Subclinical laminitis syndrome is associated with the appearance of haemorrhages in the sole and white line (Vermunt 1992). Feeding diets with a high proportion of concentrates to forage has been associated with an increased severity or incidence of sole haemorrhages (Weaver 1979; Livesey and Fleming 1984). It is widely accepted that using high levels of starchy feed ingredients may increase the risk or severity of subclinical laminitis syndrome. This experiment was designed to study the development of subclinical laminitis syndrome by feeding diets which differed in starch and fibre content when animals were bedded on chopped straw or wood shavings.

A total of 40 Holstein heifers were divided into 4 groups in a 2 x 2 factorial experiment. The duration of the study was from shortly before calving until 12 weeks after calving. Heifers were housed in cubicles on rubber mats with either chopped straw or wood shavings as bedding.