Epidemiology of Lameness in Cattle

Estimates of the prevalence of lameness and associated risk factors in dairy cattle vary with production system (pasture based or indoor housing), housing system (free stall, tie stall, or bedded packs), milking system (conventional or robotic), and lying surface (eg, sand bedding, mattresses, waterbeds, access to outdoor areas), among other factors. Typical estimates from research studies range from a low of 8% in pasture-based systems to a high of 55% in indoor-housing systems. Incidence estimates for lameness are scarce and typically unreliable, because of inconsistencies in recording and the expense of collecting this type of data in research studies.

Like many other multifactorial conditions, numerous risk factors for lameness from indoor-housing and pasture-based systems have been reported in the scientific literature, including environmental, management, and individual-cow factors and their combinations. Common risk factors include the following:

• Environmental factors: stall features, flooring surface, feed alley dimensions, and amount of rainfall (for cows on pasture)

• Managerial factors: stocking density, handling practices along the tracks or alleys, prolonged time spent standing while waiting to be milked, timing of treatment relative to lameness diagnosis, access to outdoor areas for cows housed indoors, hoof-trimming practices, and hygiene

• Individual cow factors: low and rapid loss of body condition; history of lameness events; breed; parity; and extreme behavioral, metabolic, or conformational changes

Lameness is a concern in all sectors of the beef cattle industry, including cow-calf operations, backgrounding, finishing feedlots, and processing plants. Reports from western Canada rank lameness as the second most treated condition in feedlot cattle, after respiratory disease. Despite increased awareness of its importance and impact, lameness in beef cattle has not been a focus of research in the industry in the same way it has for dairy cattle, nor have standards been developed at the industry level for beef cattle as intensively as they have for dairy cattle.

According to reports from the analysis of health records in the US and Canada, lameness accounts for 16%–40% of feedlot health problems and 3%–11% of feedlot mortality, and is detected in 5%–30% of animals at the time of slaughter. As in dairy cattle, prevalence estimates for lameness among beef cattle in the feedlot sector vary widely, ranging from 5% to 17%. Worldwide, prevalence estimates in the cow-calf sector are scarce and range from 0% to 43%. Similarly, estimates for the incidence of lameness are scarce, with one estimate placing the incidence rate at about 1 case per 100 animal-years.

Prevalence and incidence of lameness in feedlot cattle are affected by season, the source of cattle, the design and maintenance of facilities and pens, and other stressors, such as cattle handling, pre-arrival management, transportation, commingling, feed bunk management, and abrupt changes in feed. Individual risk factors associated with lameness include health status, immunity, hoof integrity, feeding behavior, cattle temperament, presence of bovine respiratory disease, and foot and leg conformation.

In dairy cattle, the great majority (80%–90%) of causes of lameness involve hoof lesions; however, hoof lesions do not necessarily result in clinical signs of lameness. In general, the most common infectious hoof lesions are digital dermatitis, foot rot, and heel horn erosion, and the most common noninfectious hoof lesions are sole ulcers, sole hemorrhages, white line disease, and toe ulcers. However, the type, frequency, and distribution of hoof lesions vary widely across countries, dairy systems, and housing. For example, in indoor-housing systems, 25%–80% of cows have at least one hoof lesion. Typically, the most prevalent hoof lesion is digital dermatitis, followed by sole ulcers, white line disease, hemorrhages, foot rot, and toe ulcers. In pasture-based systems, the range reported across the available literature is even greater, with 3%–97% of cows having at least one hoof lesion. The most common hoof lesions are white line disease, sole lesions (including hemorrhages, thin sole, and traumatic or foreign body penetration), heel erosion, and digital dermatitis.

Each type of hoof lesion differs in the pain it causes, associated welfare and economic implications, risk of recurrence, pathophysiology, and predisposing factors. Details about each type of hoof lesion are provided in Lameness Originating in the Hoof in Cattle.

In general, infectious hoof lesions are multifactorial. Environment- and management-related risk factors include unhygienic, muddy, and wet conditions; seasonality; lax internal biosecurity practices (eg, during manure handling, rearing, and dry-period management); lax external biosecurity practices (eg, during the purchasing of cattle or purchasing and maintenance of vehicles, equipment, and supplies); foot-bathing management; and youngstock management. Infectious hoof lesions are also associated with individual-cow factors, such as skin integrity, host susceptibility, and parity.

Noninfectious hoof lesions involve risk factors that might affect the internal and external integrity of the hoof, specifically of the corium, third phalanx, digital cushion, suspensory apparatus, and horn. For instance, environment- and management-related risk factors that might result in trauma or prolonged time spent standing may affect the risk of noninfectious lesion development. These factors include the comfort, design, and condition of lying and walking surfaces; stocking density; heat stress; time spent standing while waiting to be milked; and cattle-handling practices. Individual factors that might affect the structure and function of the hoof include stage of lactation, parity, size and balance of the hoof, appropriateness of hoof trimming, incidence of previous lameness, body condition, and thickness of digital cushion, along with behavioral, inflammatory, metabolic, and hormonal changes during the transition period that may affect the supportive soft tissue structures in the hoof.

Reports from the analysis of health records in North American feedlot cattle show that ~70%–75% of causes of lameness originate in the foot, and 25%–30% involve the upper leg, joints, and swollen sites of injection. Of all cattle diagnosed as lame by feedlot personnel, the most common causes of lameness involved upper-leg lameness, joint sepsis or deep digital sepsis, foot rot, injury, and sole lesions (including sole ulcers and abscesses, or toe ulcers and abscesses). Gender, age, season of placement in the feedlot, and bovine respiratory disease status have been identified as risk factors associated with the main causes of lameness. Data on hoof lesions in cow-calf operations are limited. In studies of European cow-calf operations, the most common hoof lesions were heel horn erosion, white line disease, sole hemorrhages, and horn wall fissures, with age and breed identified as risk factors.