Opal phytoliths and mineral particles in the rumen of the sheep

Examinations of various plant feeds and the contents of the rumen of sheep have revealed the presence of opal phytoliths both free and in situ in the plant tissues. Opal phytoliths make up much the greater proportion of the total particulate mineral matter in both the feeds and the rumen contents but adventitious particles of minerals and other inorganic or metallic fragments have been detected. All these particles have a higher specific gravity than plant feed and so tend to gravitate to the ventral regions of the rumen. Observations on the rumeri walls of sheep suggest that opal phytoliths and other mineral particles may affect the depth of the strata corneum and granulosum.