SOLE HAEMORRHAGES IN DAIRY HEIFERS MANAGED UNDER DIFFERENT UNDERFOOT AND ENVIRONMENTAL CONDITIONS

摘要

Sole haemorrhages associated with laminitis were studied in 30 Holstein heifers in one herd housed either indoors on concrete or out of doors on a dry lot. Examinations were at 4-week intervals during a 15-month period from approximately 13 months of age to 2 months after calving. At 13 months of age, sole haemorrhages were present in 77% of the heifers. Five heifers, affected by clinical laminitis shortly after calving, developed early sole ulcers. Indoor-housed heifers had a greater number of and more severe haemorrhages than heifers managed in dry lots (P<0.001). In both groups, hind claws were more affected than front claws (P<0.001). Lateral claws were more affected in hind limbs (P<0.001), whereas medial claws had more sole haemorrhages in front limbs (P<0.01). Heifers managed in dry lots had more sole haemorrhages in right claws than in left claws (P<0.01). The number and severity of haemorrhages differed among the six zones of the sole (P<0.001). Overall, the abaxial white zone (zone 2) had the greatest number of haemorrhages, followed by the white zone at the toe (zone 0), the bulb (zone 5) and the sole-bulb junction (zone 4), respectively. Few haemorrhages occurred in the apex of the sole (zone 1) and the axial groove (zone 3). Zone 0 was more severely affected in heifers managed in dry lots (P<0.001), whereas zones 2, 1 and 5 had greater numbers of haemorrhages in heifers housed indoors (P<0.01). Time had no effect on total haemorrhages scores, but the effect of management was significant for zones 0 and 5. Total haemorrhage scores for zone 0 were greater in heifers managed in dry lots (P<0.05), whereas zone 5 was more affected in indoor-housed heifers (P<0.01). This study shows that sole haemorrhages do occur in the claws of daily heifers managed either indoors or in dry lots, and permanent damage to the claws of these young cattle may already have occurred before they reach maturity.