1. Official Methods of Analysis,1990
2. ASABE (American Society of Agricultural and Biological Engineers). 2007. Method of determining and expressing particle size of chopped forage materials by screening. ANSI/ASAE. S424. 1:663–665. ASABE, St. Joseph, MI.
3. Ingestion and mastication of feed by dairy cattle;Beauchemin;Vet. Clin. North Am. Food Anim. Pract.,1991
4. Sterotypies as animal welfare indicatorsCurr. Top. Vet. Med. Anim. Sci. Vol. 23. D. Smidt Indicators Relevant to Farm Animal Welfare;Broom,1983
5. The Ruminant Animal Digestive Physiology and Nutrition;Church,1988