Treatment with injectible oxytetracycline (LA 200/300) WILL NOT 'clear' the infection. You cannot get enough oxytet in a cow, without replacing blood volume with it, to clear the organism.
We used to think that we could clear with two injections, or that animals that survived would clear the infection on their own. We now know that that is NOT the case... it was just that the serologic test we had for the disease was so poor that we 'missed' a large number of the infected animals ... it worked OK on clinically-affected cattle, but missed those persistently-infected 'carrier' cows.
Farmgirl's relatives should be on the lookout for additional cases... the LA will only suppress replication of the Anaplasma organism... if any of those treated animals were early in the incubation phase of the disease, once the antibiotics are depleted, the organism will pick back up right where it left off, and they may have clinical cases and death loses 3-6 weeks or so down the road.
If they treated every animal, they still need to feed (at minimum) a medicated mineral for the remainder of the fly season - but be aware that they're only controlling clinical disease... animals may still become infected, and some may not get enough CTC to prevent developing clinical disease... and any that survive &/or are infected, will be persistently infected for LIFE, and can continue to serve as a source of infection for any naive animals in the herd (or the neighbor's herd across the fence).
CTC can be fed at a high level (4X the approved level in medicated mineral) for 60-80 days and clear most(but perhaps not all) animals... but those 'cleared' animals are subject to reinfection and developing clinical disease (and death) once again. High level feeding is 'extra-label drug use', and may not even be allowed under the current VFD regulations.
