When a beef cow stands apart from the herd panting, respiratory disease is the obvious suspect, but the lungs are not always the problem, writes Sandy Stuttgen, a veterinarian and University of Wisconsin-Madison Extension livestock educator, in Farm Progress.

In the case she describes, a producer had recently added out-of-state cattle and, fearing they carried respiratory disease, vaccinated the herd using shared needles. The vet found fever, pale mucous membranes and dehydration alongside the breathing trouble, started long-acting oxytetracycline and sent blood for testing. A packed cell volume test confirmed anaemia, and a smear showed dark inclusions in the red cells — consistent with anaplasmosis, but also with theileriosis. The cow improved but aborted, and a second cow fell ill.

The two diseases both infect red blood cells, cause anaemia and fever, are spread by ticks and biting flies, and leave surviving cattle persistently infected. The absence of ticks rules out neither, because both can pass mechanically through needles and equipment that carry blood between animals, which is why the shared needles matter.

The differences decide the response. Anaplasma marginale is bacterial, occurs in Wisconsin and nationally, and can be managed with oxytetracycline, including feed directives during fly and tick season; a killed experimental vaccine is available through veterinarians in some states. Theileria orientalis Ikeda is a protozoan that does not respond to antibiotics and has no vaccine. It has not been detected in Wisconsin, nor has the Asian longhorned tick that spreads it, but both are reported elsewhere in the United States.

Stuttgen's checklist for producers: do not assume rapid breathing means lung disease; test before making herd-level decisions; test new additions before they join the herd; never share needles and disinfect anything that touches blood; control flies and ticks; and, if one animal is positive, work with the vet to decide how much of the herd to test. "When a sick cow doesn't fit the expected picture," she writes, "don't stop at the first assumption."

Source: Farm Progress