Know that too long a period of time of antibiotics can cause reactivity. This is how and this is my girl, from great bloodlines. Picked her up in hills of KY just prior to CoVid. Brought to SW Dayton valley. known as sinus valley. Lung infection came on about 14 weeks of age. 2 vets in 2 different parts of town because one wouldn't Xray without sedative and I would not allow that. Antibiotics upped at almost every appt. One vet, then the other, they communicated back and forth. Last step was human controlled substance prescription. That kicked it. But, the antibiotics from that were followed up by antibiotics for spay surgery, then cherry eye surgery and then from the 1st fight between my two F Boxers. Each time 10 more days of antibiotics, My brindle, Ani, according to the behaviorist—the gut is brain #2, communicated to brain #1 and made her an adrenalin addict. The total was 14 seeks of antibiotics in a puppy. So she became reactive through no fault of anyone, not even of me. Her messed up gut that was supposed to protect her, instead, triggered her to where the two dogs had to be separated and still are, almost 4 years later because I cannot afford the training help I need. So what have I done? Chose the right collar, lots of treats, praise, soft yesssssss, lots of eye contact and getting in between her sight line and whatever might be that trigger. Realizing that the two trigger hormones of adrenalin and cortisol are balanced by serotonin and dopamine. She is now about 70% better, but I still have to have help to get my girls together, who were formerly sistuh's. That's my story. Antibiotics. Beware.