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Effect of Energy Density in the Diet and Milking Frequency on Plasma Metabolites and Hormones in Early Lactation Dairy Cows

2004; Wiley; Volume: 51; Issue: 2 Linguagem: Inglês

10.1111/j.1439-0442.2004.00605.x

1439-0442

J.B. Andersen, N.C. Friggens, Torben Larsen, Mikkel Vestergaard, K.L. Ingvartsen,

Ruminant Nutrition and Digestive Physiology

Summary The effects of energy density in the diet [low = 0.86 SFU/kg dry matter (DM) or high = 1.06 SFU/kg DM] and daily milking frequency (two or three times) in early lactation on plasma concentrations of metabolites and hormones were evaluated in 40 Holstein dairy cows arranged in a 2 × 2 factorial block design. The four treatment combinations were L2, L3, H2 and H3, and the experimental period comprised the first 8 weeks of lactation. Plasma glucose, insulin and insulin‐like growth factor (IGF)‐I concentrations were on average 8 (3.43 versus 3.19 mmol/l), 114 (41.6 versus 19.4 pmol/l) and 60% (91.9 versus 57.4 ng/ml) higher, whereas β ‐hydroxybutyrate (BOHB), plasma urea nitrogen (PUN) and growth hormone (GH) concentrations were on average 18 (0.73 versus 0.89 mmol/l 1 ), 14 (7.18 versus 8.35 mmol/l), and 63% (1.0 versus 2.6 ng/ml 1 ) lower for cows fed diet H than for cows fed diet L. Cows milked three times daily had a 6% (3.20 versus 3.42 mmol/l) lower plasma glucose concentration and a 19% (0.88 versus 0.74 mmol/l 1 ) higher plasma concentration of BOHB compared with cows milked two times daily. Plasma non‐esterified fatty acid (NEFA) concentration was not affected by either treatment. Overall, it is concluded that increasing the daily milking frequency creates a higher metabolic imbalance in early lactation. Cows in early lactation will benefit from receiving a high energy density diet and thereby avoid a too high metabolic imbalance when mobilizing body tissue in support of milk production.