As cell counts continue to decline in herds across the country, use of selective dry cow therapy (SDCT) might be worth considering, says Valeri Ryman, an Extension dairy specialist with the University of Georgia.
The benefits: It can be as effective as treating every dry cow, use of antibiotics can be reduced as much as 21 percent and costs can be reduced as well. “Implementing SCDT can be done but it takes diligence, patience and extreme attention to detail,” says Ryman.
“However, implementation and success of a mastitis prevention and control program that utilizes SDCT is not for the faint of heart.” These are the types of herds who have been successful with it:
• Herds that consistently have a bulk tank somatic cell count (SCC) of less than 200,000 cells/mL.
• Only cows with a SCC of less than 200,000 cells/mL and no signs of clinical mastitis at dry off were considered for SDCT.
• Assessment of infection at dry off in low SCC cows by testing for the presence of bacteria is done routinely, either through culturing or PCR analysis.
• All cows, including those not receiving a dry cow antibiotic treatment, received an internal teat seal sealant.
• Meticulous records were maintained detailing history of infections, causative bacteria and so on.
Here are some additional dos and don’ts for SDCT that Ryman recommends:
• Do enroll in a milk testing program to have a comprehensive SCC history on your cows and to track SCC on fresh cows to ensure SDCT is not failing.
• Do use a teat sealant on every cow, even those not receiving antibiotic therapy. Hygiene and proper technique using partial insertion should be used.
• Do track mastitis pathogens specific to your herd, exploring on-farm culture programs or use of nearby labs.
• Don’t enroll individual cows with SCCs averaging more than 200,000 cells/mL on the last 3 tests.
• Don’t implement SDCT if you are unsure whether you have contagious mastitis pathogens in your herd, such Staph. aureus.
“Ultimately, can you make selective dry cow therapy work? It depends,” says Ryman.