Possible modulation of adipose tissue responsiveness to catecholamines by available dietary protein in dairy cows during early lactation.

Early lactation is characterised by a number of metabolic adaptations which divert nutrients from the peripheral tissues in favour of the mammary gland. One such adaptation is the increased responsiveness of adipose tissue to lipolytic stimuli. The effects of the condition score at calving and the level of undegradable protein in the diet on the responsiveness of adipose tissue to adrenergic stimulation were studied in dairy cows during early lactation. They were subjected to exogenous epinephrine challenges on weeks 3 and 8 of lactation. The responsiveness to epinephrine increased with high levels of rumen undegradable protein in the diet and a high condition score at calving, with no interaction between the 2 factors. The responsiveness to epinephrine was increased by the dietary treatment, especially on the 8th week of lactation, which suggests that the availability of protein might prolong the metabolic adaptations characteristic of early lactation.