ANS test 3 - Start Exam 3 Heredity and Environment: -and...

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Start Exam 3 Heredity and Environment: -and animal is the result of heredity and environment Heredity= foundation Environment= structure (any animal is a result of 2. what is inherits is affected by the environment) Environmental Factors- determine the extent or degree of expression of the genetic makeup: Feeding, management, disease - the environment may inhibit the full expression of the genetic potential - for maximum expression of genetic characteristics optimum environmental conditions are needed ( do have capital? Feed source?) Systems of Breeding: 1. Pure breeding- mating of animals belonging to the same breed - purebred animals have common ancestry and distinctive characteristics 2. Inbreeding- the mating of closely related individuals a. Close breeding- sire x daughter, son x dam, brother x sister (sibling) b. Line breeding- half siblings, cousins, grandsire, granddaughters 3. Out Crossing- the mating of animals of the same breed that show no relationship close up in the pedigree (1 st six generations) 4. Crossbreeding- the mating of animals of different breeds 5. Grading up- the mating of purebred sires to grade or native females Methods of selection in livestock breeding: -selection based on type of individually -standard of perfect animal doesn’t exist in real life - animals selected on the ideal or standard of perfection - selection based on pedigree -considers ancestry in selection - selection based on show ring winnings -selecting winners at livestock shows and fairs - selection based on production testing; measures individual characteristics -involves both performance and progeny testing - performance testing concerns itself with the individuals and performance -measures of his/her own performance -progeny testing considers evaluation based on the merit of their offspring Systems of selection- maximizes progress over a period of several years Tandem- select for one trait at a time, until the desired improvement is reached Establishing minimum standards for each character and selecting simultaneously but independently for each character Selection index- combined all traits into one overall value or index Reproduction:
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Male reproductive organs (anatomy) Female reproductive organs (anatomy) -because female functions is reproduction is more involved that males, producers need to know or understand more about how these organs function and anatomy The female: -produces the egg -develop new individual in uterus -expel the fully developed young - nourish the young after birth The male anatomy and reproductive tract: Testis- produces spermatozoa and androgens (male sex hormones) Scrotum- supports the testicals, controls, controls the temperature of testicals and provides protection of the testicals Spermatic cord- supports the testicals. Helps control temperature of testicals Epididymis- concentration of spermatozoa, storage of spermatozoa, maturation of spermatozoa, transportation of spermatozoa Vas deferens- transports of spermatozoa Urethra- transports semen- exit site for urinary products
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ANS test 3 - Start Exam 3 Heredity and Environment: -and...

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