|J. Chin. Soc. Anim. Sci. 34(Suppl.)|
李世昌 吳明哲 黃鈺嘉 張菊犁 李素珍 曾青雲 陳志毅
ANNUAL INCREASE OF MILK YIELD AND QUALITY OF COWS
S. C. Lee, M. C. Wu, Y. C. Huang, C. L. Chang, S. J. Lee, C. Y. Tseng and J. Y. Chen
Livestock Research Institute, Council of Agriculture, Executive Yuan
Production efficiency of dairy farm is achieved by participating test of milk quality. Application of web information of www.angrin.tlri.gov.tw for analysis of milk yield and quality, an average of number of cows per farm was 65, 70, 73, 74, and 70 head from 2001 to 2005, respectively. Daily milk yield per cow form 2001 to 2005 were 21.46 (176819 milk samples collected from 287 farms), 21.77 (220193, 315), 22.02 (243053, 348), 22.17 (248822, 345), 22.73 kg (169359, 319, only from Jan to Sept of 2005). For the last five years, an increase of 3.31% on daily milk yield was obtained with the annual increase rate of 0.83%. Elite farms having mean daily milk yield grater than 22 kg and with less than 30 x104/mL of milk were selected, there were 35 farms (30.1% of 116 high production farms having greater than 22 kg of daily milk yield) in 2001, and there were 41 farms (30.1% of 136 farms), 63 farms (39.1% of 161 farms), 79 farms (48.1% of 164 farms), and 77 farms (43.2% of 178 farms) from 2002 to 2005. Number of elite farms increased 2.2 times (77 farms/35 farms) form 2001 to 2005. Milk yield and quality from those of elite farms were averaged by milking year, daily milk yield were 24.15+1.68, 24.58+1.75, 24.41+1.73, 24.41+1.81, 24.87+2.24kg from 2001 to 2005, respectively; somatic cell counts were 21.05+4.09, 21.92+3.88, 21.02+4.00, 20.54+3.80, 19.67+5.40 x104/mL; total solid content were 12.28+0.36, 12.38+0.26, 12.39+0.26, 12.45+0.29, 12.47+0.28%; protein to fat ratio (P/F ratio) were 0.89+0.07, 0.88+0.06, 0.87+0.05, 0.87+0.06, 0.89+0.05. Annual decrease amount on somatic cell counts was 1.63% and annual increase percentage of total solid content was 0.38% for the last five years. Analysis on data of the highest daily milk yield of the year for each farm, year mean of the highest daily milk yield were 46.57+5.25, 47.26+5.37, 47.63+5.00, 46.92+4.85, 47.36+5.68kg from 2001 to 2005, respectively. It indicated that the yield peak of lactation curve was 47 kg from those cows in the elite farms. Among those of 77 elite farms in 2005, milk fat content averaged 3.73+0.23% and with 3.24+0.07% of milk protein content and 4.80+0.05% of milk lactose. In 2005, the greatest amount of daily milk yield was 31.79 kg from Hsu Farm with 16.89 x104 cells/mL and 12.60% of total solid content in milk quality. According the above results, both milk yield and quality for milking cows were improved annually.
Key Words: Dairy cows, Milk yield, Milk quality