Causes of abolition of milk yield controlled cows in the district of the agricultural Chamber of Hannover from 1958 bis 1997

Between 1958 and 1997 in the above mentioned district 13 713 649 for at lea st one year controlled cows were living. 4 205 027 (30.27%) left the farms earlier than they should have done. Problems of fertility were the main cau se for elimination (29.88%). Then followed other reasons including the shut ting down of farms (23.61%). These were followed by: cows with a small milk yield = 11.66 per cent; breeding cows were sold to other herds (9.18%); ud der problems and mastitis (8.60%); problems with claws and legs (4.50%); ot her diseases (4.49%); abnormal heavy extraction of milk (1.85%). According to their age of life 5.87 per cent of the cows were slaughtered. During the time of examination the number of cows per farm grew from 7.8 to 36.5. The amount of controlled cows rose from 57.1 per cent to 82 per cent. The aver age milk yield advanced from 4 292 kg to 7 285 kg per anno, the produced fa t from 161 kg to 311 kg and the protein (in the last 20 years) from 203 kg to 245 kg.