Anybody any info on equine mastitis. mare is due to foal mis July.?

My mare has developed chronic mastitis and as she is pregnant l am reluctant to ust antibiotics due to her losing a previous foal at only days old. Has anybody any ideas on natural, herbal remidies which may help without harming the baby. Mum doesnt appear to be in any discomfort although being the type of mare she is , she is always happy and easy going.