August 15, 2007

Zinpro outlines stress symptoms in dairy cows

Heat stress in dairy cows can be determined from decreased milk production and reproductive performance to increased incidence of lameness, according to US animal pharmaceutical firm Zinpro Corporation.

Zinpro's dairy research nutritionist Dr Dana Tomlinson said nutrition and cow comfort factors play significant roles in reducing this problem.

She outlined several clinical symptoms which 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 (acidity), 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.

If there is a high incidence of claw horn lesions due to summer heat, Tomlinson recommends using locomotion scoring as an effective means of monitoring for the prevalence of lameness. She said this system helps identify individual cows for functional hoof trimming, while comparing the incidence and severity of lameness between groups or herds.