128

42.娟姍牛在台灣夏季的乳量與乳質表現

吳明哲⁽¹⁾、賴永裕⁽¹⁾、黃鈺嘉⁽¹⁾、張菊犁⁽¹⁾、李素珍⁽¹⁾、施意敏⁽¹⁾、王政騰⁽¹⁾、

陳榮泰⁽²⁾、丁進來⁽²⁾、王忠恕⁽³⁾

⁽¹⁾行政院農業委員會畜產試驗所 ⁽²⁾中華民國乳業協會 ⁽³⁾行政院農業委員會畜牧處

娟姍牛在台灣濕熱氣候下，並在台灣乳牛飼養管理系統中進行來台的第一胎泌乳表現，其夏季月份的乳量與乳質表現更需即時評估。乳牛育種策略上，期望以乳量、乳質及繁殖性狀兼顧的選拔為主，來培育台灣乳牛具有適應濕熱環境的特色，成為乳牛熱帶品系，並出口東南亞國家。因此，本研究從DHI資料庫www.angrin.tlri.gov.tw分析五家娟姍牛場於2007年7至10月間，計680頭次乳樣記錄。娟姍牛單日最高乳量記錄為27 kg(2006年台灣乳牛記錄為63 kg)，平均為15.5+4.0 kg(2006年台灣乳牛平均為22.7 kg)。娟姍牛乳脂肪率(F)、蛋白質率(P)、乳糖率及總固形物率分別有4.69+0.97、3.48+0.40、4.83+0.30及13.71+1.04%。與2006年台灣乳牛218,818乳樣之乳脂肪率(3.81%)、蛋白質率(3.30%)、乳糖率(4.79%)及總固形物率(12.59%)平均來比較，娟姍牛乳脂肪率明顯地較高。娟姍牛體細胞數平均達72.2萬細胞/mL，較2006年台灣乳牛體細胞數平均32.2萬細胞/mL明顯地較高。娟姍牛乳尿素氮、檸檬酸、及P/F比為 14.4+5.8 mg/dL、190.0+27.9 mg/dL及0.78。當依乳量分為9 kg以下、10~21 kg及22 kg以上等三組，分佈頻率為47(6.9%)、589(86.6%)、44(6.5%)。娟姍牛高乳量組的乳量平均為23.2+1.3 kg，其乳脂肪率、蛋白質率、乳糖率及總固形物率分別有4.48+0.89、3.38+0.20、4.79+0.21及13.36+0.94%，顯示高乳量僅降低脂肪率。因此，應用乳量乳質兼顧的選拔，也有利於娟姍牛群性能之改進。

關鍵語：乳牛、選育、乳質

MILK YIELD AND QUALITY OF JERSEY COW IN SUMMER SEASON OF TAIWAN

M. C. Wu⁽¹⁾, Y. Y. Lai⁽¹⁾ , Y. C. Huang⁽¹⁾, C. L. Chang⁽¹⁾, S. J. Lee⁽¹⁾, E. M. Shy⁽¹⁾, C. T. Wang⁽¹⁾,

L. T. Chen⁽²⁾, J. L. Ding⁽²⁾ and C. S. Wang⁽³⁾,

⁽¹⁾Livestock Research Institute, Council of Agriculture, Executive Yuan; ⁽²⁾Dairy Association of ROC;

⁽³⁾Animal Industry Division, Council of Agriculture, Executive Yuan

Jersey (J) cow was raised under a hot and humid environment but they were in the same feeding program for Taiwan dairy cows. Summer milk production is critical to evaluate the performance of those of new imported Jersey. For breeding scheme of dairy cattle, selection on milk yield and quality associated with reproductive performance is essential to the hot and humid weather, and therefore selected cows will become a heat-tolerance line for exportation to Southeast Asia. In the summer of 2007, 680 milk samples taken from Jersey cow with comparison to statistics of 218,818 milk samples of Taiwan dairy cows (T) in 2006. Jersey cow had 27 kg of single day production yield (63 kg in T cow) with a mean of 15.5+4.0 kg (22.7 kg of mean in T cow). Milk fat, protein, lactose, and total solid were 4.69+0.97, 3.48+0.40, 4.83+0.30, and 13.71+1.04%, as comparison of T cow in which of 3.81% fat, 3.30% protein, 4.79% lactose and 12.59% total solid. J cows had a significantly higher fat percentage. Somatic cell counts averaged 722x10³/mL in J cow and significantly higher than the average of 322x10³/mL of T cow. Milk urea nitrogen, citric acid, and P/F ratio in J milk were 14.4+5.8 mg/dL, 190.0+27.9 mg/dL, and 0.78. When milk yield was classified into <10, 10~21, and >21 kg groups, frequency of them were 47(6.9%), 589(86.6%), and 44(6.5%). An average of 23.2+1.3 kg of milk yield in the high yield group with 4.48+0.89% fat, 3.38+0.20% protein, 4.79+0.21% lactose and 13.36+0.94% total solid. It indicated that high yield resulted in a less fat percentage. In conclusion, selection on both milk yield and quality trait in Jersey would be feasible.

Key Words: Dairy cattle, Selection, Milk quality