Embryo transfer: A faster profitable way to boost your livestock 

Dr Kasule notes that good management practices can help avoid unhealthy cows, but it is also possible to improve livestock resistance and resilience to diseases through breeding.
Infectious diseases such as mastitis, pneumonia, foot rot and many others which usually require treatment with antibiotics, can be avoided by resistant breeds. Treating diseases can be costly and result in significant losses including culling.
“A common denominator for all diseases affecting dairy cows are the financial losses due to reduced milk yield, treatment costs, increased workload and the undesirable use of antibiotics,” Dr Kasule says.

Focus on traits
Scientists have been focusing on breeding goals to embrace healthy traits in the selection of sires of sons.
At NaLIRRI, scientists at the livestock breeding laboratory, have been studying high quality Viking Jerseys imported from Denmark for semen and embryo extraction to improve dairy milk production. Today, they are able to produce up to 4,000 cloned embryos.
The process can be completed with a much less invasive procedure that takes as little as 20 minutes. 
The embryo transfer process begins with cows receiving a hormone treatment to produce more than one ovulation (egg) at a time. The cows are then artificially inseminated with bulls also possessing desirable genetics.

Seven days later, a veterinarian recovers the embryos by using a catheter and recovery fluid. The fluid passes through a specialised filter, which catches the embryos. Dr Kasule says the process produces an average of six good embryos per cow. Any fertilised embryos captured in the process can be transferred into a surrogate cow, called a recipient, that will carry the pregnancy to term, or the embryos can be frozen to be used later.

Why embryo transfer
Dr Kasule explains that with careful fertilisation process, embryo transfer is the kind of breeding farmers need.
“A farmer can clearly follow the ancestry for future reproduction. Yet the animals are resistant as the foetus grows in a stronger mother. In that way, you do not have challenges with adaptability,” he says. The economics is favourable too.

Whereas AI or natural service would produce one calf a cow a year, an animal could be flushed several times, producing an average of four embryos each time.
This means there is potential to get 20 offspring from a cow in one year. Embryos could also be frozen for future use and sexed.
He says other technologies such as rumen temperature boluses and activity collars, which could alert farmers when a cow is on heat, also provided an opportunity to improve fertility with limited labour.
Dr Kasule explains that heifers, which are the most preferred dairy animals, go up to Shs10m yet if one goes for embryo transfer, they require between Shs1m to Shs1.5m to get a purebred.

“These types of technology may have traditionally been seen as a pedigree idea, but as costs come down it is well worth considering them in a commercial setting,” he says.
He says that the success rate is at 30 per cent up to three times of embryo transfer.

Embryo transfer involves programming a cow with fertility medicines to produce more oocytes (eggs), artificially inseminating, collecting the embryos and transferring into a recipient mother.
Speaking at the just concluded Seeds of Gold Farm Clinic at NaLIRRI, a farmer outreach training organised by Nation Media Group-Uganda in conjunction with the National Agricultural Research Organisation (Naro), Dr Kasule said this development provided scope for commercial farmers to buy embryos or select their best cows for embryo transfer.
However, ensuring semen quality is a top requirement for successful breeding.

Poor quality could result from any stage of the semen handling process, but Dr Kasule suggests farm storage and handling is one of the main risks.
He explains that at NaLIRRI, they are well-equipped to carefully handle semen.
He cautions dairy farmers on reproductive assessment of the recipient for good results.

A step-by-step guide
In vitro fertilisation (IVF) is the process of harvesting oocytes from donor cows, and creating embryos by fertilising the oocytes with semen in a petri dish. The embryo is then implanted into a recipient (otherwise known as surrogate cow), or they can be frozen in liquid nitrogen indefinitely. Dr Kasule, who oversees the process at NaLIRRI explains how the process works.

How the procedure works
The first stage is the key addition to conventional embryo transfer. Eggs are removed from the donor cow’s ovary before the ovary naturally releases the oocyte down the fallopian tube.
Using a process called trans-vaginal recovery, IVF works by first removing the dominant follicle in the ovary, allowing the rest to grow. In a normal pregnancy, the dominant follicle inhibits the rest – otherwise a cow could end up developing dozens of calves in the womb,” he adds. With IVF, all follicles are left for six days to develop uninhibited within the ovary.

The donor cow is given a local anaesthetic and cleaned with a mild disinfectant and saline solution.
Then an ultrasound-guided needle enters the ovary to remove the dominant follicle and stimulate super ovulation.
Super ovulation is a three-day course of follicle stimulating hormones administered to stimulate ovaries to produce more oocytes.
The donor cow is brought into the crush collection facility, where the temperature is at 27-32 °C. Oocytes are harvested via trans-vaginal recovery, averaging 10 eggs per collection, and the eggs are matured for 20 hours.

The eggs are placed into insulated chambers at 37°C to mimic a cow’s body temperature. 
Fertilisation occurs with semen. The resulting embryos are matured for a week in the laboratory, passing through eight different maturation liquids mimicking the changing pH and gas levels inside the uterus.
The embryos can be transferred directly or packed in tubes and frozen indefinitely.