What is Laparoscopic A.I.?
It is a specialised technique to be performed by a well-trained veterinarian. In South Africa it was introduced in 1985 by dr. J.J. Steyn and since then their has been a steady increase in demand. RAMSEM has three highly trained and experienced veterinarians available namely Dr. Johan Steyn, Dr. Fanie Steyn and Dr. Nolte Troskie.
Especially in the sheep-ewe, the cervix cannot be penetrated with a normal artificial insemination pipette because of cross-pleating inside the cervix.
The consequence is that a sufficient amount of sperm cannot move through the cervix. This has a negative result on conception and fertilisation. Better results can however be achieved with goat semen due to deeper cervix penetration.
Laparoscopic A.I. is used to deposit semen directly into each of the uterine horns.
It is an essential technique for insemination with frozen semen in ewes.
Laparoscopic AI is also used in insemination of superovulated ewes during embryo transfer projects.
Sheep and goat breeders can utilise laparoscopic AI very favourably in their breeding programs.
A skilled operator can inseminate up to 400 ewes per day with either fresh or frozen semen. When fresh semen is used, approximately 150 ewes can be inseminated with one ram. Only 20 million live sperm versus 120 million for cervical AI is needed and rams can be used at a very young age.
When frozen semen is used, more ewes can be done with semen from a single ram. Several co-owners of 1 expensive ram can still make full use of the ram.
Frozen semen is a good insurance for a ram – preservation of genetic material for several years.
Rapid genetic progress – semen from rams proven on merit and based on performance testing of their progeny, can be distributed throughout the country and many studbreeders can benefit from a national program. It is more economical to buy semen from a few top stud rams than to invest heavily in only one expensive ram.
AI programs can be planned and executed properly – breeders know exactly how many doses of semen are available.
In general the technique is too expensive for commercial sheep and goat breeders.
- Endoscope light source and fibre optic cable;
- Two sets of trocars and cannulae
- A medical CO2 cylinder with pressure valve and latex tubing (to inflate abdomen);
- Transcab and Aspics (to draw semen in and to deposit it with a short sharp needle into the lumen of both uterine horns of the ewe);
- Two special manufactured trolleys (to restrain ewes on their backs and to tilt them at 45° with hindquarters elevated).
Ewes have to be starved for at least 12 hours before AI to reduce the content of the rumen and the bladder. The abdomen is prepared by shearing, shaving and disinfecting. The trocars and cannulae are inserted 7 – 10 cm ventral to the udder and 5 – 10 cm on each side of the mid-ventral line.
A scalpel blade can be used to make a small incision in the skin to facilitate penetration. The 7 mm trocar and cannula that is connected with the CO2 is first introduced and the abdomen is slightly inflated to create space in the abdomen and to reduce the chance of injury to organs.
Insertions of the first trocar and cannula should be well controlled and the sharp trocar is withdrawn as soon as the abdominal wall has been pierced. The blunt cannula is pushed well into the abdomen and the second trocar and cannula is inserted, for increased safety, after inflation with CO2. Endoscope and AI instrument go through the cannulae and the uterus is located just ventral to the uterine bladder. Semen is deposited in each uterine horn approximately halfway between the uterine bifurcation and the utero-tubal junction. A light stab action of the aspic and the turn of the plunger deposit about 0,1 ml of diluted or frozen thawed semen into the lumen of each uterine horn (total 0,2 ml). Instruments are withdrawn and put into disinfectants between each animal. An antibiotic spray is applied to the 2 wounds.
Occasionally bleeding may be caused by perforation of a subcutaneous blood vessel. The wound can be sutured or an artery clamp is applied. Fatalities can occur when the abdominal aorta is pierced with an uncontrolled insertion of the first trocar. It is possible to pierce a full rumen as well as a full bladder. Operators should be well trained.
Success of the program:
To achieve good results, the Breeder must work as a team with the A.I. Centre and the Veterinarian when his program is planned.
There are 4 basic requirements for successful reproduction:
- The presence of healthy live sperm
- The release of healthy ova by the ewe
- A favourable environment for the uniting of the sperm and ovum so that fertilisation can take place.
Poor results with A.I. reflect weaknesses in one or more of these basic requirements.
- A favourable environment where the fertilised ovum (Zygote) can grow and develop.
From this it is clear that the Breeder who is going to use laparoscopic A.I. will,
through management and feeding of the flock, in reality determine the success of the program.
RAMSEM A.I. Centre’s responsibility is to produce good quality semen after freezing.
If semen is frozen elsewhere, imported or privately stored, it must first be evaluated with a good phase-contrast microscope to ensure that the quality of semen is good.
Preparation of the ewe:
The management of the ewe flock will determine the release / production of enough healthy ova (egg-cells) and if there will be a favourable environment for the fertilisation and the development of the embryo.
The breeder must select ewes for each specific ram and this must be done as soon as he starts his program.
Fertile ewes with a good breeding history give the best results. Ewes which don’t lamb regularly cannot be cured with A.I.. Such infertile ewes are usually large, in good condition and can easily land in the A.I. group. Breeding records must thus be thoroughly checked before bringing ewes into an A.I. program.
Conception rates are usually lower in young and very old ewes as compared to mature adult ewes. Young ewes can however be inseminated successfully if they are well selected, well grown and in good condition.
All ewes with poor and damaged udders must be excluded so that “multiple births” can be reared successfully.
Condition and feeding:
Condition and feeding of ewes remains the most important factor in reproduction. The positive aspect of flush feeding and an increase in body mass 3 – 4 weeks before
A.I., is well known. It increases ovulation rate and give better conception rates. It pays to feed the ewes at this stage.
In spite of good grazing and roughage, ewes must also get supplementary feeding in the form of balanced licks or concentrates, for example, chocolate mealies. Drought survival feeding is not good enough. Find the right balance between quality protein, energy, essencial minerals and vitamins. Consult an expert if necessary.
It is important that ewes did not suffer from very low body condition and bad feeding during the 6 months prior to A.I.. Development of oocytes under influence of reproductive hormones takes about 6 months – flush feeding 6 weeks before A.I. won’t rectify the problem.
Ewes that reached optimal condition before the A.I. program, must be maintained in that condition and not be allowed to drop in condition before they are inseminated. Flush feeding is of very little value in the case of ewes in optimal conditions.
A good stockman knows his flock and can see how they respond to feeding. By weighing his ewes he will be able to judge very accurately how they are responding.
A concept that should become part of any stock farmers management is condition scoring.
The loin area of the ewe is felt while the ewe is standing. Note is taken of the amount which the spinous processes protrude. The fullness of the eye muscle is first concave 1 - 2½ (hollow), becomes level 2½ - 3½ and later becomes convex 3½ - 5 (round). A condition 3 – 3½ is ideal for a ewe prior to mating and 2½ - 3 prior to lambing.
|CONDITION SCORING IN SHEEP
clearly felt, sharp,
Form a smooth
line with deep
detectable with firm
Have to push firmly
to get fingers
Cannot be felt at all
Cannot be felt at all
Not concave nor
Very thick to form a
dip along top midline
Results with overfat ewes are usually low, i.e. ewes in show condition.
Imbalances in feeding may cause problems during any phase of reproduction. The advice of a nutrition specialist may be necessary to ensure that the ration fed is balanced. Free access to a balanced mineral lick remains a sound practise. Even under intensive conditions inbalances can easily occur. In certain areas Selenium, Copper and Cobalt, must be considered as routine supplement. Vitamin A is equally important and should be administered at least 6 weeks before breeding.
Vaccinations, dosing and dipping:
Vaccinations, dosing and dipping must be done early.
Blue tongue, Enzootic abortion and Pasteurella vaccinations must preferably be done 6 weeks prior to the start of the A.I. program. Dose at the start of flush feeding and try not to handle the ewes for 2 – 3 weeks after insemination. If ewes are on pastures during the late summer it might be necessary to dose them again just prior to inseminating i.e. at sponging or on sponge withdrawal.
After insemination ewes must be placed in worm “free” camps, as heavy worm infestations after A.I. could lead to resorbtions.
N.B. This is especially important during spring and with heavy rains.
Shearing of ewes:
Short wool ewes react better to flush feeding and synchronisation as well as being easier to handle. It is suggested that insemination is postponed till after shearing.
Blowfly strike during the breeding season, can lead to problems, therefore crutching is recommended with long wool sheep.
Lambs must be weaned at least 6 weeks before mating to enable the ewes to recover sufficiently. If however the ewes lamb every 8 months or in cases where the ewes are still suckling lambs, feeding is of great importance.
Laparoscopic insemination involves a single fixed time insemination, so it is dependant on the effectiveness of oestrus synchronisation.
Oestrus synchronisation is achieved by placing progesterone treated sponges in the vagina of the ewe and left there for 13 – 14 days. On sponge withdrawal, the ewes are injected with Pregnant Mare Serum Gonadotrophin (P.M.S.G.).
The progesterone sponges prevent the ewes from coming on heat while they are in the vagina of the ewe. The P.M.S.G. exerts a Follicle stimulating hormone and Luteïnising hormone effect, which acts to stimulate the ewes to show oestrus over a short time and can increase the number of multiple ovulations.
If two groups are to be inseminated on consecutive days, they can be sponged together and then withdrawn on two separate days. The sponges would then have been left in for 13 or 14 days respectively.
On withdrawal the sponge will be full of mucous and have an offensive smell. If good hygiene was practised during sponging, it will not have any negative effect on conception rates. The ewe will be clean when she comes on heat.
P.M.S.G.: administration and dosage:
P.M.S.G. comes in a freeze dried powder form and the dosage administered is expressed in international units (i.u.) which is then converted to volume.
One bottle P.M.S.G. contains 6 000 i.u.
It must be dissolved in 50 ml sterile water,
Thus 300 i.u. equals 2,5 ml of solvent.
P.M.S.G. is sensitive to temperature changes and must be kept cool (5 – 10 ° C). Once the solution has been made up, it must be protected against sunlight and heat (refrigerated) and used within 24 hours. Accuracy is essential. Administration is
intramuscularly – the thick rump muscle behind the hip bones and in front of the pin bones is easier to reach than the thigh muscle.
It is essential to use P.M.S.G. to ensure good synchronisation. At high doses it causes multiple ovulations, which could lead to multiple births. The standard dose is 300 i.u.
Herd history, feeding and condition does however still have an important influence on results. When a ewe flock that has a history of high conception rates, a good percentage of multiple births on first cycle, is in good nutritional status and is being mated during its natural mating season, the dosage of P.M.S.G. can be lowered.
When the opposite conditions are prevalent in a flock with poor breeding history, poor nutritional status and outside its natural mating season, the dosage may be increased.
Breeders wanting to increase the number of multiple births can also inject a higher dose.
For Merino ewes we recommend 300 i.u., for heavy mutton breeds 360 – 480 i.u. and for Angora goats 180 – 240 i.u. – depending on nutritional status, breeding history and breeding season.
It is important for the breeder and inseminator to communicate in this regard and reach a final descision.
P.M.S.G. is always administered at the time of sponge withdrawal and intramuscularly.
The time between sponge withdrawal and insemination is very important, because ovulation takes place from about 58 - 60 hours after sponge withdrawal and it is important to inseminate before that, especially when fresh semen is used. Maiden ewes usually ovulate earlier and some differences between breeds and seasons may occur.
With CIDR’s, ewes come on heat and ovulate 4 hours earlier than is the case with sponges.
Before introduction of teaser rams, it is a good practice to ensure that females have no contact with males including sight and smell, for at least 4 weeks. Keep males and females about 2 km apart.
The stimulatory effect of the presence of teaser rams in a natural mating situation is well known. When synchronising ewes, teaser rams still have an effect and it has been found that ovulation takes place a couple of hours earlier when teaser rams are
present. It is recommended that teaser rams (2 – 5 %) are placed with the ewes the afternoon before insemination. They can be left with the ewes till after insemination.
Teaser rams can be used to mark the ewes as they come on heat and as they are marked, they are removed from the group. The group that comes on heat first, are inseminated first. This is of importance when all the sponges are withdrawn at the same time.
The use of teaser rams with markers helps to give an indication of how well the group has responded to the synchronisation. If 50 % of ewes are marked at 36 hours and
80 % at 48 hours, then the response has been good. When inseminating over a number of days, it is advisable to have teasers with the first group. This will help to give an indication of how the whole lot will respond.
The markers on the teaser rams must be checked regularly to ensure that they still have sufficient wax. Any marked ewes that are to be removed, must be done as quietly as possible. Teaser rams must be rotated to allow them time to rest, drink and feed.
If teaser rams are not available the ewes may be placed next to rams or aprons can be fitted to the rams. In both cases they must be kept under observation to prevent any ewes being served.
The ewes due to be inseminated must be kept away from food and water for 12 – 18 hours before laparoscopic insemination. This makes the actual inseminating easier and prevents the ewe from aspirating rumen fluid.
Under veld and lick conditions 12 hours of fasting is sufficient, whereas under pasture or concentrate conditions an 18 hour period is necessary.
The inseminating must be done indoors where there is shelter from sunlight, wind and dust. The ewes are loaded onto trolleys with wheels and a solid, preferably cement floor is therefore necessary for free movement of the trolleys.
Two or three small camps adjacent to the work area are necessary to enable ewes to be handled easily.
A reliable 220 V power source is required and if a lighting plant is to be used, it must generate at least 1,5 KW.
A work area the size of a double garage is required. Two kitchen type tables and a chair must also be provided.
The undertaking is fairly labour intensive and the following labourers are required:
- Shearing of ewes: 1 – 2 men (shearing to be done just before A.I. so that bellies are clean)
- loading of ewes onto trolleys: 2 men
- If manpower is limited, two men could handle the loading and unloading.
Depending on facilities and ability of the labourers 4 – 8 people are required for the whole operation to run smoothly.
- Lifting and holding the ewe during insemination: 1 man.
Post insemination care:
Immediately after insemination the ewes must be kept in a holding kraal for ± 30 minutes and then released as a group. They can be watered and fed immediately and the teaser rams remain with them till the following morning. Implantation of the foetus only takes place 21 days after fertilisation. If the ewe is placed under any additional stress during this time there is a chance of resorbtion of the foetus. It is not necessary to pamper the ewes, but do not subject the ewes to factors such as a sudden drop in plane of nutrition, making them walk long distances, shearing, dipping and dosing. If the ewes must be transported over short distances it is possible to do so after a couple of days, but do not overload the truck and do not transport them in the heat of the day. Do not transport them for long distances for at least 21 days.
Follow up rams:
The length of a ewe’s oestrus cycle is 17 days (15 – 20 days) and about 21 days in goat does. It is therefore recommended that follow up rams are put with the ewes from day 14 to 21 (sheep) after the A.I. program.
During the natural mating season, February to May, the ewes that do not conceive normally, show heat on the next cycle. Whereas during the period August to December the ewes tend to go into a period of anoestrus for a couple of cycles after being synchronised. The non return rate is therefore not a good indication of conception rate and during the spring mating the follow up rams should be left with the ewes for 2 cycles (34 – 42 days) after insemination.
An ultrasonic scanner can at 6 weeks determine pregnancy and if the results of the follow up rams are also wanted, then the scanning must be done 9 – 10 weeks after insemination. The use of the scanner can be a great management aid because it is not only able to determine pregnancy, but also to determine multiple pregnancies.
The average gestation time of the merino type ewe is 150 days. After synchronisation the ewes lamb over a period of 7 – 10 days with the most lambing during the middle
three days. The advantage of a short lambing time is obvious; bad weather during this time can however cause problems.
Lamb mortality within the first three days is correlated to the concentration of ewes per camp and the number of lambs born per day. It is thus advisable to use larger camps or divide the ewes into smaller groups.
It is necessary to ensure sufficient water, food and shelter. Camps with lots of bush are useful, because the ewe is able to separate herself from the group and thus assists in preventing the lamb from not taking to it’s dam.
In more intensive systems, lambing crates can be used where the ewe and lamb can be kept under observation.
The ewe flock must be regularly inspected. Note that new born lambs tend to follow anything that moves. Lend assistance if any ewes have problems lambing and ensure that new born lambs receive colostrum within 2 – 3 hours.
It is also possible if one is expecting a large number of multiple births to freeze cow or ewe colostrum before the lambing season. Weak lambs can then be dosed with colostrum using a stomach tube. A dog urinary catheter which is available from a veterinarian is ideal for this. The daily requirements of colostrum is up to 200 ml / kg / day. Dosing however must not exceed 50 ml / kg. Note however that ewe milk replacers should not be used during the first day as they do not supply the required antibodies.
When the date and number of ewes has been finalised you will receive a complete program. It is accepted that the number of ewes might not remain exactly the same, but if they do change or the program is to be cancelled, please advise the inseminator immediately.
- Synchronisation, drugs and semen:
Exact number of sponges and doses of P.M.S.G. must be ordered well in advance.
Where private vets will be getting involved it is necessary to order the exact number of semen doses. This is necessary
because any semen that is returned to the A.I. Centre must be recounted and re-evaluated before it is accepted back.
If the intention is to use 100 doses it can be advisable to sponge 105 ewes to account for lost sponges and any ewes
It may be necessary to get in touch with the A.I. Centre at the time of sponge withdrawal, to finalise numbers and sort out
If pregnancy testing is done and/or after lambing, please advise the A.I. Centre of the results.
Laparoscopic insemination with fresh or frozen semen has become an essential and integral part of controlled breeding of sheep and goats and provide valuable practical opportunities to improve reproduction efficiency and to enhance genetic improvement.
Please contact Hendriëtte Stafford for more information.