Advantages of Artificial Insemination
- Increased Genetic Gain – The use of AI can greatly increase the number of offspring produced per sire per year. Using conventional flock/herd mating, a sire may be expected to mate 50 – 100 females per year. With fresh diluted semen and cervical insemination, a single ram or buck could be used to inseminate in excess of 1000 females in a 2 – 3 week period. With intrauterine insemination of frozen-stored semen, many thousand ewes can be inseminated with semen collected from a single sire each year.
- Easy Transport of Genetic Material – Semen is much cheaper to transport than the live animal esp. between countries and continents.
- Long-term Storage of semen – Many breeders store semen from valuable males as insurance against their premature death or possible injury.
- Increased efficiency of breeding – Subfertile rams or bucks may be readily identified and eliminated from the team of breeding males. AI also ensures that all females are mated, avoiding problems associated with male-female preferences and some oestrous females not being mated.
- Reduction or elimination of the need to maintain males on the farm
- Prevention and control of disease
- Use of incapacitated males – Sometimes a very valuable male may suffer and injury or become infirm with age, preventing him from mating females. Artificial Insemination enable his continued use for breeding if such a male has frozen semen of good quality.
- Accurate record keeping
- Use in synchronised or out-of breeding season – Breeders may wish to make use of technology which permits synchronised breeding of females. Out-of-season breeding programs may coincide with the time of year when semen quality is low, which is a problem in goats particularly. Females can be inseminated with frozen semen with good success.
- Use of other technology – Where females are superovulated for Embryo Transfer, natural mating does not result in a high level of fertilisation. Intrauterine insemination improves the fertilisation rate and renders the technique viable.
Disadvantages of Artificial Insemination
- Inbreeding – When selection intensity is high, problems associated with inbreeding may arise and care should be taken especially in small, closed flocks or herds.
- Potential of Inaccurate Breeding – There are two possible sources of inaccurate breeding when using AI. These are when fresh or frozen semen from individual sires is not carefully and properly labelled then accidental errors in insemination can occur, or when breeding values of sires have been overestimated or determined incorrectly. This could result in genetic losses rather than gains.
- Reduced fertility – This happens when methods of controlling oestrus are not properly employed or the operator is careless or negligent when handling semen.
- Cost – The greatest costs involve skilled labour, drugs and hormones. It is of the greatest importance that care should be taken to absolutely optimise every aspect of the AI program to ensure the best possible results.
Preparation of Females for Insemination
The success of an AI program depends as much on the fertility of the females as the quality of semen used for insemination.
Several weeks before the start of the program attention should be paid to the condition of the females.
Females should be in good health, free of disease and parasites, and in good body condition. Sick or malnourished females will often fail to ovulate or suffer a high rate of embryo mortality.
Nutrition is a very important factor in ensuing the success of the AI program. Ewes should be on a rising plane of nutrition and they should be on a condition score of 2.5 to 3 at the time of AI.
- Females should also not be over fat.
- Avoid sudden changes to your sheep’s diet.
- Supplementation of their diet with grains such should be considered during dry periods when adequate feed is unavailable. Have you flock’s trace elements and vitamins status checked.
- Consider Vitamin A, D and E, selenium, copper, cobalt and zinc. Allow up to 8 weeks for investigation and supplementation if necessary.
- Lambs or kids should be weaned at least 6-8 weeks before insemination of their dams.
- Stressful procedures should be avoided for 6-8 weeks before and 4 weeks after insemination. These procedures include dipping, drenching, vaccination and shearing.
- Where possible avoid moving the ewes too much in the period leading up to the AI program. Obviously, availability of sufficient nutrition over-rides the preference of not moving the flock.
- If a dog is used for moving the flock or for yard work try and use a quiet dog if possible.