Dairy Cows: Extensive Farming vs. Confined Housing in Barns

Should we prioritize dairy production systems that emphasize grazing, or, on the contrary, limit—or even prohibit—dairy cows’ access to the outdoors? While these three types of farming appear to have both advantages and disadvantages, no conclusive scientific study has truly sought to settle the question. Researchers at Queen’s University Belfast reviewed the global literature to identify scientific arguments in favor of each system, considering the effects on milk composition and quality, cows’ body condition scores, animal health and welfare, fertility, environmental impacts, and profitability.   In Northern Ireland, dairy cows have traditionally had access to grazing in the summer. But in recent years, the industrialization of production systems—which prioritizes profitability—has led farmers to adopt systems where cows are fully or partially confined indoors. These increasingly non-traditional production systems are not without their drawbacks. However, the benefits of each system are often debated in the absence of solid scientific evidence. In the hope of advancing the debate—or even settling the issue—researchers at Queen’s University have, for the first time, compiled and compared the results of nearly 200 scientific studies conducted on the subject.   According to the scientific data collected (which is still limited), it is clear that both confined and grazing systems have their own advantages and disadvantages. Farmers who keep their cows in confined systems produce more milk, although there is little effect on milk composition. Overall, the animals are less exposed to inclement weather and energy balance is improved, leading to better body condition scores. On the other hand, cows with access to grazing produce milk that is higher in fat content and healthier. Generally speaking, they are healthier (with fewer cases of lameness and mastitis) and have lower mortality rates. They are also more fertile. Calving is easier, they have fewer uterine disorders (metritis and endometritis), their ovarian activity is boosted, and early-gestation abortions are less common. Welfare indices are also much higher. Dairy cows have greater freedom to express social behaviors. When given the choice, 62% choose to go out to pasture rather than stay inside the barns. The environmental impact of using grazing is also lower, largely because this system relies less on concentrated feed and fertilizers. From an economic standpoint, production costs and financial risks are also lower for traditional systems.   Overall, the balance therefore seems to tip in favor of dairy production systems that provide animals with access to the outdoors, as they are more profitable per 100 liters of milk, per dairy cow, and per hectare. However, real-world experience shows that when managed properly—particularly with the same level of high-quality feed—both production systems can be efficient, sustainable, and equally profitable. Ultimately, a farmer’s decision to adopt one production system or another goes far beyond mere scientific considerations. This choice is influenced by personal factors, preferences, local circumstances, and input costs, as well as by each country’s agricultural policy and legislation.   For several years now, all of these factors seem to have favored the rise of confined systems, which are more industrialized and less traditional. But things are changing. Environmental and ecological constraints are becoming increasingly stringent, particularly in relation to climate change. Consumer expectations and perceptions are also playing an ever-greater role in the debate. According to a British study, 95% of consumers do not consider it acceptable to keep dairy cows indoors at all times. This paves the way for more natural milk production and marketing that is more respectful of animal welfare.