Lake says there's very little human error in this system, even though the pens receiving the high-E ration are scattered throughout the feed yard rather than being more conveniently blocked in one area of the lot. The daily information that feed truck drivers need to deliver the appropriate rations to pens is generated both manually and by computer at the Hitch feedyards.
Still, the more rations the feedlot staff are required to dispense, the more chance there is for costly human error, notes Dr. Fred Owens of Oklahoma State University. Especially as cattle near the end of the feeding period, he says, an error-free way to manage a high vitamin E program would be to provide the increased supplementation to all the cattle, whether they're in the program or not. The cost of the extra vitamin E for these nonprogram cattle could be considerably less than the cost if program cattle do not receive the right ration and the feeder loses the premium, Owen notes.
In formulating a vitamin E inclusion rate, Lake notes, it's also important to factor in the average feed intake specific to the individual pen or type of cattle going into the E program. "You need an intake history of the specific pens or type of cattle," he notes.
Lake adds the vitamin E to a sun-cured alfalfa pellet. When he was experimenting with the supplementation for vitamin E beef, he had it added to the ration by top-dressing. "It is an easy way to supplement with the higher levels of vitamin E, especially when you only have a few pens to feed," he says.
When top-dressing, Hitch employees used a custom-built hopper mounted on a pickup truck. A 12-volt starter motor, wired to a timer, powered an auger that delivered the supplement to the bunks.
"We calibrated the machine by time so we knew how much of the supplement was dispensed in a second," Lake says. "The driver matched driving speed to the amount of supplement that needed to be delivered to a certain pen. Using the machine to top-dress 20 to 30 pens took about an hour and a half."
Liquid application of vitamin E at the feed mill is another option, of course. However, when the vitamin E is added in this manner, it usually comes in a concentrated liquid form and is added to the feed in very small amounts, cautions Bill Park, a feedlot consultant in Gruver, Texas.
"This delivery method requires especially accurate scaling equipment and constant calibration to ensure that the product is being added correctly," says Park, who has conducted studies of feed uniformity for feedlots, swine operations and commercial mills. "As the day goes on, the scale and the pumping equipment will pump a little differently than they did earlier in the day. Or instead of being completely full, by the next day the drum may be only half full. All these factors impact calibration and may require flow rate adjustments in the equipment."
The spraying pattern of an individual micronutrient machine can affect the distribution of the vitamin E in the feed, Park adds. "If a mixer test comes back with unsatisfactory results for vitamin E levels, one of the ways to improve the distribution in the ration is to manipulate the way the vitamin E is sprayed on the feed."
A second way to improve dispersion of the vitamin is to fine-tune the mixing time. "The dispersion of ingredients is very sensitive to mixer type," Park notes. "One mixer may get an adequate mix using a 30-second mix; another may need 2 minutes."
From batch to batch of final ration, a reasonable range of variation in vitamin E from the original formulation is 1 to 3 percent of the target inclusion rate, Park says.
References:
- Westcott, E.A., et al. 1996. Domestic case life strategic alliance: vitamin E project. Report to the National Cattlemen's Beef Association.
