Dairy producers and heifer growers often house dairy heifers in free-stall barns as a labor-efficient heifer management system. There are many unique aspects to consider when managing heifers with a free-stall housing system.
The use of free-stall barns restricts the resting environment for heifers, allowing for easier observation, bedding, and manure management. Primarily, free-stall housing systems allow for efficient manure management and reduction of bedding. In comparison to a bedded pack, free-stall barns save on space needed per animal. The use of headlocks in free-stall housing systems also allows catching heifers with relative ease to facilitate vaccinations, breeding, and other routine management tasks associated with heifer management.
One of the biggest drawbacks of free-stall housing systems is that free-stall resting surfaces do not work well for heifers less than 400 pounds in cold climates. This is due to a difference in heifer biology as compared to lactating cow biology. Young heifers weighing less than 400 pounds have more surface area (square inches of hide) per pound of body weight than lactating cows. As a result, when small heifers rest on something cold, such as cement, a mattress, or sand, net energy is lost through conduction. Thus, the free-stall resting surface may be too cold for a lightweight dairy heifer to rest on and maintain energy balance for proper growth. Heifers less than 400 pounds housed in free-stall barns often look energy deficient during cold weather, with abnormally rough hair coats and abdominal distention. Heifers under cold stress may also be more prone to respiratory disease.
Listed below are several quirks associated with managing heifers in free-stall barns:
The manure handling systems will most likely dictate the bedding used in a free-stall barn. The primary types of free-stall bedding are mattresses and sand. Using sand as bedding has been demonstrated to provide more comfortable resting surface for the heifer, but bedding usage and labor will be higher as compared to mattresses. Sand-laden manure may require sand settling lanes or mechanical sand separation systems. Mattress free-stall systems are typically bedded with a layer of sawdust and result in a more flexible manure handling system, but they require bedding at more frequent intervals.
Overcrowding of a free-stall facility may help optimize the economics of the facility, but it may result in more heifers lying in alleyways, which are wet concrete surfaces not suitable for resting heifers. Trauma injuries can also result from heifers being housed in free-stall barns too small for their body size. Most notably, swollen hocks and other trauma injuries have been reported from the use of small stalls.
On the other hand, large stalls allow for urine and feces to fall in the resting area of the animal. This can lead to more labor time spent cleaning stall surfaces, as well as a higher rate of mastitis in heifers. While research is limited, a general guideline is to not overcrowd heifer free-stall housing systems more than 125 percent.
Access to proper bunk space may be as much or more of a critical reason to avoid overcrowding than concerns with resting area. First, limited bunk space might disallow any opportunity to limit-feed heifers, which has been demonstrated to significantly improve feed efficiency and decrease manure production. Limit-feeding strategies cannot be implemented when bunk space is inadequate. Second, severely limiting bunk space may result in shift feeding, feed sorting, and, ultimately, uneven rates of average daily gains.
Every heifer housing system is a compromise between cost, labor efficiency, and animal environment. Each of these should be taken into consideration when choosing a housing system. If you have a stable herd size and even calving distribution, free-stall barns can be a labor efficient and economically sound way to house animals greater than 400 pounds. If the choice to use a free-stall housing system for heifers is made, you must then choose what type of free-stall operation you would like to operate. The manure management systems available will most likely dictate bedding, manure scraping systems, and, ultimately, barn configuration. Other critical management systems to consider are feeding, hoof health, and animal restraint. You must also ensure your free stalls are of adequate size for the animal. They must allow adequate space for lying down as well as lunge space and appropriate neck rail and brisket board height to minimize injuries. Recommended free-stall dimensions are listed in Table 1.
|Free-stall Width (inches)||30||33||37||42||45|
|Side Lunge Free-Stall Length (inches)||60||64||72||78||81|
|Forward Lunge Free-Stall Length (inches)||72-78||76-82||84-90||90-96||93-99|
|Neck Rail Height (inches)||31||35||38||41||43|
|Curb-to-Neck Rail and Brisket Board (inches)||46||49||57||62||64|
Patrick C. Hoffman
University of Wisconsin-Madison