4 7 livestock reproduction


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4 7 livestock reproduction

  1. 1. Livestock Reproduction
  2. 2. Livestock Reproduction <ul><li>Vitally important for livestock producers </li></ul><ul><li>Low fertility causes loss of revenue for farmers </li></ul><ul><li>Many recent technological advances </li></ul>
  3. 3. Male Reproductive Tract <ul><li>Testes </li></ul><ul><li>Scrotum </li></ul><ul><li>Seminal Vesicles </li></ul><ul><li>Sigmoid Flexure </li></ul><ul><li>Retractor Muscle </li></ul><ul><li>Glans Penis </li></ul>Video
  4. 4. Female Reproductive Tract <ul><li>Ovaries </li></ul><ul><li>Oviduct </li></ul><ul><li>Uterus </li></ul><ul><li>Cervix </li></ul><ul><li>Vagina </li></ul><ul><li>Vulva </li></ul>Video
  5. 5. Differences with Humans <ul><li>Females have an Estrus Cycle </li></ul><ul><li>Animals can only become pregnant when in “Heat” </li></ul><ul><li>Timing depends on light & temperature </li></ul><ul><ul><li>Keep sheep in dark barns to synchronize estrus </li></ul></ul>
  6. 6. METHODS OF INSEMINATING LIVESTOCK <ul><li>NATURAL INSEMINATINATION - Involves using animals to mate in pastures or pen breeding. </li></ul><ul><li>ARTIFICIAL INSEMINATION - Involves collecting semen from a male and depositing it in the reproductive tract of the female. </li></ul>
  7. 7. Artificial Insemination <ul><li>Dairy Cattle used exclusively </li></ul><ul><li>Frequently used for purebred operations in beef cattle, horses, sheep & pigs </li></ul><ul><li>Thoroughbreds may not be bred by AI </li></ul><ul><li>Video </li></ul>
  8. 8. ADVANTAGES OF USING AI <ul><li>AI allows the use of semen from superior males that are owned by another party. </li></ul><ul><li>AI makes it possible for a male to breed many more females than could be done naturally. </li></ul><ul><li>Semen can be stored for a week at 41F or for several months frozen at -320F (liquid nitrogen). </li></ul>
  9. 9. Limitations of AI <ul><li>Physiological Principles: timing of heat </li></ul><ul><li>Requires skilled technicians </li></ul><ul><li>Costly to start </li></ul><ul><li>Can accentuate damage of poor sires </li></ul><ul><li>May restrict sire market (avg or poor bulls) </li></ul><ul><li>May increase spread of disease (none to date, but is possible) </li></ul><ul><li>Abuse: mislabeled semen </li></ul>
  10. 10. IMPORTANT INFORMATION IN BREEDING ANIMALS <ul><li>SPECIES AGE/BREED GESTATION </li></ul><ul><li>COW 14 MONTHS 283 DAYS </li></ul><ul><li>SOW 12 MONTHS 114 DAYS </li></ul><ul><li>EWE 17 MONTHS 148 DAYS </li></ul><ul><li>DOE 18 MONTHS 151 DAYS </li></ul><ul><li>MARE 2-3 YEARS 336 DAYS </li></ul>
  11. 11. ESTRUS SYNCHRONIZATION <ul><li>Involves using hormones to get several females to come in heat at the same time. </li></ul><ul><li>Used when using advanced breeding procedures such as superovulation (getting the female to produce a number of eggs at one time) and embryo transfer. </li></ul>
  12. 12. Embryo Transfer <ul><li>Synchronize Heat Cycles of donor & recipients </li></ul><ul><li>Inject drug to superovulate </li></ul><ul><li>Breed donor (natural or AI) </li></ul><ul><li>Collect eggs </li></ul><ul><li>Examine eggs (if fertilized) </li></ul><ul><li>Synchronize recipients ovulation </li></ul><ul><li>transfer eggs </li></ul>
  13. 13. When to Breed <ul><li>Female is only fertile when an egg is present which can be fertilized </li></ul><ul><li>Eggs short lived </li></ul><ul><li>Inseminate before egg is shed </li></ul><ul><li>Cow doesn’t shed egg until 10 hours after standing heat, lives 6-10 hours </li></ul><ul><li>Cows in standing heat in morning are bred in afternoon or evening </li></ul>
  14. 14. Manipulating Estrous <ul><li>Artificial Lighting : ewes, mares, fowl </li></ul><ul><li>Lengthen days, then shorten to simulate natural breeding season </li></ul><ul><li>Hormones : </li></ul><ul><li>Progestagens: mimics pregnancy, feed, inject, implant, for 14-20 days, when removed, cows cycle 2-8 days later </li></ul><ul><li>Prostaglandins: single dose injection, 90 hours later = estrous </li></ul>
  15. 15. Induced Calving <ul><li>Artificially shortening gestation </li></ul><ul><li>Lower birth weight, less calving difficulty </li></ul><ul><li>Predict calving dates </li></ul><ul><li>Longer period from calving to breeding </li></ul><ul><li>After 269 days, cows injected with adrenal steroid </li></ul><ul><li>Calve 5-8 days earlier, 6-8 lb lighter calf </li></ul><ul><li>Higher rate of retained placentas, lower milk production </li></ul>
  16. 16. GIVING BIRTH <ul><li>Most animals give birth without assistance. </li></ul><ul><li>Calves should be born within one hour after labor begins. </li></ul><ul><li>Calves are normally delivered with the head between the two front legs. </li></ul><ul><li>Cow may need assistance if calf is in a different position. </li></ul><ul><li>Video </li></ul>