June 6, 2004

GROUND-BREAKING RESULTS FROM RESEARCH ON STANDARD TURKEYS

New research confirms that several standard varieties of naturally mating turkeys are more disease resistant than industrial strains. These findings show that standard turkeys, popularly known as "heritage" turkeys, are better suited for range production than their industrial Broad Breasted White counterparts.

What is a Standard Turkey?
The American Poultry Association (APA) has recognized standards for poultry, just as the American Kennel Club has standards for dogs. The APA recognizes eight varieties of turkeys. These varieties are naturally mating, not requiring artificial insemination, have a specific body conformation and feather pattern, and have names like Narragansett, Bronze, Black, Slate, and Bourbon Red. There are other color variations of naturally-mating turkeys that have not been standardized.

Nearly Extinct
As recently as 1997, standard varieties of turkeys were nearly extinct. A census conducted by the American Livestock Breeds Conservancy found only 1335 breeding birds remained. (Breeding stock produces the next generation, passing their genes on to their offspring.) Once common on the American agricultural landscape, these turkeys had nearly vanished. These colorful, inquisitive, and hardy birds seemed destined to become forgotten relics of the past. Fortunately, their fate has been turned through some powerful partnerships.

The Study
The American Livestock Breeds Conservancy (ALBC), Virginia Polytechnic Institute & State University in Blacksburg (Virginia Tech), and eight breeders and producers of standard turkeys collaborated to compare standard turkey varieties and an industrial strain for immune function and in range-based production systems. The hypothesis: Standard varieties of turkeys have superior immuno-competence and perform better in range-based production systems than industrial strains.

Field Trials
The project began with field trials conducted on eight farms situated across the country. Each raised two flocks of thirty birds: a mixed flock of males and females of the standard variety known as the Bourbon Red obtained from Privett Hatchery in Portales, New Mexico, and males only of medium sized industrial line of broad-breasted white turkeys provided by British United Turkeys of America (BUT), based in West Virginia. Birds had daily access to outdoor range, forage, shelter, and roosting locations. The participants collected data on weather, health, feed consumption, morbidity, mortality, weekly weight gain, harvest weight, and dressed weight, behavioral observations and sales.

The farm participants reported some expected results to faster weight gain and improved feed conversion in the industrial line when compared with the Bourbon Red. The broad-breasted whites attained market weight in an average of 131 days, compared to an average of 185 days for the Bourbon Reds. Correspondingly, the commercial birds consumed an average of 5 pounds of feed per pound of weight gain, while the Bourbon Reds consumed 6.08 pounds. Both flocks dressed out at about 75% of live weight. The average dressed weight of the Bourbon Red hens was 7.4 pounds; Bourbon Red toms 11.3 pounds; and commercial toms 17.5 pounds.

The industrial line, however, experienced greater mortalities from shipping stress, heat, and disease. Mortalities for the industrial line ranged from 13 to 93%, averaging 46%. The Bourbon Red mortality rate ranged from 15 to 31%, averaging 21%. (Loss from predation is not included in these mortality calculations since it can be argued that such a death is not related to a bird's immune response.)

The more active standard turkeys needed slightly different management techniques to keep them in their pastures and closer to home. Lighter weight Bourbon Red hens were well equipped to fly, often escaping the confines of the pens. Both Bourbon Red hens and toms began roosting at an early age, while the industrial toms were not as inclined to roost, if at all. The Bourbon Reds were active foragers, covering the pasture and readily eating offered treats of melon and vegetables. The industrial birds were more sedentary, especially as they got heavier, primarily seeking the feed ration. The industrial birds suffered in the heat, panting and seeking relief in the cool soil in the shade of the barn. While the Bourbon Reds sought shade, they did not exhibit the same degree of discomfort and physical stress from the heat.

Laboratory Evaluation
Dr. Robert Gogal, Jr., a veterinarian, immunotoxicologist at Virginia Tech, conducted a series of laboratory tests to assess immune function on five varieties of standard turkeys (Black, Bourbon Red, Narragansett, Royal Palm and Slate) and an industrial line provided by BUT. Results from laboratory tests confirmed what the farmers witnessed.

Two measures of hematologic function were taken. Packed cell volume measures red blood cells, which carry oxygen to the cells of the body. Total protein measure globulins and albumin, both of which are critical to immune response. In both tests the higher the measure, the healthier the bird. In all instances the standard varieties had higher packed cell volume and total protein, and the industrial line had the lowest.

Two tests of immune response were conducted: non-specific T-cell stimulation and pan-lymphocyte stimulation. In each instance the standard turkeys' immune response was superior to that of the industrial line. Royal Palms performed best, followed by Bourbon Reds, and Slates.

The standard varieties had significantly higher survivability when directly exposed to disease. Royal Palm, Narragansett, Bourbon Red, Slate, and Black turkeys, and a commercial line of British United Turkeys of America were challenged with Hemorrhagic Enteritis Virus when they were six weeks old. They were then exposed to E. coli seven days later. All but two of the BUT died the first day after infection with E. coli. The remaining two died within three days. In contrast, a majority of the standard turkeys survived past three days of bacterial infection, and lived to the study's termination. None of the Black, Slate or Bourbon Red turkeys died. The Narragansett and Royal Palm did not perform as well: most of them died during the course of the study. (A paper is being prepared for submission to the journal Avian Diseases.)

Unlike humans, most mammals and birds are able to synthesize ascorbic acid, commonly known as vitamin C. Ascorbic acid has been shown to enhance immune function, modulate gene expression, act as a co-factor in enzymatic reactions, and protect organisms from free radical damage during oxidative stress. An assay measuring endogenous ascorbic acid levels in tissue and plasma samples showed that the Black turkeys had the highest average plasma ascorbic acid concentration overall. Bourbon Reds were a close second, followed by Slates and Royal Palms. The Narragansett turkeys had the lowest average ascorbic acid concentration - approximately half that of the Blacks. (Submission of a manuscript of this work to a poultry nutrition journal is planned for June 2004.)

Virginia Tech's physical evaluation confirmed weight change, with the industrial line being three times heavier than the standard varieties at nine weeks of age. Hatchability of all of the standard varieties was excellent at 75 to 88%. The industrial line was not evaluated since only males were available.

Dr. Ed Smith of the Comparative Genomics Lab, Department of Animal and Poultry Sciences at Virginia Tech, found DNA evidence indicating that the Royal Palm is genetically distinct from the other four varieties analyzed. It is most closely related to the Narragansett. The Bourbon Red, Slate and Black are more closely related to one another.

Conservation Justified
Each of these studies is interesting and valuable on its own. As a group, they are stunning. They clearly indicate that the Slate, Black, and Bourbon Red turkeys, by virtue of their genetics, have more vigorous immune systems, making them obvious choices for free range production. The only parameters on which the industrial lines excel are feed conversion and rate of gain.

Standard turkeys varieties offer a robust immune system and with it a lower mortality rate, the ability to mate naturally, excellent hatchability, active foraging, increased levels of endogenous vitamin C, intelligence and overall attractiveness.

These are very exciting findings. They demonstrate the value and importance of the genetic resources embodied in standard varieties of turkeys, supporting claims long made by breeders, and justifying turkey conservation.

Turkeys On The Rise
Since 1997, standard turkeys are making a comeback. The powerful combination of ALBC's research and census work, the Slow Food USA's Thanksgiving promotion in 2002 and 2003, and an increasing number of breeders, has moved standard turkeys back from the brink of extinction. Pasture-raised standard turkeys are a superb treat worthy of the place of honor on America's Thanksgiving tables.

While still endangered, the future of standard turkeys looks promising. ALBC conducted a census during the winter of 2002-2003. A population of 4275 breeding birds was reported, a three-fold increase since 1997. Hundreds of people have asked ALBC for more information about how to raise standard turkeys. This increased interest is translating into demand for turkeys that, in turn, supports turkey breeders.

Next Steps
ALBC and Virginia Tech will continue their collaboration over the next year, evaluating several additional varieties not included in the initial study. Breeders can select for production attributes in breeding flocks of standard turkeys, but care must be taken to retain their ability to mate naturally and promote the health and hardiness that come with immuno-competence. Thoughtful stewardship of these agricultural treasures by today's breeders will ensure their availability for generations to come.

For more information about the conservation of standard turkeys contact the American Livestock Breeds Conservancy, PO Box 477, Pittsboro, NC 27312 919-542-5704, albc@albc-usa.org, www.albc-usa.org

Note: Special thanks to the farm participants: Gerry Cohn of Snow Camp, North Carolina; Glenn & Linda Drowns of Calamus, Iowa; Harry & Gail Groot of Hiwassee, Virginia; Paula Johnson of Las Cruces, New Mexico; Pam Marshall of Amenia, New York; Frank Reese, Jr., of Lindsborg, Kansas; Heather Bean Ware of New England Heritage Breeds Conservancy in Pittsfield, Massachusetts; and Brad Smith and Dr. Paul Mueller of North Carolina State University, Center for Environmental Farming Systems in Goldsboro, North Carolina. Thanks also to Drs. Phil Sponenberg, William Pierson, and Cal Larsen of Virginia Tech in Blacksburg and to Lance Gegner of ATTRA in Fayetteville, Arkansas for their participation and support.