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Dairy: Genetics and Biotechnology (Body Condition Score (Assessment of the…
Dairy: Genetics and Biotechnology
Body Condition Score
Assessment of the proportion of body fat a cow possesses
Assess nutritional status
Good indicator of how provided diet meets energy needs of cows
Under and over conditioning of cattle pre-disposes them to diseases
Genetic Merit For Production
High genetic merit cows respond better to high concentration pasture than low genetic merit cows
Australian Breeding Value
Estimate of bulls genetic merit (must be halved)
Production traits expressed in units of measurement (e.g. L of milk)
Type traits expressed in standard deviations
Management traits (e.g. fertility) expressed as %
Genomics
Uses DNA to predict merit of bulls/cows
Used to calculate AVBs of sires and females
Double the reliability of AVBs values based on pedigree alone
Advantages for farmers
Reliable
Can be used to identify superior animals e.g. embryo transfer elite heifers, target sexed semen
Australian Dairy Herd Improvement Scheme (ADHIS)
Genetic Correlation
Genes have an effect on several traits, so a change in a single gene will affect all those traits
Heritability: allow for phenotypic selection
Repeatability/correlations: Milk yield between 1st and 2nd lactation, conception rate between years