INVESTIGATIONS ON THE REPRODUCTIVE STATUS OF DAIRY-COWS - PART-2 - MULTIFACTORIAL CORRELATIONS TO BLOOD PARAMETERS AND THE GENERAL AND GYNECOLOGICAL STATUS

Data were collected in 15 commercial dairy herds (stanchioned cattle) during 5 visits each 3 months apart. To elaborate the multifuctorial c orrelations the data (independent variables) collected per animal, eit her once or during each visit, were submitted to a multiple, stepwise regression in respect to the target parameters >>service period<<, >>o pen period<< and >>number of services per conception<<. Highly signifi cant correlations were established confirming the interactions between fertility and ovarian resp. puerperal disorders. The se two variables were omitted in a second evaluation to better demonstrate likely inte ractions with the other subordinate variables. In addition, ovarian an d puerperal disorders were classified as dependable variables and inte ractions with the other parameters monitored were tested applying a mu ltiple, stepwise, logistic regression. Main observations were as follo ws: a) increasing concentration of beta-carotin during the first 40 da ys post partum were significantly correlated with a shortened service and open period and a reduction of ovarian- and puerperal disorders; b ) an increase of average milk production was significantly correlated with an increase of the service period and the number of inseminations perconception; ci height of milk yield at onset of lactation was nega tively cell-elated with duration of the service period and - to a less er ex-tent - of the open period; d) skill leasions at the right hind q uarters (indicating a good oestrus expression) were significantly corr elated with a reduced service - and open period and a reduced number o f inseminations per conception: e) probably due to management reasons the set-vice period was significant longer in cows of the breed German Red Pied compared to German Black Pied. Correlations with blood and u rine metabolic parameters were only slightly significant, ilo relation s could be established between fertility and the observations on infec tious diseases. The statistical methods applied in order to cope with a large amount of data (>100 000) have shown to be adequate to identif y those parameters (out of an array of parameters) which interact with >>fertility<<. Also the dependable target parameters >>service period <<, >>open period<< and >>number of inseminations per conception<< hav e shown their usefulness to describe >>fertility<<. However, there was a qualitatively different spectrum of correlations between these depe ndable and the independable variables which indicates the necessity to differentiate in respect to >>fertility problems<<.