I use a mineral with methoprene as a feed-through fly control. When I put the mineral out, I know I have some cows that eat a lot of it and some that eat very little. If I hand-feed 3 to 4 ounces per head, per day every two or three days, would the methoprene stay in the cows' systems long enough to equal uniform daily consumption? I want to reduce waste and make sure each cow is getting her uniform daily consumption. When I hand-feed, it's mixed with distillers grains.
DR. MCMILLAN'S ANSWER:
I am concerned occasional feeding, as you describe, could have a negative impact on the effectiveness of both your mineral nutrition program and the insect growth regulator (IGR). Methoprene needs to be in all the manure to stop the development of horn fly larvae; minerals need to be continually available for optimal effectiveness.
Salt is what drives cattle to minerals. I have seen several cases where producers have salt blocks and a complete mineral out at the same time. This can lead to inconsistent intake of the mineral. You have to do the math to be sure your cows are getting the recommended consumption.
Let's assume a 25-head herd and a mineral with a recommended consumption of 4 ounces per head per day. This means 100 ounces of mineral should be consumed each day by a herd that size, or 6.25 pounds per day. A 50-pound bag should last eight days. If a bag is lasting longer than it should, you have to figure out why.
Consider, some minerals are more palatable than others. If that's the case, you may need a different mineral. Where is the mineral feeder located? Ideally, it should be convenient to water and rest areas. What type of feeder are you using? Do some or all cows have a problem accessing the feeder or the mineral in it? If so, you may need a different type of feeder.
Incorporating minerals into a complete ration will yield the most consistent consumption, but daily feeding is labor-intensive. Intake Modifying Technologies such as Purina Accuration and others allow for free-choice feeding of a complete ration and additional nutritional benefits. Several companies offer molasses-based IGR mineral tubs. Consult with your herd nutritionist or veterinarian to choose the one that best meets your herd's needs. And remember, when you have a complete feed out, it will have a mineral pack in it. This may reduce mineral consumption.
Please contact your veterinarian with questions pertaining to the health of your herd or other animals. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.
Write Dr. Ken McMillan at Ask the Vet, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email email@example.com.
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