Document Type


Report Number

A.S. Series 65-23

Publication Date



The lysine content of corn and barley is relatively low and pigs need a higher level in their ration to meet their daily requirements. Protein sources such as soybean meal are used to provide the necessary amino acids in the ration. Since the protein sources are expensive, the quantity added in a ration is generally just adequate to meet the animal' s requirement. Most amino acids are more than adequate in rations with soybean meal, but lysine is usually on the borderline or the most limiting amino acid. Consequently, there have been many experiments conducted to improve growth rate by adding supplement al lysine in the ration. Previous research at this station (A.S. Mimeo Series 63-7) indicated better pig performance when lysine was added to the ration. However, the small improvement in feed efficiency did not offset the additional cost of the lysine. Lysine has been use d in experimental tests to supplement low protein rations, but this approach has not been economical either. The situation is somewhat similar, yet different too, with barley. Some feeders claim their barley is testing 13 to 15 percent crude protein. Finishing pigs require only 12 per cent crude protein in their diet providing the essential amino acids are adequate. Barley fed to finishing pigs without a rich protein feed would be adequate in a few essential amino acids, borderline with histidine, isoleucine, and threonine, but low with methionine, tryptophan and especially lysine. Therefore, some protein source should be fed with the high protein barley. The North Dakota Experiment Station showed that several protein feeds can be used with barley and the percent of these feeds in the ration can be low. The objectives of the following experiments were: (1) to study the influence of supplemental lysine in the water for both good and poor quality protein rations and (2) to study the influence of supplemental lysine in feed or water for barley rations fed in both meal and pelleted form.

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Agricultural Experiment Station, South Dakota State College