The cost of production is also your breakeven price.
Most hay producers want to produce hay as profitably as possible. Establishing economic goals is the first step toward profitability. Once goals are established, farmers benefit by developing a management mindset that is centered on a business approach. This requires understanding the costs of time, effort and inputs needed to produce and market the product. Following is an example of how to calculate hay production costs in the south-central Oklahoma, north-central Texas region.
Hay production costs can be reported on a dollar/ton basis; however, this measure can easily be converted to a dollar/bale basis once the size of the bale is known.
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An article of interest you might want to check out on this topic is titled Hay Storage Analyzer.