all suprised? :wink: )
Mineral does no good if cattle don't eat it.
Quality and quantity of forage dictates mineral consumption; i.e. when the grass is green there are more nutrients in it, but also more moisture.
When the grass turns brown, the nutrients are diminished and cattle will eat more mineral. Cattle eat free-choice mineral in peaks and valleys.
I'm sure you have noticed that when cattle are ready to be moved, they eat more mineral. Then in a new pasture they will slack off their consumption, until the 'desirables' in that pasture are eaten down.
We figure mineral consumption on a per head/per year basis. You can't figure it on a week or a month, too much variation, even from year to year. We have found that cattle on Vigortone mineral will eat 3-4 oz. per head per day for 365 days. That is target consumption. At that rate, I can guarantee you that your cattle will see an increase in weaning weights, conception rates and herd health.
One of our customers has a Vigorbin that holds 7 ton of mineral. He drives under the bin with a cake feeder; goes out and fills troughs in the pasture as needed. We have figured it out from when the bin is filled, the amount of cattle supplemented and when the bin is empty. We have always come up with 3.5 oz. per head per day in that particular area.
Recommeded formulas from nutritionists, and John Patterson at MSU, who has dedicated a lot of time to mineral research--2 to 1 cal to phos or 3-1 or even 6-1; never 1 to 1 and absolutely never more phos than calcium.
When the grass is green we have our customers that are on a year-round mineral program feed a less phos mineral. It helps the cows consume more, so that they get the trace minerals at that time, and it is cheaper. Then when the grass starts to dry out (usually around Aug. 1) they should change to the higher phos mineral (3V2S--2 to one cal to phos.) As the grass dries out, so does the phos in the grass, so the cows will eat more of the lesser phos mineral trying to satisfy their phos requirements. Therefore, we have them feed the higher phos mineral at that time.
It has worked very well doing it this way.
Hope this helps!