Say you spot an animal, probably a recent arrival, looking rough. It appears gaunt and sluggish, is breathing heavily, dragging its feet and maybe even suffering from nasal discharge, diarrhea and or fever. What conditions and treatments are on your radar? Bovine respiratory disease (BRD) is a good guess, but don’t end your list there. Other dangerous conditions also can mimic respiratory symptoms.
Another possibility, which is common among weaning and transitioning cattle, is acidosis. Taking on a high carbohydrate ration too quickly causes an uncomfortable, and potentially lethal, decrease in rumen pH, resulting in lethargy and digestive distress. Cattle try to counteract the acidosis with increased respiration, resulting in labored breathing. It’s not that you haven’t noticed some defining symptom, yet simply looking at the animal won’t tell you this isn’t BRD.
The effects of acidosis can be two-fold in newly arrived cattle. Newly comingled cattle are also at the highest level of exposure to different pathogens causing BRD. The combination of increased exposure to disease-causing pathogens, changing diet and establishing a new social hierarchy all lead to a perfect storm. Having the ability to recognize and address these issues in an operation is vital. While it is tempting to maximize intake for top performers, utilizing optimal nutrition helps reduce the health risk and improve the performance of the whole herd in the long run.
If you jump to treat with antibiotics without testing rumen pH or adjusting the ration, which can easily happen if acidosis hasn’t been an issue before, then you may not find out the true cause of sickness until it’s too late. Losing an animal is bad, but not finding out what went wrong is worse. Doing a necropsy will help bring your attention to the ration, which is the real origin of the issue, and make sure you don’t continue to treat a digestive problem with respiratory medicine. It will also save you confusion about why your antibiotic is suddenly ineffective.
Since acidosis is difficult to distinguish from BRD, the best strategy is a nutrition plan that prevents it in the first place. Some young calves need more time to transition from forage to grains than others. Don’t rush change, even if it’s cheaper or your strategy has always worked in the past. Your veterinarian and nutritionist can help build and adjust your feed schedule to minimize risk. Getting expert feedback and doing some simple things like laying out some grass hay and mineral cubes while your calves need them will help ensure the digestive balance they need to safely move to a high-carb diet.
Investing in a solid nutrition program is about promoting growth performance and immune readiness as much as it is about preventing dietary imbalance. A small tweak to your ration schedule may make your entire health program better. The smoother the transition, the less ambiguity when you spot symptoms that may be BRD.