MONITORING OF DAIRY-COWS FOR METABOLIC IM BALANCES DURING HIGH LACTATION BY MEANS OF MILK PARAMETERS .1. DAILY MILK-YIELD, FAT AND PROTEIN CONCENTRATIONS, FAT-PROTEIN-QUOTIENT AND UREA CONCENTRATION

Metabolic imbalances of the dairy cow during high lactation are causin g health problems and markedly reduce its profitability. Therefore, if seems indicated to monitor the metabolism of the animals during that period at short intervals. Milk would be a: suitable medium for that p urpose, provided that the metabolic status of the cow could be adequat ely defined by simple and cost-effective parameters. The daily milk yi eld usually is a sensitive indicator of the well-being of the dairy co w and the balance of its metabolism. However, during early lactation a (relative) reduction of the daily output may persist unrecognized unl ess the daily milk yields are compared at short intervals. The fat-pro tein-quotient proved to be a useful parameter for the assessment of th e energy intake in the group as well as for the detection of metabolic imbalances in the individual animal. It can be used, however, not ear lier than with the stabilization of the milk yield and of the fat and protein concentrations (around 4(th)-6(th) week of lactation). Influen ces of management and nutrition. have to be considered. During high la ctation milk urea and protein concentrations did not give a reliable i nformation on the energy and protein intake of the dairy cow. On the o ther hand high milk urea concentrations can indicate an oversupply wit h food protein or NPN containing feedstuffs, e.g. due to over-fertiliz ation of the pasture. High blood urea concentrations, furthermore, mig ht have detrimental effects on fertility. Therefore milk urea determin ation should be routinely used as screening test.