Texas Tech University Laboratory of Animal Behavior, Physiology and Welfare
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The Sustainable Pork Farm Site

Table of Contents

What is Sustainable Pork?

Sustainable Pork® is produced in a manner that is friendly to the animals, the environment, the workers and the local community. Sustainable Pork® is also produced in a manner that is economically competitive, which preserves the ability of the pork producer to sustain the viability of the farm.

The Sustainable Pork® label is trademarked by Texas Tech University and approved by USDA.

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Feeding Outdoor Pigs

Outdoor pigs can be allowed to graze forage or other vegetation, but for good growth and lactation, they should be fed nutritionally-balanced diets that contain energy, protein (and amino acids), vitamins and minerals.

Outdoor pigs are subjected to extremes in weather. The main concerns about feeding outdoor pigs is when it is either (a) windy or (b) raining. Other weather extremes are more manageable. Also, we should recognize that the feed is typically fed on the ground, not in feeders. Thus, the feed nutrients can wash into the ground or be diluted by soil. There is not a problem with pigs eating some soil along with their meal.

To manage feed for the times when the weather is wet or windy, it is better to feed sows a pelleted or cubed feed. Generally, a pellet is smaller than a cube. The cubes we often use are from 3/8 inch to 1 inch (0.95 to 2.5 cm) in diameter and are either round or square.

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Outdoor Sustainable Pork Production

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Maintaining Ground Cover

The US Environmental Protection Agency (EPA) in part defines a confined animal feeding operation (CAFO) as a site that has animal density so high that vegetation can not grow for a period of 45 days or more per year. Thus, if vegetation is completely gone on a given site, even if the animals are outdoors, the site is a CAFO and subject to regulation as an intensive production site. Therefore, for a well-managed outdoor unit, the ground cover should be maintained.

The US EPA rules do not say how much ground cover is sufficient. Would 75% ground cover be sufficient? How about 50 or 25%, would those constitute ground cover? How would the regulators view animal densities when native grasses is the normal vegetative cover but at only 10% ground cover (in a desert or near-desert, for example)? These questions have not been answered, but rather than deal with regulatory requirements, it would be better to have a different standard.

Our proposed standard for outdoor units is that they do not allow nutrients to leave the site either through run-off or seepage into the ground. To protect from run-off, a border strip can be used around the site. We found that a 100 foot (~30 meter) vegetative border will catch run-off on a relatively flat site. Maintaining ground cover at 50% on average on a site, depending upon many factors, will collect nutrients that seep into the ground, leaving the area 24 inches (~61 cm) free from pig nutrients.

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Small Scale Sustainable Pork Production

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World-Wide Pictures of Outdoor Pigs

Below are some pictures of outdoor pigs from around the world.  Examples include England, Texas, Colorado, Spain, Brazil, Mexico, Hungry and Australia. Please click Pictures of Outdoor Pigs for more pictures and information

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References from Our Laboratory

Management and Behavior
  1. Johnson, A. K., J.L. Morrow-Tesch and J.J. McGlone. 2001. Behavior and performance of lactating sows and piglets reared indoors or outdoors. J. Anim. Sci. 79:2571-2579.
  2. McGlone J.J., and T.A. Hicks. 2000. Farrowing hut design and sow genotype (Camborough-15 vs 25% Meishan) effects on outdoor sow and litter productivity. J. Anim. Sci. 78:2832-2835.
  3. Johnson A.K. and J.J. McGlone. 2003. Fender design and insulation of farrowing huts: Effects on performance of outdoor sows and piglets. J. Anim. 81:955-964.
  4. McGlone J.J. and F. Blecha. 1987. An examination of behavioral, immunological and productive traits in four management systems for sows and piglets. Applied Animal Behaviour Science. 18:269-286.
  5. Sarignac, Catherine, J.P. Signoret, J.J. McGlone. 1997. Relation mère-jeune, comportement et performances en fonction du système de logement et de l’environnement social. Journees Rech. Porcine en France, 29:123-128.
  6. Johnson Anna Kerr, Julie Lynn Morrow, Dailey, Jeffery William, ,McGlone John James. 2007. Preweaning mortality in loose-housed lactating sows: Behavioral and performance differences between sows who crush or do not crush piglets. Applied Animal Behaviour Science. 105:59-74.
  7. Dailey Jeffery W. and J.J. McGlone. 1997. Pregnant gilt behavior in outdoor and indoor intensive pork production systems. Applied Animal Behaviour Science. 52:45-52.
  8. Dailey Jeffery W. and J.J. McGlone. 1997. Oral/nasal/facial and other behaviors of sows kept individually outdoors on pasture, soil or indoors in gestation crates. Applied Animal Behaviour Science. 52:25-43.

Growth and Meat Quality
  1. Gentry J.G., J.J. McGlone, J.R. Blanton, Jr., and M.F. Miller. 2002. Alternative housing systems for pigs: Influences on growth, composition, and pork quality. J. Anim. Sci. 80:1781-1790.
  2. Gentry J.G, J.J. McGlone, M.F. Miller, J.R. Blanton, Jr. 2004. Environmental effects on pig performance, meat quality, and muscle characteristics. J. Anim. Sci. 82:209-217.
  3. Gentry J.G, J.J McGlone, J.R. Blanton, Jr., and M.F. Miller. 2002. Impact of spontaneous exercise on performance, meat quality, and muscle fiber characteristics of growing/finishing pigs. J. Anim. Sci. 80:2833-2839.
  4. Gentry J.G, J.J. McGlone, M.F. Miller, and J.R. Blanton, Jr. 2002. Diverse birth and rearing environment effects on pig growth and meat quality. J. Anim. Sci. 80:1707-1715.

  1. Rachuonyo H.A., W.G. Pond, and J.J. McGlone. 2002. Effects of stocking rate and crude protein intake during gestation on ground cover, soil-nitrate concentration, and sow and litter performance in an outdoor swine production system. J. Anim. Sci. 80:1451-1461.
  2. Rachuonyo H.A, J.J. McGlone. 2006. Impact of outdoor gestating gilts on soil nutrients, vegetative cover, rooting damage, and pig performance. Journal of Sustainable Agriculture. 29:69-87.
  3. Rachuonyo H.A, V.G. Allen, and J.J. McGlone. 2005. Behavior, preference for, and use of alfalfa, tall fescue, white clover, and buffalograss by pregnant gilts in an outdoor production system. J. Anim. Sci. 83:2225-2234.

Immunity and Food Safety
  1. Kleinbeck Samara N, and John J. McGlone. 1999. Intensive indoor versus outdoor swine production systems: genotype and supplemental iron effects on blood hemoglobin and selected immune measures in young pigs. J. Anim. Sci. 77:2384-2390.
  2. Reed S.N. and J.J. McGlone. Immune status of PIC Camborough-15 sows, 25% Meishan sows, and their offspring kept indoors and outdoors. J. Anim. Sci. 78:2561-2567.
  3. Callaway T.R, J.L. Morrow, A.K. Johnson, J.W. Dailey, F.M. Wallace, E.A. Wagstrom, J.J. McGlone, A.R. Lewis, S.E. Dowd, T.L. Poole, T.S. Edrington, R.C. Anderson, K.J. Genovese, J.A. Byrd, R.B. Harvey. 2005. Environmental prevalence and persistence of Salmonella spp. in outdoor swine wallows. Foodbourne Pathogens and Disease. 2:263-273.
  4. Rudine A.C., M.A. Sutherland, L. Hulbert, J.J. McGlone. 2007. Diverse production system and social status effects on pig immunity and behavior. Livestock Science. 111:86-95.

  • Brain development
    1. Jarvinen Michael Keith, Julie Morrow-Tesch, John J. McGlone, and Terry L. Powley. 1998. Effects of diverse developmental environments on neuronal morphology in domestic pigs (Sus scrofa). Developmental Brain Research. 107:21-31.
  • Economics
    1. Nicholson, R.I., J.J. McGlone, and R.T. Ervin. 1995. Economic Comparison of pig feedlot housing facilities in the Southern High Plains of Texas. 8:19-26. Texas. J. Agric. Nat. Resour.
  • Review Sustainable Systems and Animal Welfare
    1. McGlone J.J. 2001. Farm animal welfare in the context of other society issues: toward sustainable systems. Livestock Production Science. 72:75-81.
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