Optimal stocking rates are determined by a good balance between reducing fixed costs per cow while maintaining welfare and performance. From an ROI standpoint, optimal rates can vary based on factors such as milk price and feed costs [i], as well as the production stage of the cows.
So how do you work out optimal stocking density for your housing system?
Research shows that for general lactating groups, stocking rates of 100% to 120% work best to maximize profitability on most farms [ii] and good management can balance out moderate overcrowding in specific pens. It is important to find the right balance between economically optimal stocking rates and animal welfare.
Profitable Stocking Density with Milk Price=$18.00/cwt and Feed Cost= $0.12/lb DM* *Created from the Stall Stocking Density Calculator algorithm developed by DeVries et. al. (2016)
Impact of stocking rates on cow behavior
From a behavior standpoint, cows spend 70 to 80% of their time eating or resting. Providing adequate space and facilities is a key requirement to maintain animal welfare, health and performance. A stocking density of 100% is defined as at least 1 lying stall and 1 headlock or 2 feet (60cm) of bunk space per cow. Insufficient stalls or poor bedding can result in reduced lying time [iii], which impacts ruminating time, production and increases risk of lameness and other health issues. Feed bunk space availability is another key factor, as competition for feed increases with higher stocking densities [iv].
Lower stocking rates are recommended for transition and sick cow pens
These issues are especially relevant for vulnerable animals, such as sick or transition cows, that require more lying space. Insufficient lying space in this period can impact milk production throughout the lactation. The recommended stocking densities for close-up and fresh cows are at or below 80% [i].
Monitoring stocking density in pens to inform your decisions
A first step in managing your stocking rates is being able to review and monitor these numbers in your on-farm systems. Having an overview of stocking density in your pens allows you to monitor how it impacts behavior, health and productivity. This will help determine the optimal numbers for your farm and inform better decisions.
References:
[i] Robertson, L., Amaral-Phillips, D.M. What is the Optimum Stocking Density for Your Housing System? Martin-Gatton College of Agriculture, Food and Environment. https://afs.ca.uky.edu/content/what-optimum-stocking-density-your-housing-system
[ii] De Vries, A., Dechassa, H., & Hogeveen, H. (2016). Economic evaluation of stall stocking density of lactating dairy cows. Journal of Dairy Science, 99(5), 3848-3857. https://www.journalofdairyscience.org/article/S0022-0302(16)00181-8/fulltext
[iii] Tucker, C. B., Weary, D. M., Von Keyserlingk, M. A. G., & Beauchemin, K. A. (2009). Cow comfort in tie-stalls: Increased depth of shavings or straw bedding increases lying time. Journal of dairy science, 92(6), 2684-2690. https://www.journalofdairyscience.org/article/S0022-0302(09)70584-3/fulltext
[iv] Proudfoot, K. L., Veira, D. M., Weary, D. M., & Von Keyserlingk, M. A. G. (2009). Competition at the feed bunk changes the feeding, standing, and social behavior of transition dairy cows. Journal of dairy science, 92(7), 3116-3123. https://www.journalofdairyscience.org/article/S0022-0302(09)70628-9/fulltext
