News last update:7 Aug 2012

How to recognize heat stress in dairy cows

Symptoms of heat stress in dairy cows range from decreased milk production and reproductive performance to increased incidence of lameness.

According to Dr. Dana Tomlinson, Dairy Research Nutritionist, Zinpro Corporation, nutrition and cow comfort factors play significant roles in reducing this problem. 

Clinical symptoms include:   
- Effect of season on somatic cell count (SCC): Summer heat appears to impact SCC. Research from the USDA found that SCC varied by season, with SCC levels being highest in summer and lowest in winter.
- Ruminal response to heat stress: Research indicates that cows exposed to heat stress conditions have lower rumen pH, predisposing cows to acidosis and claw lesions.
- Hoof trimming: Research shows that lameness incidence peaks at the end of summer. Routine hoof trimming is essential for minimizing the incidence of lameness caused by heat stress.
- Role of trace minerals: Supplementing highly bioavailable forms of zinc, manganese and copper (Zinpro Performance Minerals®) have been shown to decrease the severity of claw lesions. These trace minerals also play a key role in maintaining claw integrity.

Locomotion scoring
If your dairy operation is experiencing high incidence of claw horn lesions following the summer heat, Tomlinson recommends using locomotion scoring as an effective means of monitoring for the prevalence of lameness. "The system helps identify individual cows for functional hoof trimming, while comparing the incidence and severity of lameness between groups or herds," he notes.

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Editor AllAboutFeed

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