CANADIAN DAIRY COW DISPOSALS: II. EFFECT OF HERD SIZE AND PRODUCTION LEVEL ON DAIRY COW DISPOSAL PATTERNS

Abstract

The data were taken from 2,534 Holstein herds on Record of Performance (R.O.P.) for milk. Herd size was determined from the average inventory of cows on July 1, 1967 and July 1, 1968. Herd production was obtained for cows with records from March 1, 1967 to February 29, 1968. The cows disposed of from September 1, 1967 to August 31, 1968 were recorded in three main sections: (1) cows sold for beef, (2) cows sold for dairy purposes, and (3) cows that died in the herd. Section 1 was divided into four subsections: cows sold due to breeding or calving problems, low production, unsatisfactory type, and other reasons. Herds were categorized as constant, increasing, or decreasing in size. Within each size grouping and disposal reason, multiple regression analyses were completed for percent of cows disposed of in relation to herd size and production level. In herds of constant size, production level increases were associated with increases in total percent of cows disposed of (P < 0.01), increases in percent sold for breeding purposes (P < 0.01) and increases in percent sold for beef because of poor type (P < 0.01). There was also a decrease (P < 0.05) in percent sold for beef due to low production as the production level increased. Herd size had no effect on cow disposals.