Gestation Stalls, Animal Welfare and People

Livestock Update, September 2006

Allen Harper and Mark Estienne, Virginia Tech - Tidewater Agricultural Research & Externaion Center

Gestation stalls are specifically designed for confinement housing of pregnant gilts and sows on hog farms.  Use of this type of swine equipment is commonplace in commercial swine production.  One group of animal scientists recently estimated that 60 to 70% of gilts and sows in the US are housed in stalls throughout gestation.  The defining characteristic of gestation stalls is that each stall confines an individual sow, and stalls are arranged in the breeding-gestation barn such that the sows are confined individually in rows of adjacent stalls.  Typical dimensions of each stall are 2 ft. in width by 6 ½ ft. in length.  A drinking nipple and floor-feeding trough are located at the front of each stall and they are typically placed on slatted flooring to allow for manure collection in a manure pit below the floor.

Some groups and organizations take issue with gestation stalls and have taken the position that this type of housing results in major negative impact on the welfare of sows.  This position is based mainly on the premise that within a gestation stall, the sow is not able to turn around and positional behaviors are limited to lying, sitting or standing with only limited back and forth movement.  The gestation stall issue has been in the news recently with two groups, Farm Sanctuary and the Humane Society of the United States, conducting a campaign in the state of Arizona to establish an election year referendum proposing bans on gestation stalls for sows and tethers for veal calves.  As of the July 6 deadline, the groups had collected 218,000 signatures, well over the 122,612 required to get the proposed ban on the 2006 Arizona election docket.  The proposed gestation stall ban referendum in Arizona is very similar to a referendum the same groups initiated in Florida in 2002.  Florida voters are the first in the country to legislate a ban on gestation stalls for housing of sows.  One ironic (some would say strategic) fact about the Florida and Arizona situations is that both states are very minor hog producing states.  At this point in time referendums to ban gestation stalls as a method of sow housing have not been proposed in major hog producing states such as Iowa, North Carolina, Minnesota, Oklahoma or elsewhere.

Farm Animal Welfare in Perspective.  Gestation stalls are unique to swine production, but there are several issues in animal agriculture in which activist groups are challenging animal agriculture on animal welfare grounds.  These include such practices as beak trimming in poultry production, cage housing of laying hens, tethering of veal claves, tail docking in dairy cows, and operation of slaughter plants for cull and unwanted horses.  The subject of animal welfare is important to those who consider themselves supporters of the “Animal Rights” movement and to those who consider themselves animal welfarists.  The primary difference between these groups is that supporters of “animal rights” believe that animals should be entitled to the same rights as those afforded to humans; whereas, animal welfarists believe that animals are entitled to proper care and humane treatment but ultimately people have the right to use animals for food, fiber, work, medical research or other beneficial purposes.  Most pork, poultry, beef, sheep and dairy producers consider themselves to be animal welfarists.  They are in the business of producing food and fiber products from animals, but also realize that it is critical to provide proper care and treatment of their animals for ethical reasons and to insure that the animals are healthy and productive.

Gestation Stalls - Separating Emotion from Empirical Evidence.  The debate around gestation stalls has been going on for some time and will certainly continue.  Within this debate it will be important to consider the growing body of agricultural research which assesses the condition and productivity of bred sows housed in group pens or in individual gestation stalls.  Here at the Virginia Tech Tidewater Agricultural Research & Extension Center, we recently conducted and published a study related to this topic (Journal of Swine Health and Production, Vol. 14, pages 241-246).  In our study we compared certain welfare characteristics and reproductive performance among sows housed in small groups in pens or in individual gestation stalls.  After mating, sows were moved in groups of three into 5 ½ ft. by 10 ft. pens or individually into 2 ft. by 6 ½ ft. gestation stalls.  Overall 14 pens of three sows each were statistically compared to 14 individual sows housed in gestation stalls.  Over the first 30 days of gestation, data were recorded on body weight and backfat changes, wound scores, lameness scores, and blood cortisol levels.  After a thirty day period, sows were humanely killed using standard slaughterhouse procedures and the reproductive tracts were evaluated to assess reproductive status.  Major observations in this study are summarized as follows.

1. Sow backfat changes were not different among the two housing groups, but group penned sows gained slightly more weight during the first 30 days of pregnancy than sows in stalls.  We speculate that during the cooler night time temperatures, sows in stalls were not able to huddle to conserve body heat and therefore had a slightly higher body maintenance requirement.  However, weight gain for both groups was within normal ranges for pregnant sows.
   
   
2. Over the thirty day period, sows in group pens had a greater incidence of scrapes and lesions on the head and face, on the neck and shoulders, on the middle body and udder and on the rump, tail and vulva than sows housed in individual crates.  The most apparent cause of the lesions was increased behavioral aggression among group penned sows to establish social order and during competition at feeding time.
   
   
3. After the 30 day period, lameness scores depicting the freedom of movement of the sows indicated that the incidence of impaired mobility was greater in the group penned sows.
   
   
4. Stereotypical behaviors such as bar biting, sham chewing, floor or bar licking were similar for sows housed in pens or in stalls.
   
   
5. Blood serum cortisol levels were higher for gilts housed in the individual gestation stalls.
   
   
6. Pregnancy rate was greater among sows housed in individual gestation stalls (100% of sows bred) than in group pens (85.7% of sows bred).  Of the sows in both housing groups that were determined to be pregnant, total number of embryos and embryonic survival were not different among the two groups.

The People Factor.  One conclusion from our study is that there are potential advantages and disadvantages to either system.  In this case sows in individual stalls did not gain quite as much weight (although they gained an adequate amount of weight) and the serum cortisol levels “suggest” that they may have been under slightly greater stress than the group penned sows. 

However, we draw this conclusion with caution because cortisol levels based on a single blood sample may not be completely indicative of a chronic stress condition.  On the other hand, sows in group pens must contend with aggressive encounters and competition at feeding time that can result in various skin lesions and perhaps a greater incidence of feet and leg problems.  Furthermore, in our study the ability of the sow to conceive and maintain pregnancy was greater in the sows housed in individual gestation stalls.

As research and practical experience in this area progresses, what is becoming apparent is that swine are adaptable animals.  The housing and management systems employed must be designed to provide for animal comfort and well-being, but proper welfare can be achieved in more than one housing system type.  What appears to be the common denominator is the skill and dedication of the herdspersons that are responsible for animal care.  Although not numerous, incidences of substandard swine welfare can and have occurred in sows housed in outdoor pens, in deep bedded pens, in confinement barn group pens and in individual gestation stalls.  Other studies support the concept that people managing the animals have a predominant impact on their welfare and productivity.  For example an Australian study demonstrated that reproduction was poorer on hog farms in which breeding sows displayed a greater withdrawal response when approached by herdsmen than on farms at which there was little or no fear of humans displayed by the breeding herd.  An Illinois study demonstrated that grower pigs that had more frequent “positive” exposure to herdsmen were easier to load and experienced less stress at marketing time.  And a North Carolina study demonstrated that sows in the care of more diligent and skillful herdsmen had significantly greater pregnancy rates and larger litter sizes at birth.

The ultimate point for animal agriculture seems to be that we continue to refine and improve animal housing and management systems for improved welfare and productivity.  But we should not forget that appropriate animal welfare can be achieved with several housing systems as long as the systems are used properly by skillful and diligent herdspeople.

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