Genetics
Gene
length of DNA that codes for a specific protein
found on a chromosome
influences the characteristics of an organism
Chromosomes
DNA
Protein
Genetic Information
Use
Breeding Strategies
Higher LWG/FCR breeds – increase profit
Higher Milk Yield/Quality breeds - increase profit
Better Disease Resistance breeds – less cost
Higher fertility breeds – higher production – Increase profit
Better Health Traits – Feet/Teeth - Increase Profit
Crop Production
Larger grain size/numbers - increase profit
Disease resistance – less spray costs
Better Germination Rate – Higher Production
Short Growing Period – Better Quality Harvesting
Traits Sought
Cows
Milk Yield
Milk Composition
Conformation
Fertility
Beef/Sheep
Carcass Weight
Growth Rate
Prolificacy
Conformation
Crops
Disease Resistance
Yield
Straw Length
Frost Resistance
Types
Dominant genes are genes that are always expressed when present.
Recessive genes : only expressed in the absence of a dominant genes
Lethal gene: a gene when expressed in the phenotype will cause death of the organism
Deleterious Gene: A genetic alteration that increases an individual's susceptibility or predisposition to a certain disease or disorder.
Type
Genotype = is the genes present in an organism whether expressed or not
Phenotype = is the physical appearance of the organism
Selective Breeding: Human breed plants and animals with desirable traits and concentrate those traits in the offspring
Line Breeding: Production of desired traits through inbreeding over generations
Genetic Improvement
Increases the productivity of the animal over its lifetime
Increases the profitability of the animal over its lifetime
Herd Health Improvements
Positives
BB Double Muscle Lean Meat, Higher Yield, Low Fat
- Holstein Higher Milk Yield, Median Suspensory Ligament
Negatives
BB Bad Feet Hard calving Susceptible to Pneumonia
Holstein High forage volume required Poorer Fertility Bad Feet within Breed Pendulous Udder
Crossbreeding
Hybrid vigour (heterosis) is the increased productivity displayed by offspring from genetically different parents.
Performance and Progeny
Performance-testing evaluates the bull’s performance by comparing its weight gain and FCR with other bulls kept under similar conditions.
Progeny-testing evaluates the performance of the bull’s offspring compared to other bull’s offspring kept under similar conditions.
Economic Breeding Index (EBI)
Single figure profit index - identify the most profitable bulls for breeding dairy replacements.
Milk production - Yield, %Protein, Low SCC
Fertility – How easy they go in calf, How many calves, Calving Interval
Calving performance – How easy/hard do they calve their calf
Beef Carcass - % killout of their calves at slaughter
Cow Maintenance - How robust the cow is, Feed Intake
Cow Management – Milking Time, Temperament,
Health – Mastitis, Lameness, Disease
Environment – Methane Emissions, FCR
Euro Star Rating System
The Terminal Index - profit per direct progeny slaughtered
Carcass Weight
Calving Difficulty
Food Intake
The Replacement Index - profit per calving of each daughter
Milk Volume
Calving Interval
Carcass Weight
Calving Difficulty
Dominance
Incomplete dominance :
when two alleles are equally dominant or Recessive. phenotype is a blend of the two.
Co-dominant:
Both alleles of a gene are equally dominant and both are expressed equally
Genomics (Gene Economics)
study of animals’ DNA or Genotype “breeding using DNA”.
Identifies
which DNA chunks have been passed from the parents to it’s offspring.
animals traits (milk production, carcass weight etc.),
comparison to the genomic samples of proven animals
Genotyping
Technique used to identify differences in (genotype) an animal’s DNA sequence and comparing it sequence of other animals.
Advantages
Tailored Breeding
Higher reliability EBI/Eurostar figures: increases reliability % figures
Parentage verification: Sire & Dam confirmed (stolen cattle)
Breed verification: identify an animal’s breed makeup.
Genetic diseases: diseases/major genes (e.g. Myostatin)/lethal genes
Traceability: full traceability
Mutations
AMR Antimicrobial Resistance
Cause
overuse and misuse of antibiotics.
Incomplete course of antibiotics
Inaccurate dosage
Prevention
Implement vaccine programme
Administer antibiotics appropriately
Maintain good Hygiene levels on farms
Provide adequate ventilation
Maintain Biosecurity
Genetic modification (GM) : DNA has been changed for the purpose of improvement or to correct a defect in the organism.
Genetic Engineering: Artificially copying a piece of DNA from one organism and joining it to the DNA of another organism
Improved Production Traits
Milk Yield – Increased profit from less cows
Carcass Quality – Increased meat quality from poor breeds
Crop Yield – Increased profit from smaller acres – Less Rent]
Increased Disease/Pest Resistance
Less Chemicals sprayed to control pests/disease - Environmentally Friendly
Increased biodiversity – BEES
Less Chemical Exposure – Water/Food Quality
Improved Feed Conversion Efficiency Rate (FCE)
Less Concentrate Costs
Less Fodder/Silage - Save Costs
Genome: organism's complete set of DNA
Gene editing: add, delete or replace a base in the genome, thereby changing the sequence of the genetic code.
Mr P Reynolds