Genetics EXAM 3

Rate of Genetic Change depends on what four factors?

Heritability, Selection Differential, Population Size, and Generation Interval

Four sources of information when selecting

Individual performance, Pedigree, Progeny, and Collateral relatives

Disadvantages of just relying on individual performance

Sex-limited traits, late expressed traits, low heritabial traits, Carcass Traits

Four methods for selecting more than one traits in livestock

Selection index, independent culling levels, tandem selection, and multistage index selection

Four traits to select for in Dairy

Milk yield, milk fat yield, milk protein yield, milk fat percentage

Disadvantages of Pedigree

Records may be inaccurate or doesn’t compare individuals within same family

Advantages of Pedigree

Cheap, sex-limited traits, late-expressed traits, low heritability traits

Advantages of Collateral Relatives

Sex-limited and traits that require slaughter

How to increase the accuracy of Collateral Relatives

higher heritability, closer relationship, more sibs, higher environmental correlation

Advantages of Progeny

Low moderate heritability traits and detecting recessive alleles (qualitative traits)

BIUP

Best Linear Unbiased Prediction

Fertility Traits

Rebreeding rate, heifer pregnancy, calving ease, Daughter pregnancy rate, fertility index, age of first calving, days open

Type Traits

Dairy strength, rump angle, feet/leg structure, foot angle, dairy form, body condition, and stature

Dairy vs Beef

Dairy fixes the environment for animals, and beef fixes animals for the environment

bST

Bovine Somatotropin (milk regulator), Adequate increase I6F-1 (Insulin Growth Factor) but also rick mastitis

GEBV

Genomic Estimated Breeding Value

Cervical Vertebral Malfunction

SLC35A3

Bovine Brachyspina Syndrome

FANCI gene on chromosome 21

Bovine Leukocyte Adhesion Deficiency (BLAD)

Single Point Mutation (Adenine to Guanine) CD18 gene

Syndactyly (Mule Foot)

LRP4 gene, Carriers have superior milk and fat, variable penetrance

Bovine Progressive Degenerative Myeloencephalopathy (weaver)

Major Differences of Beef from Dairy

Producers’ goals, objectives, environment, natural resources, traits of economic importance, sources of performance records, slower adaptation to technology

Purebred selection goals

Breed standard, high EBV/EPD, Maternal traits

Cow/Calf selection goals

Fertility, weaning weight, calving ease

Stocker selection traits