Laminitis

Dr. Clell V. Bagley, D.V.M.
USU Extension Veterinarian
Laminitis has a complex etiology. In herds with a high prevalence of laminitis, the primary factors to rule out include subacute ruminal acidosis and excess standing time on concrete. Each of these factors can result from any of a number of management practices, decisions, and accidents. Thorough evaluations of rations, feeds, rumen fluid, feed delivery schedules, cow and heifer facilities and groupings, and milking schedules can identify problems and solutions.

In 1995, we reviewed laminitis as the most consistent clinical sign seen in herds with subacute ruminal acidosis. While I continue to view laminitis as usually associated with ruminal acidosis, we have worked with some “acidosis” problem herds that have little or no laminitis. These have been intensively managed rotational grazing herds where the exposure of cow hooves to concrete is limited to less than 4 hours per day. Ruminal acidosis does not always result in laminitis. If the cows stand and walk on an earthen, cushioned surface, the degree of ruminal acidosis needed to trigger laminitis must be more severe than if the cows have significant exposure to concrete.

Conversely, some “laminitis” problem herds have no signs or history of, and low potential for, subacute or acute ruminal acidosis. However, these herds have had facilities problems that would force cows or heifers to stand on concrete for long priods of time. Generally, we have come to view ‘excess standing time on concrete’ as a factor of equal importance to ruminal acidosis in laminitis problem herds.

Factors that affect standing time on concrete

• Stall availability
• Stall comfort
• Time in holding area and parlor
• Availability of feed
• Access to earthen lots for exercise

Ruminal acidosis risk factors

Ruminal acidosis is a huge risk factor for laminitis for cows in confinement systems. The following items are the primary factors in creating subacute ruminal acidosis:

• Ration formulation errors
• Substitutions of unanalyzed feeds
• High dry matter intake
• Highly digestible corn silage
• High fat content of TMR
• Grain processing and moisture content
• Inadequate particle size
• Excess forage particle size that allows sorting of TMR
• Irregular feeding schedules
• Reduced forage dry matter intake because of failure to monitor changes in moisture content of feeds in TMR
• Inadequate transition from dry cow to lactation ration
• Excess grain in early post-partum phase with component-fed rations
• Competitive feeding systems that put timid animals in a competitive situation for forages
• Excessive interval between concentrate and forage meals.

NOTE: The content of the preceding article was abstracted from: Sore feet, sour rumens, clinical quandaries. Ken Nordlund, DVM, Dip ABVP (Dairy). The AABP Proceedings, Vol. 33, Sept. 2000, pg. 58-64.