Herds with lactating dairy cattle exceeding fecal phosphorus levels from 0.55 to 0.80% on a dry matter basis have opportunity for improvement. Herds that have implemented precision feeding and removed all inorganic phosphorus can maintain these levels.
http://extension.psu.edu/animals/dairy/nutrition/nutrition-and-feeding
Different cattle feeding production systems have separate advantages and disadvantages. Most cattle have a diet that is composed of at least some forage (grass, legumes, or silage). In fact, most beef cattle are raised on pasture from birth in the spring until autumn (7 to 9 months). Then for pasture-fed animals, grass is the forage that composes all or at least the great majority of their diet.
https://en.wikipedia.org/wiki/Cattle_feeding
All of our feedyard locations purchase and use hay and feedstuffs every day. We purchase all of the following types of feed stuffs year-round: alfalfa hay, corn stalks, forage sorghum, straw, grass hay, corn silage, and milo silage as well. Lane County Feeders and Pioneer Feedyard both purchase and store dry corn. This corn is then flaked and added to our high quality feed to help realize substantial gains. We offer our farmers competitive market pricing for their quality crops.
http://feedcattle.com/
Welcome to Feedcattle.com. FeedCattle.com is an organization of cattle feedyards located in Western Kansas and Southwestern Nebraska. We pride ourselves in doing business with local and area farmers and ranchers. From purchasing calves, high moisture corn, hay and feedstuffs to providing custom feeding services and selling manure, we specialize in helping you increase your profitability.
http://feedcattle.com/
1 Cows will consume between 1.8% and 2% of their body weight on a dry basis of a low quality feed. 2  Cows will consume between 2.0% and 2.2% of their body weight on a dry basis of an average quality feed.
http://www1.agric.gov.ab.ca/%24department/deptdocs.nsf/all/faq7811
Condition scoring your cattle is also a useful management tool, as a thin cow (condition score = 1 or 2) will consume more than a fleshier cow (condition score = 3). Other physiological factors include the sex, age and if the animal is dry or lactating.
http://www1.agric.gov.ab.ca/%24department/deptdocs.nsf/all/faq7811
The debate is whether cattle should be raised on diets primarily composed of pasture (grass) or a concentrated diet of grain, soy, corn and other supplements. The issue is often complicated by the political interests and confusion between labels such as  free range ,  organic , or  natural .
https://en.wikipedia.org/wiki/Cattle_feeding
Dairy nutrition is essentially as simple as understanding the nutrient requirements of dairy cows at various stages of lactation and combining various feed ingredients to meet those needs in a cost-effective manner.
http://extension.psu.edu/animals/dairy/nutrition/nutrition-and-feeding
PDF, 1.7 MB. Proper feeding of the dairy cow is complicated and requires a combination of scientific knowledge, creativity, and good management skills to balance the needs of the rumen microorganisms and the needs of the animal.
http://extension.psu.edu/animals/dairy/nutrition/nutrition-and-feeding
Feeding Low Protein Diets to Dairy Cows. Feeding diets with lowered protein content reduces nitrogen input, improves nitrogen utilization efficiency, and reduces nitrogen losses from manure. Reducing dietary protein also benefits the producer by reducing feed cost and improving overall farm profitability. These interventions, however, have to be balanced with the risk of loss in milk production. If the true animal requirements for metabolizable protein are not met, long-term production cannot be sustained.
http://extension.psu.edu/animals/dairy/nutrition/nutrition-and-feeding
what do you feed cattle?
Feed grass, legumes, or silage to cattle. You feed Grass, Legumes, or Silage to a cattle.