Animal Reproduction Animal Science II. Estrus Cycle Time of day when a female will accept a male for...
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Transcript of Animal Reproduction Animal Science II. Estrus Cycle Time of day when a female will accept a male for...
Estrus Cycle
• Time of day when a female will accept a male for breeding
• Length– 21 day cycle
• Cow- 16-18 hours• Sow- 2 days
• Best indicator is when the animal stand to be mounted
Ovulation
• Release of the egg from the ovary• Number of young born is an
indicator of eggs released– Sows: 10 to 15– Cow: One
• Split eggs produce identical twins, triplets, etc.
Methods of Reproduction
• Natural• Artificial Insemination (AI)• Embryo Transfer• Cloning using Nuclear Transfer
Artificial Insemination
• Steps– Insert hand into the rectum and grasp
cervix– Insert insemination rod– Deposit bull semen from the middle of
the cervix to just into the uterus
Artificial Insemination
• Advantages– Wider variety of superior bulls used– Increase number of cows that can be
bread to a superior bull– Reduces disease– Don’t have to keep a bull on the farm
Artificial Insemination
• Disadvantages– Requires a trained inseminator– Requires more time and herd
supervision
Embryo Transfer
• Procedures– Superovulate donor– AI– Flush embryos (catheter)– Isolate and classify embryos– Store in liquid nitrogen– Transfer to recipient– Diagnose pregnancy 1 to 3 months later
Embryo Transfer
• Advantage– Genes of the female (dam) can be
passed on faster than natural breeding
Cloning
• Using Nuclear Transfer• Procedures
– Flush (same as embryo transfer)– Filter– Remove genetic materials from
recipient oocytes– Nuclei is removed through
microsurgery
Cloning
• Procedures (continued)– The nuclei are separated and each
one is transferred to an unfertilized egg cell that has had its nucleus removed
– Plugs are placed in sheep for 5 to 6 days (develops to the 32 to 64 cell stage)
– Embryos are placed in surrogate, frozen or used to clone more animals
Cloning
• Advantages– Increase herd uniformity– Increase herd quality– Produce genetically identical animals
Parturition Process
• Increased estrogen causes uterus muscles to contract
• Water bag appears and breaks• The second water bag appears
with the fetus
Parturition Process
• Normal Presentation• Front feet first• Nose• Head and shoulders• Hips• Rear legs• Rear feet last
• Any presentation not in order could cause death of the baby and/or mother