1994 ^. Volume 17, Number 6

Many producers utilize flow agents, bentonites, or certain clays to help offset the effects of aflatoxin or as pellet binders. Several key points should be considered when using any of these compounds. First, according the 1994 Feed Additives Compendium (page 171) carbadox (Mecadox®) cannot be fed to swine in a diet containing bentonite. Furthermore, because these clays bind or adsorb aflatoxin there is a potential for them to bind drugs and nutrients such as phosphorus. Also, clays are non-digestible and pass through the animal with the feces and upon entry into the waste handling system they will accumulate in the waste storage facility (i.e., lagoon). This will then contribute to solids buildup in the waste handling system.

Typically, the inclusion rate of bentonite or other clays needed to help alleviate the effects of aflatoxin is .5% or 10 lb./ton of diet. In the following example we can calculate the annual contribution of bentonite to a waste handling/storage system.

Assumptions:

• 4-880 head finishing barns (3520 head inventory)
• 2.8 turns per year (9856 marketed annually)
• 50 to 240 lb. weight range or 190 lb. of gain per pig
• 2.80 feed efficiency (or 2.8 × 190 lb. gain = 532 lb. feed/pig produced)
• 9856 pigs/year × 532 lb. feed/pig = 5,243,392 lb. feed fed/year
• 5,243,392 lb. feed fed/year × .005 lb. bentonite/lb. feed = 26,217 lb. of bentonite/year

In the above example bentonite would contribute 26,217 lb. of non-digestible waste per year to your lagoon using the above assumptions. This may be an overestimate if bentonite is not fed continuously through the year. However, over a 5 year period this would equate to about 131,085 lb. or 65.5 tons of non-digestible sludge buildup. On a positive note, most clays are used to seal lagoons, but the continued use will reduce the lifespan of your lagoon.

Jeffrey A. Hansen

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Last modified August 7, 2000.