Extending Herd Longevity to Mitigate Enteric Methane Emissions

Climate variability due to human interruption of the biosphere will continue to be an important topic for animal agriculture. Dairy producers are frequently being asked to quantify and support the sustainability of their operations, in some cases this affects access to markets.

Dr Nico Vreeburg, an experienced dairy veterinarian and technical services deployer for ruminants at Lallemand Animal Nutrition, suggests that focusing on animal health delivers multiple benefits. “Maintaining healthier cows isn’t just economically sound; it’s also proving to be a crucial strategy for farmers looking to reduce the carbon intensity of dairy production.“ He says.

The Link Between Longevity and Sustainable Production

Longevity is a keyword in dairy farm sustainability. According to research, dairy cow productivity increases with each lactation cycle until reaching a plateau around the fifth lactation (Table 1). This increased lifetime production leads to lower methane emissions per unit of milk. By investing in herd health to extend productive lifespans, farmers can optimise their environmental impact per litre of milk.

“Doubling a cow’s lifetime lactations from two and a half to five reduces the need for herd replacements while typically increasing milk output“ Vreeburg explains. He points to farms where exceptional longevity resulted in replacement rates of just 12-15% over eight years, equivalent to six to seven lactations per cow. “Measures often focus on daily production per cow, but lifetime production serves as a more meaningful sustainability indicator.“

During the 23 months it takes to raise a heifer and the dry period before calving, cows eat feed and produce methane but don’t make milk (Table 2). Minimising these unproductive phases can help increase overall output while reducing emissions per kilogram of milk.

Building the Foundation: Health Management

Extending cow longevity requires comprehensive health management that addresses problems before they force early culling. “The focus should shift toward reducing health risks through preventive measures, including adequate, comfortable housing and sound nutrition” notes Dr Vreeburg.

Reproductive issues are a leading cause of cow culling, making fertility management crucial for extending herd longevity. “The critical window lies in those first 100 days of lactation, when a cow’s nutritional status can make or break her reproductive future. During early lactation, maintaining optimal body condition becomes a delicate balancing act.”

“Farmers understand that a cow cycling regularly and conceiving on schedule represents the successful orchestration of dozens of interconnected management practices,” Vreeburg observes. “Each one contributes to her ability to maintain both peak milk production and reproductive readiness simultaneously.”

Maximising Feed Efficiency for Improved Sustainability of Milk Production

While reproductive success keeps cows in the herd longer, the nutritional foundation that supports both reproduction and overall cow performance centres on rumen health and feed efficiency, particularly during the challenging transition from dry cow to peak lactation.
Research has shown that a rumen-specific live yeast can stabilise the rumen microbiota during the dramatic dietary shift from dry cow to lactation rations. This specialised yeast promotes beneficial bacteria growth and helps buffer rumen pH, which can help reduce the risk of acidosis that commonly disrupts feed intake during early lactation.

Studies also quantified these benefits, showing that rumen specific live yeast supplementation can reduce bodyweight loss by up to 30kg in the first 60 days of lactation – representing 5% of a typical 600kg dairy cow’s total bodyweight. This benefit in the maintenance of body condition translates to fewer health problems and enhanced reproductive performance, while simultaneously boosting feed efficiency by up to 7%, allowing cows to extract more energy from the same ration.2 The combined effect creates a positive cycle where optimised rumen health drives improved overall cow performance.

“When we can help cows extract more energy from every kilogram of feed, we’re not just improving economics, we’re reducing the environmental cost per liter of milk produced,“ Vreeburg explains. “It’s a perfect example of how nutritional precision supports both longevity and sustainability goals.“

Quality Forage is a Cornerstone of Enhanced Milk Production

Maximising the use of homegrown forages is central to profitable dairy farming and plays a key role in producing milk more efficiently. Improving silage quality begins with excellent crop and bunker management—skills that many dairy farmers have already mastered. “However, taking shortcuts in these processes, such as skipping the application of silage inoculants, can compromise quality and undermine overall silage goals. This not only leads to suboptimal nutritional outcomes but also negatively affects production performance and the farm’s sustainability targets,” he warns.

The Path Forward: Integration for Impact

By investing in optimising herd performance through proper nutrition and management, farmers can increase the proportion of cows who remain productive for longer, maximising the potential of every animal. The key lies in understanding how each management decision contributes to the ultimate goal of extending productive herd life.

“When we focus on maintaining optimal cow performance, we’re not just thinking about today’s milk production, we’re adapting our herd management to more sustainable practices,” says Vreeburg. “Every day a cow stays productive in the herd is a win for both farm economics and milk carbon intensity.”

In an industry facing increasing environmental scrutiny, the solution may be as straightforward as helping every cow reach her full productive potential.

Table 1. Methane exhaust per lactation (Van Laar e.a., 2004, Van Straalen, 2006, CRV 2010)

Table 2. Milk production related to first calving age (Van Laar e.a., 2004,Van Straalen, 2006)