Featured in our 2019 Winter issue, written By Todd Bilby, Ph.D., M.S., Associate Director of Ruminant Technical Services, Merck Animal Health.
Outstanding milk quality herds, regardless of size, have several things in common. To keep somatic cell count (SCC) low, they follow detailed protocols and make it a goal to assure all employees understand the importance of working together every day to maximize milk quality. Developing a protocol to monitor for mastitis, successfully treating infections and managing a cow’s environment play a role.
FINE-TUNE MASTITIS MONITORING
Lactating cows with subclinical mastitis may show no clinical signs or visual changes in the milk for weeks but have SCCs greater than 200,000 cells per milliliter. Monthly Dairy Herd Improvement (DHI) testing provides dairies with the ability to track trends in milk production and investigate changes so issues can be addressed. DHI reports also identify cows with higher-than-desirable SCCs as well as cows that have been chronically infected, making it simpler to identify individual cows for further testing. One of the best ways to detect mastitis is by implementing a test/culture system (e.g., California Mastitis Test [CMT]), which is a measure of the inflammation within a quarter. When done early, CMT can help identify infection before it impacts performance and milk quality.
CULTURE MILK TO TARGET TREATMENT
After individual cows have been identified, the only way to know what pathogens are impacting milk quality is to culture milk samples. You can work with your vet clinic to run cultures or train someone on your dairy on on-farm culture testing and interpreting results. Culture tests are relatively inexpensive, assure the correct animals are treated and help reduce unneeded antibiotic use. Positive test results identify mastitis as contagious or environmental. Contagious infections spread between cows and reveal the presence of gram-positive pathogens, such as those in the streptococcus and staphylococcus families. Environmental pathogens come from sources such as bedding and reveal gram-negative bacteria are present, such as E. coli. Cows often fight off gram-negative infections without intervention, but without treatment, gram-positive infections can become chronic and need immediate attention.
ENSURE TREATMENT SUCCESS
Once mastitis is detected in lactating cows, deploying an effective cure is critical. Using an intramammary antibiotic like Amoxi-Mast® effectively treats mastitis quickly and limits the circulation of infections in the herd. With an 86% cure rate for Streptococcus agalactiae1 and an economical 60-hour milk withhold, this product with short-tip tubes is proven to yield higher cure rates and fewer new infections.2
Milk taken from animals during treatment and for 60 hours after the last treatment must not be used for food. Treated animals must not be slaughtered for food purposes within 12 days after the last treatment. For complete information, refer to the product label. Monitoring treatment success assures the protocol is working and results in a lower relapse rate. Follow through on all treatments even if milk quality improves after one treatment.
CONTROLLING ENVIRONMENTAL INFECTIONS
If milk culture results reveal gram-negative pathogens are present, then a thorough review of management practices is necessary. The goal is to create an environment in which it is hard for these organisms to survive.
Train employees on the importance of keeping cows and their bedding clean and dry, as well as keeping milking equipment running and cleaned properly. Milk contagious cows last and move infected cows to a different area to reduce the spread of contagious organisms.
Make sure the teat dip is effective against the organism you are combating and that employees have been trained on proper teat coverage. Since milk film harbors bacteria, make sure employees understand the importance of removing milk film from the teat before milking.
Lower SCCs are important to your dairy’s success. Benefits include increased milk production, improved reproductive performance and longer milk shelf life. By monitoring milk quality, identifying the pathogens that are causing mastitis and appropriately treating clinical cases, you’ll keep your dairy running smoothly.
Talk with your veterinarian to develop a plan that achieves the goal of high-quality milk production on your farm.
1. Wilson, DJ et al. Comparison of seven antibiotic treatments with no treatment for bacteriological efficacy against bovine mastitis pathogens. J Dairy Sci 1999; 82:1664-1670.
2. Boddie, RL and SC Nickerson. Dry cow therapy: Effects of method of drug administration on occurrence of intramammary infection. J Dairy Sci 1986:69-253-257.
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