Rams are not bulls, they do not need to scent out ewes in oestrus. Ewes come to the ram and her "hot" behaviour entices him to do the biz. Plunge or shower dipping may affect mob ovulation rate slightly, resulting in 1 or 2% lower scanning rate due to stress.
The biggest danger with plunge and shower dipping in cold temperatures is causing ram infertility by killing off the maturing sperm cells. However his fertility becomes restored after a month to six weeks.
Electro dipping (tip spraying with high concentrated chemical mist) has no affect on either rams or ewes.