The effect of selected cereals contained in feed ration on the amino acid composition of cows' milk

The aim of this study was to evaluate the possible effects of maize replacement in feeding rations on the amino acid content in cows' milk. Czech Pied cows were fed a total mix ration based on maize, clover silage and hay. There was a difference in the concentrate of the feeding ration. The first group (fed maize) was the control group, another two groups were experimental, one fed wheat and second fed triticale. During six weeks, 26 milk samples were taken from the cows. The groups were balanced in terms of milk yield, stage and number of lactations. The samples of feedstuffs as well as milk were modified for the analysis using acidic and oxidative hydrolyses. The analyses of amino acids content and composition of the sample hydrolysates were performed chromatographically by an AAA 400 analyzer using Na-citrate buffers and ninhydrin detection. Total nitrogen content was determined according to Kjehldahl and the crude protein of the samples was determined by conversion from the nitrogen content multiplied by the appropriate factor. The high content of crude protein in wheat did not influence the composition of milk from dairy cows fed this type of feedstuff. With respect to resulting amino acid content and composition of milk samples, none of the tested grains can be recommended as a full-value maize replacement. Each feedstuff is an abundant source of several and typical amino acids in milk. However, triticale (cultivar Kitaro) seems to be an acceptable replacement of maize owing to better crude protein efficiency, composition and health indicators of milk quality.