Good breeding, environment and nutrition play a role in combating lameness of dairy cows. But new research has found that genetics plays a bigger role than previously thought.
The research, conducted by the University of Liverpool, Scotland Rural College (SRUC) and the Royal Veterinary College, shows that a genetic marker of lameness in the UK – the lameness advantage AHDB (LA) – can have a significant impact on eradicating the condition.
It does this by decreasing the tendency of cows to have various causes of lameness, especially single ulcers and only bleeding or bruising.
“Several current studies have shown the heritability of lameness to be between 1% and 20%,” says Georgios Okonomo, Professor of Cattle Health and Welfare at the University of Liverpool.
Mr. Oikonomou was co-supervisor of the Biotechnology and Biological Sciences Research Council (BBSRC) initiative.
These lower estimates—sometimes expressed as 0.01–0.20—cast doubts about how quickly and efficiently farmers can make improvements in lameness through breeding.
But the research showed a significantly higher heritability of lameness, especially for solitary ulcers, at 0.35 (or 35%), and for solitary bleeding at 0.29 (or 29%).
This puts lameness on a par with most morphology traits, which can generally be more easily quantified.
Furthermore, by having a genomic index of LA computed by AHDB for each animal participating in the experiment, the researchers showed that LA has a strong association with lameness in later life.
In fact, the probability of a cow developing a single ulcer decreased by 32% for each Los Angeles point increase in the participating animals.
“To put this in context, a recent study indicated a 20% reduction in the odds of developing a single ulcer in cows whose foot was prophylactically trimmed before dehydration,” Professor Okonomo said, adding that pruning of the foot was considered key in preventing sole ulcer.
“For this reason, we advise producers to use LA as a genetic selection tool as part of sole ulcer and sole bleeding prevention,” he said.
“The cost of selecting highly qualified personnel is negligible compared to other interventions, which often include housing remodeling or increasing the frequency of foot trim.
“And the magnitude of the potential reduction in the incidence of single ulcers that could be achieved through genetic selection would result in a significant improvement in both animal welfare and farm efficiency.”
high quality data
The researchers involved more than 2,000 dairy cows in their study, and recorded their pests themselves, using the same trained veterinarian for each cow.
This gave a better and more consistent measure of the cows’ phenotype (their actual physical appearance or performance), and removed much of the so-called “noise”, which was generated by other factors, including inconsistent recording.
As a result, the researchers were able to create a higher quality data set than had previously been achieved.
Foot trim records
The trial demonstrated the potential to use reliable lameness records in genetic selection to reduce claw horn lesions, solitary ulcers, and solitary hemorrhages.
“For genetic selection to work, we need big data,” says Professor Okonomo. “The AHDB currently uses the health data collected by logging the milk into the LA account, and that works really well.
But this data can be incomplete or skewed towards more serious causes of lameness. We can improve the dataset by using foot pruning records.”
For this reason, the team at Liverpool, together with AHDB, has entered into a partnership with foot trimmers through the National Cattle Foot Drivers’ Association and the Cattle Hoof Care Standards Board.
They are also collaborating with commercial software companies, including All4Feet, VetImpress and Hooftec, with the goal of making foot trimming data more accessible.
Their goal is to create a single national database, and to integrate different registries of UK foot-bikers that will be used for genetic assessment of foot pest resistance.
“If we can get foot pruning data from thousands of farms instead of hundreds, it will improve the quality of the data and the effectiveness of learner independence,” he says.
The challenge, however, was to obtain formal consent to share the data, and he urged farmers to ask foot cutters or veterinarians how to give their consent.
“We have to get better with the limp because it’s a financial and financial concern,” he says.
“It has to be addressed through better management, housing and diet, but if we can raise a more resistant cow, that gives us a head start.”
The lameness advantage score was developed by AHDB in 2018, using records collected in farm programs and collected through milk logging.
It was included in the UK’s national breeding target, the Profitable Life Index (PLI), in 2019.
This means that selecting offspring based on PLI will actually help farmers reduce their cows’ tendency to be lame, says Marco Winters, head of animal genetics at AHDB.
“However, if producers wish to target lameness in particular, they should research PLI components and ensure that they select a litter with a positive lameness advantage. [LA] score,” he says.
“The Liverpool study showed that for every two-point reduction in lameness advantage, the risk of developing a solitary ulcer doubles,” he says. “This shows how effective breeding is for Los Angeles.”
“However, the study also demonstrates the benefits of more data and more data consistency, which means using foot shear logs.
“We urge farmers to give consent to use their data, as this will make the LA result more effective and allow them to more quickly generate natural resistance to lameness in their cows.”
Sole ulcer and only bleeding
A single ulcer is an area of a damaged unicornuate that has lost all of the horn tissue except for the corium (the tissue that produces a new unicornuate).
It occurs when the supporting structures of the pedal bone inside the hoof weaken.
The bone can then move and sink, causing damage to the horn. With the erosion of the sole, the area of \u200b\u200bthe damaged horn is exposed, which leads to the development of ulcers.
Sole bleeds, or sole bruises, are characterized by red and sometimes yellow marks or areas on the sole, and may occur when the sole is particularly tender.
It is caused by pressure on the corium, which leads to damage to cells and blood vessels.
Inflammatory chemicals can cause permanent changes to the pedal bone, and possibly the digital cushion, resulting in more bruising.
Solitary bleeding is the usual precursor to a solitary ulcer.