Discussion
The udder health data from this trial did not reveal any
significant difference between calves fed with heat-treated
and untreated mastitis milk. Results from the suckling
period, however, indicated that calves fed with unheated
mastitis milk suffered more diarrhoea days than calves
receiving milk after heat treatment.
Blinding was not possible in this study as the same
person prepared the milk and took care of the animals.
Housing at the experimental unit was designed to separate the two groups from each other in order to prohibit
microbial carryover on calves of the other group.
As we collected the milk sample from each heifer
immediately after calving, it seems reasonable to rule
out that the pathogens ingested during the suckling
period might cause mastitis. Intramammary S. aureus
infection discovered later might much more likely have
been acquired via alternative infection pathways, for
example during the milking process or by cow to cow
transmission [36]. We intended to exclude these two
factors with the chosen study design. In addition, there
is evidence from the literature that the majority of intramammary infections occur at the beginning of the lactation [13]. Even subclinical cases should have been