CAJ | 학술논문

为研究日粮中不同比例小麦替代玉米对奶牛氮代谢参数的影响，选择8头泌乳天数为84±17 d，体重为569±47 kg的经产中国荷斯坦奶牛作为试验动物，采用重复4×4拉丁方设计，分别饲喂含不同比例粉碎小麦（ GW）和粉碎玉米（GC）的日粮，4个处理组分别为（DM基础）：W0组（0％GW＋27．9％GC），W9．6组（9．6％GW＋19．2％GC），W19．2组（19．2％GW＋9．6％GC）和W28．8组（28．8％GW＋0％GC）。结果表明：奶牛的产奶量、乳蛋白率和乳蛋白产量未受影响；随着日粮中小麦比例的增加，奶牛的干物质采食量（DMI）呈二次曲线增加趋势（P＝0．07），牛奶尿素氮（MUN）浓度线性增加（P＜0．01），且W28．8组显著高于W0和W19．2组（P＜0．01）；粪氮排出量未受日粮影响，尿氮排出量呈线性增加趋势（P＝0．08）；尿氮（P＝0．02）和总排出氮（粪氮＋尿氮）（P＝0．05）占食入氮的比例呈二次曲线降低；尿素氮产量（P＜0．01）及其占总尿氮的比例（P＝0．03）线性增加，且W19．2和W28．8组的尿素氮产量显著高于（P＝0．01）其他2组；尿中尿囊素（P＝0．05）和总嘌呤（P＝0．09）产量呈线性降低趋势，W9．6组的微生物氮产量显著（P＝0．02）高于W28．8组。结果提示：泌乳盛期奶牛日粮中用9．6％的粉碎小麦替代玉米效果最佳，高比例的小麦替代玉米（ W28．8组）时能够增加尿氮及奶和尿中尿素氮的排出量，降低微生物氮的合成。
위연구일량중불동비례소맥체대옥미대내우담대사삼수적영향，선택8두비유천수위84±17 d，체중위569±47 kg적경산중국하사탄내우작위시험동물，채용중복4×4랍정방설계，분별사위함불동비례분쇄소맥（ GW）화분쇄옥미（GC）적일량，4개처리조분별위（DM기출）：W0조（0％GW＋27．9％GC），W9．6조（9．6％GW＋19．2％GC），W19．2조（19．2％GW＋9．6％GC）화W28．8조（28．8％GW＋0％GC）。결과표명：내우적산내량、유단백솔화유단백산량미수영향；수착일량중소맥비례적증가，내우적간물질채식량（DMI）정이차곡선증가추세（P＝0．07），우내뇨소담（MUN）농도선성증가（P＜0．01），차W28．8조현저고우W0화W19．2조（P＜0．01）；분담배출량미수일량영향，뇨담배출량정선성증가추세（P＝0．08）；뇨담（P＝0．02）화총배출담（분담＋뇨담）（P＝0．05）점식입담적비례정이차곡선강저；뇨소담산량（P＜0．01）급기점총뇨담적비례（P＝0．03）선성증가，차W19．2화W28．8조적뇨소담산량현저고우（P＝0．01）기타2조；뇨중뇨낭소（P＝0．05）화총표령（P＝0．09）산량정선성강저추세，W9．6조적미생물담산량현저（P＝0．02）고우W28．8조。결과제시：비유성기내우일량중용9．6％적분쇄소맥체대옥미효과최가，고비례적소맥체대옥미（ W28．8조）시능구증가뇨담급내화뇨중뇨소담적배출량，강저미생물담적합성。
Eight multiparous Holstein cows ((569 ±47) kg of BW;(84 ±17) DIM),were used in a replicated 4 ×4 Latin square design to evaluate the effects of different levels of ground wheat ( GW ) as replacements for ground corn ( GC) in diets on metabolic parameters of nitrogen in dairy cows .The cows were allocated to the dietary treatments as follows (DM basis):W0 diet:total mixed ration (TMR) containing 0% GW and 27.9%GC;W9.6 diet:TMR containing 9.6%GW and 19.2%GC;W19.2 diet:TMR containing 19.2%GW and 9.6%GC;W28.8 diet:TMR containing 28.8%GW and 0%GC.The results indicated that milk production ,percentage and yield of milk protein not affected by treatments;However ,increasing dietary levels of GW ,DM intake tended to increase qua-dratically (P=0.07),concentration of milk urea nitrogen (MUN) increased linearly (P<0.01),and significantly increased (P<0.01) in cows fed the W28.8 diet compared with the cows fed the W0 and W19.2 diets;Excretion of fecal nitrogen (N) not affected by diets,however,excretion of urinary N increased linearly (P<0.08);as a pro-portion of N intake ,urinary N losses and total ( urinary plus fecal ) N losses tended to decrease quadratically ( P=0.08);urinary urea N loss (P<0.01) and as a proportion of urinary N loss (P=0.03) increased linearly,and urinary urea N loss significantly increased (P=0.01) in cows fed the W19.2 and W28.8 diets,compared with oth-er two diets;Urinary allantoin ( P=0 .05 ) and purines derivatives ( P=0 .09 ) tended to decrease linearly ,microbi-al N synthesis significantly increased (P=0.02) in cows fed the W9.6 diet compared with the cows fed the W28.8 diet .Results from this experiment indicated that 9 .6%of GW substitution for GC appeared to be an appropriate lev-el in diet for early lactation dairy cows ,a great amount of GW (28.8%) in the diets could increase the excretion of urinary N and urea N loss from the milk and urinary ,and decrease microbial N supply .