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During tight economic times, pen density is one of the most common subjects asked about during farm evaluations and walk-throughs. The answer is: “It depends!”
While most dairies have experienced the benefits of lower pen densities in the prefresh and postfresh pens, there remains a significant temptation to overstock pens that house cows later in lactation.
Since stocking rates are influenced by many factors which are not limited to season, feeding practices, ventilation, and cow size, it is critical to understand the interaction of these factors for your dairy. The table below illustrates the interaction of pen density, milk production and income over feed cost (IOFC) for a 200-cow pen.
The calculations are based on a pen with 400 linear feet of bunk space, which provides 2' per cow at 100% stocking density. Milk price is constant at $14 per cwt. for all pen density levels. Based on the assumed dry matter efficiency changes for each pen, milk production was calculated to provide the same IOFC per pen for all pen densities.
Corresponding cow values were assigned, reflecting the increased health and productivity of cows under less stress. While the assumptions in this example may seem a bit arbitrary, the results resemble the productivity factors of many herds.
Do you track the changes in feed efficiency and income over feed cost as you change the stocking rate of pens for your dairy? It is difficult for lenders to alter asset values based on housing practices, yet the cow values reflect the conditions that are seen under many management systems. Note that in this example, the highest stocking rate is producing 26% more milk for the same net income as the lowest stocking rate!
The most common example of overstocking is when 10% of a late-lactation group is removed for dryoff but the pen milk production remains the same. The same interactions are true for other stages of production. But it is impossible to fine-tune stocking density for a specific dairy without tracking the variation in resulting changes in profitability as related to stocking rate.
For assistance in tracking pen performance, you may want to check out www.dairyprofitanalyzer.com for daily profitability calculations for your dairy.