After reading what we all wrote on loss of coat I thought this might be useful. Found the info whilest searching the internet. None of it is meant to be alarmist but of general interest.
Demodectic Mange in Cattle
the entire life cycle is completed in 18 to 24 days. Mites from one host will not transfer to a different host species. Some mammals are infected with more than one species of Demodex. signs range from a few small areas of partial hair loss (localized demodicosis) to extensive regions of hair loss (generalized demodicosis).
In most cases, the infestation is mild. Lesions first appear on the head and forelimbs and from there, may spread over the entire body. Nodules may be present.
Chorioptic Mange in Cattle
Egg laying females may live as long as three weeks, adult males up to seven to eight. Infection is spread mainly by direct contact between cattle. However for animals housed in barns, grooming tools may become contaminated and help spread infection. These instruments should be thoroughly disinfected after each use. The mite can live for only a short time off the host, so ground-to-cow contamination is less common. t is thought that those on cattle, horses and sheep are one species, Chorioptes bovis. The mite can potentially be transferred from other domestic animals to cattle. Cattle may show little evidence of skin irritation, but small crusty scabs (approximately 3 mm in diameter) may be seen on the scrotum, udder, feet and thighs.