Friday, August 22, 2025

Calcium tests in poultry offer chance for improved feed efficiency

Poultry nutritionists show results in calcium bioavailability, digestibility tests connected

University of Arkansas System Division of Agriculture

Ben Parsons-Poultry Nutrition — image:
Ben Parsons, an assistant professor of poultry nutrition with the Arkansas Agricultural Experiment Station, and colleagues in the Center of Excellence for Poultry Science compared the results of two calcium availability tests — a classic approach and a newer, speedier test — and found that both tests offer reliable results that can help poultry producers optimize calcium digestibility.
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Credit: U of A System Division of Agriculture photo

By John Lovett

University of Arkansas System Division of Agriculture

Arkansas Agricultural Experiment Station

FAYETTEVILLE, Ark. — One percentage point of feed conversion loss in large-scale poultry production can cause millions in lost revenue, so even small improvements — like fine-tuning a single nutrient in feed — can make a big difference.

Calcium plays a key role in poultry feed conversion. In addition to bone density, enzyme activation, muscle contraction, and other critical functions, calcium affects the efficiency of turning food into weight gain. But in broilers, it’s not just the amount of calcium that matters. What really counts is bioavailability: how much of that nutrient the bird can actually use.

Accurately measuring calcium bioavailability has been tricky for poultry scientists.

“The biggest challenge we have is analytically picking up the calcium content of our samples accurately,” said Ben Parsons, an assistant professor of poultry nutrition with the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, and the Dale Bumpers College of Agricultural, Food and Life Sciences. “Our main calcium sources — dicalcium phosphate and limestone — are rocks. You may get a big piece or a little one in the sample, and it causes variability.”

A new study by Parsons and his colleagues in the Center of Excellence for Poultry Science compared the results of two calcium availability tests — a classic approach and a newer, speedier test — and found that both tests offer reliable results that can help poultry producers optimize calcium digestibility.

Arkansas has consistently ranked as the third-largest producer of broiler chickens in the nation, producing more than 7.4 billion pounds of broiler meat in 2023, according to the latest Arkansas Agricultural Profile. Bringing in $6.5 billion, broiler production represents about 45 percent of all agricultural cash farm receipts in Arkansas.

In the quest to formulate optimum-performance poultry feed, poultry nutritionists have been looking at not just how much calcium is in the feed but how much is digested and absorbed by the bird.

Currently, the feed is formulated to meet a total calcium requirement in the diet, which does not account for differences in calcium availability among sources. Even among different sources of the same ingredient, calcium availability can vary due to factors such as solubility and particle size.

Value in the millions

Limestone is the most common calcium source in poultry diets, Parsons said. It’s inexpensive and widely available, but its digestible calcium content can range from as low as 20 percent to nearly 80 percent. To be safe, feed producers often add more than needed — but too much calcium can reduce the availability of other nutrients, such as phosphorus, and may even worsen disease challenges, Parsons explained.

“Some recent work is showing that excess calcium can exacerbate disease and pathogen challenges,” he said. “We don’t understand how right now, but we know that there’s value in trying to get more precise in how we’re meeting the animal’s calcium requirement.”

The value could be worth millions. As Parsons explained, feed conversion ratio is a numerical value that can have a big effect even when it’s a small number due to the high volume of birds being grown by the largest poultry producers.

“If you have a 1-point performance loss, that equates on a yearly basis to around $20 million to $24 million,” Parsons said of large-scale poultry farms. “Small things that impair performance could end up costing a lot of money because that little reduction in performance gets amplified.”

Two ways to measure calcium availability

Parsons and Rebekah Drysdale, Ph.D. poultry science student in Bumpers College at the University of Arkansas, conducted studies showing that a relatively new and speedy method of measuring calcium digestibility in the small intestines reflects results of an older and more time-consuming method of measuring bioavailability using ash or mineral content of a chicken’s leg bone.

Drysdale developed the method to measure calcium bioavailability using bone ash in modern broiler chickens as part of her master’s thesis, Parsons noted.

“The bone ash method is a classic approach that has been around for decades, mainly for trace minerals and phosphorus but very recently we’ve developed a regression approach for bone ash to measure calcium,” Parsons said. “Our goal was to compare it to the new method, and if we could show they are similar, then we could move forward in using these tools to evaluate a lot of different calcium samples.”

The newer method is called the “apparent ileal digestibility test” and involves collecting the partially digested feed known as digesta in the ileum, which is the end of the small intestines. The difference in calcium that was in the feed and what was left after digestion in the dried digesta can then be calculated.

While the apparent ileal digestibility test can be done in 24 to 72 hours with as few as one diet, the bone ash test process takes two weeks before the nutrients are absorbed in the bone and twice as many diets are needed compared with the newer digestibility test.

Results of the study indicate that the newer, more rapid digestibility test can be used to assess calcium availability in feedstuffs. Also, relative calcium bioavailability values based on bone ash content can also be used to predict or estimate calcium digestibility values.

Parsons said while the digestibility test is useful in providing direct measurements of calcium availability, tests for calcium bioavailability based on bone ash can be helpful to confirm results from digestibility tests while also eliminating analytical errors. The calcium bioavailability based on bone ash will also account for absorption, transportation and usage within the body, which offers additional insights beyond absorption or digestibility, Parsons added.

Finding the ‘sweet spot’

Parsons said a long-term goal for poultry nutritionists is to move from total calcium requirements in poultry feed to digestible calcium levels.

“There’s a big challenge in that because you’ve really got to have a good robust data set or database of calcium availability of different sources,” Parsons said.

With varying levels of calcium digestibility in different sources of limestone, Parsons said both methods of testing can help poultry producers screen calcium sources that are causing problems and find sources with a “sweet spot” of digestibility based on solubility rates.

“You want a limestone that’s in the middle of this solubility distribution,” Parsons said. “If you get something that solubilizes rapidly in the GI tract, that’s actually problematic and leads to reduced availability of other nutrients like phosphorus. If you get it solubilizing too slowly, the bird can’t use it.”

Drysdale and Parsons published the results of their experiments in the journal Poultry Science under the title “Comparison of relative calcium bioavailability based on bone ash and apparent ileal Ca digestibility in broiler chickens.”

Seth Hufford, a program technician in the poultry science department, has also been a collaborator on the calcium studies.

To learn more about the Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website. Follow us on X at @ArkAgResearch, subscribe to the Food, Farms and Forests podcast and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. Follow us on X at @AgInArk. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.

About the Division of Agriculture

The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.

The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.

Pursuant to 7 CFR § 15.3, the University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.

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Broiler chick held by Rebekah Drysdale, a Ph.D. student in the poultry science department for the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas. Drysdale and her adviser, Assistant Professor Ben Parsons, conducted studies that can help poultry producers optimize calcium digestibility.

Credit

U of A System Division of Agriculture photo

Journal

Poultry Science

DOI

10.1016/j.psj.2025.105274

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Comparison of relative calcium bioavailability based on bone ash and apparent ileal Ca digestibility in broiler chickens

Article Publication Date

22-Aug-2025

Germany's Porsche is closing battery subsidiary Cellforce, reports say

By Doloresz Katanich
Published on 21/08/2025 -

According to German media reports, the sports car maker has decided to largely shut down its battery-making and research subsidiary Cellforce, cutting hundreds of jobs.

German sports car giant Porsche plans to close the majority of operations at its subsidiary Cellforce, a factory for high-performance battery cells.

According to the German newspaper Der Spiegel, the sports car manufacturer plans to lay off around 200 of its 286 employees at the factory in Kirchentellinsfurt, Germany.

The cuts suggest that, at best, a small research and development unit would remain at Cellforce’s site.

Porsche declined to comment on the reports, but Der Spiegel noted that a corresponding mass layoff was reported to the employment agency in the nearby city of Reutlingen on Wednesday.

Porsche invested in Cellforce Group GmbH in 2021. At first, it was a joint venture between Porsche AG and battery cell manufacturer CustomCells.

In an effort to establish Baden-Württemberg as a leading battery location, the state also offered €17 million in funding to Cellforce in 2022.

Porsche reports significant plunge in European and Chinese deliveries

In 2023, Porsche then took over the business entirely with the promise of producing high-performance battery cells on a much larger scale than previously planned.

However, it was a short-lived ambition. In April this year, Porsche announced that it would not continue to operate the battery cell subsidiary independently.

According to Der Spiegel, representatives from BMW visited the site at the beginning of August, and defence companies were also said to have been interested in the factory for developing batteries for military drones. Yet the latest media reports suggest that no new investors are on the horizon.

The depreciation of Cellforce's production facilities is allegedly costing Porsche €295mn.

Meanwhile, around 200 employees face unemployment because, unlike its parent company Porsche, there is no employment guarantee and no works council at Cellforce.

All employees have been invited to a town hall meeting on 25 August, at the "Cellforce 1" building in Kirchentellinsfurt. Employees are also banned from taking holiday on that day, according to reports. Michael Steiner, Porsche's chief development officer and vice president, will address the staff.

The closure of the battery business highlights fundamental challenges to Porsche’s electric strategy, pursued by CEO Oliver Blume. Cellforce was intended to help increase the firm's EV sales and profits by allowing the manufacturer to draw upon its own high-performance cells.

New AI model can help extend life and increase safety of electric vehicle batteries

Uppsala University

image:
Daniel Brandell, Professor of Materials Chemistry at the Department of Chemistry and Director of the Ångström Advanced Battery Centre at Uppsala University
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Credit: Tobias Sterner/Bildbyrån

Batteries in electric vehicles wear out too quickly and this is slowing down the electrification of the transport sector. Researchers at Uppsala University have now developed an AI model that can provide a much more accurate picture of battery ageing. The model could lead to longer life and enhanced safety for electric vehicle batteries.

It is not uncommon for batteries in electric cars to be the first component of the vehicle to age. This is a major waste of resources today and is holding back the transformation of the transport sector. To address this issue, the automotive industry is developing software, often based on AI, to optimise battery management and control. Researchers at Uppsala University have now produced a new model that can increase the robustness of battery health predictions by up to 70 per cent.

“Being able to learn more about the life and ageing of batteries will benefit future control systems in electric vehicles. It also shows how important it is to understand what happens inside the batteries. If we stop looking at them as black boxes that are simply expected to provide power, and instead acquire a detailed picture of the processes, we can manage them so that they stay in good condition longer,” says Professor Daniel Brandell, who led the study and is in charge of the Ångström Advanced Battery Centre at Uppsala University.

Can map the battery life cycle

Several years of battery testing are behind the study, carried out in collaboration with Aalborg University in Denmark. A database was built up by collecting data from numerous very short charging segments. This was then combined with a detailed model of all the different chemical processes taking place inside the battery.

“Altogether, this gives us a very precise picture of the various chemical reactions that result in the battery generating power, but also of how it ages during use,” says Wendi Guo, who conducted the study.

Reduces need for sensitive vehicle data

The discovery could also affect the safety of electric vehicles. The safety problems that can occur in the battery are often due to design flaws and side reactions, which can also be predicted by studying data from the battery’s charging and discharging.

“The fact that we only use short charging segments is probably an added advantage. Battery data from electric vehicles is sensitive, both for the industry and from an anonymisation point of view for users. This research shows how far you can get without needing complete datasets,” says Brandell.