Anaplasmosis now hits year-round

Anaplasmosis is usually thought of as a late summer and early fall problem in the Midwest, but more and more it is causing problems year around. Dave Sparks D.V.M., Area Extension Food animal Quality and Health Specialist for Oklahoma State University offers the following advice.

It's caused by a tiny parasitic organism called Anaplasma marginale that invades the red blood cells. The animal's immune system tries to deal with the problem, but in destroying the organism the red cells are also destroyed. This results in a series of symptoms associated with anemia and the characteristic yellow or orange coloration of the body tissues, which comes from pigments released as the red cells are broken down.

Anaplasmosis is not contagious, spreading directly from one animal to the other; however, it can be transmitted by both biological and mechanical vectors. The main biological vectors are ticks while mechanical vectors include biting insects and various working instruments, such as needles, dehorners, knives, ear taggers, and implant guns. Biological vectors can carry the infection for months, while mechanical vectors can only transfer the organisms for less than five minutes.

During an outbreak, most infected animals are identified by clinical signs including weight loss, depressed lactation, hard green feces, dark yellow urine, high fever, and respiratory distress.

Recovered animals are carriers for life, unless they receive specific treatment to remove the remnants of the infection. Recovered animals can show signs of active disease a second time, but it is extremely rare.

Although total elimination of vectors is not practical, there are things you can do to help. Both biological and mechanical insect vectors can be managed with insecticides and proper disinfection of instruments while processing cattle should be standard practice. In addition, keeping brush and high weeds down in pastures can reduce the habitat of ticks.

Carriers can be eliminated by feeding or injecting high levels of tetracyclines over a period of time. This is not effective on all animals so it may also be necessary to serum test the herd and cull any carriers that remain.

Vaccination is limited at this time and vaccines of the past caused problems with newborn calves. Vaccination doesn't eliminate the infection, but helps to minimize clinical signs. Perhaps a better control measure is to feed low levels of chlortetracycline in the mineral. In the past, many producers have used this method during the insect vector season, but it may very well pay to consider this as a year round option. When fed on a year round basis lower levels of the drug can be utilized and it is helpful in preventing other problems such as footrot and pinkeye. Visit with your veterinarian for specific recommendations and protocols effective to prevent infections or to eliminate the carrier stage.

Anaplasmosis is one of the major problems facing cow-calf producers, but it doesn't have to be devastating. In the winter most producers see their cows daily but in the summer and fall when not feeding daily, it is easy to get involved with haying, farming, back to school, or other activities. Check your cows regularly so that you are aware of the first case, before she contaminates a large portion of the herd.