Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Behavior is shaped by both genetics and experience--nature and nurture. This book synthesizes research from behavioral genetics and animal and veterinary science, bridging the gap between these fields. The objective is to show that principles of behavioral genetics have practical applications to agricultural and companion animals. The continuing domestication of animals is a complex process whose myriad impacts on animal behavior are commonly under-appreciated. Genetic factors play a significant role in both species-specific behaviors and behavioral differences exhibited by individuals in the same species. Leading authorities explore the impact of increased intensities of selection on domestic animal behavior. Rodents, cattle, pigs, sheep, horses, herding and guard dogs, and poultry are all included in these discussions of genetics and behavior, making this book useful to veterinarians, livestock producers, laboratory animal researchers and technicians, animal trainers and breeders, and any researcher interested in animal behavior. Includes four new chapters on dog and fox behavior, pig behavior, the effects of domestication and horse behavior Synthesizes research from behavioral genetics, animal science, and veterinary literature Broaches fields of behavior genetics and behavioral research Includes practical applications of principles discovered by behavioral genetics researchers Covers many species ranging from pigs, dogs, foxes, rodents, cattle, horses, and cats

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Over-selection for production traits has caused animal welfare problems such as feather pecking in hens, tail biting in pigs, and overly aggressive animals. In dogs, over-selection for appearance traits has caused neurological problems such as deafness. Both feather pecking and tail biting may be displaced foraging behaviors, because these behaviors are reduced by providing foraging materials such as straw. Another problem is hunger in broiler breeder hens and breeding sows. Animals that have been selected for rapid growth are also selected for a huge appetite. If breeder animals eat to satiation, they will become obese and have health problems. High-roughage feeds may improve welfare. Researchers suggest that new genetic breeding tools could be used to select against harmful behaviors and still have a productive animal. Breeders must avoid creating animals that will have poor welfare even when they are housed in the best environment.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

The domestic dog has many phenotypic and behavioral forms. In this chapter we describe five different kinds of dogs and how each has been derived. We trace the background village dog adapting to the age of agriculture, with the coincident transformation of human behavior to permanent settlement. Over centuries, this village dog has changed, adapting to its different geographies and to local agricultural activities. In tandem, people began sorting through the village populations for dogs with appropriate behaviors, and these eventually became the founding stock for breeding programs. In recent centuries, samples of these working and hunting breeds have been collected by kennel clubs, and sexually isolated, becoming at best historic representations of the working or hunting breeds. More commonly they are used as pets, or household dogs, sometimes with sport competitions in the show or agility ringl

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Since the late 1990s there has been a substantial increase in horse behavior genetics research. This chapter reviews recent work in molecular genetics, pre-and postnatal effects on behavior, the relationship between hair whorls and temperament, and lateralization in the nervous system. These factors are critical to understanding individual differences. Advancements in molecular genetics have identified genes associated with novelty seeking and gaited horse traits. Foal “imprint” training procedures are reviewed, and a gentle method for training foals is presented. Finding appropriate methods for reducing fearfulness in horses has important practical implications. High hair whorls are associated with reactivity, but differences are less apparent in calm breeds. Behavioral asymmetry is a fundamental feature of animal brains. Left-eye systems control avoidance behavior and right-eye systems control approach behaviors. An understanding of the cognitive and perceptual abilities is necessary to ensure horses receive proper training, handling, management, and care.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Behavior is shaped by both genetics and experience--nature and nurture. This book synthesizes research from behavioral genetics and animal and veterinary science, bridging the gap between these fields. The objective is to show that principles of behavioral genetics have practical applications to agricultural and companion animals. The continuing domestication of animals is a complex process whose myriad impacts on animal behavior are commonly under-appreciated. Genetic factors play a significant role in both species-specific behaviors and behavioral differences exhibited by individuals in the same species. Leading authorities explore the impact of increased intensities of selection on domestic animal behavior. Rodents, cattle, pigs, sheep, horses, herding and guard dogs, and poultry are all included in these discussions of genetics and behavior, making this book useful to veterinarians, livestock producers, laboratory animal researchers and technicians, animal trainers and breeders, and any researcher interested in animal behavior. Includes four new chapters on dog and fox behavior, pig behavior, the effects of domestication and horse behavior Synthesizes research from behavioral genetics, animal science, and veterinary literature Broaches fields of behavior genetics and behavioral research Includes practical applications of principles discovered by behavioral genetics researchers Covers many species ranging from pigs, dogs, foxes, rodents, cattle, horses, and cats

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Dog domestication involved long-term genetic selection for behavior. The genetics-centered view of domestication is supported by experimental selection of farm-foxes (Vulpes vulpes) that began in the 1950s. Selection of foxes, separately, for tame and for aggressive behavior, has yielded two strains with markedly different, genetically determined behavioral phenotypes. Tame-strain foxes communicate with humans in a positive manner and are eager to establish human contact. Foxes from aggressive strains are aggressive to humans and difficult to handle. Although selected solely for behavior, changes in physiology, morphology, and appearance with significant parallels to characteristics of the domestic dog, were observed in tame-strain. Ongoing research is focused on identification of molecular genetic mechanisms associated with selection of foxes for behavior. Identification of behavioral loci in the fox genome in the region which is homologous to the region in the dog genome that differentiates dogs from wolves lead to the hypothesis that domesticated behavior in dogs and foxes may have similar genetic bases.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

In these classic experiments, quail chicks were selectively bred for the behavioral traits of fear and social reinstatement. Over a period of 20 generations, four separate genetic lines were created. They were high and low fear and high and low social re-instatement. The duration of tonic immobility was used as a measure of fear and social reinstatement was measured with a treadmill test. In this test, the time that a bird will walk on a treadmill to stay close to its flockmates is measured. Since the publication of this chapter in 1998, many scientists have carried out with these genetic lines. Duration of tonic immobility does not all measure all types of fear. Fear maybe multidimensional because selection for tonic immobility has little effect on behavioral reactions to novelty. More recent research has also discovered linked traits such as low social reinstatement birds have stronger ultradiam rhythms.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

In this chapter, we begin by defining domestication as a genetic process, whereby animals change phenotypically and genetically as a response to living under human supervision. This has caused a convergent set of phenotypic modifications across numerous different species, through a combination of relaxed natural selection, increased human selection, and correlated responses. The genetic mechanisms underlying these processes are discussed in addition to genetic drift and inbreeding. The driving types of mutations are dealt with, as is the way in which genes are organized in the genome to give rise to a specific genetic architecture facilitating selection responses. The different methods used to discover genes and mutations are divided into either top-down approaches, where one starts with the phenotype and uses mapping methods to find the causative genes, or bottom-up, where the genetic polymorphism is the starting point and the phenotype the desired response variable. A number of examples of single genes and mutations that have been coupled to behavioral variation are given, among them genes showing pleiotropic effects on pigmentation, and genes involved in regulation of the effects of neuropeptides. Finally, the relatively novel area of behavioral epigenetics is examined, in particular with its possible relation to domestication effects.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Research in behavioral genetics is important for pig welfare. Consequences of the ongoing selection for high production on pigs’ behavior need to be studied, as well as possibilities to select directly for changed behavior. The Farm Animal Welfare Council’s definition of welfare is based on five freedoms related to hunger and thirst, discomfort, pain, injury or disease, fear and distress and normal behavior. All these freedoms are associated with pig behavior. Maternal behavior related to piglet survival and aggressive behavior of pigs kept in groups are especially important for welfare. Pig breeding programs could be further developed by including behavioral traits relevant for welfare.

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Genetics and the Behavior of Domestic Animals

Different tests have been developed for evaluating the temperament of cattle, pigs, and sheep and some studies appear to have conflicting results. This may be due to confusion between the basic emotional systems of fear and separation distress (panic). Methods used for temperament tests can alter results such as how tightly an animal is restrained in a squeeze chute during temperament evaluation. Animals with a more reactive (fearful) temperament will exhibit greater agitated behavioral reactions when suddenly confronted with novel objects. Animals can be habituated to new things but learning is very specific. Habituation to one type of strange object may not transfer to other types of objects. Animals with smaller-diameter leg bones and slender bodies may be more reactive (fearful). Facial hair whorl position is related to a vigilant temperament and it may be more evident in populations with more diverse genetic backgrounds.