bovis - Articles
Artificial insemination
Synonym(s): AI
Introduction
- Artificial insemination (AI) has been said to be the most important single technique devised for the genetic improvement of animals, because it allows a few select males to produce enough sperm to inseminate thousands of females per year.
- The technique permits cooling or freezing of semen for storage and shipping to remote destinations allowing a greater geographical distribution of genetics.
Uses
Advantages
- Allows widespread use of outstanding sires from around the world increasing genetic gain.
- Increased utilization of the best genetics with stud bull use much greater than can be achieved in normal breeding lifetimes Genomics: overview.
- Improved biosecurity: AI negates the risk of sexually transmitted infectious disease, eg campylobacter Campylobacter spp.
- Allows for greater flexibility and choice in bull use, on an individual cow basis, for example, bull breed, traits etc.
- Negates the risk of infertile ill or lame stock bulls during the breeding season.
- Negates the risk of work, health and safety issues concerned with stock bull use.
Disadvantages
- Requires heat detection Estrus: signs and detection by farm staff, or estrus synchronization.
- Requires appropriately trained insemination technicians.
- Increased pressure on technicians in terms of results achieved
- Requires accurate record keeping.
- Propagation of genetic defects on a large scale, eg Mulefoot, CVM.
Technical problems
- Inexperienced staff.
Alternative techniques
- Natural mating.
Time required
- Thawed semen is highly susceptible to cold and heat shock and must be inseminated within 6-8 minutes of thawing.
- Straws should be removed from the canister with a pair of forceps and thawed at 35°C for 45 seconds (range 30-60 seconds).
- Experienced, competent inseminators should not thaw more than 6 straws at once, straws should be protected from heat or cold shock and all 6 straws should be inseminated within 15 minutes of thawing.
- 10 seconds to search for and identify the appropriate straw of semen.
- One minute per animal for accurate data recording.
Decision taking
Timing of insemination
- Ovulation occurs 24-32 hours after the onset of standing heat.
- The estimated life span of the ovulated ovum is 8-12 hours.
- The estimated lifespan of bull sperm is 30 hours, with 6 hours required for capacitation and 6-12 hours to reach their destination, the caudal oviductal isthmus.
- Studies using conventional semen indicate that the optimum time of insemination after standing estrus is 12 hours.
- Studies using gender selected semen indicate that the optimum time of insemination after standing estrus is 8-24 h in beef heifers and 4-12 h in dairy cows.
- At present, the standard industry approach is the “am-pm rule” whereby those females first seen in standing estrus in the morning are inseminated later that day, and those in the afternoon, inseminated the following morning.
- Alternatively, those animals on synchronization programs are fixed time inseminated as per the program design which may utilize observed estrus, single or double fixed timed inseminations.
Requirements
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Preparation
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Technique
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Aftercare
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Outcomes
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Further Reading
Publications
Refereed Papers
- Recent references from PubMed and VetMedResource.
- Diskin M G (2018) Review: Semen handling, time of insemination and insemination technique in cattle. Animal 12 S1, 75-84 PubMed.
- Hall J B, Kasimanickam R K, Glaze J B, Roberts-Lew M C (2017) Impact of delayed insemination on pregnancy rates to gender selected semen in a fixed-time AI system. Theriogenology 10, 154-161 PubMed.
Other sources of information
- Ax R L, Dally M R, Didion B A, Lenz RW, Love C C, Varner D D, Hafez B, Bellin M E (2016) Artificial Insemination. In: Hafez and Hafez Reproduction in Farm Animals. 7th edn. pp 376-390.
Organisation(s)
- University of Florida digital collections. Website: ufdc.ufl.edu.
- Penn State University. Website: https://extension.psu.edu.