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Comprehending Selective Breeding

Written by Alana Schoffstall, Director-Project Management & Marketing, American Kunekune Pig Registry

Are you prepared to develop a breeding strategy in order to recognize and realize your individual herd goals?

Well then let’s get started. 


The first and most important step towards anything at all is the power of selection.   You’ve likely already practiced this rudimentary skill—you’ve chosen your base stock.   Now let’s familiarize ourselves with how we intend to govern our choice Kunekunes to develop breeding program of significance. 


Selection is a powerful tool for changing or maintaining an animal population, and is a critically important aspect of breed maintenance.  Selection is a very important source of uniformity within breeds and herds.  Any individual breeder tends to favor a certain look and function over others.  Over time a herd under a single breeder’s care and selection will tend to express that look more and more strongly.  Selection and inbreeding frequently act together as potent forces for uniformity especially in individual herds.  – D. Phillip Sponenberg/Dongald E. Bixby, Managing Breeds for a Secure Future 


Selection will play a role regardless of which of the following strategies you utilize.   Each pairing you mate….Each animal you retain…Each animal you harvest…  These choices, dictated by you, the overseer, govern your program further in the direction you envision for your herd. 


First let’s refresh a few important points.  

The Kunekune breed is a standardized breed:

Standardized breeds are those which are enrolled in a herd book, and specifically mated to conform to a written standard (usually called a breed standard, or a standard of perfection) that describes the ideal physical (or in some cases behavioral) type of the breed.*

The Kunekune is a head breed:

A wide head, dished face, and short snout which becomes increasingly upturned as the pig matures—The American Pig Registry Breed Standard In a head breed the structure of the head is preponderant.  The most defining element of breed type…

The Kunekune is a small heritage breed:

Relatively short legs, ranging in weight between 100-300lbs.  Kunekunes mature at a slower rate into their third or fourth year of age.  They are a lard breed like most antiquarian breeds of swine.


 Heritage breeds are traditional livestock breeds that were raised by our forefathers. These are the breeds of a bygone era, before industrial agriculture became a mainstream practice. These breeds were carefully selected and bred over time to develop traits that made them well-adapted to the local environment and they thrived under farming practices and cultural conditions that are very different from those found in modern agriculture. –Livestock Conservancy:


Breeds can only be sustained if their biological character and political aspects are both managed for success.  Understanding the basic strategies of conserving a heritage breed are vital.  The very definition of a “breed” is a group of genetically consistent animals that reproduce themselves.   Breeds breed true.  So our goal is to govern our herds to breed true to Standard.   How do we consistently do that?  Regardless of which of the following methods you put into practice throughout the duration of your breeding program selection will take prominence. 

As we know, the Kunekune breed was a critical breed not so very long ago.  When a breed population plummets to fewer than 100 animals (The Livestock Conservancy definition of a critical breed) , and in the Kunes’ case, much less than even that, all remaining animals are utilized for conservation.   As of 2014 the American Kunekune is no longer critical or even threatened.  With over 3000 animals registered in the Foundation Herd Book the breed is achieving recognition as a recovering heritage breed. 

As breeders we need to shift from the mindset that our breed is in need of diverse genetics and realize that we are now in need of strong genetics.    There is no longer a need to perpetuate “genetic diversity”.  The time has come to direct our herds for the future—to promote our breed as a progressive component in the trending agricultural market.  By molding our methods to meet the Standard of Perfection we will produce animals suitable for pasture, pork, and progeny.  Breeds breed true. 


Linebreeding  and Inbreeding are two terms closely entwined.  The definition of inbreeding is, technically, the pairing of any related animals.   Ideally, linebreeding would involve the pairing of less related animals (uncle to niece or grandparent to grand-offspring) without pairing so closely as to mate first degree relatives—offspring, parents, and siblings.

Linebreeding and inbreeding form the basis of “selective” breeding and standardized breeds.  Pioneer livestock breeders relied upon these two practices long before science had advanced enough to explain genetically what they were accomplishing.  Thus breeding is rightly termed an art:  the expression or application of human creative skill and imagination.  And as we know all art incorporates science to some degree.  

Linebreeding produces and increases genetic uniformity in offspring.  As the gene pool is limited generation after generation by selectively pairing related animals, uniformity of appearance and performance is achieved. Linebreeding increases homogeneity and predictability and is a reliable asset if practiced responsibly.   Note that this uniformity can be either favorable or unfavorable and that the quality of the base stock and government of the breeder will determine the end result.  These two methods must be employed with a staunch and unyielding commitment that detrimental or undesirable traits be ruthlessly culled out of the breeding population.  


In the words of one of them most noteworthy selective breeders of Kunekunes—Andy Case of Long Ash Farm, Dorsett England “Breed close and cull hard.”


 It should be every programs goal to produce a productive and predictable breed type.  Breed type is the sum of physical, behavioral, and functional traits, and while these may not always relate directly to functional conformation they do serve as important indications of the integrity of a breed’s genetic package.*  You see, without consolidating genetics in order to breed true we would in fact, be accomplishing the opposite.  Instead of focusing on diversifying the genes (genetic instability) within our herds, we rather focus on accomplishing genetic strength. 


Each breeder must tailor a strategy for the specific mix of philosophies, situations, and goals that are unique to the herd he or she is breeding. 

– D. Phillip Sponenberg/Dongald E. Bixby, Managing Breeds for a Secure Future 


Not every keeper of Kunekunes will progress to become a breeder capable of manipulating and improving and the breed to such a scale, but fanciers still play an important role in breed conservation as they contribute to population and facilitate awareness of the breed’s assets. 


Can problems arise?   What are the problems I should look for?

In order to maintain responsibility should a problem arise, an outcross would be made.  Outcrossing is a philosophical and biological opposite of linebreeding/inbreeding.* Outcrossing or outbreeding is recognized as either crossbreeding or linecrossing.  Since we are working with purebred herds only lincrossing applies.

In order to understand linecrossing we must first understand the definition of a bloodline.  

A bloodline is a subpopulation within a breed that has been isolated from other lines or strains for several generations—usually four or more. Due to this isolation the genetics contained within said bloodline are somewhat genetically distinct from the other lines.

A few of the common problems that may appear if we have been unintentionally consolidating negative recessive traits in our herds are loss of general vigor and especially loss of reproductive performance.  (Those of us who have been breeding since the beginning remember when reproductive performance was a very real concern.   Today thanks to responsible outcrossing those concerns have dwindled almost completely.) 

Should we begin to suspect that we are encroaching upon negative performance we would then choose to outcross.  By outcrossing/linecrossing to a diverse line we should experience a burst of “hybrid vigor” achieved from mating two unrelated parents.  While it is not the true hybrid vigor obtained through crossbreeding, the effect is nonetheless sufficient to alleviate the consolidation of unwanted genetics expressed.   For a fully comprehensive explanation of outcrossing, linecrossing, and crossbreeding reference Managing Breeds for a Secure Future, D. Phillip Sponenberg/Donald E. Bixby, published by the Livestock Conservancy 

Usually, unless a herd is of substantial size, and individual lines (subpopulations) are rigidly maintained within that herd, you would look outside your own herd for a suitable animal to outcross.  This further emphasizes the case for each breeder seeking to develop their own herd strength.  If breed conservation is approached by the philosophy that genetic diversity be amassed and maintained by each individual breeder there will be no betterment of the breed.   Problems will arise that are breed wide with no suitable amendment available.   Only by responsible and rigid government will the Kunekune population thrive and excel.  By establishing our own genetic dominance within individual herds we are, in a sense, creating our own bloodlines.   This community of distinctive, purebred, genetic pockets can then be interchanged within programs as the need arises.   And as breeders always looking to improve, unique accomplishments within others’ herd will also draw us to incorporate an outcross into our own herd towards a favorable end.  A fellowship of passionate breeders producing towards a Standard of Perfection is truly breed conservation. 


The ability to utilize linebreeding to the fullest can only be achieved through time and experience.  Recognizing individuals with positive genetic strengths and then saturating generations with these consolidated traits takes time and patience.   It is not a one litter fix but a long term goal. 

Dedication and endurance combined with passion for the Kunekune breed will propel your herd to excellence.   The American Kunekune Pig Registry is in place not only to keep the Foundation Herd Book and Standard of Perfection but to empower its registered breeders by research, documentation, public awareness, educational publications, sanctioned showing and events, as well as individual guidance. 

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