Melin M, Svennersten-Sjaunja K, Wiktorsson H
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden.
J Dairy Sci. 2005 Nov;88(11):3913-22. doi: 10.3168/jds.S0022-0302(05)73077-0.
Two groups of dairy cows monitored from 3 to 19 wk postpartum were subjected to 2 different cow traffic routines in an automatic milking system with control gates and an open waiting area. Using different time settings in the control gates, the groups of cows were separated by average milking frequency; cows in the high milking frequency routine had a minimum of 4 h between milkings (MF(4)) and were milked 3.2 +/- 0.1 times daily, whereas cows in the low milking frequency routine had at least 8 h between milkings (MF8) and were milked 2.1 +/- 0.1 times daily. Cows in the 2 groups were switched to the opposite milking frequency control for wk 18 and 19. The increased milking frequency resulted in a higher milk yield of about 9% through 16 wk of early lactation Although the higher milk yield was not significant when measured as energy-corrected milk, significant interactions of milking frequency and study period for milk yield and energy-corrected milk yield were consistent with a yield response when cows were milked more frequently. Meal criteria estimated for each individual cow were used to group feeding visits into meals. During MF4, cows fed in fewer meals per day and had longer meals than during MF8. The control gates were used efficiently, with only a few passages not resulting in actual meals. Although the voluntary meal intervals seemed to be short, the average milking frequency was far below that theoretically possible. This was explained by individual differences in milking frequency and long intervals from when a cow was redirected in a control gate until it arrived in the milking unit. A wide individual range in the voluntary interval between the first and the second meal in the milking cycle suggests that fixed time limits for control gates set on group level have no justifiable biological basis. It was also concluded that primiparous cows were well adapted to the automatic milking system after 2 wk in the barn.
对两组产后3至19周的奶牛，在一个带有控制门和开放式等候区的自动挤奶系统中采用两种不同的奶牛通行程序。通过在控制门中设置不同的时间参数，根据平均挤奶频率将奶牛分组；高挤奶频率程序组的奶牛挤奶间隔至少为4小时（MF(4)），每天挤奶3.2±0.1次，而低挤奶频率程序组的奶牛挤奶间隔至少为8小时（MF8），每天挤奶2.1±0.1次。在第18周和第19周，将两组奶牛的挤奶频率控制程序进行对换。在泌乳早期的16周内，挤奶频率增加使产奶量提高了约9%。尽管以能量校正奶衡量时，较高的产奶量并不显著，但产奶量和能量校正奶产量的挤奶频率与研究时期之间的显著交互作用表明，奶牛挤奶更频繁时会有产奶量反应。根据每头奶牛估算的采食标准将采食访问分组为采食餐次。在MF4期间，奶牛每天采食餐次较少，但每次采食时间比MF8期间长。控制门得到了有效利用，只有少数几次通行未导致实际采食。尽管自愿采食间隔似乎较短，但平均挤奶频率远低于理论上可能达到的频率。这可以通过挤奶频率的个体差异以及奶牛在控制门中被重新引导直至进入挤奶单元的间隔时间较长来解释。挤奶周期中第一餐和第二餐之间的自愿间隔存在很大的个体差异，这表明在群体水平上为控制门设置固定时间限制没有合理的生物学依据。研究还得出结论，初产奶牛在牛舍中饲养2周后能很好地适应自动挤奶系统。
