Modern Reproductive Technology: A Breeding Revolution or a Bubble Ready to Burst?
Advanced reproductive technologies such as Embryo Transfer (ET), Intracytoplasmic Sperm Injection (ICSI), and Ovum Pick Up (OPU) have become increasingly prevalent in the breeding of sport horses. These techniques offer undeniable advantages for horse breeding and this article delves into the complex landscape of their impact on the world of sport horses, questions whether there might be a saturation point, and discusses emerging concerns related to both market dynamics and ethical considerations. The intent of this article is not to advocate for or against any of the mentioned technologies. Rather, its aim is to prompt horse breeders to make informed decisions based on understanding of the pros and cons with available reproductive technologies.
The Rise of Reproductive Technologies
During the last 20 years, the reproduction technologies Embryo Transfer (ET), Intracytoplasmic Sperm Injection (ICSI), and Ovum Pick Up (OPU) have gained quickly in popularity among breeders of sport horses. Since ET allows mares to have more than one foal per year and have a competition career at the same time by the use of surrogate mothers, it can greatly benefit the advancement of successful dam lines. As an example, the frequent use of ET on exceptional broodmares has significantly contributed to the remarkable development of Belgian show jumping breeding over the past decade. Major stakeholders Keros and Joris de Brabander in Belgium were some of the most important forerunners, ensuring easy access to the technology to Belgian breeders at an early stage. According to the BWP breeding management, the BWP alone currently registers almost 600 foals made by ET annually, and additionally more than 100 foals made by ICSI, together around 20 % of the registered BWP foals. Being only one of the three principal sport horse studbooks in Belgium today, the others being Studbook Zangersheide and Le Cheval de Sport Belge (Stud-book sBs), the numbers could probably be doubled for Belgium as a whole. A similar development has followed in other major sport horse producing countries. According to a report from the French studbook Selle Français (SF), the number of foals produced by ET has more than doubled during the past 10 years and now constitutes about 16% of all registered SF foals.
ET, ICSI and OPU: Revolutionizing the Breeding Game:
ICSI, a form of fertilization made in a laboratory, involves manually selecting a single sperm and injecting it into an egg. The whole process takes part outside the mare, and the fertilized egg (embryo) is implanted in a surrogate mare once the viability of the embryo is verified. This technology revolutionizes the breeding game, as a single dose of sperm can be used almost limitlessly, enabling stallions to sire a higher number of offspring than ever before.
The OPU technique allows mares to produce many more eggs than they normally would, which potentially increases the numbers of foals a mare can produce, even more than with ET. When performing OPU immature oocytes (eggs) are aspirated from the mare’s ovaries. The process is performed trans-vaginally on a sedated mare, epidural anesthesia is common. Maturation of the oocytes in the laboratory follows, before ICSI, embryo development and embryo insertion can take place.
Picture of ICSI - the procedure where one single sperm is injected into an oocyte (egg). Image by Freepik.
Maximizing Genetic Potential and Accelerating Progress
From a genetic progress point of view, the use of ET, ICSI and OPU is a schoolbook example on how to make best use of the best genetics, as long as it can be ensured that it’s the best individuals that are selected and allowed to multiply extensively:
Stallions that have proven themselves as sires can cover a limitless number of mares, even long after they’ve passed away which ensure reliability in the production of sport horses.
The generation interval, which is typically long in sport horses, can be shortened by letting young talented mares from proven dam lines produce numerous offspring while they simultaneously pursue a sport career.
Valuable mares that for some reason have become unable to reproduce naturally, can often continue to produce foals by using OPU and ICSI.
Recent years have seen these techniques enable prestigious foals and embryos from renowned mares and dam lines, combined with top-performing stallions, to be available on the market. When more breeders can get hold of genetically superior breeding stock, it potentially increases the pace of genetic progress by increasing the selection intensity when producing more horses with genetically high potential.
The Impact on the Equine Market
Foals with famous parents and siblings have so far commanded high prices at prestigious auctions, often marketed as "a unique opportunity". But are they still genuinely unique? Is there a risk of oversaturation of famous bloodlines and celebrated relatives? While these celebrity foals still fetch good prices, are there cracks appearing in the ICSI bubble? In an environment where virtually anyone with sufficient funds can acquire foals from the most distinguished and coveted stallions and dam lines, the uniqueness of offspring may diminish, potentially leading to reduced prices due to basic economic principles of supply and demand. Perhaps then breeders with more limited financial resources could access presumably genetically superior animals for breeding, further accelerating the quality improvement of show jumping breeding. But will the producers of these yet exclusive foals and embryos find it worthwhile if they don’t gain as much from each sale?
Concerns About Selection, Performance & Health
Within the breeder community, the modern reproduction techniques are used by many. Others have raised concerns about the procedure of replacing the natural sperm competition with human intervention in the selection process – the “playing God part”. When using ICSI, the natural selection process that occurs in traditional fertilization is bypassed and replaced by manual selection of that single lucky sperm. How does this impact the horse's performance in sport and even more important, the health and durability of the horse? The truth is no one knows – yet. So far, no studies have been produced that affirm those concerns, neither that shows proof of the opposite. Perhaps the lack of studies in this field is due to the shortage of data? Far from all sport horse databases have records on how the horse was produced and if they do, it mostly relies on a voluntary basis to register that type of information. Even if there were reliable data available, it’s probably difficult to discern the effect of breeding methodology on performance, when other factors such as genetic set up, training, feeding and rider heavily influence the performance of the horse. To evaluate the health of the horses produced by ICSI a large number of horse owners would have to willingly subject their horses to a thorough health examination. Plausible? Probably not. Expensive? Definitely. But impossible? Definitely not. Researchers today have access to sophisticated tools to solve the mentioned problems with confounding effects. But a significant public demand for this kind of information would be necessary. Otherwise, there might be reluctance to register the data, let alone finance this type of research.
Is Inbreeding a Potential Threat?
With more offspring per individual for both mares and stallions, the risk of increased inbreeding becomes apparent. As breeders, it is still possible to avoid excessively high levels of inbreeding because there are still unrelated individuals to choose from. However, when faced with the choice between a celebrity stallion and a less famous, although less closely related option, the decision often falls in favor of the celebrity stallion.
When not only a limited number of stallions and stallion lines but also a limited number of dam lines become dominant, the path towards high levels of inbreeding can be swift. The effects may not manifest themselves immediately. Initial signs of inbreeding problems typically emerge gradually, beginning with reduced fertility, which can be partially concealed by modern breeding techniques. Next, issues related to health and durability in various forms become more pronounced. Previously unknown genetic diseases start to appear when offspring get disease causing gene variants from both sire and dam. Only after this stage does impact on performance become noticeable, which is further complicated by the fact that numerous other factors, such as the rider, feeding, and training, have a significant influence. Conclusion: It’s possible to reach high levels of inbreeding before it’s perceived as a real problem. However, equipped with modern genetic technology, those levels of inbreeding should be easy to avoid, as long as the sport horse breeding community commits to monitor the inbreeding levels on a regular and frequent basis.
Equine Welfare and Public Awareness
In a time when the words 'Animal Welfare' and 'Social License to Operate' is very much on everyone’s lips the ethical perspective of the modern reproduction techniques must be considered. The implications of public awareness regarding the procedures of ET, ICSI and OPU, raises questions about whether society will accept the extensive treatments and surgical procedures that mares undergo for the sake of producing animals for leisure and sport. Some mares display behavioural changes when subjected to the modern reproductive techniques. Of course, with our still limited understanding of animal behaviour it’s hard to interpret why, and how the treated mares perceive the procedures. The OPU procedure would be very painful for the mare if it wasn’t for the heavy sedation. Numerous mares undergo the procedure several times without problems but possible complications after the procedure incudes bleeding, rectal rupture, inflammation and in worst case death of the mare.
Navigating the Ethical Waters: The Future of Equine Breeding
There is no doubt that the modern reproductive technologies can be a powerful tool to obtain fast progress for sport horse breeding. But the sustainability and long-term consequences of these technologies in the equestrian world remain subjects of ongoing discussion and contemplation. As we embrace advanced reproductive technologies in sport horse breeding, we must also grapple with the ethical questions they raise. Are we willing to accept the extensive treatments and surgical procedures that mares undergo for the sake of producing animals for leisure and sport? In an era where 'Animal Welfare' and 'Social License to Operate' are paramount, the equestrian world stands at a crossroads. The implications of public awareness regarding these procedures demand not only our consideration but our collective conscience. How we navigate these ethical waters will shape the future of sport horse breeding.
