Artificial nests improve animal welfare and increase productivity in the pork industry

São Paulo startup develops biodegradable material that resembles branches, leaves, and grass used by pregnant sows in nature to prepare their birthing environment.

By Roseli Andrion  |  Agência FAPESP – In nature, pregnant sows leave their group shortly before giving birth. They gather branches, leaves, and grass to build a nest and prepare the environment for birth. They will give birth in this space and protect their piglets during their first days of life. However, in modern production systems, this instinct rarely has a place.

This is because the logic of efficiency prevails in these enclosures: clean, sanitized, and structured environments to maximize productivity. Sows spend the last days of their pregnancies in narrow stalls known as farrowing crates. These stalls are surrounded by bars and often have concrete floors. There is no dirt to dig, branches to carry, or grass to pile up.

The result is a common sight for those who live with these animals – restless females who bite the bars, stomp their feet on the concrete, rub their snouts on the floor, or perform other repetitive movements. They do this to compensate for their inability to express their instinctive behavior of building a nest.

This state of anxiety affects the animal’s physiology by causing an increase in the production of stress hormones, such as cortisol, and a reduction in substances necessary for smooth delivery. The females express their discomfort through reactions that have negative consequences throughout the entire phase, including delivery and lactation.

Veterinarian Matheus Saliba Monteiro, a researcher at Nerthus, a startup in the state of São Paulo, Brazil, was bothered by this scenario. With a master’s degree in experimental epidemiology applied to zoonoses, as well as specialization in pig production, reproduction, nutrition, and health, Monteiro closely monitors pig farm routines.

He says that if females receive a handful of grass or hay at this stage, they react immediately. “They become different. They interact less with the floor, bite the bars less, and start organizing the material with their snouts,” he says. “However, grass and hay clog the farm’s sewage system. For this reason, few farms provide material for nest building, even though they’re aware of this need in sows.”

According to him, this instinct is present even in intensive breeding environments. “They [the sows] express the need to build a nest before giving birth because they want their piglets to be warm and safe,” he points out. “It’s important to allow the animal to do what nature has programmed it to do. And the bonus, which makes all this possible, is knowing that the action brings economic benefits.”

Biodegradable and sustainable

Monteiro points out that this occurs worldwide. For example, the European Union has had animal welfare directives since 2008 to guide producers in providing materials for sows to build nests for farrowing. However, the materials initially tested, such as straw and hay, cause damage and health risks by clogging the sewage system on farms. “Everyone wants to comply with the law, and with our solution, this will be possible,” the researcher says.

The solution came from materials engineering. Marcos Nicolino, a specialist in bioplastics from natural sources, applied scientific innovation to create a sustainable, biodegradable, polymeric material strong enough for sows to handle that disintegrates in water. “With it, they can build nests, which enhances animal welfare,” he says.

In addition to providing comfort for the females, this innovation does not interfere with the production process. “Straw, hay, and grass work, but they clog sewage systems and biodigesters, and produce waste that’s difficult to manage. Our material, on the other hand, breaks down on contact with water and waste – this prevents clogging.”

The product resembles branches; it is made of long, flexible filaments that can be pulled, bitten, and manipulated by the females during the pre-farrowing period. “When we offer the material to the sow, she manifests the instinct that’s there, ready to be expressed,” Monteiro says.

Various agro-industrial residues, such as sugarcane bagasse and citrus pulp, are used to produce the formulation. “We work with the logic of the circular economy, transforming what would be discarded into a high-value-added solution for animal production,” Monteiro describes. “Thus, waste becomes a solution,” adds Nicolino. The project was supported by FAPESP’s Innovative Research in Small Businesses Program (PIPE).

The researchers are studying the incorporation of bacteriophages and probiotics into the formula to reduce the need for antibiotics in production. Another possibility under analysis is using waste material to increase biogas production in farm biodigesters, contributing to clean energy production. “It’s a project that looks at all aspects: animal welfare, environmental impact, sustainability, and, of course, economic gains,” Nicolino summarizes.

Animal welfare

The material lasts for 24 to 48 hours – enough time for the sow to express her instinctive behavior during the critical period before and during farrowing. “She picks up those ‘twigs,’ spreads them around the pen, arranges them as she wants, and becomes visibly calmer,” Monteiro reports. “This simple behavior makes a big difference in the animal’s well-being and in the physiology of farrowing and lactation.”

Expressing this behavior releases beneficial hormones, such as oxytocin, which improves uterine contractions, and prolactin, which stimulates milk production. The result is visible, measurable benefits that link animal welfare directly to productivity gains.

According to the researchers, a meta-analysis of scientific articles in the field reveals that this behavior has positive impacts. Studies show that when sows have access to materials that allow them to express this instinct, their stress levels decrease, they give birth up to 30% faster, and their piglets’ survival rate increases.

This is because birth occurs more naturally when the female is calm, with fewer risks for her and her young. “Piglets are born more active because they suffer less time from contractions of the maternal uterus during birth,” Monteiro explains. “And every piglet that doesn’t die represents money in the producer’s pocket,” Nicolino says.

In practical terms, this also means fewer stillborn piglets and healthier weaning. Additionally, less stressed sows produce more milk, meaning the piglets gain more weight before weaning. “There are more live animals, heavier piglets, and a healthier herd,” Monteiro summarizes. “A study with a small number of animals proved the reduction in delivery time. We want to test it on a larger scale to prove the other productive gains.”

Overall well-being

The effects can extend to the farm’s daily routine. “An environment with less animal stress is also less stressful for employees. All births are assisted, and those who accompany them have to deal with the pressure of attending to several at the same time,” Nicolino points out. “When the females are calm, the process occurs more smoothly, efficiently, and naturally.”

With faster births, employees can assist more females in the same period. “When there are fewer stillborn piglets, the psychological impact on farm workers is less, because they know they’ll experience fewer losses. It seems like a small detail, but it makes a difference in everyday life,” he adds. In other words, investing in animal welfare improves the quality of life and efficiency of workers. “It’s a very important intangible aspect.”

Nerthus has already presented its development results in Germany and the Netherlands, where discussions on animal welfare are more advanced. The reception there has been great. “The idea has attracted a lot of attention. We’ve been contacted by researchers and companies from Europe, Australia, and Latin America,” Nicolino says.

An article about the project published in a scientific journal has attracted interested parties. “A researcher from the Australian pig research sector told us that the article had reached them and contacted us for more data,” Nicolino reveals. “He even gave us tips on the next steps in the research.”

Meanwhile, demand is growing in Brazil. According to Normative Instruction 113/2020 from the Ministry of Agriculture, Livestock, and Supply, commercial pig farms must adhere to good practices for animal management and welfare. This includes providing nesting materials for pigs in maternity systems, which opens the door for practical and sustainable solutions, such as those offered by Nerthus. Consequently, large meatpacking plants and producers are showing interest in this option.

However, large-scale adoption still depends on practical factors. These include the cost of producing the material, adapting management systems, and producer acceptance. The researchers are investigating these aspects to ensure the economic viability of the solution.

Currently, the startup has been pre-approved for the Catalisa program, which is run by the Brazilian Micro and Small Business Support Service (SEBRAE). The program seeks to transform scientific research with innovation potential into high-impact businesses. During this process, Nerthus plans to conduct commercial-scale tests with industry partners. “The idea is to prove that the benefits remain when the solution is applied to thousands of animals.”

A more ethical future

Nerthus’s competitive advantage lies in engaging with a global trend of aligning productivity and animal welfare. “In the future, there may be a label indicating that the meat comes from sows that were able to express their natural instincts,” Nicolino points out.

Later this year, Nerthus plans to have customers test the product commercially. The long-term strategy is even more ambitious and aligned with the innovation ecosystem: licensing the technology to companies around the world. “We won’t be able to produce millions of tons on our own,” Nicolino acknowledges. “The idea is to license it to those who have the production structure. Nerthus will develop the formulation and adapt the product to different production realities, but large-scale manufacturing should be left to industrial partners in Brazil and abroad.”

There is the potential for this market to consume thousands of tons annually in Brazil alone, as there is an increasingly clear demand from society for more ethical, sustainable, and transparent production systems. The export potential extends to Europe, the United States, and Asia. The goal is for the product to be available by the end of 2026, initially on an experimental basis and then on a commercial scale.