Signs of neurotoxicity in a Belgian Blue herd after ingestion of moulded silage

After ingestion of moulded beet pulp silage, cases of cerebro-cortical necrosis (CCN) and
mortalities were observed in a dual purpose Belgian Blue (BB) herd. Contamination with
Paecilomyces spp., a mould that produces byssochlamic acid, malformins and patulin, was
proven.
Twenty-five days after progressive introduction of beet pulp silage into the ration, most of the
animals showed diminished appetite, excessive salivation and decreased milk production.
Some of them showed anorexia, head pressing and blindness while 4 animals died within 1
week after onset of neurological symptoms. The survivors had been treated successfully with
thiamine and recovered completely within five days. Once the beet pulp silage had been
identified as causative agent, it was removed from the animals’ ration and no more clinical
cases were observed.
Silage was obviously moulded and analysis revealed the presence of 1.6 million CFU
Paecilomyces spp./g of silage. Although no further investigation was undertaken to identify
the mycotoxins, intoxication with patulin was suspected, since other mycotoxins produced by
these species are less toxic. Although it has not been described that CCN can be induced by
ingestion of Paecilomyces spp., it seems that there is a close relation between ingestion of
Paecilomyces-contaminated silage and clinical signs observed in this herd.