ANSC 4395 Exam 1

ANSC 4395 Exam 1 What is Animal Breeding - ✔✔Scientific field that uses the principles of genetics to aid in the improvement of livestock. What are the 3 classes of cattle? - ✔✔British American Exotics- usually Euro ...

ANSC 4395 Exam 1 What is Animal Breeding - ✔✔Scientific field that uses the principles of genetics to aid in the improvement of livestock. What are the 3 classes of cattle? - ✔✔British American Exotics- usually European Who is Robert Bakewell? - ✔✔"Father of Animal Breeding" - Leased out Bulls What did Robert Bakewell not hesitate to mate? - ✔✔"best to the best" with little regard to ancestry. Not afraid to inbreed. What was one of the first organized breeds of livestock in 1580? - ✔✔Shorthorns Who is Gregor Mendel? - ✔✔He established basic genetic principles that are still accepted today. What did Gregor Mendel study? - ✔✔The genetics of the garden pea. Population Genetics - ✔✔Branch of genetics which deals with the factors that affect the genetic structure of populations. *what % of alleles and genotypes* What two guys were involved with population genetics? - ✔✔1. Dr. Sewell Wright 2. Sir Ronald Fisher Dr. Wright did research with who? - ✔✔USDA and then later at the University of Chicago Worked at the Rothamstead Experiment Station in Great Britain. - ✔✔Dr. Fisher Dr. Jay Lush - ✔✔"Father of MODERN animal breeding" *established a formal theoretical framework to the science of animal breeding* Dr. Jay Lush established what principles? - ✔✔The principles of selection, the use of inbreeding to conserve genes of some individuals, and crossbreeding systems to take advantage of HYBRID VIGOR. During the last 30 or 40 years, the use of what has greatly enhanced the potential for genetic change? - ✔✔Computers/ technology Artificial Insemination and embryo transfer have allowed for what? - ✔✔Faster progeny testing and selection has become much more efficient. What is the primary goal of animal breeders? - ✔✔Identify animals with desirable genes and increase the frequency of those genes. *they want a bunch, they're the ones they select to be parents to pass on the good genes* What is the best animal? - ✔✔-Lab- Show winner or best retriever -Cattle- cutability/% muscle (limousin) or quality grade (angus) -Dairy Cattle- most milk or best udder, feet and legs. **all depends on what they want as "best"** In the 50-60s how were cattle bred? - ✔✔Short/stubby How were cattle bred in the 80s? - ✔✔tall, large How are cattle bred today? - ✔✔Moderate (between) How do you breed an animal so offspring will be the best or better than the parents? - ✔✔-Selection-want genetic improvement, identify best animals and breed those. -Genetic principles -Animal breeding technologies Systems Approach - ✔✔More OBJECTIVE means of determining the best animal. Systems Approach requires what? - ✔✔A detailed knowledge of importance and how performance in these traits interact with such factors as the ENVIORNMENT, MANAGEMENT POLICIES, COSTS, and REVENUES. System - ✔✔a group of interdependent component parts. *use when selecting best genetics* Example of systems- Consider the system that is a single ranch: - ✔✔Components: animals (genotypes), physical environment, fixed resources, management, and economics. *Systems Approach* Animal- - ✔✔Characteristic genotype(s), may be more than one. - Small size, low feed intake, low production, high milkfat. (not much to maintain)-*low lbs --> high dairy* - Large size, large intake, high production, low milkfat. (more to maintain)-*high lbs --> low dairy* *Systems Approach* Physical Environment- - ✔✔Elements of the environment over which human exert little or no control. *Systems Approach* Physical Environment examples- - ✔✔- Weather, altitude, soil, quality and quantity of forages. *Systems Approach* Fixed Resources- - ✔✔the size of the farm, ability of the farm to grow supplementary feeds, and available labor. *Systems Approach* Management- - ✔✔all policies implemented by the farmer-(feeding, healthcare, length of time an animal is on the farm) **FEED IS PRIMARY EXPENSE** *Systems Approach* Economics- - ✔✔Costs of farm inputs like feed, labor, and supplies and the prices of farm outputs (revenue), long and short term interest rates. Traits - ✔✔any observable or measureable characteristic of an animal. -Observable- Color, size muscling, leg set, head shape. - Measurable- Weaning weight, lactation yield, hip height, REA, staple length. *what you can observe about an animal* Phenotype - ✔✔An observance category or measured level of performance for a trait in an individual. *DESCRIBES the color, or the temperament* *more specific* Examples of traits vs. phenotypes: 1. Color is the2. Brown is the3. Temperament is the- __________ 4. Foul would be the _______ 5. Presence of horns= Horn, polled, dehorned= 6. Height= 14 hands. 50 inches= 7. YW= 850lbs, 1250lbs= 8. Calving ease= assisted, unassisted, surgical= 9. Litter size= 5,11,14 = - ✔✔1. Trait 2. phenotype 3. trait 4. phenotype 5. Trait, phenotype 6. Trait, phenotype 7. Trait, phenotype 8. Trait, phenotype 9. Trait, phenotype Genotype - ✔✔-the genetic make-up of an individual - punnette square Ex: Bb, BB, bb, Genotype provides what? - ✔✔the genetic background for phenotypes What is the mathematical equation for phenotype? - ✔✔P=G+E *phenotype = genotype + environment* Environmental Effect - ✔✔the effects that external factors have on animal performance Phenotype is determined by? - ✔✔It's genotype and the environment it experiences Biological Type - ✔✔a classification for animals with similar genotypes for traits of interest Similar genotypes have the same? - ✔✔biological type Interaction - ✔✔a dependent relationship among components of a system in which the effect of any one component depends on other components present in the system The best genotype will depend on? - ✔✔environment management economics and how these components interact to affect profitability Genotype by Environment interaction - ✔✔a dependent relationship between genotypes and environments in which the difference in performance between two or more genotypes changes from environment to environment GxE interactions occur when - ✔✔the difference