Does the location of concentrate provision affect voluntary visits, and milk and milk component yield for cows in an automated milking system?

Given the challenge in delivering the targeted concentrate provision to dairy cattle milked in an automated milking system (AMS), the substitution effect reducing partial mixed ration (PMR) intake when
increased AMS concentrate is provided, and that milk yield and milk component yield are not improved, we
set out to test whether location of concentrate provision, under isocaloric dietary conditions, would affect voluntary attendance and milk and milk component yield for cows milked in an AMS. We hypothesized that increasing concentrate provision for cows in a guided-traffic flow AMS will not improve voluntary attendance and
milk yield and composition when total dietary energy is balanced.

These findings further support the concept that increasing the AMS concentrate provision leads to a reduction in PMR intake and will further alter the forage-to-concentrate ratio of the diet consumed.These data suggest that increasing the amount of concentrate offered in the AMS, without corresponding changes in the total dietary energy supply does not affect milk yield or composition. Others have also attempted to maintain total dietary energy supply and found that increasing concentrate provision in the AMS did not enhance milking frequency or milk yield (Bach et al. 2007). Interestingly, increasing concentrate provision in the AMS without changes in PMR energy density has also been shown not to improve milking frequency or milk yield.The findings of the current study and previous studies challenge the notion that increasing the provision of concentrate in the AMS will improve voluntary visits and milk and milk component yield in guided-traffic systems.

Results of this study indicate that in a feed-first, guided-traffic flow barn, providing a PMR with greater
energy density, while limiting the quantity of concentrate in the AMS, may improve dry matter intake (DMI), increase the PMR eating rate and meal size, and may reduce sorting of the PMR when compared with feeding a low-energy PMR coupled with high-AMS-concentrate allocation. Moreover, for every 1 kg increase in concentrate provision in the AMS, we observed a 1.58 kg reduction in PMR intake. Thus, providing a greater proportion of the dietary nutrient supply in the PMR, rather than the AMS, may improve the ability of dairy producers to manage nutrient supply for cows milked in a guided-traffic flow AMS.