John Doerr, Ph.D., PAS, Dpl. ACAP
Vice President, Science and Technology
Perhaps you saw it. Dairy Herd Daily (April 20, 2020) ran an article on the rise of Salmonella dublin on mid-west dairy farms. Now, still in the midst of collateral damage to dairies from COVID-19 (milk-dumping), many are prompted to feed back dump-milk to their herds to reduce feeding costs. I am neither a Salmonella expert (if you wish to know more about S. dublin, check out: Salmonella Dublin in dairy calves by Angel Abuelo, Michigan State Univ. Large Animal Clinical Sci. and Faith Cullens, Michigan State Univ. Extension) nor a professional purveyor of feeding/nutrition of cows advice. But, the report seemed like a good opportunity to remind you of the tools you have available to mitigate this bacterium’s assault on your herds, whether dairy or beef.
S. dublin is a bit more insidious than other Salmonella species in that as a host-adapted organism it knows its way around dairy cows and can do much more than the typical intestinal problems associated with other salmonellae. S. dublin has risen from a rarity 20 years ago to the predominant species isolated from dairy animals. It is insidious because apart from intestinal disorders, it produces respiratory disease and even joint issues in affected animals. What’s more, it can live almost dormant in lymph nodes and periodically become active; cows with this feature are carriers and can spread the bacterium to others in the herd through contact, feces, milk, etc., and diagnosis can be tricky. Incidentally, since it can be passed through milk, dumped milk should be pasteurized or acidified before feeding to calves or cows.
The means of combating S. dublin are several. It is possible to obtain bacterins (antibiotic proteins produced by other bacteria), antibiotics, and, also, vaccines. The latter are probably a good choice in the growing calf and adult cow. But what about that new-born calf? It is nursing and living in an environment that may be rife with S. dublin, and its immune system is not able to handle a vaccine yet. But go look on your shelf. You probably have some Convert™ Day-One Calf Gel and Convert™ Ranch Pak. Among the constituents of this product line are bovine-specific antibodies against several important bacteria and a few viruses. And, yes, one of those antibodies is developed against S. dublin (good news! It also cross-reacts with S. newport). And that’s important because when the gel is given early enough after calving, a portion of those antibodies do get into the circulation and provide additional internal protection while the rest remain in the GI tract and tackle those S. dublin bugs just coming into the system. The Ranch Pak, when used for the next 21 days as recommended, keeps that gut protection going while the calf is developing its adaptive immune capacity and can begin taking over responsibility for self-protection! Convert, then, is the stop-gap that completes the range of armaments against pathogens such as S. dublin in those weeks post-partum when the calf is most vulnerable. Keep your calves alert, active, with good appetite, and free of scours while helping to slow the spread of this cattle challenge. What’s even better is that Convert is on a special in September. Buy 5, Get 1 Free on Multi-dose tubes and Buy 16, Get 2 Free on Single-dose tubes. Don’t wait. Contact your Select Sires or Agrarian Solutions representative and double down!