Feed Bunk Space in Automated Milking Systems

As more farms adopt robotic milking or build new barns, feed bunk space is an important consideration for both barn design and daily management. This article reviews current research on feed bunk space in automated milking systems (AMS) and how it can be evaluated on-farm.

Feeding Behavior in AMS vs. Parlor Systems

In parlor systems, cows are milked as a group and return to the pen together, which often leads to many cows eating at the same time after milking (DeVries and von Keyserlingk, 2005). In contrast, AMS allow cows to visit the robot individually, so feeding is more spread out across the day (Jacobs and Siegford, 2012; Wagner-Storch and Palmer, 2003). Despite these differences, cows in AMS still follow consistent daily patterns. Feeding activity increases after fresh feed delivery, while lying time peaks overnight. Even in robotic barns, crowding at the feed bunk can occur during peak feeding times because cows are highly motivated to access fresh feed.

Why Feed Bunk Space Matters

In AMS, cows can choose when to eat, but they can only do so comfortably when enough space is available at the bunk. When bunk space is limited, competition increases (Huzzey et al., 2006; DeVries et al., 2004), particularly during peak feeding times. This can lead to the displacement of more subordinate cows.

Research conducted in AMS barns has shown that limited bunk space changes how cows eat throughout the day. When space is restricted, fewer cows eat at the same time, individual meals are shorter, and daily feeding and resting patterns shift, even when stall space is adequate (Witaifi et al., 2018). This shows that feed bunk space affects when and how cows eat over the day, not just access to feed. In the first lactation, smaller and lower-ranking cows are often the most affected.

Effects on Milk Production

Studies in AMS herds show that feed bunk space is linked to milk production (Matson et al., 2021; Deming et al., 2013). In one study, each 4-inch increase in feed bunk space per cow was associated with about 0.7 pounds more milk (Matson et al., 2021). While this difference may seem small at the cow level, it can add up across the herd. Research in Midwestern U.S. AMS herds also shows that management and housing factors that support consistent feed intake and reduce competition are linked to higher milk production (Siewert et al., 2018). Overall, these findings suggest that feed bunk space is one of several key factors that help support consistent intake and performance in AMS herds.

Effects on Lameness

Lameness is an important issue in AMS herds because cows need to willingly walk to the robot several times per day. Cows with poorer gait scores visit the robot less often, while cows that visit more frequently are usually sound (Borderas et al., 2008). Lame cows are also more than twice as likely to need to be fetched for milking (King et al., 2017).

Management factors like feed bunk space can also play a role. Providing more bunk space has been linked to lower lameness. In one study, adding 4 inches of bunk space per cow reduced lameness by about 1.7 percentage points (Matson et al., 2022). Lame cows also change how they lie down and rest (Westin et al., 2016). Because lying time is closely tied to cow comfort and hoof health, adequate bunk space may help reduce standing time and competition at the feed bunk and support better mobility.

How Much Space Do Cows Need?

Dairy housing guidelines commonly recommend 24 inches of bunk space per cow. In practice, however, bunk space varies widely across farms, with some providing less than recommended and others providing more. Research in AMS herds suggests that providing more space – around 25-28 inches per cow on average – can be associated with higher milk production (Matson et al., 2021; Deming et al., 2013). Management practices such as frequent feed push-ups can help keep feed within reach, but they do not eliminate competition when bunk space is limited. Providing adequate bunk space remains one of the most effective ways to reduce crowding at the bunk and support consistent feed intake.

How to Check Your Barn

Producers can easily evaluate feed bunk space in their own barns with a simple calculation. Measure the total usable length of the feed bunk and divide it by the number of cows in the pen to determine inches of bunk space per cow. For example, a pen with 120 feet of bunk space and 60 cows provides 24 inches per cow. This value can then be compared across pens and over time to identify potential limitations in feeding space.

Take-Home Message

Even though cows are not milked in groups in AMS, they still compete for space at the feed bunk, especially during peak feeding times. Research shows that feed bunk space affects feeding behavior and is linked to both milk production and lameness. Providing enough space helps cows eat more comfortably and consistently, supporting feed intake, milk production, and overall herd health.

References

Deming, J. A., R. Bergeron, K. E. Leslie, and T. J. DeVries. 2013. Associations of housing, management, milking activity, and standing and lying behavior with milk production in freestall-housed dairy cows milked by automatic milking systems. J. Dairy Sci. 96:5252-5262.

DeVries, T. J., M. A. G. von Keyserlingk, and K. A. Beauchemin. 2004. Effect of feed alley space on the feeding behavior of lactating dairy cows. J. Dairy Sci. 87:1440-1446.

DeVries, T. J., and M. A. G. von Keyserlingk. 2005. Time of feeding affects the feeding and lying patterns of dairy cows. J. Dairy Sci. 88:3553-3562.

Huzzey, J. M., T. J. DeVries, P. Valois, and M. A. G. von Keyserlingk. 2006. Stocking density and feed barrier design affect the feeding and social behavior of dairy cows. J. Dairy Sci. 89:126-133.

Jacobs, J. A., and J. M. Siegford. 2012. Invited review: The impact of automatic milking systems on dairy cow management, behavior, health, and welfare. J. Dairy Sci. 95:2227-2247.

Matson, R. D., M. T. M. King, T. F. Duffield, D. E. Santschi, K. Orsel, E. A. Pajor, G. B. Penner, T. Mutsvangwa, and T. J. DeVries. 2021. Benchmarking of farms with automated milking systems in Canada and associations with milk production and quality. J. Dairy Sci. 104:7971-7983.

Matson, R. D., M. T. M. King, T. F. Duffield, D. E. Santschi, K. Orsel, E. A. Pajor, G. B. Penner, T. Mutsvangwa, and T. J. DeVries. 2022. Farm-level factors associated with lameness prevalence, productivity, and milk quality in farms with automated milking systems. J. Dairy Sci. 105:793-806.

Siewert, J. M., J. A. Salfer, and M. I. Endres. 2018. Factors associated with productivity on automatic milking systems dairy farms in the Upper Midwest United States. J. Dairy Sci. 101:8327-8334.

Wagner-Storch, A. M., and R. W. Palmer. 2003. Feeding behavior and milk production in automatic milking systems. J. Dairy Sci. 86:2726-2732.

Westin, R., et al. 2016. Lying times of lactating cows on dairy farms with automatic milking systems and the relation to lameness, leg lesions, and body condition score. J. Dairy Sci. 99:551-561.

Witaifi, A. A., A. B. A. Ali, and J. M. Siegford. 2018. Stall and feed bunk stocking rates impact cows' diurnal behavior and activity in automatic milking system farms. J. Vet. Behav. 24:48-55.