【摘要】 通过连续5年每月定期测定不同产犊季节奶牛2 179头次的产奶量,绘制季节性产奶量变化曲线、泌乳曲线,并计算305d产奶量,探讨不同产犊季节奶牛产奶量和泌乳曲线及其机理。结果表明,3~8月份产奶量较高,促进产奶潜力的正常发挥,而9~2月份产奶量较低,阻碍产奶潜力的发挥,两个阶段产奶量差异显著(P<0.05);春、冬、秋、夏产犊时奶牛305d产奶量分别为8 298.5、8 280.2、8 139.2、7 924.5kg,其中春冬与夏之间差异极显著(P<0.01),秋与夏间差异显著(P<0.05),不同产犊季节奶牛泌乳曲线变化趋势不同。包头地区不同产犊季节奶牛305d产奶量,春冬季最高、夏季最低,而秋季居中。其305d产奶量取决于一个泌乳期中促进(或阻碍)产奶潜力发挥季节的产奶天数长短和所处泌乳阶段。更多还原

【Abstract】 In this study 2179 records from one large scale dairy farms were applied to analyze the influence of calving seasons on milk yield and lactation curves.Average monthly milk yield of individual dairy cows were recorded in consecutive 5years(from June,2009 to May,2013)and 305 days milk yield was calculated.The results showed that the milk yield of dairy cows calved during March to August was higher than that of dairy cows calved during September to February(P<0.05).305 days milk yield were 8298.5kg,8280.2kg,8139.2kg and 7924.5kg for dairy cows calved in spring,winter,autumn and summer,respectively.No significant difference was found among dairy cows calved in spring,winter and autumn in305 days milk yield.Compared with dairy cows calved in summer,305 days milk yield of dairy cows calved in spring,winter(P<0.01)and autumn(P<0.05)was significantly higher.The variation trend of lactation curve to dairy cows calved in different seasons is not the same.In conclusion,305 days milk yield was the highest for dairy cows calved in spring and winter,the least for dairy cows calved in summer,and medium for dairy cows calved in autumn.305 days milk yield of dairy cows calved in different months depended upon the length of promoting or suppressing milking days and the lactation stage.更多还原