Breeding management and genetics

Artificial insemination

• insertion of a desired males sperm into desired females uterus using non-living or mechanical means
• process: collection, evaluation, storage/extension, insemination, pregnancy diagnosis
• still in vivo

Collection of semen

• sexual stimulation 
  • elicit mounting behaviour
  • visual, olfactory, auditory stimulation
  • novelty is important 
• sexual preparation
  • intentional prolongation of sexual stimulation
  • series of false mounts 
• alternative methods 
  • electroejaculation
  • massaging pelvic accessory genital organs - ampullae through rectal wall
  • collecting semen from vagina of female 

Evaluation of semen 

• motility, velocity, acrosome integrity (releases enzymes to penetrate the egg), morphology, enumeration (concentration), differential live-dead staining, metabolic reaction rates, pH
• it can be possible to sex sperm with up to 90% activity

Extension of semen

• used to increase volume, preserve viability, provides energy supply, protect against by products of metabolism
• can incorporate antibiotics - Campylobacter fetus

Freezing sperm

• cryoprotective agent in extender
• cooled and stored to -196c in liquid nitrogen
• semen straws

Embryo transfer

• superovulation
• early embryos removed from donor
• oestrus synchronisation/observation of recipient
• transfer to uterus of recipient female
• pregnancy detection in recipient
• embryos located using dissection microscopes - 3 options: immediate transfer, prepare for vitrification and embryo splitting by microsurgery (no effect on growth whole vs demi)
• transfer - loaded into specialised insemination 'gun' in embryo straw

Embryo transfer uses 

• structured/highly selective breeding programmes
• disease control
• importation/exportation of livestock
• screening of AI sires for genetically recessive characteristics 
• research tool for foetal-maternal interactions
• treatment of infertility
• conservation
• welfare - reduced transport/risk

Embryo transfer downsides

• expensive procedure
• requires highly trained staff
• invasive 
• welfare
• disease transfer - blue tongue virus…