The body weight of the dairy cow: III. Use for on-line management of individual cows

This paper presents possible practical management applications of dairy cows' body weight (BW) data. Daily BW and milk yield (MY) data of 80 primiparous and 128 multiparous cows were collected during complete lactations in a commercial dairy and analyzed in relation to health problems, nutrition and milking frequency (MF). The criteria for health problems were established on half of the total events, and checked on the other half. Approximately 50% of health problems were identified by BW changes up to 3 days prior to the MY drop that set off the health alarm. Physiological criteria for cows to be transferred from recommended post-partum (pp) total mixed ration (TMR) to a normal recommended TMR of higher or lower density, were quantified by changes in coefficients of a 10-days-running linear regression of 3-days-running average daily BW and MY data as dependent variables, and day pp as the independent variable. These criteria were set as rules that were incorporated into a fuzzy logic (FL) expert system (ES) which was applied to the second half of the data set. In all cases the transfer decision was within 2 days of the time calculated individually for each cow. A similar technique was used to define criteria to reduce high MF after calving in order to: (a) prevent metabolic stress, and (b) decrease MF after achieving sufficient pp stimulus for the carry-over effect. It is concluded that daily BW data are valuable as information to improve both diagnosis and management decision making.