Hot and dry summer conditions combined with dirt cattle lots can lead to significant dust formation, especially in windy conditions. Though seemingly unavoidable in South Dakota’s windy environment, there are methods to reduce the amount of dust generated in a dry lot. We will examine some straightforward solutions to dust problems in dry lots.

Organic matter removal

Small particles are more easily carried by the wind than larger particles. Organic matter in the form of feces and feed are very small particles that are extremely light when dried. The most critical strategy to reduce the amount of dust liberated in a dry lot is to avoid build-up of organic matter. In order to minimize dust generation fastidious cleaning and removal of manure to keep the depth of loose manure less than 2 inches is very important. It is generally recommended to scrape lots a minimum of once every 3-4 months.

Removing feces and feed on a regular basis not only limits the amount of dust in dry conditions, but also helps limit moisture build up in the soil surface when the weather is wetter.

Lot treatments to reduce dust

The most common lot treatment is water application. Systems can either be permanent or truck based. The amount of water required will depend on the area of the lot and the dryness of the lot surface. The surface manure in a lot should be maintained between 25% and 35% moisture to limit both dust emissions and odor (don’t get it too wet). If the lot is very dry, apply water at a rate of 1 gallon per square yard daily in the evening until the surface soil moisture level reaches the desired range (25-35%). After the range is reached maintain the moisture level with daily additions of .5-.75 gallon per square yard applied in the evening. Treatments should occur in the evening when cattle are more active, and the lot surface is at its driest after the heat of the day. Table 1 below demonstrates the amount of water required to initially treat and then maintain lot surface moisture levels between 25-35%.

Table 1. Water Requirements for Dust Mitigation

Number of Cattle on Feed

Lot Area (Assuming 300 ft2/hd)

Water Requirement in Gallons
(1 gallon/yard2)

Water Requirement in Gallons
(.5 gallon/yard2)

40

12,000

1333

667

80

24,000

2667

1333

120

36,000

4000

2000

200

60,000

6667

3333

600

180,000

20000

10000

999

299,700

33300

16650

1500

450,000

50000

25000

2500

750,000

83333

41667

*Note: If you would like to precisely calculate your water requirements to limit dust in dry conditions. 1) Determine your area in square feet and divide by 9 to get the area in square yards. 2) The area in square yards is equivalent to the gallon requirement to re-wet dry surfaces (1 gallon/square yard). 3) Half of the area in square yards is equivalent to the gallon requirement to maintain 25-35% surface moisture (0.5 gallon/square yard)

For larger lots utilizing trucks to move and apply water can be time consuming. As an example consider the 2500 head lot above in table 1. Each day the operator would have to apply 41,667 gallons of water to the lots. A 4000 gallon tank truck would require 11 trips every evening. Permanent sprinkler systems reduce the amount of time that is required to manage the system as water can be delivered directly to the animals and only pumped once. They can be constructed and operated for a total cost of ~$1.25 - $2.35 per head marketed, assuming a functional system life of 25 years. More information on pricing can be found in the 4th document from Texas A&M in the recommended references.

One benefit of developing a dust management strategy is that the same system can be used for heat stress management. View Heat Stress Preparations for Feedlot Cattle for more information..

There are several commercially available chemical compounds that are meant to reduce dust on roadways and in industry applications. The chemical treatments have not been demonstrated to be useful in dry lot situations, and in some cases can complicate manure disposal.

Increase stocking density

Concentrating animals (up to 100 ft2/head) in a lot during hot weather has been demonstrated to successfully limit dust by increasing the amount of water per unit area distributed by the cattle. There are several potential issues that can result, including: muddy conditions if weather changes, inadequate bunk space, increased disease transmission, and lower efficiency of gain. From a management perspective increasing the stocking density is a low cost, but potentially high risk endeavor. Each operation must weigh the potential benefit against the potential risk.

Conclusion

If you are struggling with dusty conditions on your operation a good first step is to scrape your lots. Slightly wetting the lot prior to scraping can help keep the dust down, try to do it on a calm morning or evening. Regular exposure to dust can lead to respiratory issues in both cattle and workers, and physical irritation to the eyes can predispose cattle to pinkeye.