A Kentucky-based study that links foal growth measurements and radiographic findings to sales and racing performance has yielded intriguing findings in its just-completed pilot phase. Researchers now want to go global with it, and are seeking the help of Thoroughbred breeders worldwide to deepen the data pool.
“One of the things that we're hoping to discover is a way of understanding if foals are high-risk for developing problems,” the study's director, Dr. Joe Pagan, told TDN. “We want to have a way that we can identify at-risk foals earlier in their lives so that we can take the necessary precautions to reduce problems from occurring.”
Pagan is the founder and president of Kentucky Equine Research (KER), which since 1988 has been an international consulting and product development firm in the areas of equine nutrition and sports medicine. Pagan received his B.S.A. degree from the University of Arkansas in animal nutrition, and his M.S. and Ph.D. degrees from Cornell University in equine nutrition and exercise physiology.
KER works with feed manufacturing companies all over the world to help improve nutrition for specific regions and sport horse disciplines. One of its oldest clients is Lexington-based Hallway Feeds, which bills itself as the only family-owned and operated feed company dedicated to the horse industry. It is a major supplier of feed to Kentucky's breeding farms and racing operations.
For more than 30 years Pagan has spearheaded research on the effects of nutrition and growth on skeletal disease in Thoroughbreds. In the early 1990s, he began looking more closely at the relationship of how big foals are and their incidences of osteochondritis dissecans (OCD), a relatively common developmental disease that affects the cartilage and bone in the joints of horses.
Around that same time Hallway began its mobile foal weighing program, which is a perk for clients that want to obtain basic growth data for their young horses but don't have the time or scales to do the measurements themselves. Over the decades, Hallway has been able to generate and anonymize tens of thousands of data points on foal growth that Pagan was able to analyze.
In the early 2000s, Pagan began to correlate growth data to sales and racing performance. He started what was to become his pilot study in 2013 by charting 318 foals from 12 individual crops at six Kentucky commercial breeding farms that agreed to participate, with Hallway collecting the growth measurement data.
In addition to the growth stats, Pagan began collecting spring survey and sales radiographs, combing this additional data for clues about the incidence of skeletal issues in developing Thoroughbreds.
“In the early days when we were doing this, we were focused almost entirely on OCD,” Pagan explained. “But since the advent of the digital radiograph, more and more breeders have become interested in sesamoiditis [chronic inflammation of the sesamoid bones and the tendons]. That was a problem that you really couldn't see very well in old-style film radiographs. But now that they have improved that technology, breeders pay a lot of attention to it. They're very worried about it, and we wanted to see how it affected sale prices and racing performance.”
“The findings we have are interesting,” Pagan continued, delving into a summary of the pilot study. “We found that size did have an effect on the incidence of OCD and sesamoiditis. Basically, large foals were more susceptible to get OCD. Sesamoiditis seemed to happen not in the biggest foals, but in foals that were just sort of average size. These are foals that possibly got a little behind after weaning, and in the process of sales-prepping they caught up, and expressed a greater degree of sesamoiditis.
“When we looked at sales and racing performance, we found that again, size made a big difference,” said Pagan. “At yearling sales, the size of the foal is a very important parameter for sale price, both body weight and the height of the foal. So much so that the median price paid for foals in the top 25% of body weight as yearlings was five times greater than in the bottom quartile. So there was a massive difference there.
“But when we drilled down to how that size affected their racing performance, it didn't really match the sales data. We actually found that sort of middle of the road for size, the second quartile particularly, seemed to produce the best racehorse.”
“Surprisingly, when we looked at the racing and the sales performance of horses that had evidence of OCD in their spring radiographs, we found that hock and fetlock lesions, which are two common sites for these problems to occur, didn't really have an adverse effect on the sale price of the foals that were offered for sale,” Pagan continued, adding this caveat, “But that doesn't say anything about whether foals ended up not going to sales because they had those problems. We couldn't really address that from the information that we had.
“But of the foals that were presented at sales that had the hock and fetlock lesions in their spring surveys, they weren't knocked in terms of sale price,” Pagan said. “Stifle lesions seemed to be a different matter. Horses that developed stifle lesions, they did seem to sell for a lower price, so that was problematic.
“When we looked at racing performance, horses that had hock and fetlock OCD did not really have reduced racing performance, except that foals that had hock OCD in their spring surveys made their first starts at a significantly older age than those that didn't,” Pagan said.
Pagan broke down the findings even further, looking at when those foals were born.
“I think this is an important finding that we had for these Kentucky foals: A lot of the foals that developed OCD were born in April and May, and they were big foals,” Pagan said. “Horses that had sesamoiditis in their spring survey radiographs tended to be early foals. We found that foals born in January and February tended to be smaller foals. They grow less rapidly the first month or two, and part of that is because they're born when there is not great pasture availability in Kentucky.”
Pagan said he knew from a previous study of 4,000 broodmares that mares that foaled in January or February were also known not to produce as much milk.
“Foals that are born later in the year, those mares gained weight during lactation,” Pagan said. “And their foals tended to be bigger, and they grew faster early on.”
But Pagan noticed another seasonal effect that sort of works to even out the growth discrepancies in Kentucky foals.
“Later in the year, the foals that are born in January and February, after they're weaned, they actually have a tendency to grow quite fast. And they grow fast because they are typically weaned at an older age. And during that weaning time is when there is abundant grass in the autumn,” Pagan said.
Conversely, he added, “the foals that are born in April and May tend to be big, and they grow early when they're on the mare. But when they're weaned, they tend to grow less fast, because a lot of that time is through the following winter, when pastures are again sparse.”
A potential solution, Pagan explained, is for KER to work with feed companies to come up with region-specific nutritional plans that address these types of seasonal plusses and minuses.
“So for instance, if these early-born foals and their mares are not getting enough to eat, we might be able to modify how we feed these early-foaling mares during late pregnancy and early lactation so that the foals are born at a more normal size and grow more normally early,” Pagan said.
Even though he is pleased with the data the pilot study generated, Pagan said the research needs better depth, both in terms of the number of participants and geographic diversity.
“We're calling it a pilot study because it had over 300 foals,” Pagan said. “But in the grand scheme of things, that's still a fairly small population. We need bigger numbers to add more statistical significance to the findings. We're taking this pilot study and we're ramping it up now. We're asking more farms to participate, and there's been great enthusiasm worldwide amongst breeders who want to participate.”
Beyond the United States, KER is seeking the help of breeding farms in England, France, Australia, New Zealand and Japan that are willing to provide growth data for the expanded study. You can view a recap of the pilot program here and a list of guidelines for prospective participants here.
Breeders based in Kentucky who are Hallway customers can take advantage of the monthly mobile weighing service the company already provides to have their foal growth measurements entered directly into the research database.
“Kentucky will far and away be our largest database for two reasons,” Pagan said. “One is there are a lot of Thoroughbred mares in Kentucky. The other is that Hallway has such an advanced weighing program that we get really good growth data, because they go out and do this on a monthly basis.”
Anthony Koch, the director of sales and marketing at Hallway, explained that the firm's technical services team works with farm personnel to make the monthly measurement services as seamless as possible.
The Hallway team uses a mobile scale with cushioned matting to safely weigh the foals. The team also measures height to the withers and assigns a standardized body condition score on a scale of 1 to 9. The team provides copies of the data to farm personnel before they leave the grounds, and customers have additional access to online growth records.
“In the busiest time of the year, the summer, when all the yearlings are in town and all the babies are on the ground, our technical service team weighs and measures around 2,000 horses every single month,” Koch said. “Our team takes the having to keep up with the when, where, why and how out of the process.”
Saracen Feeds have been generating data with their clients since 2002.
Representatives from Hallway and Saracen will be reaching out to customers to see if those farms would like to participate. Pagan added that any farm owner who wishes to contact him directly about the study can do so via email (pagan@ker.com).
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