The effect of feeding urea and stilbestrol on ration digestibility and on calcium, phosphorus and nitrogen retention in lambs

Considerable information may be derived through the use of digestion and balance studies in determining the utilization of feed nutrients by livestock. Microorganisms found in the gastrointestinal tract of ruminants do a large part of the digestion, which results in the production of various nutrients that are necessary for the proper growth of the body. As an example, urea nitrogen may be broken down by these bacteria to be used to produce some of the essential amino acids for body growth.

For a number of years, organic forms of nitrogen have been substituted for a part of the protein requirements for ruminants, Comercial urea, which contains nitrogen equivalent to 262 percent crude protein, is the common form of organic nitrogen fed to livestock. Many experiments have been conducted to study the feeding value and use of urea as a protein substitute.

Recently, considerable work has been devoted to study the value of stilbestrol for fattening farm livestock. Stilbestrol is a synthetic chemical compound with estrogenic properties which has been shown to have some effect on rate of gain, feed efficiency and carcass quality with some classes of livestock. There is very little information regarding the metabolic action of this compound and its effect on urea utilization.

This investigation was conducted to determine the effect that stilbestrol had when added to the rations of chewed grass hay plus either corn and cottonseed meal or corn and urea. Digestion and balance studies were made to determine the percentage of digestibility of feed nutrients and to determine the amount of calcium, phosphorus and nitrogen that was retained by the lambs fed various rations.