How Many Mineral Feeders Do I Need?
Let me relate The Tale of the Vanishing Mineral.
From 1998 to 2001 I took care of cattle for one of my customers in Shackelford County, Texas, NE of Abilene. Those were intensely dry years in our area. In 1998 the ranch manager was going to a planned grazing/rotational system. These were fall-calving cows and we weaned in June. As we weaned each pasture, we threw all the cows into one herd, so instead of multiple small herds to travel to and care for, I had one herd of 500 mother cows.
Pastures were of varying sizes and watered by surface tanks. Some pastures had more watering areas and others fewer; some pastures were 4 sections, some were one. As I began to put out mineral for those cattle, there was one mineral feeder at each tank. The first pasture we rotated through was 4 sections with three waters.
I would put out mineral on a round, making a couple of rounds a week. I was putting out enough mineral per head to last the 500 cows more than a week but every time I made a round the mineral feeders were slick empty! This was after the calves had been weaned and consumption should have been very low. Those feeders looked like they had been washed out with a high-pressure water hose. I put out more bags per round. Still the same scoured feeders.
Yet more bags each round. The same: empty feeders.
The mineral the ranch was feeding was a custom mix I had formulated for their deficiencies, and the cows had been on it for a couple of years, but consumption was three times higher than it should be. Baffling.
Finally, I had the chance to start rounding up mineral feeders from other pastures. At each of the three tanks where I had mineral, I put another feeder. Still, at each round I found empty feeders. These dry pregnant cows should not be eating this much mineral! I rounded up more feeders. Same song, 4th verse.
I at last got consumption down to the one- to two-ounce level when I had 16 feeders. That is about 1 feeder to 30 head.
So why the high consumption?
The hills west of Albany are notorious for extremely low phosphorus levels. The old-timers would say if you ran out of salt and bone meal, within three weeks you would start seeing creepy cows. In this instance, I concluded that when cattle concentration went up upon combining herds, dominant cows were limiting access to timid cows. When a timid cow finally had a chance to consume mineral, she was in hyper-deficiency for phosphorus and would over-consume, cleaning out mineral feeders. Let the dominant cows come back around for mineral to find a feeder empty and they started into deficiency. A cycle of over-consumption set up when mineral was unavailable 24/7 for all cattle. It was simply an issue of the ability of each cow to consistently approach feeders. Within a week of establishing one feeder to 30 head, consumption of mineral dropped dramatically.
I have concluded that these factors can determine the number of mineral feeders needed:
- size of herd
- stockers or brood cows
- horned or polled cattle
- size of pastures
- number of waterings
- breed of cattle and level of herding instinct.
After 35 years’ experience, I think as a general rule one feeder for every 25 to 30 head per watering is optimal.