Lec 3

• Genetics


  A discipline of life sciences, concerning the heredity, inheritance of characters
• Animal Breeding


  The application of principles of genetics in the breeding and selection of animals
• Animal Breeding


  • To improve productivity of livestock
  • To enhance animal care
• Pharmacogenomics


  How genetic characteristics affect response to drugs
• Pharmacodynamics


  Drugs interaction with cell receptors
• Gene therapy


  1. Viral transfection

  2. Liposomes
• Antisense technology


  Altering gene expression using drugs to increase or decrease, modify DNA methylation
• Sub-disciplines of genetics in Animal Breeding


  • Mendelian/Classical Genetics
  • Population Genetics
  • Qualitative Genetics
  • Quantitative Genetics
• Genetics


  A discipline of life sciences, concerning the heredity, inheritance of characters
• Animal Breeding


  The application of principles of genetics in the breeding and selection of animals
• Animal Breeding


  • To improve productivity of livestock
  • To enhance animal care
• Pharmacogenomics

  How genetic characteristics affect response to drugs
• Pharmacodynamics

  Drugs interaction with cell receptors
• Gene therapy


  How to alter gene expression using drugs to increase or decrease DNA methylation
• Gene therapy - Viral transfection

  1. DNA virus infects host cells: antibody reaction

  2. Liposomes fail to be absorbed or rapidly degrade new DNA
• Antisense technology


  Altering gene expression using drugs to increase or decrease DNA methylation
• Sub-disciplines of genetics in Animal Breeding

  • Mendelian/Classical Genetics
  • Population Genetics
  • Qualitative Genetics
  • Quantitative Genetics
• Use of genetic principles in livestock improvement


  • Improving yield and performance
  • Reducing genetic defects to increase survivability and animal care
  • Exploiting genetic resources to enhance adaptability
  • Breeding for more efficient animals to reduce cost
• Benefits of applying genetic principles in livestock improvement

  • Increase farm income
  • Give high return on investment
  • Reduce importation of livestock products
  • Expand various industry sectors including supply chain components
• Roles of applying genetic principles in livestock production

  • Improve the performance of animals in terms of productivity and adaptability
  • Reduce frequency of cases of genetic defects that reduce productivity and adaptability
  • Utilize genetic resources available to enhance productivity and adaptability
• Breeding for Commerce - First concern

  Yield: High number, heavy body weight, high volume
• Production Traits of Economic Importance

  • Dairy cattle: Milk yield, % milk fat, % milk protein, conception rate, no. of services per conception
  • Beef cattle: Weaning weight, average daily gain (ADG), calving rate, dressing %, % lean in carcass
  • Meat goats: Weaning weight, kidding rate, ADG, % lean in carcass
  • Poultry - layers: Egg number, egg weight
  • Poultry - broilers: Feed conversion ratio (FCR), feed intake, body weight, yield of breast portion
  • Swine: Body weight, ADG, FCR, litter size
• Breeding for Commerce - First concern

  • Brangus bull (beef cattle): Breeding for higher body weight as a 2-year old
  • Boer goat (meat goat): Breeding for heavy weight at 9 months of age
  • Broiler chickens: Breeding for high feed efficiency
  • Layer chickens: Breeding for high egg number
• Breeding for Commerce - Second concern


  • Survivability & reduced mortality
  • Fertility & prolificacy
  • Disease resistance & parasite tolerance
• Breeding for Commerce - Third concern

  • Presence of genetic defects - identification of carriers
  • Reducing frequency of congenital birth defects
• Breeding for Show

  Displaying best phenotypes in terms of hair/feather colour, pattern, symmetry in physical features
• Breeding for Performance

  Selecting animals to excel in certain activities like racing, endurance
• Some breeds have higher endurance capability trotting over longer distances, e.g. Arabian horses than Thoroughbreds
• Racing Thoroughbred horses have been selected for speed over short distances
• Breeding for More Efficient Animals


  Finding breeds more efficient in feed conversion ratio (FCR) to reduce production cost
• Use of selection index to select for several traits simultaneously weighted for economic importance
• Genetic Defects


  Deformities that exist at birth, many are lethal or semi-lethal
• Genetic Defects in Sheep

  • Cleft palate, cryptorchidism, spider leg, inverted eyelids
• Metabolic Errors in Cats

  Mucopolysaccharidosis - a group of lysosomal storage disorders that involve the deficiency of specific enzymes required for the degradation of glycosaminoglycans
• Effects of Genetic Defects

  • Reduced productivity/total farm output in farm animals
• Congenital Birth Defects in Dogs

  Due to chromosomal recombination and alteration during meiosis, all dogs carry hidden recessive genes, close inbreeding in show dogs may lead to desirable or undesirable characteristics
• Congenital Birth Defects in Dogs

  • Hip dysplasia in Labradors
• Genetic Animal Models of Diseases

  • Overexpression of G93A mutation in superoxide dismutase (SOD) created a mouse model of ALS
  • Initial animal models for Alzheimer's disease lacked manifesting the full spectrum of the disease
• Animal Genetic Resources


  Both of native and introduced origins, having valuable adaptive merit for disease resistance, parasite tolerance, and mitigating climate change effects
• Animal Genetic Resources


  • Chickens - Kampong chickens, jungle fowl
  • Ducks - Jawa ducks
  • Goats - Kajang, Jamnapari
  • Cattle - Kedah-Kelantan, Bali
  • Buffalo - Swamp buffalo, Murrah buffalo