Longevity

Abstract

Investigations of culling and particularly involuntary culling (“functional” longevity) have often used different criteria on herds of varying size in different regions and with divergent average milk outputs (Young, Waddington, Sales, Bradley and Spooner, 1983; Esslemont and Kossaibati, 1997; Forbes, Gayton and McGeogh, 1999; Whitaker Kelly and Smith, 2000; Figure 1). Thus the evidence of increasing or decreasing culling for any particular entity is uncertain.