The primary purpose of laparoscopic artificial insemination (LAI) is to ensure the highest rate of conception with an optimum number of lambs. The veterinarians at GeneCo, Dr Frans Jooste and Dr Hendrik du Toit, have been successfully performing this veterinary procedure, in which semen is deposited directly into the uterus, for some time now.
Dr Du Toit explains that the technique is used mainly to inseminate ewes at a set time when oestrus, or heat, is synchronised. “Two small incisions are made in the ewe’s abdomen. The laparoscope provides a direct image of the uterus, and a small needle is then used to inject semen into the uterus.”
He emphasises that the natural cycle of ewes is only manipulated and that they are not artificially brought into heat. “Synchronisation also has no side effects or lasting effects on the fertility of ewes.”
Synchronising for artificial insemination (AI) is a vital technique in commercial reproduction programmes. Dr Du Toit summarises the reasons for this as follows: “It reduces the need for labour to detect oestrus and since ewes have a very short lambing period, the effectiveness of labour can be intensified during lambing. Approximately 500 ewes can be laparoscopically inseminated in one day.
“Heats must be synchronised for ewes to reach oestrus on the same day, which means ewes that are impregnated using LAI, will lamb within approximately five days of one another. Non-pregnant ewes remain fairly well synchronised in respect of the heat cycle when they return to oestrus roughly 17 days later. These ewes will then become pregnant with follow-up lambs and their subsequent lambing period will also be short.”
There are typically two peak times when lambs are born following synchronised heat. Between 70 and 80% of ewes lamb in one week, about five months after synchronised heat and LAI, followed by approximately ten days in which no lambs are born. A week after this the ewes that are pregnant from follow-up rams, will lamb. The lambing period can therefore be thoroughly planned and managed.
Nutrition and health management
According to Dr Du Toit, it is easy to increase predator control during lambing, since the ewes lamb over a very short time. Ewes can be moved to safer camps or to intensive lambing pen systems to limit lamb losses.
“With regard to their reproduction status, the nutrition and health of the ewes can be managed more effectively if they are synchronised. The supplemental nutrition of ewes in late gestation and ewes with lambs, is more effective because most ewes are in the same phase of pregnancy. Vaccines and anthelmintics can be administered during the right phase of gestation to provide lambs with optimal protection.
“Supplements and creep feed for lambs become more effective and economical, as most of the lambs are the same age,” he explains.
Effective use of rams
He believes that using LAI at a set time ensures the effective use of top rams in breeding programmes. “With natural mating an adult, fertile ram can cover roughly 50 to 100 ewes in a 35- to 42-day mating season. In an LAI programme a ram with high-quality semen can be used to inseminate roughly 200 ewes on the same day. Using oestrus synchronisation and LAI, a ram can impregnate more ewes in a single breeding season than it could over a lifetime of natural mating.
“LAI facilitates the use of frozen semen in breeding programmes in instances where the ram is unavailable or the semen of top rams is purchased, as the freezing and thawing process causes considerable damage to the sperm cells and shortens their lifespan.
“To ensure acceptable fertilisation, frozen semen must be deposited directly into the uterus using LAI. The quality of frozen semen after thawing is too poor for it to move through the cervix into the uterus and still ensure acceptable fertilisation,” he explains.
Dr Du Toit says synchronisation facilitates good record-keeping and animal selection. It also simplifies the calculation of indices and BLUP values, as uniform groups of lambs are used.
Reproduction programme guidelines
To manage a successful reproduction programme, producers should keep the following aspects in mind:
- The nutritional status and condition of ewes is of utmost importance when planning an AI-programme. Ewes should be in a condition score of 3 to 3,5 (on a scale of 5) about six weeks before the programme commences. Keep in mind though that synchronisation and artificial insemination are only an aid and not a cure for poor reproduction.
- Start flush feeding roughly four weeks prior to the start of the synchronisation programme.
- Ewes with udder problems (mastitis) and teat problems should be culled before commencing with a reproduction programme.
- It is practical to wean all lambs that are still with the ewes. The suckling lamb causes the ewe to secrete endorphins, which suppress ovarian activity. Once the lambs have been weaned, the reproductive ability of the ewes will improve.
- Dose and vaccinate ewes before starting the reproduction programme. It is not advisable to subject ewes to dosing and vaccination during the synchronisation programme or during early pregnancy.
- It is advisable to shear ewes with long wool six to eight weeks prior to commencement of the reproduction programme. Ewes should not be shorn during the programme or within six weeks after LAI.
- Make sure that young ewes lambing for the first time, reach at least 75 to 80% of their adult weight when the programme commences.
- Contact the veterinarian who will handle the reproduction programme well in advance, so that ewes and rams can be properly prepared.
Dr Du Toit says the costs are relatively low and the number of multiplets and extra lambs born, more than compensate for any costs incurred during ewe preparation and for LAI. “Most producers who make use of the process have a lamb weaning figure that is 30 to 40% higher, thanks to the extra lambs.”
A producer’s experience
Casper Byleveld, a small-stock producer from Kareehoek in the Britstown area, says he makes use of LAI because:
- It simplifies the management of his farming enterprise.
- His ewes have an 84% conception rate and 60% multiplets, thanks to the process. The number of lambs is increased, with the multiplet factor playing a big role.
- LAI contributes to the genetic progress of his flock.
- Enough lambs are market ready at the same time.
Unproductive ewes are quickly identified and culled. – Carin Venter, Stockfarm
For enquiries, phone GeneCo on 083 308 5277, send an email to firstname.lastname@example.org or phone Casper Byleveld on 082 785 9343.