American Bison - Buffalo Field Campaign

4.3 Domestication
The number of bison in commercial herds has grown rapidly over
the past five decades as many ranchers enter the bison industry
to capitalise on the economic opportunities offered by this
species (Dey 1997). The increase in commercial bison production
may reflect the recognition of the advantages afforded by the
adaptations and ecological efficiency of bison as an indigenous
range animal. Bison possess several traits that make them
preferable to cattle as a range animal, including a greater ability
to digest low quality forage (Hawley et al. 1981; Plumb and
Dodd 1993), the ability to defend against predators (Carbyn et
al. 1993), the ability to survive harsh winter conditions, and a low
incidence of calving difficulties (Haigh et al. 2001). According to
federal government surveys, the commercial bison population
in North America is about 400,000, divided almost equally
between the U.S. and Canada (Chapter 7). Despite the current
plateau in beef and bison meat prices, both the Canadian Bison
Association and the U.S.-based National Bison Association
predict very favourable long-term growth of the bison industry.
The number of bison in conservation herds is currently estimated
at only 20,504 plains bison and 10,871 wood bison. Therefore,
approximately 93% of American bison are under commercial
production and experiencing some degree of domestication.
Domestication is a process involving the genotypic adaptation of
animals to the captive environment (Price 1984; Price and King
1968). Purposeful selection over several generations for traits
favourable for human needs, results in detectable differences
in morphology, physiology, and behaviour between domestic
species and their wild progenitors (Darwin 1859; Clutton-Brock
1981; Price 1984). Humans have practiced domestication of
livestock species for at least 9,000 years (Clutton-Brock 1981).
As agriculture precipitated the settlement of nomadic human
cultures, the domestication of several wild mammal species
made livestock farming possible (Clutton-Brock 1981). Intensive
management practices and competition between domesticated
animals and their wild ancestors often pushed wild varieties
and potential predators to the periphery of their ranges or to
extinction (Baerselman and Vera 1995; Hartnett et al. 1997;
Price 1984). Examples of extinct ancestors of domesticated
animals include the tarpan (Equus przewalski gmelini), the
wild dromedary (Camelus dromedarius), and the aurochs (Bos
primigenius) (Baerselman and Vera 1995).
The domestication of cattle provides a relevant history from
which to consider the issues of bison domestication. Before
cattle (Bos taurus) were introduced to North America they had
experienced thousands of years of coevolution with human
cultures in Europe (Clutton-Brock 1981; Hartnett et al. 1997).
During the domestication process cattle were selected for
docility and valued morphological and physiological traits,
but not without adverse consequences. Genetic selection has
24 American Bison: Status Survey and Conservation Guidelines 2010
produced an animal that is dependent on humans, is unable to
defend itself against predators, and has anatomical anomalies,
such as a smaller pelvic girdle, which cause calving and walking
difficulties (Kampf 1998; Knowles et al. 1998; Pauls 1995).
Domestication has altered the wild character of cattle, producing
animals maladapted to the natural environment. Furthermore,
because the aurochs, the wild ancestor of European domestic
cattle, became extinct in 1627 (Silverberg 1967), domestic cattle
have no wild counterpart to provide a source of genetic diversity
for genetic enhancement and maintenance.
While it has been suggested that domesticated animals can
be reintroduced into the wild and revert to a feral state (Kampf
1998; Lott 1998; Turnbull 2001), such attempts do not restore
the original genetic diversity of a species (Price 1984; van Zyll
de Jong et al. 1995). Experience has shown that recovery of
original genetic diversity is difficult or impossible once domestic
breeds are highly selected for specific traits and wild stocks are
extinct (Price 1984; Turnbull 2001; van Zyll de Jong et al. 1995).
For example, in the 1920s, two German brothers, Heinz and
Lutz Heck, set out to “re-create” the aurochs by back-breeding
domestic cattle with other cattle demonstrating aurochs-like
qualities (Fox 2001; Silverberg 1967; Turnbull 2001). They
produced one successful line, the Hellabrunn breed, also known
as Heck cattle. This is an animal that looks very much like an
aurochs, but is devoid of the wild traits and hardiness of the
original wild form (Fox 2001; Silverberg 1967). This illustrates
that the original wild genotype is no longer available to the
cattle industry for improving domestic breeds. The history of
the aurochs offers a lesson for bison: domestication can lead
to altered genetically based behaviour, morphology, physiology,
and function, and the loss of the wild type and the genetic
diversity it contains.
The primary goal of many commercial bison ranchers is to
increase profits by maximising calf production, feed-to-meat
conversion efficiency, and meat quality (Schneider 1998).
This requires non-random selection for traits that serve this
purpose, including conformation, docility, reduced agility, growth
performance, and carcass composition. Selection for these
traits reduces genetic variation and changes the character of
the animal over time (Schneider 1998). Although a growing
number of consumers prefer naturally produced meat products
without hormones, antibiotics, or intensive management (Morris
2001), the demand for bison cannot currently compete with the
much larger scale of the beef industry. Therefore, many bison
producers apply cattle husbandry practices and standards to
bison. Artificial selection based on husbandry and economics
may make good business sense in the short term, but it will not
conserve native bison germplasm.
The long term objectives and goals that drive commercial bison
production generally differ from the major issues associated with