Poultry Breeding and Genetics PDF PowerPoint 2024

Poultry Breeding and Genetics APSC 301 Poultry Science Bartlett, 2024 APSC 301  Poultry Breeding Breeding uses principles of applied genetics to develop strains or breeds that are best suited for production of meat and eggs Poultry breeding has reached pract...

Poultry Breeding and Genetics APSC 301 Poultry Science Bartlett, 2024 APSC 301  Poultry Breeding Breeding uses principles of applied genetics to develop strains or breeds that are best suited for production of meat and eggs Poultry breeding has reached practical levels not even approached by large animal breeding Bartlett, 2024 APSC 301  Poultry Breeding – Due to unique biological advantages: – Chickens reach sexual maturity at an early age – Female chickens can potentially produce a fertilized egg every day – Embryonic development takes place outside the body of the female – Incubation period is only 21 days Bartlett, 2024 APSC 301  Poultry Breeding These are traits contributing to an increase in net returns for the producer: – Fertility – Hatchability – Growth rate – Egg production – Feed conversion (Feed efficiency) Bartlett, 2024 APSC 301  Poultry Breeding Continuous genetic improvements, in combination with management practices, the poultry industry is growing at about 5% annually Bartlett, 2024 APSC 301  Poultry Breeding Major interests of animal breeders: – Increase product output per bird – Increase efficiency of production – Improve quality of product (eggs and meat) Bartlett, 2024 APSC 301  Poultry Breeding Hens- Traits of economic importance as measured by the Random Sample Egg Laying Tests: – Large numbers of large and extra large eggs – Rearing and laying mortality – Body weight – Albumen quality – Feed conversion – Hatchability – Shell thickness Bartlett, 2024 APSC 301  Poultry Breeding Broilers and turkeys: – Fast growing – Acceptable body conformation – Good feed conversion ratio – Free from leg weakness – Resistance to diseases Bartlett, 2024 APSC 301  Poultry Breeding Genetics: – Science devoted to the study of inheritance Cell: – Represents the basic constituent of all living material Types of cells: – Somatic: cells comprising all tissues of the body – Sex cells: responsible for continuation of the species Bartlett, 2024 APSC 301  Poultry Breeding The cell has three basic parts: – Cell membrane: prevents contents of cell from mixing with contents of other cells – Cytoplasm: lies outside the nucleus but within the cell membrane – Nucleus: transmits hereditary material Bartlett, 2024 APSC 301  Poultry Breeding Chromosomes: – Rod-like structures within the nucleus of the cell – Carriers of genetic information – During mitosis they occur in pairs each one carrying identical information Bartlett, 2024 APSC 301  Poultry Breeding Chromosomes: – When the sperm fertilizes the egg, half comes from sperm and the other half from the egg – Both parents contributing to the genetic information of the embryo Bartlett, 2024 APSC 301  Poultry Breeding Two types of chromosomes: – Autosomes: All chromosomes in the body except one pair – Sex chromosomes: associated with determining sex of individual Bartlett, 2024 APSC 301  Poultry Breeding Genes: – Within the chromosomes, genes are responsible for hereditary transmission of specific characteristics that differentiate one part of the body from another and one species from another – They are the units of heredity – Identical genes are located in each pair of chromosome Bartlett, 2024 APSC 301  Poultry Breeding Deoxyribonucleic Acid (DNA): – Although the gene is the unit of heredity, it’s the molecular make-up of the gene that determines the gene action – Most important genetic material in the cell nuclei is DNA Bartlett, 2024 APSC 301  Poultry Breeding DNA – molecule consisting of repeating units of four nucleotide bases: – Guanine (G), cytosine (C), thymine (T), and adenine (A) – all associated with phosphoric acid and a sugar Bartlett, 2024 APSC 301  DNA Molecule showing bases associated with a sugar and a Bartlett, 2024 APSC 301 phosphate group  Poultry Breeding Nucleotide bases are in sequences of 3 called a codon Base sequences act as code to transfer information from one cell to another during cell division Each sequence representing an amino acid Bartlett, 2024 APSC 301  Poultry Breeding The code can then be translated by cells to: – Make proteins and enzymes that determine their function – Controls differentiation – Determines the outcome of the embryo Bartlett, 2024 APSC 301  Poultry Breeding Male chickens have 38 pairs of chromosomes + 1 pair of complete sex chromosomes (ZZ)=39 pairs Females have 38 pairs + 1 single complete sex chromosome (Z) and 1 incomplete sex chromosome (W) Sex chromosomes in females (ZW), males (ZZ) Bartlett, 2024 APSC 301  Poultry Breeding Females are the heterogametic sex while males are homogametic Females determine the sex of the offspring Bartlett, 2024 APSC 301  Poultry Breeding Since females have one complete and one incomplete sex chromosome Ova from 50% ovulation containing a Z chromosome, if united with any male sex chromosome, will produce male offspring Other 50% will produce females Bartlett, 2024 APSC 301  Poultry Breeding Specific location of gene on the chromosome called the locus Pair of genes carried at each locus is alike and represent a particular trait They exist in different forms called alleles Bartlett, 2024 APSC 301  Poultry Breeding You need to know the following definitions related to basic genetics – Homozygous- paired genes (alleles) at the same locus on paired chromosomes code for the same characteristics (traits) – Heterozygous- same as above except code for different characteristics Bartlett, 2024 APSC 301  Poultry Breeding Dominant- characteristics that masks the expression of its paired allele and is expressed in the phenotype Recessive- characteristics that are masked by its paired allele and is not expressed in the phenotype Bartlett, 2024 APSC 301  Poultry Breeding Genotype- actual traits coded in paired genes or allele at the same locus on paired chromosomes Phenotype- The observable expression of traits coded in paired genes (allele) at the same locus on paired chromosomes Bartlett, 2024 APSC 301  Poultry Breeding Complete Dominance- The complete masking of the expression of one paired allele by the other allele Incomplete Dominance- Partial expression of both paired alleles resulting in a blending of the two traits in phenotype Bartlett, 2024 APSC 301 Poultry Breeding Bartlett, 2024 APSC 301  Poultry Breeding – Some traits are simply-inherited, meaning only a few genes are involved in its expression. E.g. comb type Bartlett, 2024 APSC 301  Poultry Breeding ‘R’ is the symbol used for rose comb ‘r’ is the symbol for single comb This is because rose comb is dominant to single comb. Single comb is recessive ‘R’ and ‘r’ are alleles, or alternate forms of a gene for the same trait Bartlett, 2024 APSC 301  Poultry Breeding Genes located on the sex chromosomes are known as sex-linked genes One example of a sex-linked trait is the barred feather color pattern Barred (B) is completely dominant to non- barred (b) Bartlett, 2024 APSC 301  Poultry Breeding There are enterprises that specializes in breeding like Ross, Arbor Acres, Hubbard These companies have what is called Foundation Breeders They furnish eggs to hatcherymen or Multipliers through a contractual agreement The multiplier then hatch the eggs and send the chicks to grow-out farms Bartlett, 2024 APSC 301  Poultry Breeding Some Mating Systems of Poultry: – Flock Mating: in this system, a few males are allowed to run with an entire flock of females. Male to female ratio depends on age and size; heavier breeds 1:10-12; lighter breeds, 1:15-20 Bartlett, 2024 APSC 301  Poultry Breeding – Males generally not used for more than 3 years after which time, spiking is practiced – Spiking is the replacement of older birds with younger ones to increase fertility Bartlett, 2024 APSC 301  Poultry Breeding Pen Mating: a pen of females is mated to a single male Fertility is not as good as flock mating because there is no competition for the male so he tends to get lazy Bartlett, 2024 APSC 301  Poultry Breeding Stud mating: females are mated to individual males kept in cages by themselves. It’s labor intensive, birds are mated once per week. Generally reserved for very valuable males Artificial insemination: (Will talk about in another lab) Bartlett, 2024 APSC 301