ANSI 4023 Lecture 17 Poultry Genetics Student View PDF

Breeding & genetics ANSI 4023 Differences in poultry genetics 1. Breeding program is based on pedigree &/or grandparent or great- grandparent lines These are subjected to intense selection 2. Much larger number of generations subjected to intense selection due to very rapid repr...

Breeding & genetics ANSI 4023 Differences in poultry genetics 1. Breeding program is based on pedigree &/or grandparent or great- grandparent lines These are subjected to intense selection 2. Much larger number of generations subjected to intense selection due to very rapid reproduction 3. Breeding/genetics is concentrated in a few large international companies Overview of poultry company structure Genetic Selectors (genetics company) Genetic Suppliers (distributors/breeders) Commercial Producers (producers/farmers) Consumers (grocery stores) 3 Key players in commercial layer genetics 4 2 companies control layer genetics 5 Hy-Line Genetics history Founded in 1936 by Henry A. Wallace Southern IA farm Principle of Hybridization Corn breeding model as Pioneer Hi-Bred Hy-Line “Firsts” Hybridization Blood Serotyping Avian Leukosis Eradication Feather Sexing Franchise Distributors Global Production Molecular Genetics Hy-Line Genetics today Largest layer breeding program in the world Products sold in >120 Countries Hy-Line breeds recognized for Feed Efficiency Livability Productivity Unique research-to-production process Global production capability Leader in molecular genetics Key players in commercial broiler genetics Remember…  Genetic change: 3 years Broiler industry: Genetic structure Pedigree Primary breeder Great grandparents Grandparents Broiler producer Parents/Broiler breeders Broilers Bird numbers from pedigree lines to commercial broilers increase from thousands to billions Broiler industry: Genetic structure Laying hen industry: Genetic structure Pedigree 1 Primary breeders Great 10 grandparents 100 Grandparents 10,000 Parent stock 1,000,000 Laying hens 300,000,000/year Eggs Commercial hens lay an average of 300 eggs per year! Commercial genetics explained Closed pedigree lines intensely selected Great-grandparent & grandparent lines derived from these These lines crossed to give parent lines Parent lines crossed to produce broiler chicks, pullets, or poults Broiler industry takes advantage of heterosis Superior growth rate than breeders Hybrid vigor Heterosis= biological phenomenon that causes crossbreds to outperform the average of their parents Hybrid seed for corn was the first major example Inbred lines crossed (“outbreeding”) Still not fully understood Percentage hybrid vigor= Crossbred average – Parent average x 100 Parent average Origins White egg layers: White Leghorns Brown egg layers: Rhode Island Red & Plymouth Rock Male broilers: Cornish Female broilers: Barred Plymouth Rock & White Plymouth Rock Relatively limited genetic diversity at this point Goals of poultry genetic selection 1. Increased product outcome per bird (or unit of space) 2. Increased efficiency of production per unit of feed 3. Improved product quality & disease resistance Careers in poultry genetics Geneticists Computer/data specialists Veterinarians Pathologists Nutritionists Ethologists What would be key selection indices for broilers & turkeys? What would be key selection indices for layers? Other valuable selection indices for both? DISCUSSION with a classmate: What has changed since poultry lines diverged in the 1950’s? Importance of genetics to poultry production Greater progress in efficient production has been accomplished through genetics in poultry than any other livestock Key improvements: Reduced time to market (less than half) Increased market weight (more than double) Reduction in feed required (less than half) Changes in U.S. broiler performance Year Days to market Market weight (kg) FCR 1935 98 1.3 4.4 1955 70 1.4 3.0 1975 56 1.7 2.1 1995 47 2.1 1.95 2015 48 2.8 1.89 2018 47 2.9 1.82 2023 47 3.0 1.75 U.S. per capita meat consumption But genetics aren’t everything… Nutrition Housing Ventilation Cannibalism Hazards in cage-free systems Disease prevention Parasites Bacterial infection Viruses: Biosecurity Genotype x environment= phenotype Skin & shank color: yellow shanks Carotenoid pigments in the epidermis from diet Lack of melanin pigment is genetic Livability Viability is greatly influenced by diet, husbandry, & vaccinations Birds show genetic differences in disease resistance/susceptibility Geneticists have focused on strains with higher livability 2-3% mortality vs. 25% from leukosis Genotype x environment = phenotype Egg color Breed/genetics Brown eggs: higher levels of protoporphyrin IX between calcium carbonate crystals in the shell gland Blue eggs: contain oocyanin, a bile production byproduct White eggs: absence of pigment Beginning of lay= lighter shell color Coccidiostat drug nicarbazin causes a loss of coloration