Feeding of concentrates of different origins and protein content to cows
1991
Hunt, Ue. (Estonian Agricultural Univ., Tartu (Estonia))
To study the influence of concentrates of different origins and protein content on milk yield a trial with 11 cows was carried out at Experimental Unit "Raeni". It was divided into three experiment periods (besides pre- and postexperimental periods). All the experimental periods lasted for two weeks. Between the experimental periods there were two overgoing periods each of one week. Rations were calculated at the beginning of the trial and they were not changed until the end of the trial. In each period of the trial different concentrates were fed, metabolizable energy content of the whole ration, however, remained on the same level. On average 8 kg of hay, 20 kg of fodder beets and 4.5...8.1 kg of concentrates of different compositions were fed a cow per day. During the pre- and postexperimental periods the cows were fed on barley meal with 10.7 protein. During the 3 experimental periods the following mixed concentrates were fed: I period - mixed concentrate rich in soybean meal oil(20,0 crude protein), II period- mixed concentrate containing fish meal (21.4 crude protein), III period- barley meal with 2 urea. According to the results of this trial the milk yield of cows can be increased by enrichment of barley meal with urea. However, the effect is more satisfactory when mixed concentrate rich in soybean oil meal or fish meal is fed. The absorption of fish meal protein by cows is somewhat better than that of soybean oil meal. Differences in the content of blood and urine ammonia were observed, there were also differences in the nitrogen content of urine. These changes may be due to various kinds of protein and its level in the ration.
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