CANADIAN DAIRY COW DISPOSALS: I. DIFFERENCES BETWEEN BREEDS, LACTATION NUMBERS AND SEASONS

Primary reasons for disposal of 26,651 dairy cows of the Ayrshire, Guernsey, Holstein and Jersey breeds were collected in Canadian Record of Performance herds from September, 1967 to August, 1968. Reproduction and low milk production were major causes of voluntary herd removals. The percentages culled annually for these problems ranged from 13.4 to 24.4% and from 15.5 to 28.3%, respectively. The Guernsey breed was highest (24.4%) in the percentage culled because of reproduction. The Holstein was lowest (15.5%) in the percentage culled because of low production, but highest (10.2%) in the percent removed because of udder problems. Disposal patterns changed with the lactation number of the cow. Young cows were culled more heavily for low production than their older herdmates. This was offset by increases in the percentages of older cows removed for reproduction, diseases and weaknesses in udders. No major monthly trends were observed in these data, although there was a statistically significant increase in summer sales for dairy purposes with a parallel decrease in beef sales.