Relationship Between Cytologically Determined Early Lactation Hepatic Lipid Content and Energy Balance, Health, and Milk Production in Grazing Dairy Cows

The aim of this study was to evaluate the relationship between cows’ hepatic lipid content (HLC) at 10 days in milk (DIM) and their metabolic status, health, and production during transition and early lactation periods. HLC was determined in 103 cows from a grazing Chilean dairy herd via cytologic examination of the liver through fine needle biopsies, categorized as mild, moderate, or severe. Blood metabolites were evaluated in the transition period, together with diseases in the postpartum period and milk production during the first 90 DIM. In pre-partum and postpartum periods, primiparous cows with severe HLC showed higher plasma cholesterol than multiparous cows with mild HLC. Postpartum, cows with severe HLC had higher serum non-esterified fatty acids (NEFAs) and NEFA/cholesterol ratios than those with mild HLC. Similarly, cows with moderate and severe HLC presented higher plasma β-hydroxybutyrate and greater risk of subclinical ketosis than cows with mild HLC. Additionally, cows with severe HLC had higher milk production and lower milk protein content than those with mild HLC. These results indicate that moderate to severe HLC at 10 DIM was associated with negative energy balance and subclinical ketosis, whereas severe HLC was associated with increased milk production and decreased milk protein content.