Gerald Leigh Lectures 2024 - Optimizing Youngstock Growth and Development

Adam Jackson MRCVS

Beaufort Cottage Educational Trust hosted the annual Gerald Leigh Memorial Lectures at Tattersalls in Newmarket, UK on June 11th.  These lectures are in association with the Gerald Leigh Charitable Trust as a way of recognising Mr. Leigh’s achievements as a racehorse owner and breeder as well as continuing his passion for scientific knowledge and welfare of horses in the race industry and the equine industry as a whole.  

Dr. Chavatte-Palmer provided a very insightful and interesting talk on the influence of maternal and environmental factors during the prenatal period on athletic performance.  The lecture discussed the phenomenon of Developmental Origins of Health and Disease (DOHAD) which is demonstrated with the increasing evidence of the role in parental nutrition and environmental conditions, from periods preceding conception and throughout gestation, on phenotypic development in horses.  She described how the nutritional environment before birth can affect the postnatal performance of the offspring as it is believed that nutrients can alter the way genes are expressed resulting in developmental trajectories that have repercussions on postnatal development.  With a strong understanding and knowledge in DOHAD, nutritional strategies can be considered and developed to optimize youngstock growth and development.  This is an exciting field as further research will potentially allow veterinarians and breeders to work cooperatively to optimize athleticism as well as the wellbeing and health of foals and mares. 

Dr. Joe Pagan of the Kentucky Equine Research to discuss equine feeding management practices and equine nutrition in sports medicine. His first lecture discussed the effects of season on mare and foal nutrition.  Through various studies some conclusions could be made and these conclusions do appear to be a global trend.  It was found that colts are heavier and taller than fillies.  

After 1 month of age, fillies were fatter than colts.  Foals born in January and February were smaller at birth and grew more slowly in early life but by 150 days of age this lag disappeared.  In addition, mare weight changes and body condition scores were related to season and management factors, as winter-foaling mares lost weight and had lower body condition post foaling than spring-foaling mares. 

Dr. Pagan continued with a lecture on the right balance for optimal growth and development of youngstock.  Recent research has shown that the health of the offspring of overweight mares may also be compromised. In addition, studies have shown that excess maternal nutrition during pregnancy can alter glucose and lipid (fat) metabolism in foals until 160 days of age.  Another study reported a higher incidence of osteochondrosis (OC) in foals born to dams that were fed concentrates during gestation rather than forage. 

A more recent study on the nutrition of the mare during the last trimester and subsequent foal health revealed some interesting observations.  It was found that the growth of foals from 6-24 months of age was not affected by maternal diet and maternal undernutrition appeared to affect bone growth as foals from dams fed forage only had narrower cannon bones than foals from dams fed forage and barley.  In addition, it was found that overfeeding negatively affected yearlings from mares fed barley and forage more than yearlings from broodmares fed only forage.  

Finally, there was a decrease in insulin sensitivity and enhanced insulin levels suggesting insulin dysregulation in yearlings from mares fed both barley and forage and not yearlings from forage-only mares.  Another exciting field of research that will also lead to greater cooperation of breeders and veterinarians in providing good health and wellbeing to foals and mares.   

These lectures had the pleasure of hosting Paul Overton, who is an equine agronomist with a strong understanding of pasture management.  His passion for his area of expertise and in helping with improving management of studs was abundant as he outlined the aims of pasture management that included the need to provide safe grazing pastures from parasites, colic and grass sickness, atypical myopathy and other ailments as well as to provide a safe area to exercise horses of all ages.  In addition, he made clear that fresh leafy bite grass in the paddocks all year round is key.  

We were reminded of the fundamentals of good basic pasture management that included a removal programme for muck, providing a dense leafy grass sward, sharing and mixing the paddock use with other livestock (sheep and cattle) and moving horses to various paddocks around the stud to maximize rest of all paddocks. To optimize paddock health, it should be remembered that all paddock management follows the horses around the seed, be guided by the weather rather than the calendar and work quickly to maximize rest periods. Finally, good simple paddock and grassland management can help a multitude of issues and every marginal gain is helpful. 

Julian Dollar gave us a wonderful insight into a stud manager’s approach to soundness.  It was an integral part of the lecture programme as it provided the audience with another perspective of stud management. He made it clear that a variety of factors must be considered when breeding and raising sound horses but two main criteria is a strong team and an attention to detail. 

The team needed is one that is completely dedicated and passionate about their horses and should consist of a veterinary service, farriers, nutrition/feed and land management support. There must be a cooperative work ethic in order to provide the best all round management as possible. This team must strive for excellence and work on marginal gains.
A sound breeding and rearing programme starts with mating focusing on sound parents, especially the mare, to produce sound offspring.  It is important to work with mother nature rather than interfering with it, thus focusing on a healthy environment. This strategy must be flexible that will allow one to provide the horses with a quality paddock. 

The offspring should be between 121lbs - 132lbs (55-60 kg) and they should have a seamless transition from birth to exercise and living out.  In addition, the foals should be monitored and assessed closely in order to achieve timely and maximum beneficial interventions that may include selective surgeries.  Finally, it is believed that the perfect preparation for a yearling to go into training would be some controlled exercise combined with turnout the rest of the time. 

Professor Jacqui Matthews, the director of Austin Davis Biologics, provided some sobering information on parasites and their resistance.  She explained that intestinal worms are found in most grazing animals and most breeding premises are at high infection risk due to the presence of young animals grazing permanent pastures as well as having a history of interval deworming treatments. 

In addition, wormer resistance is being reported in all major parasitic worms of horses.  Therefore, it is vital to have control plans that include a risk-assessment approach.  Professor Matthews made it very clear that we need to be concerned regarding parasites and their resistance to wormers and we need to act now.  She explained the action that is needed which includes evidence-based worm control.  This approach requires risk assessment that allows one to identify potential issues in the management, the avoidance of all horses regularly being treated, the assessment of wormer effectiveness as well as the effectiveness of interventions. 

With respect to the management, there are some principles behind reducing anthelmintic use.  Good pasture hygiene can substantially reduce infective egg and larval stages in the environment and the lowering of this pasture contamination decreases parasites acquired when grazing.  Pasture management must include: 

  • Dung removal works! Full removal of dung at least once per week and place it away from pastures and water courses.  

  • Maintain low stocking density 

  • Rest pastures – ideally 12 months and avoid grazing foals on same paddocks every year 

  • Consider grazing with ruminants between equine groups 

With respect to treatment, make informed choices by using various tests such as fecalfaecal worm egg counts, fecal egg count reduction test, antibody-based tests to identify worms, and other tests.  Ultimately, do not blindly treat horses without considering the reason for worming and assessing wormer effectiveness. 

Professor Matthews followed up with a second lecture on integrating diagnostics into sustainable equine helminth control programmes.  An integrated diagnostic-led control programme should consider: 

  • Fecal egg worm count in late winter if grazing year-round.  Recommend treatment if 200 or more eggs per gram and select your anthelmintic according to its sensitivity. 

  • Tapeworm test in spring to identify individuals with tapeworm burdens and treat infected individuals as these horses will contaminate the paddocks with cestode eggs. 

Late spring/early summer perform fecal egg worm count reduction test in order to assess anthelmintic effectiveness annually.  Worm all horses that have FEC of >200 eggs per gram.  Perform FEC test at day 0 and 14 days after treatment. Calculate the mean percentage.

  • Reduction in FEC between 0 and day 14 post treatment. 

  • In late summer/early autumn perform tapeworm test to identify individuals that have, over the summer grazing period, accumulated high tapeworm burdens which may put them at risk of colic  

In late fall perform a small redworm test.  In low infection-risk situations, test in late autumn/winter to identify individuals that do not require treatment for small redworm.  Use in low-risk groups where owners usually apply all-group larvicidal treatments.

With good pasture management one can lower the selection for resistance, leading to a lowering the need for wormer treatments, a lowering in the proportion of horses that test positive and a lowering of paddock contamination; therefore, less horses are likely to be infected and more likely to have lower burdens. 

With his 20 years of buying and selling thoroughbred bloodstock, Jamie Railton gave us a wonderful insight into the business of foal purchasing.  He discussed all of the variables that must be taken into account when selecting foals for purchase.  Skill and experience are needed in spotting the foal with the potential to increase in value because of its physical improvement and its pedigree.  He explained that a team of people are required as well as having a system to select foals; however, the system must be flexible and one must still want to continue to learn from the process and adapt and later the selection criteria. In addition, he discussed the need to reinvent oneself with the continuous change in the trends seen in the market. 

Dr. Rebecca Mouncey is a veterinary surgeon and post-doctoral research fellow, currently investigating early-life determinants of performance and economics of Thoroughbred breeding.  

Dr. Mouncey discussed how musculoskeletal disease and injury remains the greatest barrier to thoroughbreds being retained within the industry and realizing their maximum athletic potential, and is likely to have important economic consequences.  She explained that lameness/musculoskeletal injury and disease are the most common barriers to performance.  The causes of these conditions of developmental orthopedic diseases are fractures and tendon/ligament injuries. 

By improving the foal’s/yearling’s strength to withstand training and resist injury, while avoiding trauma, one can help with the prevention of these diseases.  Unfortunately, there are still important knowledge gaps. It is possible to optimize musculoskeletal health during early-life with exposure during critical stages of growth and development that changes the distribution of cell types, alters metabolic function and ultimately altering the susceptibility and injury in adulthood.  

Postnatally the period of greatest plasticity, response to external stimuli/exposures is during periods of most rapid growth and development.  By 24 months of age, the horse is 96% mature bodyweight and 98% mature height and reached peak bone mass.  There must be a balance in early-life exercise and activity as too little will delay musculoskeletal development and too much will cause tissue damage and trauma.  We must always consider the animal’s growth, nutrition and exercise as a whole and not mutually exclusive.  

Abigail Kent MRCVS from Rossdales Veterinary Surgeons, presented an interesting lecture on the diagnosis and treatment of limb deformities in foals.  Dr. Kent is very knowledgeable in all aspects of equine elective and emergency surgery and has a particular interest in orthopedics, specifically arthroscopy, angular limb correction and fracture repair.  

Limb deformities in foals are developmental orthopedic conditions, that can be subdivided into 2 major groups: 1) angular limb deformities, in which there is deviation, primarily in the frontal plane, originating at a joint and/or growth plate and 2) flexural limb deformities, in which there is persistent hyperflexion or hyperextension of the limb. 

These conditions may be acquired or congenital and the etiology is multifactorial.  Early appropriate intervention is the key to the best outcome. Angular limb deformities are relatively common in foals and strategies for management, including surgical techniques, are well established.  Early recognition, diagnosis and monitoring are essential in order to ensure optimal outcomes. 

In cases of severe deformities that fail to respond adequately to conservative approaches (restricted exercise, splints, corrective hoof trimming and shoeing) other treatments such as timely surgery may be used.  Transphyseal screws are effective for the corrections of both forelimb and hindlimb limb deformities.  Flexural limb deformities can be treated conservatively with the mainstays of limited controlled exercise, nursing care, manipulation of the foot with trimming/shoes, splinting/casting and pain management.

Surgical intervention is typically recommended when conservative treatment is not effective or for severe or rapidly worsening deformities. The goal of surgery is to release tension in the restrictive musculotendinous unit, allowing for greater stretch and more normal range of motion of the affected joint. 

In conclusion, all the contributors provided the participants a very interesting and illuminating day.  This event highlighted the lengths that all stakeholders and the veterinary profession are taking to constantly improve the health and wellbeing of the horses and the health of the race industry.  








Conformation and breeding choices

By Judy Wardrope

A lot of factors go into the making of a good racehorse, but everything starts with the right genetic combinations, and when it comes to genetics, little is black and white. The best we can do is to increase our odds of producing or selecting a potential racehorse. Examining the functional aspects of the mare and then selecting a stallion that suits her is another tool in the breeding arsenal.

For this article we will use photos of four broodmares and analyze the mares’ conformational points with regard to performance as well as matings likely to result in good racehorses from each one. We will look at qualities we might want to cement and qualities we might hope to improve for their offspring. In addition, we will look at their produce records to see what has or has not worked in the past.

In order to provide a balance between consistency and randomness, only mares that were grey (the least common color at the sale) with three or more offspring that were likely to have had a chance to race (at least three years old) were selected. In other words, the mares were not hand-picked to prove any particular point. 

All race and produce information was taken from the sales catalogue at the time the photos were taken (November 2018) and have not been updated. 


Mare 1

Her lumbosacral gap (LS) (just in front of the high point of croup, and the equivalent of the horse’s transmission) is not ideal, but within athletic limits; however, it is an area one would hope to improve through stallion selection. One would want a stallion with proven athleticism and a history of siring good runners.

Mare 1

The rear triangle and stifle placement (just below sheath level if she were male) are those of a miler. A stallion with proven performance at between seven furlongs and a mile and an eighth would be preferable as it would be breeding like to like from a mechanical perspective rather than breeding a basketball star to a gymnast.

Her pillar of support emerges well in front of the withers for some lightness of the forehand, but just behind the heel. One would look for a stallion with the bottom of the pillar emerging into the rear quarter of the hoof for improved soundness and longevity on the track. Her base of neck is well above her point of shoulder, adding additional lightness to the forehand, and she has ample room behind her elbow to maximize the range of motion of the forequarters. Although her humerus (elbow to point of shoulder) shows the length one would expect in order to match her rear stride, one would likely select a stallion with more rise from elbow to point of shoulder in order to add more lightness to the forehand.

Her sire was a champion sprinter as well as a successful sire, and her female family was that of stakes producers. She was a stakes-placed winner at six furlongs—a full-sister to a stakes winner at a mile as well as a half-sister to another stakes-winning miler. Her race career lasted from three to five.

She had four foals that met the criteria for selection; all by distance sires of the commercial variety. Two of her foals were unplaced and two were modest winners at the track. I strongly suspect that this mare’s produce record would have proven significantly better had she been bred to stallions that were sound milers or even sprinters.


Mare 2 

Her LS placement, while not terrible, could use improvement; so one would seek a stallion that was stronger in this area and tended to pass on that trait. 

The hindquarters are those of a sprinter, with the stifle protrusion being parallel to where the bottom of the sheath would be. It is the highest of all the mares used in this comparison, and therefore would suggest a sprinter stallion for mating.

Mare 2

Her forehand shows traits for lightness and soundness: pillar emerging well in front of the withers and into the rear quarter of the hoof, a high point of shoulder plus a high base of neck. She also exhibits freedom of the elbow. These traits one would want to duplicate when making a choice of stallions.

However, her length of humerus would dictate a longer stride of the forehand than that of the hindquarters. This means that the mare would compensate by dwelling in the air on the short (rear) side, which is why she hollows her back and has developed considerable muscle on the underside of her neck. One would hope to find a stallion that was well matched fore and aft in hopes he would even out the stride of the foal.

Her sire was a graded-stakes-placed winner and sire of stakes winners, but not a leading sire. Her dam produced eight winners and three stakes winners of restricted races, including this mare and her full sister. 

She raced from three to five and had produced three foals that met the criteria for this article. One (by a classic-distance racehorse and leading sire) was a winner in Japan, one (by a stallion of distance lineage) was unplaced and one (by a sprinter sire with only two starts) was a non-graded stakes-winner. In essence, her best foal was the one that was the product of a type-to-type mating for distance, despite the mare having been bred to commercial sires in the other two instances.


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Ontario Breeding

By Alex Campbell

The Ontario breeding industry has experienced a number of twists and turns since the provincial government canceled the lucrative slots-at-racetracks program back in 2013. Prior to the cancelation of the program, the once robust industry had years where more than 1,600 mares were bred in the province, according to numbers published by The Jockey Club. In 2018, that number was down to 733.


While the cancelation of the program has impacted the majority of the province’s breeders, well-known breeding operations in Ontario have experienced success through all of the uncertainty. Sam-Son Farm won back-to-back Sovereign Awards as Canada’s top breeder in 2013 and 2014, while Frank Stronach’s Adena Springs won three straight Sovereign Awards between 2015 and 2017 when they bred two Queen’s Plate winners in that time, including Shaman Ghost in 2015 and Holy Helena in 2017. 

Along with these big operations, several other commercial breeders are also experiencing success, not only in Ontario but throughout North America and internationally as well. Ivan Dalos’ Tall Oaks Farm bred two Gr1 winners in 2018, including full brothers Channel Maker, who won the Joe Hirsch Turf Classic at Belmont Park, and Johnny Bear, who won the Gr1 Northern Dancer Turf Stakes at Woodbine for the second consecutive year. In addition, Dalos also bred Avie’s Flatter, Canada’s champion two-year-old in 2018; dam In Return, who produced Channel Maker; and Johnny Bear, which was Canada’s Outstanding Broodmare. As a result, Tall Oaks Farm won its first Sovereign Award for Outstanding Breeder in 2018 as well.

Horses bred by David Anderson’s Anderson Farms and Sean and Dorothy Fitzhenry also were big winners at last year’s Sovereign Awards. Anderson bred Queen’s Plate winner and 2018 Canadian Horse of the Year, Wonder Gadot, while Fitzhenry’s homebred, Mr Havercamp, was named champion older male and champion male turf horse. Both Anderson and Fitzhenry have also had success selling horses internationally, primarily at Keeneland. In 2017, Anderson sold Ontario-bred yearling, Sergei Prokofiev—a son of Scat Daddy—to Coolmore for $1.1 million. One of Fitzhenry’s success stories is that of Marketing Mix, who he sold for $150,000 to Glen Hill Farm at the 2009 Keeneland September Yearling Sale. Marketing Mix went on to win the Wonder Where Stakes at Woodbine as a three-year-old in 2011, and captured two Gr1 victories later on in her career in the 2012 Rodeo Drive Stakes at Santa Anita and the 2013 Gamely Stakes at Hollywood Park.

For Anderson, commercial breeding is all he’s ever known. The son of the late Canadian Horse Racing Hall of Fame inductee, Robert Anderson, David Anderson grew up around horses at his father’s farm in St. Thomas, Ontario. In the 1970s and 1980s, Anderson Farms was one of the biggest breeders and consignors in the province, breeding several graded stakes winners. In fact, in 1985, Anderson Farms was the leading consignor at both the Saratoga and Keeneland yearling sales.

“That’s what my father established years ago, and that’s what I grew up with was breeding and selling at all of the international sales,” David Anderson said. “We haven’t diverted from that philosophy in nearly 50 years. It’s what I learned growing up, and I try to buy the best quality mares that I can and breed to the best quality sires that I can.”

David Anderson (blue suit) with Peter Berringer

While Anderson closely watched his father build up the Thoroughbred side of the business, he got experience of his own breeding Standardbreds. After all, the farm’s location in Southwestern Ontario is in the heart of Standardbred racing in the province. Anderson said the Standardbred business had a number of success stories spanning more than a decade: breeding champions such as Pampered Princess, Southwind Allaire, Cabrini Hanover, and The Pres.

In 2010, Robert Anderson passed away from a heart attack, and the farm was taken over by David Anderson and his sister, Jessica Buckley, who is the current president of Woodbine Mohawk Park. Anderson went on to buy Buckley out of her share of the farm and took on full control. He also decided he wanted to focus exclusively on Thoroughbred breeding and racing.

“After my Dad died I decided I wanted to jump back into the Thoroughbreds,” he said. “I sold all the Standardbreds and put everything I had back into Thoroughbreds. I came full circle back to my roots, and this is where I really love it.”

It’s been a long-term project for Anderson to get the farm to where it is today. After taking control of the farm, Anderson sold off all of his father’s mares—with the exception of one—and began to build the business back up. Anderson said his broodmare band currently sits between 25 and 30, which is where he wants to keep it.

Fitzhenry, on the other hand, took a much different path to his current standing in the Thoroughbred breeding industry. Fitzhenry said his start in Thoroughbred racing came through a horse owned by friends Debbie and Dennis Brown. Fitzhenry and his wife, Dorothy, would follow the Brown’s horse, No Comprende, who won seven of his 30 starts in his career, including the Gr3 Woodbine Slots Cup Handicap in 2003.

The Fitzhenrys decided they wanted to get involved in ownership themselves and partnered with the Browns on a couple of horses. The more Fitzhenry got involved, the more the breeding industry appealed to him.

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