We’re getting lots of e-mail, phone calls, and other communications these days asking whether the AVMA is “for” or “against” the use of gestation stalls for housing pregnant sows. What AVMA is really “for” is good welfare. We want housing that: (1) ensures good nutrition and, correspondingly, good body condition; (2) maximizes the health of the pig (i.e., absence of disease and injuries); (3) provides a good environment in terms of things like air quality, temperature and humidity; and (4) promotes good mental health (e.g., supports the expression of normal patterns of behavior and minimizes stress). The housing systems currently available for pregnant sows vary in their ability to meet these needs.
Examples of individual housing include 2 ft by 7 ft gestation stalls (most common by far), individual pens, and turn-around stalls. Individual housing actually does a pretty good job at achieving (1) and (2) on our wish list above, but presents challenges when it comes to (4). When sows are housed individually, it’s possible to easily monitor each sow’s health, and to know how much food and water each is receiving and consuming—all things that contribute to the sow’s good welfare. However, sows housed individually have less opportunity to socialize and, depending on the configuration of the housing system (e.g., stalls, turn-around stalls, individual pens) and what is included in the enclosure (e.g., nothing [barren], straw, other enrichments), the sow’s movement may be restricted and she may not be able to behave in ways that would be considered “normal” in a more natural environment—all potential welfare negatives.
Gestation stalls were developed as a way to make efficient use of space and keep expenses low while preserving good nutrition and health of individual sows. You can achieve many of the same animal welfare benefits by utilizing an individual pen that allows more freedom of movement—but typically at a greater dollar cost. And, just as for any other business, that higher cost is passed on to the consumer.
In comparison to individual housing, housing sows in groups can facilitate (4) on our wish list in that sows are able to socialize and perform more of their normal behaviors (assuming that the group enclosure the sows are housed in has the right design and the right things in it to facilitate those behaviors). This housing approach, however, may present more challenges in achieving (1) and (2). More animals in one place makes it harder for caretakers to monitor their individual health, and competition for food among sows in the group can result in less dominant sows receiving less nutrition. As sows in groups establish their social ranking and dominance within the group, they may fight and injure each other—and sometimes those injuries can be quite severe.
We’ve barely scratched the surface of what we have to consider when we try to decide what housing system is “best.” Management, genetics, how many pigs are in a group, whether groups are ‘static’ (all sows in a pen enter it when the group is formed) or ‘dynamic’ (sows enter and exit the group at different times), and the environmental features of the enclosure (how it’s designed [corners versus round, presence or absence of hiding places], what’s in it) are just some of the things that can impact sow welfare. What we would like to see are efforts to retain the advantages of current systems while working aggressively to resolve their disadvantages. It’s not about supporting the status quo for any type of housing; instead, it’s about always looking to improve the system to provide the best health and welfare for the pigs, as well as safe food for people.
And, while veterinarians and other scientists can evaluate housing systems and try to measure how they affect animal welfare, there are always going to be value judgments involved in choosing what is “best.” Science doesn’t tell us how much “protection from injury” is equal to how much “freedom of movement,” and may or may not be able to tell us which attributes are most important from the perspective of the animal. People fill these knowledge gaps by deciding what’s most important to them and make choices accordingly.