Trying to summarize DL's info, she is using Bovi Shield 2 shots 2 to 4 weeks apart for her calves 1st shots and is saying that if you think that 2, 7-way colstridial shots are warranted in your part of the country she would shoot also, I personally do shoot 2- 7-way +somus here along with cattle master 4 or 5. Once DL has the initial immunity set up, she boosters 2 times per year with cattle master more than likely with cattle master 5-VL. She is using modified live @ a young age then boostering. I hope this helps you. Like I said previously, you kinda need to know what you want to vaccinate for and understand how the different vaccines work.