According to Plumb's Veterinary Drug Handbook, enrofloxacin has at least twice the bioavailability of ciprofloxacin after oral dosing in the dog.

I just went thru a "protocol" with a girl who has had several smaller litters (3-4) as a result of surgical implants. I talked to my regular (breeder) vet and my repro service about suggestions on how to get the numbers up and here's what we did.

A few months before she cycled, we did a guarded culture and found very high levels of e-coli bacteria. We did a 10 day treatment of antibiotic then, it was not Baytril so probably Cipro. When she came into heat I started her on another 7 or 10 (can't remember precisely) day treatment. She did concieve 5 puppies after a surgical.

HOWEVER, when we did all of this, my repo vet said that the probably benefit would be in the case of a natural or AI breeding but not so much a surgical. In a surgical implant the semen doesn't have to "Run the Guantlet" so to speak and would not have been exposed to the e-coli bacteria.

I will say, my repro vet did not recommend the antibiotic treatment without the guarded culture first. Perhaps identifying the bacteria determines which is the better antibiotic.

Hope this helps.