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Line Breeding to Outcrossing-What's it all about?
By Daniel Powell
 Traditionally,
North American llama breeders have shunned all facets of line
breeding. But as the suri llama industry stands poised to
move to breed status, and become respected as a healthy livestock
investment, owners need to recognize that line breeding has
given rise to nearly every breed of domestic animal that walks
the planet. Even our painstakingly out-crossed modern llama
herds descended from judiciously line bred pre-Columbian ancestors.
This being the case, why do so many serious breeders uphold
a tradition that has done nothing to create predictability,
sustainability, and therefore value in their herds?
Complications of Tradition
In the early days of llamas in North America, out-crossing
became the preferred modus operandi. The llama population
was extremely small, and the "forefathers" of the
industry were more conservationists of rare exotics than livestock
breeders with the goals of predictability and uniformity in
the herds.
As traditions have been handed down, the llama breeding community
has inherited a disdain for any degree of inbreeding or linebreeding,
and a distinct bias in favor of out-crossing. While out-crossing
has great value as a breeding tool, if it is not judiciously
used it can quickly create a lack of uniformity and genetic
unpredictability in a population.
Out-crossing decreases the chance that an individual's offspring
will be similar to itself. In a breeding program where out-crossing
is used generation after generation, outstanding suri llamas
may emerge, but they will not be pre-potent for type. Some
very successful breeders of other livestock regularly line
breed; use a judicious outcross to "infuse new blood",
and then go back to the line bred family for the next generation.
Alternating in this manner can be an excellent way to avoid
the pitfalls of constant line breeding while maintaining a
high level of uniformity in an established herd.
"Urban Legends" in the Country?
To my knowledge, a "line" in the true sense does
not exist in the North American llama population. Still, the
term "line" is commonly used loosely and generally
over-used. Llama breeders may refer to an animal as of the
"Kantu line" when the animal is merely a great,
great granddaughter of the legendary Kantu. Consider that
after four generations of out-crossing, that animal would
statistically have inherited no more than 6.25 percent of
its genes from Kantu. Only if Kantu appears on both sides
of an animal's pedigree may that animal be accurately said
to be 'line bred to Kantu'. (Understanding this principle
alone makes it easy to see why we have only begun to tap the
genetic power of some of these great suri sires and dams,
and also why we are in no imminent danger of having a bottleneck
of suri gentics. See Boys
On the Side)
The term "line", when properly used, refers to
a group of line bred animals maintained as such for the purpose
of concentrating the genes of an exceptional ancestor or group
of ancestors. A well-maintained line demonstrates all the
health, vigor, and reproductive soundness of the general population,
but it is also pre-potent for the valued traits. Prepotency
refers to an animal's ability to reproduce consistently its
likeness in its offspring.
Selecting for the Ideal
The aim of line breeding is to produce llamas that are a
desired type and which can reliably reproduce their characteristics
in their offspring. When combined with proper selection, line
breeding results in the production of individuals with a greater
degree of homozygosis for those desirable traits of the common
ancestor. It is this homozygosis that is the machinery of
prepotency. Line breeding, when practiced properly, can be
a powerful tool in producing pre-potent individuals and in
"fixing" desirable characteristics in a herd.
Particularly important to the process of fixing traits and
creating sustainability is the selection and creation of superior
individuals that represent the ideal animal. Special attention
must be paid to an animal's phenotype, how closely it represents
the breed standard, and also to its parents. The ideal suri
llama should represent the idealized animal phenotypically
as set forth by the breed standard and be free of undesirable
traits, such as light wool coverage and light bone. But further,
the desired goal is that the animal should be the "spittin'
image" of both its dam and sire. In short, it should
already be the product of "like to like" breeding.
The Bad Comes with the Good
Unfortunately, undesirable characteristics are inherited
just as easily as desirable ones, and those characteristics
also can become "fixed" in a herd. Line breeding
should be considered only if the common ancestor is truly
outstanding, and defect-free. Any faults present in the common
ancestor will become obvious in the line bred offspring. In
fact, the faults can be more serious in the progeny, since
that generation is likely to be pre-potent for such traits
and may, in turn, consistently pass on these defects. Thus,
line breeding is the proverbial double-edged sword.
In the hand of a breeder skilled in the art of selection
and unrelenting in culling practices, line breeding can very
quickly sculpt a herd of masterpieces. But, in the hand of
the unskilled, sentimental breeder with an untrained eye and
a lack of understanding of pedigrees, the double-edged sword
of line breeding can be the undoing of the breeder' enterprise.
Fame can be Fleeting
It then becomes of paramount importance for a breeder to
undertake a thorough investigation of pedigrees before any
line breeding program is considered. It might be assumed that
a llama that had been a famous producer would naturally be
a prime choice to whom to line breed, but this is not necessarily
the case A famous ancestor must be viewed in the context of
the era in which it became famous. While it may have out-produced
every animal of its time, it may still fall far short of standards
and requirements expected of top producers today.
The Importance of Homework
Line breeding, a mild form of inbreeding, does not pose the
risk that many imagine. But a very real drawback of line breeding
is the potential for "inbreeding depression." Inbreeding
does not necessarily cause genetic defects; it simply exposes
hidden recessive traits, many of which are deleterious.
Inbreeding depression is outwardly expressed as a loss of
vigor and reduced reproductive fitness, and it typically increases
as the degree of inbreeding increases. Not all species, breeds
or lines within breeds have the same tolerance to inbreeding.
Some withstand a high level of inbreeding without any adverse
effects, others tolerate very little. For most domestic species,
brother-sister mating is considered to be too close, while
half-sibling pairings are considered to be safer. First cousin
mating -- as well as granddaughter to grandsire mating --
can be very useful and safe, provided a breeder has done the
necessary homework and the animals being used represent the
ideal specimen.
In the Interests of Progress
Considering the potential for inbreeding depression and exposing
deleterious hidden recessives, why would one consider line
breeding as a possible breeding program component? The answer
is straightforward as evidenced among all purebred animals:
line breeding is the surest way to create uniformity and prepotency
for the traits we desire. Without it, the very machinery of
domestication would grind to a halt.
With the decision to line breed comes the profound responsibility
of stewardship and shaping the future of our camelid resources.
Suri lama breeders choosing to enter this bold frontier, this
inevitable next phase of the llama breeding tradition, have
at their disposal a treasure trove of unpolished genetic wealth.
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