Latest research has shown that resistance to lameness can be bred into cows more easily than previously thought. And now researchers and foot trimmers are hoping to create a database that will speed up the process.
TEXT ANN HARDY
Controlling lameness is a focus for all dairy herds, and efforts to tackle this issue typically include better husbandry, cow housing and tracks, and nutrition. But what about genetics? It’s now possible to breed cows with an inherent resistance to the main causes of lameness, which can stack the odds in favour of cows remaining sound on their feet.
Breeding to reduce lameness has previously been a challenge, due to the low heritability (reflecting the degree to which a trait is passed down the generations) of its causes. But this is at odds with many producer observations. Many have noted that resistance to lameness can run through specific bloodlines. Research from by University of Liverpool, SRUC and the Royal Veterinary College adds support to this observation and also demonstrates that the genetic index for lameness – AHDB’s Lameness Advantage – can make significant inroads into tackling the issue. It does this by reducing the tendency of cows to be lame, particularly due to sole ulcers (SU) and sole haemorrhage (SH), or bruising.
The trial, involving more than 2,000 cows, used the same trained vet to record the hoof lesions in every animal. This gave a better and more consistent measure of each cow’s phenotype (her actual physical looks or performance), and removed much of the so-called ‘noise’, which is created by other factors, including inconsistent scoring.
As a result, the team was able to create a high-quality dataset and this was key to achieving significantly higher heritabilities and, therefore, demonstrating a greater scope for genetic improvement compared to previous trials.
Heritability estimates for lameness have historically been as low as between 1% and 20% – also expressed as 0.01–0.20. But the latest study showed figures of 0.35 (or 35%) for SU and 0.29 (29%) for SH, which is on a par with most conformation traits that are typically considered to be more easily improved through breeding.
By having a genomic index for Lameness Advantage (LA) calculated by AHDB for every animal in the trial, the researchers also demonstrated a strong association between the LA index and actual lameness later in life. The work showed that the odds of a cow having sole ulcers declined by 32% for every point increase in LA in the trial animals.
“This may be even higher than preventive foot trimming at drying off, which is considered to play a key role in lameness prevention by reducing the odds of a sole ulcer by 20%,” says University of Liverpool’s Georgios Oikonomou, co-supervisor of the Biotechnology and Biological Sciences Research Council-funded initiative.
For this reason, he urges producers to use Lameness Advantage as a genetic selection tool. “The cost of selecting high LA sires is negligible in comparison to other interventions that often include re-designing housing or increasing foot-trimming frequency.” He adds that the level of improvement the work demonstrated could be further increased by making changes to Lameness Advantage. But to do this, he says the team needs to create a more consistent and reliable database to describe hoof health across the whole national herd. “This could be achieved with foot-trimmers’ records, which could be used in the calculation of genetic evaluations.
"For genetic selection to work, we need big data,” he explains. “AHDB currently uses health data collected through milk recording in their calculation of Lameness Advantage and that’s working really well. But these data can be incomplete or skewed towards the more severe causes of lameness, and we feel we can make the dataset even better by using foot-trimming records.”
For this reason, the team at Liverpool, together with AHDB, have partnered with foot-trimmers through the National Association of Cattle Foot Trimmers and the Cattle Hoof Care Standards Board.
Helping hand: foot-trimming records will improve index dataset
They are also collaborating with commercial software companies including All4Feet, VetIMPRESS and Hooftec, with the aim of facilitating access to foot-trimming data.
“If we can get foot-trimming data from thousands of herds, rather than hundreds, then it will improve the quality of data and the effectiveness of Lameness Advantage,” he says.
The challenge has been to obtain formal consent for data-sharing, and he urges producers to ask their foot trimmers or vets how they can give their consent. “Lameness has to be tackled through better management, housing and diet, but if we can breed a more resistant cow that gives us a head start.”
Lameness Advantage Index
Lameness Advantage was developed in 2018 using records gathered via farm software and milk recording. It was added to PLI in 2019.
This means selecting sires based on PLI will already help producers reduce their cows’ tendency to be lame. The Liverpool University study shows that for every two-point decline in Lameness Advantage (LA), the risk of sole ulcer doubles.
The study also highlights the benefits of more consistent data, which means using foot-trimmer records. But producers must give consent for use of their data that, in turn, will make LA more effective and allow cows to be bred with a natural resistance to lameness more quickly than before.