Top Quality Commercial Market Hogs and Champion Show Pigs, Are They the Same? Part 2

Livestock Update, June 2004

Allen Harper, Extension Animal Scientist ­ Swine, Tidewater AREC

In last month's Livestock Update article (May, 2004), I discussed the question: are top quality commercial market hogs and champion show pigs the same? The basis for determining an answer to this question was to assess the carcass pricing grid for a major regional packer and relate this to what is often seen in the carcass traits of champion show hogs. Using this approach it appears that deep loin muscle and other large muscle patterns are desirable traits for both the commercial packer and in champion show pigs. The desired backfat depth on top quality commercial pigs is ideally around 15 to 16 millimeters (about .6 inches). Carcasses with fat depths substantially above this have reduced price premiums and extremely high fat depths result in carcass price discounts. As backfat depth declines below 15 mm, the premium becomes less and carcasses with only 10 millimeters of backfat depth or less are actually at even value with the base carcass price. In other words, the packer buying system encourages lean pigs, but when backfat depth becomes extremely low, it is less desirable.

This is where top value commercial market hogs and high ranking show pigs diverge. Careful observation of ultrasound and other carcass measures indicate that many top placing show pigs have very low external fat depth, often in the range of 8 to 10 millimeters.

So why could this be a problem? After all, it was improvements in genetics, feeding and management to get hogs leaner that has helped keep pork competitive among other muscle foods in the marketplace. No one likes fat in their food anymore. But some baseline level of fat in meat products seems to be essential for acceptable moisture retention, juiciness, flavor and texture in the cooked product. "Marbling" or the small particles of fat within the lean tissue appears to be correlated with external fat depth. As backfat depth declines, marbling also declines. Yet, it is well accepted that a moderate level of marbling in pork is needed for acceptable cooking and eating qualities. There also appears to be problems with very thin backfat carcasses in processing. When whole loins are trimmed on rapidly moving processor lines, it is not uncommon for excessive trim to occur because the fat depth was too thin for even the slightest trim knife error.

Based on these observations it is fair to say that in some instances show pigs are too extreme in their leanness traits to be in line with what would be considered a top quality commercial market hog. In reality, serious show pig people are producing market hogs with a different objective. They are trying to produce the leanness, deepest muscled market hog that is structurally sound enough to present in the show ring. Show judges have difficulty doing anything but placing such pigs high in the show class because such pigs are "exhibiting" the most leanness and muscling.

In the case of youth exhibitors is this sending the best educational message, probably not. A youth market hog (or steer or lamb) project should not focus only on doing things with the sole purpose of obtaining and producing a champion show pig. The project should also teach practical swine husbandry skills, the biology of the pig, the business aspects of raising livestock and the importance of market hog quality for wholesale and retail pork production.

A good example of the different objectives of commercial market hog production and show pig production can be seen in the story of the "stress" gene. Folks in the pork industry have known about the stress gene (also called the "halothane sensitivity" gene) for many years. It is a naturally occurring gene in the domestic pig population. Thankfully it is not prevalent in the commercial pig population although it is more prevalent in some breeds than others (Pietrains, for example).

Just over ten years ago, the ability of labs to do DNA profiling tests for such things as the "stress" gene improved and became more cost effective. So testing for the stress gene from pig tissue samples (blood, skin, etc.) became more feasible and potential breeder pigs could be genetically characterized as homozygous for the stress gene (two copies), heterozygous (one copy of the stress gene, one non-stress) or homozygous stress gene free (no stress gene present). About this same time hog packers changed buying systems to a carcass basis that rewarded producers with leaner, deeper muscled pigs and discounted price for fatter, lighter muscled pigs.

It so happens that that stress gene positive pigs (even heterozygous carriers) tend to have less external fat and larger muscle structure. So some breeders and producers attempted to use breeding stock with the stress gene "strategically" to produce market pigs that were stress gene carriers, thus improving price potential in carcass based buying systems. Show pig breeders and producers have done, and in some cases, continue to do the same. The problem is that, in addition to the benefits of the stress gene, there are some very real disadvantages. Even carrier pigs tend to react more negatively to stressors such as heat, moving and transport. Also, the pork from stress gene pigs tends to have quality problems such as poor water holding capacity, more drip loss and pale meat color (so called PSE or pale, soft exudative pork).

When research made these problems clear in the mid-1990's, most folks in the industry including producers, packers, reputable breeders, breeding stock companies, and animal scientists recommended selecting breeding stock that was known "free" of the stress gene rather than try to "strategically" use the gene. But this has not necessarily been the case with the small part of the swine industry that caters to the show pig market. For example a number of artificial insemination boar studs that sell semen for the production of potential show pigs have boars that are advertised as homozygous stress gene positive or as heterozygous carriers. In effect, they advertise this characteristic as a "positive" trait, although the commercial swine industry position is quite clear that the stress gene has negative impact on pork quality.

Certainly there is nothing illegal about the stress gene. And in most cases there are no rules against pigs that carry it. But a wise man once said that the terms "legal" and "ethical" do not necessarily mean the same thing. Adults working with young people involved in the market hog project and in youth livestock exhibitions should help keep things in proper perspective. Emphasis should be placed on doing a good job on all facets of the project, not just the ultimate result in an exhibition. Participants who do their best with the project from beginning to end and who accept high placing at the show graciously and lower placing honorably, will leave the event with a justifiable sense of pride and accomplishment.

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