Neurodegenerative diseases occur spontaneously in other domestic animals, especially in cats (Chambers et al., 2015), although brain pathology in these other species is much less studied. In the hippocampi of naturally aged domestic cats, Aβ accumulation, NFTs formation and neuronal loss were observed (Chambers et al., 2015) and this might contribute to cognitive decline in this species, although this has not yet been firmly established. Cognitive deficit may occur in the horse, as clinical signs similar to cognitive impairment have been observed, but no detailed studies focusing on age-related neurologic aberrances have been conducted so far. In one study, TAU protein was shown to be present in equine hippocampal neurons, but no NFTs were detected (Capucchio et al., 2010). Some horses develop equine motor neuron disease, but none have been associated with pathological accumulation of dementia related proteins (El-Assaad et al., 2012; Youssef et al., 2016). Interestingly, a recent study negated the belief that abnormally behaving stereotypic horses (Equus caballus) are cognitively impaired (Briefer Freymond et al., 2018).