Relation Between Dietary Energy Source and Body Fat Mobilisation and Blood Metabolites in Dairy Cows

The characteristics of metabolic and reproductive disorders in early lactation suggest a role for the balance in availability of lipogenic and glycogenic nutrients (Van Knegsel et al., 2005; Reprod Nutr Dev 45, 665¿688). The objective of this study was to compare the effects of a glycogenic or a lipogenic diet on body weight change and metabolites in dairy cows in early lactation. Sixteen dairy cows were housed in climaterespiration chambers from week 2 to 9 postpartum (pp) and fed either a lipogenic or glycogenic diet. Diets were fed isocaloric. Mobilisation of body reserves was measured weekly. Blood was sampled weekly. Results are presented as LSMEANS ± SE. Cows fed a lipogenic diet mobilised more body fat (31.2 vs 18.6 kg), had higher non-esterified fatty acid levels (0.46 ± 0.04 vs 0.37 ± 0.04 mmol/ml, p = 0.09) and lower insulin levels (4.0 ± 0.5 vs 5.5 ± 0.6 lIU/ml, p = 0.04) than cows fed the glycogenic diet. No difference was found on b-hydroxybutyrate (2.2 ± 0.2 mmol/ml) and IGF-1 (16.4 ± 1.0 ng/ml). This suggests that the severity of body fat mobilisation and metabolic disorders in early lactation can be altered by feeding isocaloric diets differing in lipogenic and glycogenic nutrient content.