How biomarkers can help uncover hidden flock health issues

As poultry production systems become increasingly data driven, producers are generating more information than ever before – but turning those figures into practical management decisions remains a challenge.

While modern units routinely monitor feed intakes, mortality, environmental conditions and growth rates, these measurements often show what has already happened, rather than identifying issues developing within the bird.

See also: Why rearing organic poultry is good fit for dairy farm

However, combining this farm data with blood biomarkers could offer producers a more predictive approach to flock management, according to Ursula McCormack, global technical and innovation manager at DSM-Firmenich.

She says biomarker analysis – alongside microbiome profiling and machine-learning models – is increasingly being used to identify nutritional, skeletal and health-related issues before they become clinically visible.

“We’re trying to move away from descriptive analytics – what has already happened on the farm – to a more predictive, or ‘what-will-happen’, approach,” she explains.

What do biomarkers measure?

This work forms part of DSM-Firmenich’s Verax precision service platform, which combines biomarker measurements with farm records to help identify patterns associated with health, welfare and production challenges.

Biomarkers are measurable indicators of biological processes within the body and can provide insight into nutritional status, inflammation, mineral balance, organ function and metabolism.

Using portable point-of-care devices, more than 20 blood biomarkers can be measured on farm in poultry, including:

• Calcium and phosphorus
• Sodium, chloride and potassium
• Glucose and haemoglobin
• Enzymes linked to inflammation and immune function
• Indicators associated with acid-base balance.

The aim is to connect these physiological measurements with flock performance and production records to identify underlying issues before performance drops.

The data can then be used in poultry management for routine flock monitoring, investigating specific health or production challenges, benchmarking management or nutritional changes, or evaluating feed additives or dietary adjustments.

Tackling femoral head necrosis with biomarkers and farm data

The potential value of such an approach was demonstrated on a broiler unit investigating femoral head necrosis (FHN) – a condition that can result in severe lameness and increased mortality. Despite advances in genetics and nutrition,

FHN remains a challenge in some fast-growing broiler systems, with multiple nutritional, physiological and management factors believed to contribute to its development.

In the study, two sites within the same broiler business were experiencing skeletal health challenges, but at different stages of production.

One was recording elevated mortality within the first five days, alongside severe FHN by seven days of age, while the second was seeing skeletal issues later in the production cycle, at about 28 days.

To investigate the challenge, 40 birds were sampled across the two sites and three hatcheries, combining blood biomarker analysis, microbiome profiling and farm production data.

“Probably to no-one’s surprise if we’re talking about bone health, the main biomarkers that were coming out were calcium and phosphorus,” says Ursula.

However, she stresses the relationship between skeletal health and mineral status is far more complex than simply increasing dietary inclusion rates.

Modern broiler genetics are highly sensitive to changes in calcium and phosphorus supply, while producers are simultaneously trying to optimise bodyweight gain and feed conversion efficiency.

“There’s an internal battle, not just between the nutritionists and the vets, but inside the animal themselves, on what gets the calcium and phosphorus: is it the body growth or is it the skeletal?” she points out.

Other factors can also influence calcium and phosphorus utilisation, including:

• Limestone quality
• Phytase inclusion
• Vitamin D status
• Water quality
• Bird age
• Genetics
• Acid base balance.

Drawing on data collected from about 10,000 commercial broiler farms globally,

Ursula says the company has built a substantial database of blood biomarker measurements, helping establish benchmark ranges for mineral status in commercial flocks.

However, the FHN investigation pointed to another measure as being potentially more informative than total calcium alone.

Role of ionised calcium in skeletal health

One of the clearest findings to emerge from the work was the relationship between ionised calcium and skeletal health.

Unlike total calcium, ionised calcium represents the biologically available “free” calcium circulating within the blood and may provide a more accurate indication of skeletal health risk, says Ursula.

While about 99% of calcium in the body is stored in the skeleton, the small proportion circulating in the bloodstream exists in different forms.

Some is bound to proteins such as albumin, some is bound to compounds including phosphate and lactate; the remainder exists as ionised calcium.

Ursula says it is this ionised fraction that is immediately available for biological processes.

The investigation showed ionised calcium can fluctuate significantly depending on blood pH and acid-base balance.

“For every 0.1-unit change in pH in the blood, we get a 2-4% change in ionised calcium in the blood,” she explains.

This means factors affecting acid-base balance, including sodium, chloride and potassium levels, can influence calcium availability even when total calcium concentrations appear adequate.

The availability of ionised calcium can also be affected by albumin, phosphorus and lactate concentrations.

Birds with lower ionised calcium concentrations were found to be at significantly greater risk of FHN, while total calcium and phosphorus levels showed less direct association.

The picture differed slightly for tibial dyschondroplasia, where total calcium and phosphorus status appeared to play a greater role.

“[As such,] it’s not necessarily just so simple as changing things directly in the diet,” warns Ursula.

Microbiome insights

To gain further insight into the challenge, microbiome analysis of the caecum (part of the large intestine) was also carried out at the two sites.

This identified significantly greater populations of two bacterial species, Enterococcus hirae and Bacteroides fragilis, at the site experiencing the highest mortality and most severe FHN issues.

E hirae is known to be associated with mortality issues in poultry; B fragilis is considered an opportunistic pathogen and has previously been linked with osteomyelitis and bone infections in other species, Ursula explains.

These findings demonstrated the value of combining multiple datasets rather than relying on a single measurement, she says.

Rather than changes in nutrition, the combined biomarker and microbiome data pointed towards a greater focus on flock health management, including sanitation protocols, vaccination programmes and hatchery-related factors.

“In this case, it wasn’t necessarily a diet or nutrition recommendation that was given – it was actually more associated with sanitation or vaccine programmes on the farm, or specifically with the hatcheries they were getting the birds from,” she adds.

In practical terms, the findings enabled the business to move beyond treating the issue as a mineral nutrition challenge.

Instead, it could investigate potential disease pressure and bird source factors that may have been contributing to the high incidence of FHN and mortality.

Value of predictive management

The long-term aim is to combine information about the bird with production records and management data to better understand the factors influencing performance.

As poultry systems continue pushing for greater efficiency, Ursula believes this type of predictive approach will become increasingly valuable.

“It’s really about providing more insights into [exactly] what’s happening inside the animal.”

Ursula McCormack was speaking in a seminar at the recent Pig & Poultry Fair at the NEC, Birmingham