DEPOSITION AND MOBILIZATION OF DEPOT FAT IN DAIRY-CATTLE DURING REARING AND FIRST LACTATION

Aim of these investigations was to answer the question which influence the height of fat deposition at calving has on milk yield, feed intak e and fertility during early lactation of the first calving and whethe r the backfat thickness and other parameters identify the metabolism t ype of dairy cow already in rearing. 52 animals (Deutsche Schwarzbunte with 75% Holstein Friesian genotype), which were kept under identical environmental and feeding conditions, were included into evaluation. Higher backfat thickness at calving increased the mobilisation of depo t fat (lipolysis), which negatively influenced the feed intake, but ha d a positive influence on the milk yield. For the milk yield, the mobi lisation of the fat depots is decisive rather than the fat quantity at partus. Cows with a higher backfat thickness at calving tended to hav e a shortened intercalving period. The fatty acid pattern in milk fat is influenced by a different mobilisation of depot fat at the beginnin g of lactation. With the growth parameters (weight, backfat thickness and its gain) and the somatotropin concentration during rearing 25 per cent of the total variance of the change of backfat thickness from 4t h up to 16th lactation week in the first lactation can be defined.