Climate change is intensifying the challenges faced by dairy farmers, particularly through increasingly frequent and severe droughts that directly impact forage availability. In regions such as the Massif Central in France, where semi-mountainous grasslands have traditionally supported dairy farming through natural grasses and hay preservation, shifts in climate patterns are compelling farmers to adopt new strategies. One notable adaptation involves integrating fodder crops like corn silage into cattle diets, a practice that historically has been secondary in renowned cheese-producing areas. This shift raises critical questions about how these evolving feeding regimes influence both the quality of milk and the characteristics of cheese produced, which are essential factors for maintaining regional gastronomic identities and market values.
Researchers from the French National Research Institute for Agriculture, Food and Environment (INRAE) and VetAgro Sup have been at the forefront of investigating how these adaptive feeding practices affect dairy outputs. Their recent study employed a rigorous, four-month experiment on an INRAE experimental farm situated within the Massif Central. This controlled trial involved 40 dairy cows split into four groups designed to mimic varying levels and types of forage availability reflecting real-world agricultural responses to climate-induced drought. Two groups received diets primarily based on grazed grass—one group consumed 75% grazed grass, while another replaced half of the grass intake with hay, simulating drought conditions that limit fresh grass. The remaining two groups were provided diets incorporating corn silage, with one consuming 75% corn silage combined with 25% grazed grass, and the other receiving a complete corn silage diet devoid of fresh grass.
Milk harvested from each of these dietary treatments was transformed into Cantal-type cheeses, a traditional French cheese variety known for its distinctive sensory attributes. Through comprehensive analysis, both the nutritional content and sensory profiles of milk and cheese samples were scrutinized. The study revealed that diets richer in fresh grazed grass significantly enhanced the milk’s and resultant cheese’s omega-3 fatty acid content. Omega-3 fatty acids are well-recognized for their positive implications on human cardiovascular health, presenting an important nutritional advantage. This finding underscores the profound influence of pasture quality and composition on the biochemical properties of dairy products, reinforcing the link between animal diet and consumer health benefits.
A sensory evaluation, critical for gauging consumer acceptability and product authenticity, was conducted with a panel of ten trained assessors. They systematically scored the cheeses on 28 distinct criteria encompassing color, odour, taste, aroma, and texture using intensities rated from zero to ten. Results indicated that cheeses derived from cows consuming high proportions of grazed grass exhibited smoother textures, a richer yellow hue, and more pronounced aromatic qualities. Conversely, cheeses from cows fed little to no fresh grass appeared whiter, exhibited firmer textures, and presented milder flavour profiles, factors that might influence consumer preferences and market positioning, especially in protected designation of origin (PDO) contexts.
The increasing adoption of corn-based forage systems, propelled by climate-induced challenges to grassland productivity, was shown to have a pronounced detrimental impact on cheese quality, particularly when fresh grass was absent from the diet. The research highlights the critical role even a modest inclusion of fresh grazed grass plays in preserving both the nutritional status and prized sensory characteristics of traditional cheeses. These insights suggest that despite crop diversification as an adaptation measure, maintaining pasture access remains indispensable for preserving the unique qualities that define regional cheeses, especially in agroecological transition zones like the Massif Central.
In situations where farmers rely on grass-based systems supplemented with hay to counter drought-induced forage shortages, the impact on cheese quality was comparatively less severe. This traditional approach appeared to buffer against drastic declines in sensory and nutritional properties, providing a viable, though potentially limited, strategy for short-term adaptation. It also supports the resilience of established farming practices and highlights the importance of strategic forage conservation in the face of increased climatic variability.
Beyond simply assessing cheese attributes, the research undertook a holistic examination of the dairy production ecosystem. Samples were collected meticulously across multiple environmental and biological stages: from the soil composition of the grasslands, the microbial surfaces of the fresh grass, and the anatomical sites of the cows such as their udders, to the faecal microbiota of rats that consumed the cheese. These analyses are anticipated to provide unprecedented insights into microbial transmission along the agri-food chain as influenced by diet composition, which may have far-reaching consequences for food safety, animal health, and human microbiota interactions.
This multidisciplinary study was facilitated by the Herbipôle facility as part of the larger TANDEM research project under the Holoflux metaprogramme, illustrating the collaborative spirit essential for addressing complex agroecological challenges. The project united expertise across 11 INRAE research units covering a spectrum from animal genetics and integrative biology to environmental biotechnology and applied mathematics, alongside multiple industry and regional stakeholders including producer organizations and chambers of agriculture. This integrated approach ensures that findings not only contribute to scientific knowledge but also have direct applicability in local farming systems and policy making.
The implications of this research extend significantly into agricultural management, animal nutrition science, and food technology sectors. Maintaining animal diets inclusive of fresh grazed grass emerges as a pivotal factor for sustaining product excellence and consumer health outcomes under climatic pressures. Moreover, these findings emphasize the need for future agricultural policies that promote diversified forage systems incorporating both traditional and innovative practices adaptable to evolving environmental conditions.
In summary, as climate change continues to disrupt established agricultural paradigms, the dairy industry’s resilience will increasingly depend on evidence-based adaptation strategies that safeguard product quality and sustainability. This groundbreaking work from INRAE and VetAgro Sup not only reveals the nuanced relationships between forage management, animal performance, and final dairy product quality but also calls attention to the intricate microbial and ecological networks underpinning agricultural food chains. As a result, farmers, scientists, and policy makers alike are equipped with critical insights needed to navigate and mitigate the complex challenges posed by our changing climate while honoring the traditions and economic viability of cherished dairy regions.
Subject of Research:
Effects of climate change-induced forage shortages on dairy cow diets and the resulting impact on milk and cheese quality in semi-mountainous grassland and corn-based systems.
Article Title:
Adaptation strategies to manage summer forage shortages improve animal performance and better maintain milk and cheese quality in grass- versus corn-based dairy systems
Web References:
http://dx.doi.org/10.3168/jds.2024-25730
Image Credits:
INRAE – Christophe Maître
Keywords:
Climate change, dairy farming, drought adaptation, forage strategies, grass-based systems, corn silage, milk quality, cheese quality, omega-3 fatty acids, sensory analysis, microbial transfer, agroecology
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