Hopefully, you can get Tylan 50 injectable at your feed store. Call and ask if they have it in stock. Most antibiotics have been removed from feed stores by the FDA this month. However, you might be able to get 99% Tylosin powder from Jedds.com to put in her water 1 tsp per gallon, or 1/4 tsp per quart for 3-5 days. Here is a link:
https://jedds.com/products/tylosin-powder
https://jedds.com/products/tylosin-powder