In the pig industry there are multiple versions of artificial insemination intra-uterine insemination catheters, IUI, generally consisting of relatively small diameter rigid tubes, inside regular traditional pipettes. This smaller tube is gently pushed through the gilt’s cervix and directly into the uterus.
While there can be advantages to this method, it has the potential of injuring the sow by scraping or puncturing delicate tissues in the reproductive tract. This type of pipette also collects a small amount of bacteria laden matter when it is threaded through the cervix. This becomes an even more significant issue with reduced concentration doses.
The cervix’s primary role is to keep bacteria and contaminants from entering the uterus and uterine horns (the animal’s reproductive tract). Once a foreign substance enters the uterus, the animals are more prone to infections, abortions, smaller litter sizes, and lesser farrowing percentages.
Deep intra-uterine insemination
Another option for pig breeding is deep intra-uterine insemination, DIUI. This is a new procedure; one that uses a thin flexible tubular pipette that is approximately 1.7 meters in length. The tube’s extreme length allows it to be inserted all the way to the uteral tubal junction where its design allows it to place small amounts of semen in one horn. This artificial insemination method may work in clinical trials performed by doctors; but this technology is not ready for mainstream use yet.
Absolute Swine Insemination Co. has developed patented hydraulic AMG series catheters. These catheters are designed to combine the performance of DIUI and the safety of traditional cervical inseminations in both horns at the same time.
They have a flexible membrane that moves forward when a technician squeezes on the semen tube, flat pack or bottle. Because the pipette’s membranes turn themselves inside out while moving forward; the aforementioned plug of bacteria is actually re-deposited at the very beginning of the cervix. The only substance entering a sow or gilt’s reproductive tract is what is inside the semen container.
Figure 1 is a picture of a parity 4 sow’s reproductive tract. This sow was injected with a dye using the AMG catheters. After injecting the dye, the reproductive tract was removed and opened. The dye advanced up both horns to the uteral tubal junction instantaneously without any injury to the sow.
Figure 2 also is of a parity 4 sow bred using a traditional foam tip pipette. The majority of semen is trapped in the cervix and some has advanced a short distance up the horns. The semen still has a long way to travel before reaching the uteral tubal junction awaiting ovulation. It’s important to note that most of the semen will die along this journey due to Phagocytosis. The immediate injection of semen into the uteral tubal junction allows for very low concentrations of spermatozoa to be used successfully.
While many in the pig industry talk about low-dose inseminations, it’s important to discuss how and where genetic material is delivered into the reproductive tract.
The volume of the extended dose of semen used in IUI or DIUI inseminations still plays a critical role. In nature, a normal pig ejaculate is 250-300ml (on average), which is already far more than today’s standard of 70-80ml. An adequate volume of fluid is needed to carry the spermatozoa to the sow’s uteral tubal junction, especially in older parity sows.
Maintaining a volume of 70ml when extending semen, even in the lower concentrations allows for a hydraulic catheter to carry the semen to its final destination the uteral-tubal junction. Reducing the concentration of spermatozoa to 400 million and the extended solution below 70ml is not recommended; the same as repacking pig semen into two new containers resulting in 35mls each is not recommended. For optimal results discuss the lower concentration doses with your genetic supplier.
Advances in artificial insemination
“The role of artificial insemination in delivering the ‘best of the best’ genetics - and farrowing rates of up to 95 percent - is already firmly established as pivotal to the success of the pig industry,” says Stephen Waite, head of science at JSR Genetics. “Can Research and Development yield real positive benefits? In our experience, the answer would be yes. One such project is the viability of offering sex selected semen, which would be a huge step forward for the pig industry. The potentially achievable, and preferable, split would be eight gilts to two boars.”
“Once we can ascertain an optimal low dose for pigs – and we suspect this may be around 400 million - we will carry on our work with the University of York, who are currently involved in research with flow cytometer manufacturers, to make that dose as easy as possible to sex,” says Waite. “Every year, sexing cells is getting faster, say by a factor of ten. Now new chemicals that bind onto the male/female cells to make them easier to sort by weight are opening up yet another promising avenue for research. Just one breakthrough could revolutionize the pig industry.”
Deeper innovation for insemination technologies
“To keep up with pig breeding developments such as the regular use of frozen artificial insemination and the use of lower semen concentrations as well as potential new technologies such as semen sexing and embryo transfer, catheters have been developed to allow ever deeper insemination,” says Walling.
Some of the concerns over deep insemination catheters have been the potential damage to sow’s reproductive tract using the long rod attached to the catheter. This can be avoided by using a balloon- type membrane at the end of the catheter instead of the long rod. Without a pointed end it’s not possible to damage the tract and the membrane simply navigates its way through by gently moulding its shape to that of the sow.
This modification has overcome one of the major concerns many pig production managers had of their staff using deep artificial insemination catheters. Semen is deposited deeper in the inter-uterine tract at the uteral tubal junction rather than in the cervix.
Concentrations can be reduced to 500 million sperm per dose in contrast to the 2.5 billion used with conventional catheters; this allows pig farms to run with fewer boars and allows for more inseminations from the same boar reducing variability in the progeny. In addition to using fewer boars, it may be an opportunity to use boars of a higher genetic merit. It also offers the opportunity to use frozen semen which due to the mortality of the sperm during the freezing process may be at a lower concentration than the conventional dose.
“This is an illustration how technology can advance relatively quickly going forward when the incorporation of one innovation allows the use of several other technologies, says Walling. “It is for this reason why science tends to jump forward rather than a series of small discoveries. Ultimately a relatively small but innovative change has allayed many of the fears of using deep insemination catheters and we expect to see significant uptake of this technology.”