The special interest in the equines has led throughout history to the development of modern breeding technologies. (Gardón Poggi and Satué Ambrojo, 2023). Let’s explore together how breeding technologies are affecting stud books and breeding societies around the world.
The role of advanced reproductive technologies in the evolution of equine breeding
Throughout history, equines have held a special place in human culture, not only as companions and work animals but also as symbols of status and prestige. This deep connection has spurred the development of advanced reproductive technologies that have transformed the equine industry. In recent decades, artificial insemination, embryo transfer, and in vitro fertilization, among others, have revolutionized horse breeding, enabling selective breeding, genetic preservation, and the overall improvement of animal quality. These advancements, as noted by Gardón Poggi and Satué Ambrojo (2023), are the result of a marriage between tradition and innovation, reflecting a desire to both honor the legacy of the past and forge new paths for the future of equine breeding.
The twentieth century marked a significant shift in the way horse breeding was perceived and practiced. It evolved from a primarily profit-driven endeavor into a comprehensive 360-degree activity that requires balancing economic goals with ethical responsibilities. Breeders, owners, and institutions alike are now more than ever tasked with ensuring the welfare of the horses they breed, recognizing that the pursuit of excellence must not come at the expense of animal health and well-being.
One of the central challenges in modern horse breeding is finding this balance between selecting the best individuals for reproduction while maintaining the genetic diversity necessary for the long-term viability of equine populations. Studbooks and breed societies have become key players in this balancing act, acting as policymakers within the equestrian world. These institutions serve as the critical bridge between innovation and tradition, ensuring that cutting-edge breeding practices are employed to improve genetic diversity while preserving the integrity and historical value of established breeds.
The economic landscape of horse breeding
Understanding the global economic context is essential when analyzing horse breeding programs. The equine industry is a significant contributor to the global economy, with horse racing being one of the most lucrative segments. As of 2023, the global horse racing market was valued at approximately USD 438.72 billion, and it is projected to reach USD 867.13 billion by 2031 (Business Research Insights, 2024). This immense market size motivates all stakeholders within the ecosystem to perform at their best, driving the adoption of modern breeding technologies and data-driven breeding strategies to foster growth and maintain competitive advantages.
The economic incentives tied to horse breeding have led to the development of sophisticated breeding technologies that aim to produce superior offspring, enhance genetic selection, and preserve valuable bloodlines. However, with these advancements comes a heightened responsibility to ensure that economic gains do not overshadow the ethical considerations and welfare of the animals involved.
Accelerating genetic progress through technology
In the competitive world of horse breeding, the primary goal of breeding programs and technologies is to produce better offspring. The more successful a horse is in competition, the more valuable it becomes, making the stakes incredibly high. As Palmer and Chavatte-Palmer (2020) highlight, breeding strategies play a direct role in determining the number of offspring that each mare or stallion can produce in a given season. Technologies such as embryo transfer, genomic selection, and artificial insemination are crucial in increasing the number of offspring that high-quality mares and stallions can produce each year. This, in turn, accelerates genetic progress within a breed.
Embryo transfer, in particular, has become a game-changer in the industry. This technology allows breeders to collect eggs from a mare, fertilize them in vitro, and then implant the resulting embryos into surrogate mares. This process enables a single mare to produce multiple foals in a single breeding season, significantly boosting the genetic advancement of a breed. When combined with genomic selection, which uses DNA testing to identify the best breeding candidates, these technologies have revolutionized the way breeders approach horse reproduction.
However, the increased focus on genetic progress has also raised concerns about the potential for narrowing the gene pool. As breeders increasingly favor certain bloodlines, the risk of inbreeding becomes a pressing issue. This is particularly true in the case of thoroughbreds, where the economic demand for popular bloodlines has led to a significant reduction in genetic diversity.
Preserving valuable bloodlines while maintaining genetic diversity
In the modern equine industry, the value of a horse is often closely tied to its pedigree. As McGivney et al. (2020) observed, the economic demand for certain bloodlines has led to an intense focus on breeding horses with prestigious pedigrees. However, this focus on pedigree can come at a cost. A study conducted by McGivney, Han, Corduff, et al. in 2020 analyzed the genomes of 10,000 thoroughbreds from around the world, revealing that a staggering 97% of them could trace their lineage back to the Canadian champion Northern Dancer (Morton, 2022). This concentration of genes from a single ancestor highlights the growing problem of inbreeding within the thoroughbred population.
Over the past five decades, there has been a noticeable increase in inbreeding across the global thoroughbred population. This trend has prompted institutions and breeders to take a more proactive role in regulating inbreeding practices and promoting the benefits of assisted reproductive technologies (ART). By leveraging ART, breeders can manage genetic diversity more effectively, ensuring that valuable bloodlines are preserved without compromising the health and vitality of the breed.
The challenge lies in striking the right balance between preserving the genetic traits that make a breed unique and avoiding the pitfalls of inbreeding. This requires careful management and a long-term perspective, as the consequences of inbreeding can take generations to become apparent. By adopting a more holistic approach to breeding, one that prioritizes both economic value and genetic diversity, the equine industry can safeguard the future of its most cherished breeds.
Horse welfare in breeding programs
The welfare of horses is a critical consideration in any breeding program. As studbooks and breed societies work to approve and recognize offspring within their registries, they must also take into account the welfare implications of the breeding techniques used. Neither natural-cover methods nor those facilitated by ARTs are entirely free from potential negative side effects on the horse’s welfare.
For example, thoroughbred studbooks typically approve a horse for racing only if it has been conceived through ‘natural cover,’ meaning that the mare and stallion must mate naturally without the aid of reproductive technologies. This rule, while rooted in tradition, has significant welfare implications. A successful stallion may be required to cover up to 200 mares in a single breeding season, which can mean performing two or three times a day (Campbell and Sandøe, 2015). The physical and psychological stress associated with such intense breeding schedules can take a toll on the stallion’s well-being.
Improving Thoroughbred welfare with ARTs
Approving the use of ARTs in such cases could help alleviate some of the welfare concerns associated with natural cover. By using artificial insemination, for instance, breeders could reduce the need for stallions to repeatedly perform during a breeding season, thereby minimizing the physical strain and stress on the animal. Additionally, embryo transfer and other ARTs can allow mares to produce offspring without undergoing the physical demands of pregnancy and foaling, further contributing to improved welfare outcomes.
It is important for breeders and institutions to remain vigilant about the welfare of horses in breeding programs. This includes not only addressing the immediate physical demands placed on breeding animals but also considering the long-term health implications of selective breeding practices. By integrating welfare considerations into the breeding process, the equine industry can ensure that the pursuit of genetic excellence does not come at the expense of the animals themselves.
Defining standards for international breeding values
As the equine industry becomes increasingly globalized, the adoption of “remote” breeding techniques has led to a significant increase in the import and export of horse genetic material. This global exchange of genetics has created a pressing need for internationally standardized criteria to define breeding values. These values are essential for comparing and evaluating horses across different regions and countries, ensuring that breeding decisions are based on reliable and consistent information.
A numerical breeding value can be calculated using a “Best Linear Unbiased Predictor” (BLUP), a statistical method invented by Charles R. Henderson. BLUP estimates the genetic merit of an animal by analyzing data from multiple traits and sources, providing a robust measure of an animal’s breeding potential (Zeng, 2023; Henderson, 1984). While BLUP is typically used within a single population, the multi-trait across-country evaluation (MACE) system, developed by Schaeffer in 1994, extends this concept to estimate genetic correlations between traits in different countries. MACE effectively addresses the international needs of the equine industry, allowing breeders and institutions to make informed decisions based on global data.
A unified information management system to support breeding values
The ultimate goal of international federations is to create a unified information management system that can handle the complexities of global breeding. The Interstallion Committee, founded in 1998 by the European Association for Animal Production (EAAP), represents the first significant initiative in the equestrian world to define breeding objectives, improve genetic evaluation systems, and compare evaluations across countries for warmblood breeds (Hellsten, 2008). This committee laid the groundwork for a more coordinated and standardized approach to breeding in the equine industry.
In the years since its founding, the Interstallion Committee has been joined by other influential organizations, including the World Breeding Federation for Sport Horses (WBFSH) and the International Committee for Animal Recording (ICAR). These collaborations have helped to advance the development of international breeding standards and improve the accuracy of genetic evaluations.
Today, the WBFSH is still working towards the implementation of an “International Breeding Value,” a standardized measure that could revolutionize horse genetics on a global scale (WBFSH, 2024). This effort is particularly important as the equine industry continues to embrace modern breeding technologies, such as genomic selection and advanced data analysis tools. These technologies are instrumental in managing the vast datasets required for accurate genetic evaluations and ensuring that breeding decisions are based on the most reliable information available.
The future of equine breeding
The integration of advanced reproductive technologies into equine breeding has opened new possibilities for improving the quality, health, and genetic diversity of horses worldwide. However, this progress comes with the responsibility to ensure that ethical considerations, such as animal welfare and genetic diversity, remain at the forefront of breeding practices.
As the industry continues to evolve, breeders, studbooks, and international organizations must work together to develop and implement standards that support both innovation and tradition. By doing so, the equine industry can continue to thrive, producing horses that are not only exceptional in their performance but also resilient and healthy, ensuring the sustainability of this noble animal for generations to come.
References:
Business Research Insights. (2024) ‘Horse Racing Market Report: Global Forecast From 2024 To 2032’.
Palmer, E. and Chavatte-Palmer, P. (2020) ‘Contribution of Reproduction Management and Technologies to Genetic Progress in Horse Breeding’, Journal of Equine Veterinary Science, 89, p. 103016. doi: 10.1016/j.jevs.2020.103016.
McGivney, B.A., Han, H., Corduff, L.R. et al. (2020) ‘Genomic inbreeding trends, influential sire lines and selection in the global Thoroughbred horse population’, Scientific Reports, 10, p. 466. https://doi.org/10.1038/s41598-019-57389-5
Campbell, M.L.H. and Sandøe, P. (2015), ‘Welfare in horse breeding’. Veterinary Record, 176: 436-440. https://doi.org/10.1136/vr.102814
Gardón Poggi, J.C. and Satué Ambrojo, K. (2023) ‘History of Horses and the Biotechnologies Applied to Its Reproduction’, 10 June 2023. Intechopen.
DOI: 10.5772/intechopen.1001925
World Breeding Federation for Sport Horses (WBFSH). (2024). ‘An Introduction to IBV: International Breeding Values’.
Zeng, J. (2023) ‘Best Linear Unbiased Prediction (BLUP)‘
Henderson, C.R. (1984) Applications of Linear Models in Animal Breeding. Guelph: Charles R. Henderson.
Henderson, C.R. (1975) ‘Best linear unbiased estimation and prediction under a selection model’, Biometrics, 31(2), pp. 423-447. DOI: 10.2307/2529430.
Ruhlmann, C., Janssens, S., Philipsson, J., Thorén-Hellsten, E., Crolly, H., Quinn, K., Manfredi, E. and Ricard, A. (2009) ‘Genetic correlations between horse show jumping competition traits in five European countries’, Livestock Science, 122(2-3), pp. 234-240.
Hellsten, E.T. (2008) International Sport Horse Data for Genetic Evaluation. Doctoral thesis. Uppsala: Swedish University of Agricultural Sciences.
Schaeffer, L.R. (1994). ‘Multi-trait, across country evaluation of dairy sires’, Interbull Bulletin.
