Growth rate and weight are important factors. Large breeds - Golden Retrievers, Labrador Retrievers, and Saint BernardsĪbnormal development of the elbow joint that can lead to inflammation. Although polygenic traits are complex, the ability of careful selective breeding practices to alter characteristics, such as hip dysplasia and other physical features, demonstrates that some control over polygenic traits is possible.Ī condition in which the hip joint develops incorrectly and can lead to inflammation. Because multiple (and often undiscovered) genes are involved, these traits are difficult to predict and control through breeding.
Most aspects of a dog’s phenotype, including height, gait, and appearance, are controlled by polygenic traits. It is this polygenic nature of traits that breeders must understand, because unobserved genetic traits that exist in the otherwise “ideal” dog may come to light with some breeding practices. However, other modifying genes can impact the expression of coat color, such as the modifying dilution gene that leads to the expression of black coat color as grey. Black is the dominant form of the gene and in the absence of a single dominant black gene, red (or tan) coat color can be expressed and is the recessive condition. An example of dominance is the gene that controls coat color. If those differ in form, one will have a greater influence (termed dominance) on the observed trait, and the other will have less influence (termed recessive). In the simplest terms, for most genes there are two versions (alleles) that are inherited.
TRAINING FOR NARCOLEPSY CATAPLEXY ANXIETY SERVICE DOGS SERIES
Although the information in this series may be applicable to any breed or mixed breed, it will focus on the most commonly used breeds for service dog work: Labrador Retrievers, Golden Retrievers, German Shepherd Dogs, Saint Bernards, Collies, and Cocker Spaniels.Ībout 500 genetic diseases have been identified in purebred dogs, and it is presumed that every dog is a carrier for several defective genes. Retriever breeds are often selected for mobility assistance because of their consistent temperament, trainability, and their predilection to retrieve objects ( Burghardt, 2003 Weiss & Greenberg, 1997 Ostrander, et al., 2006). Table 1 shows the common breeds and their general characteristics. Several breeds of dog have many of the necessary morphological (the form and structure of an organism) traits and general behavioral tendencies suitable for assistance work. The current article addresses morphological and health considerations the remaining articles will focus on behavior and temperament characteristics and research in the field of service dog training. This is the first of three articles on the selection and breeding of dogs for service work. Service dog training programs nationwide can benefit from selecting and breeding dogs based on characteristics relevant to their service dog specialty. Targeted selection and breeding of physically and behaviorally healthy dogs would allow organizations to allocate their resources more efficiently, reduce training costs, and increase the supply of service dogs to those in need. Hereditary diseases and behavioral problems are the most common reasons for a dog to be released from a training program ( Wahl, Herbst, Clark, Tsai, & Murphy, 2008). According to some estimates, only 50% of dogs entering training progress to the level of service dog ( Batt, Batt, Baguley, & McGreevy, 2008), increasing the cost of training and limiting the number of available dogs. Service dogs are generally trained for a minimum of 18 months, and training can cost anywhere from $10,000 to $20,000 ( Allen & Blascovich, 1996). Winkle, Crowe, & Hendrix, 2012), and average wait times of up to three years for a well-trained dog are not uncommon. They are trained to “provide work or perform tasks related to an individual’s disability.” When accompanied by a service dog, the individual with a disability is afforded some public access protections ( Parenti, Foreman, Meade, & Wirth, 2013).Ĭurrent demand for service dogs outweighs supply ( M. Service dogs include dogs for mobility, vision, hearing, developmental disabilities, diabetic alert, seizure alert, and psychiatric support.
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