Sheep / goat insemination
Reasons to apply AI and comparison with other, existing mating methods
One of the basic benefits is the better use of a ram or a buck. Compare the following mating systems:
1) Group mating: 3% of rams with sheep over a 6 week period. It takes 30 - 40 sheep per ram during this period (season).
2) Mating from the hand: Sheep in estrus are separated and brought to the ram. Ram is able to mate 5 - 10 sheep a day or every other day. The mating is mostly once and is monitored. One ram can pair 20 - 30 sheep/week. Workforce engagement is required, that is, investing time in observing, extracting, and recording mated sheep.
3) AI with fresh semen, cervical method: Sperm are taken on a farm. Ten sheep can be inseminated with one ejaculate. Basically, two consecutive ejaculates are collected at intervals of a few minutes (often 15 - 20 minutes). On average, about 20 sheep are inseminated per ram per day.
4) Freshly chilled semen, cervical method: Fresh sperm cooled to 15°C (French experience; shorter distance from center to farm and shorter transport period, semen is stored 8-12 hours) or up to 5°C (e.g. Australia - due to long distances, semen is stored for up to 3 days in this way). The number of inseminated sheep per ram is, on average, about 20 sheep.
5) Laparoscopic intrauterine AI with fresh or frozen sperm: Only 20 million live sperm are required for fertilization (Australian recommendations) or 50-150 million (European recommendations). Up to 100 sheep, a day can be inseminated with fresh semen on a daily basis. With frozen semen, an experienced operator can inseminate up to 300 sheep a day (the limit is the speed of insemination, not the amount of semen).
There are three techniques of artificial insemination:
- vaginal insemination,
- cervical insemination and
- laparoscopic insemination.
AI with frozen semen with vaginal insemination was developed only in Norway. The insemination is carried out in sheep that have spontaneus oestrus. Otherwise, in all other countries it is done exclusively with fresh semen.
Goat insemination with frozen semen with vaginal method is a generally accepted in intensive goat farming in developed countries where genetic progress is very important. The system of selection, control, production of semen, insemination and preparation of females must be brought to the highest level. The system does not suffer any improvisation.
Cervical insemination with fresh sperm
The basic equipment consists of a speculum with a built-in light source and pipettes connected to a 1ml syringe (plastic disposable straws are popular in Australia, New Zealand, USA). The French method (IMV Biotechnology) is using mini straws and AI sheats, similar to cattle, only smaller in size (represented in our country).
The animal is restrained by lifting hind legs over the rail and with head hanging down. The height should be 80 - 90 cm and the front legs should remain on the floor. One helper stands next to the sheep and secures the hind legs. The vulva of the sheep is wiped with a cotton swab, cloth or handkerchief. The speculum is slightly lubricated with a non-toxic semen lubricant and carefully introduced into the vagina to a depth of 10 - 13 cm. The opening of the cervix is easily recognizable (picture below). There are large differences in the size and shape of the cervical aperture between individual females. In young sheep, it is sometimes seen only as a cleft at the entrance of the vagina, while in older sheep the cervix is usually protruding into the vagina. The opening of the cervix must be lifted by the tip of a pipette. An attempt should be made to find a space between the folds of the cervix.
Laparoscopy enables artificial insemination of sheep directly into the uterus, via the abdominal wall, with minimal surgery. The laparoscopic insemination procedure was first applied by Australian researchers in 1982, which revolutionized the technique of sheep insemination. This procedure requires expensive equipment and a trained crew. The "RAM GEN" center has three trained and experienced veterinarians who apply this technique.
In sheep, the cervix is an anatomical obstacle that prevents the semen from depositing directly into the uterus during vaginal or cervical artificial insemination with a pipette due to annular folds of the cervix.
As a result, one-fold higher sperm concentrations are needed, which will be sufficient for fertilization compared to laparoscopic techniques. Better results can be obtained in goat insemination because of the possibility of deeper penetration through the cervix. The laparoscopic technique avoids the cervix as an anatomical barrier, and the semen is directly injected into each horn of the uterus. There are papers indicating that a single horn application is sufficient. This is essential for the technique of fertilization with frozen semen in sheep, precisely in order to achieve a sufficient number of vital sperm.
Advantages of using laparoscopic insemination:
• Fertilization success with LAI is similar to natural mating (laparoscopic AI with fresh semen) and ranges between 75% to 85%. With frozen semen, AI success ranges from about 60 - 75%. If natural cycles are used, 5-10% better success is expected than only hormone-induced cycles, but this method is not used in Serbia because of small flocks. The reason is that not all sheep respond to hormone cycle induction.
• A large number of sheep can be inseminated in one day (better organization of lambing and farm work). A skilled operator can inseminate up to 300 sheep a day with either fresh or frozen sperm/semen. When using fresh semen, up to 150 sheep with one ram's sperm can be inseminated. Only 20 million motile sperm are needed for laparoscopic VO versus cervical / vaginal insemination, where 150 million are needed.
• More precise lambing period and organizing farm work in a period associated with other activities (eg sowing, harvesting, etc.).
• Better care of lambs, the possibility of lambing and redistribution of lambs, better dedication to work, round-the-clock production, uniform quality.
• Frozen semen can be imported or exported more easily than live animals.
• Rams are of proven health status and fertility. Serum positive findings (positive rams for Medi visna, Brucella ovis, chlamydia, paratuberculosis was detected in 16% of licensed throats), with general and genital abnormalities, up to 20% of rams can have some of the defects that can lead to impaired fertility or its complete unusability (Milovanovic et al., 2011).
• Holds fewer rams.
• Sheep and goat breeders can use laparoscopic AI whenever is favorable in their breeding programs.
• When frozen semen is used, more sheep can be inseminated with semen from one common ram. It is possible for several co-owners to acquire one expensive ram, to split the cost of the acquisition, and to use it more intensively.
• Frozen sperm is good security for the owner, in terms of preserving genetic material for a number of years, as well as being able to trade in the semen of excellent genetics.
• Rapid genetic progression - Semen of proven rams based on good traits and based on progeny testing can be distributed throughout the country and many herd breeders can benefit from it. It is more economical to buy semen from several top rams than to invest money in just one expensive ram.
The use of frozen sperm provides a wider range of available genetics.
The equipment consists of:
• Endoscopic light source and fiber optic cable;
• Two sets of trocar and cannula;
• air pump with filter and latex tubes (for inflating the stomach);
• Transcap and aspic (to insert semen with the aid of a short sharp needle into the lumen of both uterine horns);
• Two or three special laparoscopic cradles (to fix the sheep to the back and to tilt at an angle of 45 ° with the hind legs up).
The success of the program: In order to achieve good results, the breeder must work as a team with the AI Center and veterinarians in order to make this program successful, well planned and implemented.
• The presence of vital, quality sperm of ram semen;
• production and release (ovulation) of healthy ovine ovum cells;
• a favorable environment for sperm and egg cells to fuse so that fertilization can be maintained;
• a favorable environment where a fertilized egg (zygote) can grow and develop.
Poor AI results occur when one of these basic requirements is not met. From this, it is clear that a breeder using a laparoscopic AI will determine the success of the program through the management and feeding of the herd.
In our conditions, the presence of moldy foods, lack of vitamin-mineral supplementation and low body condition scoring are the main reasons for poor fertilization success.
Place for laparoscopic insemination
It is optimal to perform AI in a covered place, with concrete flooring, protected from sun, wind and dust. The sheep are tied into a solid laparoscopic cradle with small wheels. It is optimal that space is with concrete flooring to allow the cradle to move freely. It is necessary to have two or three small boxes near the working area into which the sheep will be sorted before and after AI. A reliable power supply with 220 volts is required as well as a light source. Orientationally, a double garage work area as well as one kitchen table (or two if farm semen have to be taken on a farm) and one chair is required.
Conclusion Laparoscopic insemination with fresh or frozen semen has become essential and integral to the controlled rearing of sheep and goats and provides valuable practical opportunities to improve reproductive efficiency and genetic progression. Please contact the "RAM GEN" center for more information.
The record number of live-born lambs is 7 (Hancko Đerđ, Kula, Suffolk breed).
One example of successful implementation of laparoscopic insemination of domestic sheep in the Republic of Serbia: 9 sheep - 19 lambs (same age) (breeder Mićuka Milutinović, Lojanice, Vladimirci municipality)