The science speaks: 95% of yearlings show minimal risk under new sale scoping system

Cover image courtesy of The Image Is Everything

The change from the Lane-Bain Fallon classification system to the Havemeyer system will give vendors and buyers more clarity around scopes at the sales, which is why all three major sales companies have come together in agreement to adapt the change. But the truly exciting part of the new classification system is that, when combined with updated science, buyers will have more certainty and less risk around the old Grade 3 rated scope results.

Funded by Agrifutures, a team of scientists led by Josie Hardwick, Ben Ahern, and Sam Franklin did a two-year study on the issue of endoscopic examinations in Australia. They looked at understanding stakeholder concerns over the scoping systems, identified areas for improvement, and clarifying the association between yearling laryngeal function and future race performance by assessing 5000 endoscopies from Australian sales.

“Scoping is a very commonly performed procedure on yearlings, and every yearling who goes through a sale undergoes a series of scopes as an examination of the upper airway.

“Before the sales, yearlings are often checked at home to ensure they are not going to fail on arrival at the sale, then on arrival a pre-sales scope is performed by a sale company nominated veterinarian and the results are uploaded into the online repository along with x-rays, which allows a buyer’s veterinarian to have a look,” said Dr Josie Hardwick.

For a long time, Australian sales companies have used the Lane-Bain Fallon 5-point grading system which was first described in 1993 by Dr Geoff Lane at the Bain Fallon Proceedings, with grades 1, 2, and 3 being deemed a pass in the Conditions Of Sale, and a 4 or 5 being a fail which allowed the buyer to pull out of the sale.

The reasoning behind using sale scopes

“The main reason for scoping yearlings is to identify those who are at increased risk of developing recurrent laryngeal neuropathy (also known as ‘roarers’). Approximately 10 per cent of the population will develop clinical signs of roaring as they age, usually developing symptoms from three years of age and upwards. The nerve that supplies the muscles in the left side of throat stops working, resulting in narrowing of the airway and reduced airflow to the lungs which ultimately leads to reduced performance”

Recurrent laryngeal neuropathy (RLN) is a disease that progresses with time, and often a horse shows no clinical signs as a yearling or as 2-year-olds. Use of the Havemeyer grading system when grading laryngeal function in yearling has been shown over time to have more accuracy, clarity, and consistency in use at sales in Europe and America, hence why it is being adopted here.

“The problem isn’t that apparent when horses are young, as it’s a degenerative disease, so a horse could look normal as a yearling then develop symptoms as an older horse. And obviously, if a horse shows symptoms while young, they are probably going to get worse, so scoping them is about minimising risk.”

Buyers can feel confident in Havemeyer system

The Havemeyer grading system changes how veterinarians assess the horses who were rated as Grade 3 under the old Lane-Bain system. These horses still passed the scope under the Lane-Bain system, but due to a small subset of Grade 3’s who developed problems after sale, the whole Grade 3 group were given a bad name. Under the Havemeyer System, which has seven grades, Grade 1 remains unchanged as I, Grade 2 becomes II.1, and importantly the old Grade 3 horses are split into II.2 and III.1. The old Grade 4 becomes III.2 and III.3, and Grade 5 becomes IV.

Table: Grading scales for assessment of laryngeal function

“The first part of our two-year project was to do stake holder engagement on the issue. We talked to 29 industry professionals, breeders, buyers, and veterinarians and asked for their opinions on the sales scoping process, and any concerns they had.”

This study was published in the Australian Veterinary Journal, titled 'Stakeholder perceptions of thoroughbred yearling sales endoscopy in Australia: can we do better?'

“We identified that the main concerns were that people had a lack of clarity about the grades given on a scope, and then they wanted to know how a grade correlated with future race performance.”

Approved by the University of Adelaide’s Human Research Ethics Committee, this study held focus groups with 29 individuals - nine veterinarians, 11 breeders, and nine yearling buyers – and each individual had more than 20 years experience in the racing industry. Of the 11 breeders, three were from farms with more than 100 foals bred each year, three from farms with 51-100 foals bred each year, three from farms with 21-50 foals bred each year, and one from a small farm with 20 or less foals bred annually.

“The outcome was that people were most worried about the horses who were given a Grade 3 rating under the old system. It’s a pass mark under the conditions of sale but many buyers don’t want to buy a horse with a Grade 3. This led to the next study, again funded by Agrifutures, where we looked at over 5000 yearlings over a two year period.”

A study of over 5000 yearlings

The next part of the study was published in the Equine Veterinary Journal as 'Yearling laryngeal function Grades II.2 and below are not associated with reduced performance' in November 2024 and looked at the scopes of 5175 yearlings as well as their racing performance post-sale.

“This was a very large, statistically robust study. The main finding is that 95 per cent of the yearling sales population were found to have a scope grade of I, II.1 or II.2 on the Havemeyer scale, and importantly there was minimal differences in race performance between these three grades. When we get to the horses who were graded III.1, they performed as well as the Grades I and II’s as two and 3-year-olds, but from age four onward, they earned less. It makes sense as the disease is degenerative.”

Less than 1 per cent of horses were graded as ‘fails’ with a III.2 or worse, but this is self-selecting as many horses are scoped before they are taken to the sale and simply not taken if they don’t meet the conditions of sale. With the old Lane-Bain system’s Grade 3 and the Havemeyer systems II.2 and III.3 being the same, what does this mean for vendors going forward?

“There were several myths around the old Grade 3 group with some people saying they’d never had a problem, and others having issues, and this often led to vendors struggling to sell horses who were rated Grade 3, even though it was technically a pass. It was these concerns that led to the pre-sale scope being available. It used to be a post-sale scope only and as long as a horse was Grade 1, 2, or 3, the sale would go through. But because of concerns around the Grade 3 group, pre-sale scopes became more common until now when they are done on almost every yearling.”

“What we found is that 80 per cent of the old Grade 3 horses were rated II.2 by Havemeyer, and 20 per cent were III.1. Given there was no difference in race track performance between Grade II.2 and the Grade I and II.1 groups, the performance of the small proportion of horses graded as III.1 was impacting on the majority of Grade 3 horses.”

“This new system, along with this study, will mean that everyone is more informed about the risks when buying young horses.”

Racing outcomes

What the study found, across those 5175 horses was that there was no difference in race performance for the horses rated I, II.1, or II.2. The interesting part of the study was the III.1 group, who made up 4 per cent of the study, earned the same as the Grade I, II.1 and II.2 horses as 2 and 3-year-olds, but from four onwards, they earned significantly less.

“There was no difference in race performance for II.2 compared with I and II.1, and this equates to 95 per cent of the yearling population. Only five per cent of horses are medium to high risk in terms of yearling scopes with 1 per cent failing,” said Hardwick.

"The other four per cent – those rated III.1 – performed similarly to the lower grades for their two and 3-year-old career, and the only difference was from four years and upwards. So for a buyer in Australia, where there is good prizemoney for two and 3-year-old racing, there isn’t going to be much difference. If you are buying a later maturing stayer-type, particularly a tall horse, who are known to be higher risk already, then the scope may make a difference to your buying decision.

“People have been agonising over scope grades and hopefully these findings take some of the importance off, and ease the pressure. It’s only a very small subset of horses with issues.”

Tie-back surgery study

The next step for roarers is to get tie-back surgery to correct any throat issues, technically known as prosthetic laryngoplasty, which enables horses to breathe again. Hardwick was also involved in a smaller study that looked at horses who’d had tie-back surgery.

“We’ve done a study on horses that subsequently had tie-back surgery. It looked at 150 horses who had tie-back surgery.” The study, published in May 2024 by Equine Veterinary Journal was called ‘Yearling laryngeal function in Thoroughbreds that underwent a laryngoplasty differs from controls.’

“There are many factors involved with needing this surgery. Taller horses are higher risk due to increasing nerve length, there is a genetic component but that wasn’t included in this study, and growth rates are also a contributing factor. It's not cut and dried, but these types of studies are about looking at risk.”

The study took 600 control horses and looked at the yearlings scopes of both the 150 horses who’d had surgery and the 600 horses in the control group and analysed their scopes using the Havemeyer method. Horses who’d had tie-back surgery came from all grades as yearlings, but it was a sliding scale for risk with horses who’d rated worse as yearlings being more likely to have issues later in life.

Table: Comparison of horses who’d had tie-back surgery vs control group who hadn’t

What is next?

“The next step is to educate veterinarians to ensure that the results are repeatable. Many stakeholders felt that veterinarians were too variable in their grading system, so we are developing training modules for veterinarians on using the Havemeyer method.

“The Havemeyer method is clearer, and more precise and these studies show that people don’t need to be worried about the old Grade 3 as it’s split into two new categories now.”