사료중 질소원 및 유황첨가에 따르는 조기 이유 송아지의 성장에 미치는 영향 = The Effect of Dietary Source of Nitrogen and Sulfur Intake on the Performance of the Early Weaned Calves

다국어 초록 (Multilingual Abstract)

Diets containing 21, 18, 15, and 12 per cent crude protein were fed to 56 early weaned male, Friesian calves between 5 and 12 weeks of age. There were three sources of supplementary nitrogen: meat meal, soy bean oil meal and urea, and two levels of sulfur in the diets. There were no statistical differences in the liveweight gains of the feed conversion ratio between the major treatments of protein level, protein source and sulfur supplementation. However, the feed conversion ratio showed a significant interaction between sulfur supplementation and protein levels so that the calves fed the sulfur supplemented diets required more feed per ㎏ of weight gain at the lowest dietary protein level (12 per cent crude protein). There was a trend towards lower weight gains and poorer efficiency of feed conversion in the calves fed the diets containing 12 per cent crude protein, and this was significant at the 10 per cent level of probability. There was a clear respond that the concentration of urea nitrogen in the blood plasma increased as the dietary crude protein level increased from 12 to 21 per cent. Although, no effect of sulfur supplementation was shown at either stage 1 or 2 (after weaning and 11-week age), replacing the dietary nitrogen by urea-N at about 29 per cent resulted in an increase in the concentration of urea nitrogen in the plasma of the calves.