What is your opinion about feeding natural diatomaceous earth to cattle? Would DE dusted on cattle kill flies?

There is not a lot of research-based information available using diatomaceous silica. Our nutrition group has conducted a trial to look at the inclusion in a feedlot trial and the effect on performance. They also looked at the effect of diatomaceous silica on some internal parasites. Diatomaceous silica is known to kill insects, but its effects on internal parasites and coccidiosis have not been reported.

DiaFil, diatomaceous silica (CR Minerals Corporation), is thought to have potential benefits as a feed ingredient and/or additive for finishing cattle, based on field observations. It has been suggested that inclusion of diatomaceous silica, also referred to as diatomite, into the ration enhances health status and increases weight gain. Diatomite can be used in the human food industries as anti-caking agents and as a mild abrasive in toothpaste. DiaFil is comprised of skeletal remains of single-cell aquatic plants consisting of a single size and shape known as Melosira and contains less than 0.1% crystalline silica. Although informal reports are available, the effect of feeding DiaFil to finishing cattle has not been investigated in a controlled research setting. Rumensin®/Tylan® is a feed additive combination widely used in the feedlot industry for improved feed efficiency and control of liver abscesses and coccidiosis. The objectives of this experiment were to evaluate the effects of DiaFil on performance and carcass characteristics of feedlot cattle fed a corn-based finishing diet with or without Rumensin/Tylan and determine the effects of DiaFil on internal parasites and coccidiosis.

Although interactions between DiaFil and the combination of Rumensin/Tylan were observed for animal performance, feeding DiaFil alone does not appear to enhance performance of finishing cattle when compared to diets without the feed additives evaluated in this experiment. Based on the response observed in feed efficiency, steers fed diets containing DiaFil alone were 8% less efficient than those fed the control diet. Additionally, steers fed Rumensin and Tylan were 9% more efficient than those fed DiaFil. This would suggest that replacing 3% of the corn in a finishing diet with DiaFil decreased the energy concentration of the diet. Therefore, any benefit from DiaFil inclusion must be large enough to overcome this reduction in dietary energy concentration

Averaged across treatments, 16% of the steers used in this experiment had parasitic eggs present in the feces on day 0. Following 28 days on feed, parasitic eggs were for the most part undetectable across treatments. Only 2.2% of the steers fed DiaFil alone were found to have parasitic eggs present in the feces at day 28. This small and insignificant incidence is most likely a function of these steers having the highest concentration of parasitic eggs on day 0. The higher numerical count of fecal egg counts at the beginning of the experiment is merely due to random chance since the cattle were allotted to treatments based on weight alone. Averaged across treatments, 20% of the steers used in this experiment had coccidia in the feces on day 0. By the conclusion of 28 days on feed, those steers fed diets containing Rumensin/Tylan had no detectable coccidia, whereas those steers fed the control diet or DiaFil alone did have detectable levels of coccidia present in the feces (2.2 and 6.7%, respectively). Although coccidia were present in all treatments on day 0 and a portion of the steers had coccidia in the feces on day 28, no clinical signs of coccidiosis were observed for any steer during the experimental period.