The relations of some milk indicators of energy metabolism in cow, goat and sheep milk

The milk indicators (MIs) of energy metabolism, protein (CP), fat (F) and acetone (AC) determine and also influence the qua lity of milk. Deterioration in their values point to animal fertility disorders. Thus, these MIs can be used for monitoring and preventing the negative energy balance (NEB) in animals at the beginning part of lactation. In this way both animal health and milk quality can be improved. For this reason, selected relations between the energy metabolism indicators (AC and the fat/protein (F/CP) ratio) were studied in bulk cow (Czech Fleckvieh (CF), n = 40; Holstein (HN), n = 36), goat (White short-haired (WS), n = 40) and sheep (Tsigai (TS), n = 40) milk samples in the first half of lactation. The cows were fed a total mixed ration (TMR) based on maize, alfalfa and clover silage with brewers draff and concentrates. The goats and sheep grazed on a semicultural grazing growth and fattened up by concentrates. The differences in CP, F, F/CP and AC were significant for both breed and species (P 0.05). The highest AC (12.68 (8.73 xg) mg.l^–1) was in TS. The F/CP variability was relatively low and in AC in contrast high as is typical for health indicators, from 54.5% (HN) to 98.9% (WS). Whereas the AC means (TS, CF 7.77 (6.34 xg) and HN 2.03 (1.60 xg) and WS 7.55 (3.50 xg) mg.l^–1) can be considered species specific, the same is not true for their variability. Positive relations were found between AC and F/CP in cows CF and HN (r = 0.34, P 0.05; r = 0.15, P 0.05) and in sheep (r = 0.40, P 0.05). A negative relation was surprisingly found for goat milk (r = –0.22, P 0.05). This shows good agreement in the informative ability for both the indicators of energy metabolism not only in cow but also in sheep milk. Further studies are necessary in the case of goat milk. The F/CP ratio is accessible from routine milk recording, in contrast to the less frequent AC examination