AVS 101 1st Edition Lecture 12Reproduction & Artificial InseminationTestosterone Secondary sex characteristics, libidoFSH SpermatogenesisLH Maintenance of interstitial cells – produce testosterone Sex differentiationDuring early gestation fetus possesses bothSex differentiation Male - wolffian ducts Female – mullerian tract Develops depending on predominant hormoneSex Differentiation Free Martin Female born twin to male95% of females are infertileOccurs in cows M & F placenta fuse & exchange fluids & hormonesBirth ratio Animal kingdom 50:50 male/femaleSlightly more males are conceivedSlightly more females are bornWhat’s new in reproduction?Estrus synchronization All animals in heat at same time Offspring born at same time Can occur naturally Series of hormone injectionsPGF2αOva transplants Egg from one animal transplanted to another animalSurrogate motherPlacental compatibility Transfers placentas within species Increase endangered speciesEmbryo splitting Produce twinsStem Cell Research Regenerate damaged cellsArtificial Insemination (AI) Began in 1500s 50% of US dairy All turkeys Not extensively used with other animalsSemen collection Artificial vagina ElectroejaculatorElectric probe rod in rectumNot as good quality semenUnhappy bullSemen dilution Egg yolk/glycerol Buffer for pH Antibiotics for foreign organism Frozen in liquid nitrogen at -196° C/ -320° FCan remain frozen for yearsAdvantages Many offspring Decrease disease Safer for handlersDisadvantages Decrease male population Limits gene pool More labor – check for estrus Quickly disseminate undesirable traits
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