Feed & Additive Magazine Issue 47 December 2024

ARTICLE 80 FEED & ADDITIVE MAGAZINE December 2024 The transition period in dairy cows is a critical phase in their production cycle; cows experience several physiological, metabolic, and environmental changes. Ultimately, the immune system will be disrupted, leading to inflammation, oxidative stress, and excessive lipid mobilization. These challenges require a holistic solution approach. Despite intensive academic and industry focus, the transition period remains a big challenge to animal welfare, farm profitability, and dairy sustainability. Research shows that 75% of dairy cow diseases happen in the first month after calving (LeBlanc et al., 2006), while 65% of clinical mastitis cases occurring during the first two months of lactation originated during the dry period (Cobirka et al., 2020). Post-partum diseases such as ketosis has been recently identified to cause an annual losses per cow of 134 USD (average from 183 milk-producing countries) but is also considered as gateway diseases, greatly reducing the chance of full productivity throughout the subsequent lactation (Goff, 2008), and has been associated with increased odds of other dairy cattle diseases (Rasmussen et al., 2024). The old dogma or principle emphasizes that adipose tissue-released non-esterified fatty acids (NEFA) and the resulting hepatic-derived ketones coupled with hypocalcaemia lead to immune suppression, which is responsible for transition disorders. In other words, this old dogma suggested these metabolites and hypocalcaemia were causal to transition cow problems. However, the new insight from research takes a more holistic and preventive strategy in managing dairy cows during the transition, placing inflammation as a cornerstone of transition disorders (Horst et al., 2021). Calving transition presents the cow with multiple metabolic stresses that often lead to pathological permeability of the intestinal wall, what is called "leaky gut syndrome". A leaky digestive system and immune activation at calving can be the root cause of transition disorders. The physiological, environmental, and psychological stressors during the transition period disrupt barrier integrity, increasing permeability at epithelial interfaces (e.g., uterine, mammary, intestinal, and lung), which are exposed to pathogens and colonised by commensal microorganisms. When microorganisms breach the epithelial barrier (through the leaky gut), activation of the immune response leads to inflammation — a result of lipopolysaccharide (LPS) translocation into the systemic circulation (Figure 1). The aim during the transition period is to limit inflammation, extract more energy from the diet, and limit oxidative stress. On the same leaf, the several challenges during the transition period evidence the need for a holistic approach. The goal is to opDairy cow transition challenges: HOLISTIC SOLUTION APPROACH Clothilde Villot R&D Program Manager Lallemand Animal Nutrition

RkJQdWJsaXNoZXIy MTUxNjkxNQ==