Cattle are capable of digesting cellulose present in the grass and/or fodder that they eat. This ability is attributed to the

Cattle and other ruminants are unable to produce cellulose-degrading enzymes themselves because vertebrates lost this ability during evolution [t6]. Instead, they rely on a symbiotic relationship with a diverse microbial population in the rumen, which acts as a fermentation vat [t3, t4]. This microbial community consists of anaerobic bacteria, protozoa, and fungi that produce the necessary enzymes (cellulases) to hydrolyze complex plant polymers like cellulose and hemicellulose [t1, t2]. Specifically, cellulolytic bacteria adhere to the surface of plant fibers to facilitate rapid degradation [t1, t5]. While the rumen provides a favorable environment with specific physicochemical properties like temperature and pH, it is the presence of these specialized microorganisms that allows the conversion of recalcitrant biomass into volatile fatty acids (VFAs), which serve as the primary energy source for the host animal [t3, t7].

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC9785684/