乳中尿素態窒素と乳蛋白質率による泌乳牛の栄養診断
生田健太郎 小鴨 睦 篠倉和己 凾城悦司
| 兵庫県立淡路農業技術センター（〒656-0402 兵庫県三原郡三原町八木養宜中560-1） |
（1999年6月21日受付・1999年11月17日受理）
要 約
| 泌乳牛32頭を供試し，飼料給与状況と乳中尿素態窒素（MUN）および乳蛋白質率との関係を月1回調査し，適正給与状態にある個体のMUNと乳蛋白質率から栄養診断のための指標値を設定した．MUNは給与飼料乾物中の粗蛋白質（CP）含量および可消化養分（TDN）含量とは有意な正の相関，TDN充足率とTDN/CP比とは有意な負の相関を示した．一方，乳蛋白質率は，これらの項目との間にMUNとは逆の相関が認められた．MUNと乳蛋白質率は飼料給与状況と密接に関連しており，栄養診断に利用できると判断された．その指標値は，泌乳前期（分娩後100日以下）ではMUNが8.6〜19.2mg/dl，乳蛋白質率が2.80〜3.31％，中期（101〜200日）ではそれぞれ8.6〜16.7mg/dl，3.09〜3.53％，後期（201日以上）では6.1〜12.5mg/dl，3.35〜3.91％となった． ―キーワード：乳牛，乳蛋白質率，乳中尿素態窒素，栄養診断．
--------------------日獣会誌 53，289〜292（2000）
Evaluation of Nutritional Condition on the Basis of Milk Urea Nitrogen and Milk Protein Concentrations in Dairy CowsKentaro IKUTA, Mutsumu KOKAMO, Kazumi SASAKURA and Etsuji HAKOGI
SUMMARY This investigation was conducted to evaluate nutritional condition in 32 dairy cows by
using milk urea nitrogen (MUN) and milk protein concentrations as indicators. Relationships between MUN,
milk protein concentrations and feeding condition were investigated at monthly intervals. MUN was positively
associated with crude protein (CP)% and total digestible nutrients (TDN)% in dry matter and negatively
associated with TDN sufficiency and the TDN/CP ratio. Milk protein concentration was inversely related
to the same items. As MUN and milk protein concentrations are closely related to feeding condition, it
is concluded that they are useful for evaluating nutritional condition. Ranges for normal MUN concentration
in each lactation stage are as follows: early stage (1〜100 days after parturition) 8.6〜19.2 mg/dl, mid
stage (101〜200 days after parturition) 8.6〜16.7 mg/dl, and late stage (over 201 days after parturition)
6.1〜12.5 mg/dl. The corresponding ranges for milk protein concentration are as follows: early stage 2.80〜3.31%,
mid stage 3.09〜3.53%, and late stage 3.35〜3.91%.
--------------------J. Jpn. Vet. Med. Assoc., 53, 289〜292 (2000) |