Preparation for AI
The insemination of sheep must be timely planned.
Sheep insemination technique is not a remedy (method) for bad management, low body condition, moldy feed, with continuous poor reproductive results. AI as an insemination technique should only be an upgrade to farmers who are good and conscientious breeders, who already have good results in the percentage of lambs and breeding lambs.
The owner of the sheep/goat herd indirectly influences the growth, maturation, and release (production) of a sufficient number of healthy ova and whether it will be a favorable environment for embryo fertilization and development. The breeder must determine the mating plan (selection of sheep/goats and rams/goats) and this must be done as soon as he begins to plan his mating program. It is not good practice to leave rams inside the flock and then to submit remained unpregnant sheep to AI procedures.
The best breeding results can be expected from fertile sheep/goats with good breeding history. Sheep/goats that have not been lambed regularly are not eligible for AI investment. Such infertile sheep and goats are usually large, in good condition and, if we do not have a history of such animals, they can easily join a group of sheep/goats suitable for AI. Breeding records must be thoroughly checked before the introduction of sheep or goats into the LAI program.
The conception rate is lower in young animals (under 12 months) and in very old sheep/goats (over 8 years), compared to mature, adult sheep/goats. Young sheep/goats can be successfully inseminated if a good selection of individuals is made, in good condition, feed without mycotoxins and supplied with mineral-vitamin supplements. All sheep/goats with small and dysfunctional udders must be excluded from the program so that newborn lambs can be successfully reared. Avoid rearing of underfeed animals. The fertility of young animals largely depends on the rearing conditions in the first weeks (months) of life.
All intended activities (clipping, parasite clearing, vaccinations, hoof trimming, relocation, sudden meal changes) must be discontinued 3-4 weeks before and after insemination (6 weeks optimum).
Vaccinations, anti-parasite treatment and bathing must be done on time, carried out 6 weeks before the start of the AI program. It is important to ensure the absolute rest of the sheep in the next 4 - 5 weeks after insemination. According to British studies, any manipulation after insemination or breeding can reduce the number of lambs born by up to 20%, and even just chasing sheep with sheepdogs, in particular bathing, wool shears, vaccinations, bad blood collection organization (eg no sheep corridor for implementation of these interventions), etc….
Lambs and kids weaning: Ideally, lambs must be weaned at least 6 weeks before mating in order to sufficiently recover the body condition of sheep. However, if the sheep are under intensive breeding program and lamb every 8 months or in cases where the sheep are still nursing, then the diet is very important. If the sheep diet is good and if the sheep are in good condition (BCS equal or greater than 2.5), well-fed, then the sheep can be inseminated from 7-8 weeks after lambing. Our main recommendation is to dry off sheep, start with an intensive flushing diet for 15-20 days, and then put sponges (this is 15 days more for the recovery period). Anyway, optimal is to inseminate sheep not earlier than 3 months after lambing.
In general, insemination of sheep in lactation decreases fertility by about 10%.
Sheep should not be inseminated during the period of drying off when a regimen of poor nutrition or complete discontinuation of a concentrated and energy-rich vault is applied.
For milking sheep and goats, insemination is often performed 5 months after lambing, when milk production starts to decline and animals start to correct BCS.
Sheep shearing: Sheep respond better to the flushing diet (enhanced pre-dairy diets), synchronization and are easier handling if are sheared. We suggest that sheep shearing is done a couple of weeks before or it has to be postponed 2.5 months after insemination.
Hoggets should be sheared at 6-8 months of age. In Serbia, sheep owners have a bad habit to conduct first shearing after first lambing (with 15-16 months old animals).
The use of teaser rams is a common practice in Norway, Australia and New Zealand. These rams/bucks are used to detect females in oestrus, to promote its appearance and to increase the success of conception. Rams/bucks are unable to impregnate sheep/goats as they are vasectomized or they have aprons. Ideally, rams/bucks are equipped with crayon harnesses to mark mounted sheep. Marked sheep/goats can be inseminated 12 hours after marking by the farmer (especially suitable for goat farmers who are trained to inseminate goats in their own flock). So, the sheep that are marked in the morning, are inseminated in the evening, and the sheep that are marked in the evening, are inseminated in the morning.
The unique practice of sheep insemination with frozen semen by the vaginal method is a commonly accepted method in Norway by their farmers as success is around 50-60%. AI in sheep is done solely after the estrus detection by the teaser rams since hormone synchronization is prohibited.
The stimulative effect of the presence of a ram in a natural mating situation is well known. In synchronized sheep, rams have the effect to stimulate ovulation. It is recommended to put 2 - 5% of rams with aprons among sheep in the afternoon, before insemination. They can be left in the flock even after insemination. Rams with crayons can be used to mark sheep when they enter in heat. Labeled sheep are removed from the group for AI. The group of sheep that first enter in estrus is the one that is first inseminated. This is important when all sponges are removed at the same time.
Ram with harnesses Marked sheep with 2 colors (rebreeding)
Using rams with crayons can help to discover how many synchronized sheep have responded to synchronization. If 50% of sheep were tagged in 36 hours or 80% in 48 hours, the answer was good. Once the insemination is complete, it is recommended that you have a first-mover try in a few days. This will help indicate how many have responded successfully to insemination.
Ram's markers must be checked regularly to ensure that there is sufficient chalk on them. Marked sheep should be removed as quietly as possible. Teaser rams must be rotated to give them time to rest, drink and eat. If you do not have enough vasectomized teaser rams, then a fertile ram with an apron can be used. Of course, these rams must be kept under observation in order to prevent unwanted pregnancies by losing an apron.
The same is for bucks.
Eating and feeding: Sheep that we plan to inseminate must be starved for 24 hours and their water is withheld 12 hours before laparoscopic insemination. This makes insemination easier, with less risk of the rumen and bladder punching and preventing the inhalation of fluid from the rumen while the animal is in a suspended position on the laparoscopic table.
It is essential to clean the straw bedding from the floor in the boxes where sheep are starving.
• capturing and loading sheep in the cradle: 2 persons (men);
• disinfection of sheep abdomen: 1 person;
• unloading of sheep: 2 persons (men);
• If the number of available people is limited, two could do loading and unloading cradle.
• Raising and keeping sheep during insemination: 1 person.
Depending on the capacity and ability of the worker, 4 (up to 50 sheep) and 6 people (over 50 sheep) are required to complete the operation quickly and smoothly.