Figure 9. Two small models of the tool with about $50 in materials cost.

Figure 10. A larger model of the tool with more components and a materials cost of about $100 to $150.

Figure 11. A large model of the tool with wide runners and a roof over the salt-mineral feeder. This unit's materials cost is about $200 to $250.

Material cost of the tool ranged from about $50 to more than $250, depending on the model and use of new or used materials. These costs do not include the cattle rub (wick). Materials for the tool similar to that depicted in Figure 9 should cost about $50, whereas a larger model, similar to that depicted in Figure 10 would cost up to $150 or more. A large roofed model similar to that in Figure 11 would cost about $200 to $250. Using salvaged materials that most graziers have can substantially reduce direct materials cost. Having the tool made by a commercial welder will add 100 percent or more to total cost over materials cost.

In relatively high density grazing, the larger models with a 10-foot cattle rub can service 150 to 175 head of cattle, so the material cost is approximately $1 per head for that number of cattle. That cost is further diluted over time. Over a 5-year time span, material cost is only about $0.20 per head when one 150 head herd used the tool per year. Over time, material cost per head is minimal per head of use and it gets near zero. It is much lower cost than many common commercial insecticide methods, which usually include more labor and equipment expense. A 10-foot cattle rub (wick) costs about $20 to $25. These rubs have lasted us about two to three years depending on herd size. The more larger herds use them, the quicker the rubs wear. Cost for the rub for 150 head for three years is about $0.05 per head.

Insecticide and diluent (diesel) costs are variable between herds and years. Overall, our costs have been about $1 per head per year, and that includes all the multiple uses of the tool charged to the cattle insecticide mixture. It is appropriate to repeat that the cattle are never gathered for these uses.

The well-made metal frame models, properly cared for, have lasted over 10 years with minimal repair. Maintenance cost to re-weld or replace a rusted runner or other parts have been minimal. The poly drum for the salt-mineral feeder remained in good shape after more than 10 years of use. Dark-colored (blue and black) poly drum life is unknown but very long. Wooden models are expected to require more maintenance.

The life span of the cattle rub may be extended by storing it in the shade, and out of the rain, when it is not in use. Sun (ultraviolet rays) deteriorates the rub cover. Wrapping the new rub with salvaged burlap or other acceptable material will extend the life of the rub.

Our experience with the cattle rub is primarily with small herds of up to about 150 stockers or cows with calves. Fly control and other benefits were excellent in these cases. The P.H. White Co. recommends using one cattle rub per 30 to 50 head of cattle or less (P.H. White, personal communication). This would likely be the case under continuous stocking or lax rotational stocking where there is less animal control. We have had excellent results with one tool for up to 150 head of beef cattle stocked within about one-fourth mile from the tool. When there are more than about 150 head, fly control may be reduced. In these cases, more than one portable tool should be used. With herds of 200 head and more of cows plus their calves, two tools must be used. The tools should be in separate locations in the paddock. The number of well-spaced tools needed for herds of over 200 head must be determined through trial and error for a given operation.

A limitation in practical use may be with very large herds and great expanses of acreage. At some point, there is a tradeoff of the management of the tool, its effectiveness, and the time required to manage the system. Individual managers can determine that point for themselves through trial and error. A trailing distance to and from the tool of up to about one-half mile does not seem to be a limiting factor for a well-managed tool in a well-managed rotational stocking unit.

Extremely large paddocks may present a problem with parasite control due to infrequent use by the cattle. Maximum paddock size for optimum use of the tool is not known. On Noble Foundation demonstrations, most paddocks involving the use of the tool were about 50 acres or less with no adverse effects. Trailing distance to the tool of up to about 2,000 feet did not seem to hinder fly control results with herds accustomed to the technique.

With regard to fly control, the cattle rub is primarily for face flies, horn flies and heel flies. The tool prevents a buildup of lice. Tick control can also be good with proper insecticide dosage (Gentry, 2001). Appropriately managed, the cattle rub appears to repel some deer and horse flies, but control is not good. Other methods of control must be used for deer and horse flies, or cattle must tolerate them.