Summer somatic cell count blues
by Gabe Middleton, DVM
In much the country, this summer was especially hot and humid. The increase in temperatures led to an increase in bulk tank somatic cell count and cases of clinical mastitis. If you are like most dairy producers, the weather gets blamed and we move on. While there is no doubt that the impact of hot, humid weather is significant, there must be a plan to deal with the newly infected cows as well as a plan to reduce SCC in the tank. Upper echelon producers don’t simply place blame on uncontrollable factors – they establish a plan to solve problems.
As temperatures have started to moderate across much of the U.S., take intentional steps to reduce bulk tank SCC instead of just hoping the counts simply come down on their own.
Clinical mastitis: While culturing clinical mastitis is always a good idea, it’s particularly important during times of increased clinical incidence. The benefits are two-fold. You can get an idea of what organisms are causing mastitis and you can properly treat the clinical cases so they don’t become chronic. Setting up an on-farm culture lab can work quite well if training is properly conducted. Many veterinary clinics also offer their expertise to culture mastitis to yield fast and accurate results. As an example, most gram-negative mastitis does not warrant antibiotic therapy, while gram-positive mastitis cure rates can be positively impacted by antibiotic therapy in most situations.
Chronically infected cows: Cows who are chronically infected over the summer months are typically good candidates to either cull or monitor. Treatment of chronically high SCC is often unrewarding, as the infection has invaded deeper tissue. Work with your vet to develop a plan for these cows. New products are on the market to deal with chronic cows; however, there is not clear evidence that they are consistently effective.
Environmental management: Examine stalls critically to determine where improvements can be made. Sand-bedded stalls can become wet and compacted as urine production increases in summer months as a result of increased water intake. Consider digging out the back of the stalls and replacing with fresh, clean sand. For sand-bedded barns, make an effort to bed more often so cow cleanliness improves. Broken or damaged free-stall loops should be fixed so cows can lie down properly.
Re-evaluate protocols: Make sure your milking procedure is still the most effective at cleaning and stimulating the teat. Post the procedures in the parlor for the employees to see, read and understand. Meet with them periodically to review the protocol and gather feedback. Make sure protocol drift is not occurring. They need to understand the “why” of the milking procedure. Summer is a busy time for many dairies who raise their own crops. Autumn presents an excellent opportunity to take time to resume farm meetings to discuss a continuous improvement plan.
Perform a milking system check: Ask your milking equipment service provider or your vet to check the milking system. There are some tests that should be done dry (pulsators) and some wet/during milking (teat end or mouthpiece chamber vacuum). Critically evaluate the system to make sure function is still optimal.
These discussion topics seem very elementary, but controlling mastitis in the summer is no different than any other time of year. The basic mastitis control measures still need to be followed, along with excellent heat abatement. Own the problem and come up with possible solutions. Simply blaming the weather without evaluating other factors is not proper management. There’s less room for error than ever in the dairy industry. Make positive, common sense changes instead of excuses.