Calves produced in the cow-calf operation may be kept for various lengths of time according to the need for replacement and market conditions.
Calves are fed on either pasture and hay, grain and pasture, or corn silage, for long enough to bring them up to 270–380kg each (about 6 months).
This is known as backgrounding or growing, after which calves are assembled into reasonably uniform groups and sold to feedlots.
Calves may be kept longer (1 year) and sold to feedlots at 320–360kg each.
On feedlots, the cattle are finished. In other words, brought up to market weight on a diet of silage and protein supplements. Alternatively, finishing may be on grain and pasture.
The finishing of cattle on feedlots is a very high-density confined-animal system.
Cattle are grouped by type, age, sex, and weight in outdoor pens and provided with feed and water.
Many pens are grouped together into a single feedlot operation, and conditions are ideal for fly breeding: large accumulations of manure, ample moisture from urine, rain and watering devices, and nutrient-rich feed which is often spilled around the feed bunkers.
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| Wet area in the edge of a stable, not trampled by cattle and suitable for fly breeding. |
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| Feedlot runoff into low area suitable for fly breeding. |
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| Edge of concrete apron of feed bunker where fly breeding may occur. |
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Major problem areas for fly breeding are spilled feed mixed with manure under the feed bunkers, and runoff areas where water and manure drains into depressions.
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| Base of fence line where manure accumulation may support fly breeding. |
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| Manure under raised feed bunker where fly breeding may occur. |
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| Waterer in feedlot with wet manure around base - fly breeding may occur. |
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Pens for housing sick animals have bedding and also provide a habitat for the development of flies, especially house flies and stable flies.
