Benefits of AMS adoption for dairy producers include reduced stress and labor requirements and greater time flexibility. The reduction in labor and modification of how time is spent in the barn is helping smaller farms and those wishing to grow remain functional without hiring outside labor. Furthermore, large farms are also increasingly adopting AMS in an effort to combat both increasing labor costs and shortages of available laborers.
From a cow health and welfare perspective, AMS give cows more freedom to control how they spend their time and to perform desired behaviors. In a recent survey we conducted, 66 percent of Canadian dairy producers reported that after transitioning to AMS, they changed their health management strategy, and 80 percent of producers found illness detection to be easier than before because of the AMS and the associated health monitoring software. In that work, we reported little to no perceived change in rates of lameness and culling, and most dairy producers reported that rates of mastitis were similar or lesser than before, and conception rates in their cows were improved. Overall, AMS producers generally feel successful about their transition to AMS and new health management systems.
While various benefits to cow health and welfare related to adoption of robotic milking are possible, not all of these may always be realized on-farm. Several impediments to good health and welfare on AMS farms may exist, including having cows that cannot milk when they want to, cows that do not want to go milk voluntarily, poor udder health management and improper nutritional management.
Ideally, dairy cows will voluntarily visit the AMS for milking and do so at an appropriate frequency each day. With variable milking intervals, dairy producers need to target, on average, greater than three milkings per cow per day to achieve milk yields that would match those seen with conventional 3X milking. This is not always easy to accomplish because of many factors, including housing design, traffic flow and stocking density; all of these need to be managed appropriately to encourage cow motivation and ability to visit the AMS.
The voluntary nature of milking in AMS provides more behavioral freedom for cows, but this also creates challenges for managing milking intervals and udder health. In AMS, cows can make more choices about their daily routine and time budget and, particularly with free cow traffic, cows are able to move throughout the barn freely. It is plausible this behavioral freedom improves cow health and welfare in AMS because cows can make decisions according to their individual needs.
Instead of free cow traffic, producers may choose to use directed/guided traffic to force cows through the AMS. While no empirical evidence exists to indicate any differences in milk yield or cow stress between traffic designs, free traffic is much more conducive to improved rumen health due to better eating patterns (i.e., more frequent meals of PMR per day at the feedbunk).
Free cow traffic arrangements also have lower waiting times, especially for low-ranking cows, who typically spend more time waiting to be milked and are milked less often and at less preferred times of the day. In guided traffic systems, low-ranking cows may wait longer in front of the AMS. To better accommodate lower-ranking cows, a free cow traffic barn design with a split-entry holding pen near the AMS can be used, increasing cows’ chances to milk when needed and reducing their wait times.
Another potential challenge to cow health and welfare in AMS is when cows do not want to go milk voluntarily. One of the primary inhibitors to voluntary milking in AMS is poor cow mobility due to lameness. In field studies of AMS farms in Canada and the U.S., we have reported the prevalence of lameness on AMS farms is similar to that on conventional milking farms. While the proportion of those cows that are severely lame (i.e., those reluctant to bear weight on any one limb) is quite low (presumably because these cows do not milk voluntarily at all), the numbers of cows that are more moderately lame (i.e., those with any impairment to their gait or a moderate limp) are still concerning. In that work, we reported that this lameness, albeit not severe, comes with consequences: Lame cows have more involuntary milkings (i.e., need to be fetched more often), milk less often and, as a result, they produce less milk.
In our research, we were able to identify risk factors associated with that lameness prevalence – not surprisingly, those factors are similar to those seen in conventional systems, that is, things that either limit cows from lying down when they want to or cause cows to stand for longer periods of time than needed. Examples of such risk factors for lameness include freestalls that are too small (i.e., too narrow), obstructed lunge space in freestalls, mattress-based stalls (as opposed to deep bedding) and greater stall stocking density.
While udder health management is a concern for some AMS farms who experience challenges with udder health and milk quality after adoption of AMS, the majority of farms do not share that experience. The risk of poor udder health and high milk bacteria counts in AMS are related to host resistance (i.e., ability of cows to prevent infection) and environmental pressure (i.e., number of challenging microbes to the udder). Host resistance is primarily influenced by stress and nutritional status; by managing cows to minimize stress and feeding them to meet requirements, we are able to maximize the ability of the cow to fend off any potential infection.
Proper and adequate teat disinfection is also important for minimizing the spread of pathogens. Given that pre-milking teat cleaning may not be as thoroughly done in AMS, as compared to manual cleaning and disinfection, even more attention needs to be placed in AMS barns to promote cow hygiene – this includes maintaining clean lying stalls, walking alleys and milking equipment.
There are also opportunities in udder health management in AMS. For example, we know gradual cessation of milking at dry-off is important for reducing pain associated with dry-off (particularly for those cows still at a high level of production at the time of dry-off) and for maintaining good udder health after dry-off and into the next lactation. While implementing good dry-off strategies in conventional systems may be difficult, AMS can be programmed to allow for a more gradual dry-off by controlling milking intervals and feed consumption. Such strategies are likely to become more important as we move toward reduced dependence on antimicrobial dry cow therapy.
A final impediment to good health and welfare of AMS farms is improper nutritional management. While there are many opportunities to improve nutritional management in AMS through meeting individual cow needs through “precision feeding,” some challenges may exist. An example of that includes some evidence, from a field study of herds in Ontario, Canada, that the prevalence of ketosis may be greater in AMS herds as compared to those herds milked conventionally. In other research, we have identified a risk factor for that elevated ketosis: Specifically, there may be situations where cows are not receiving sufficient supplementation at the AMS unit in the first week of lactation to support production. This highlights the need for feed tables (of AMS concentrate) to be based on both stage of lactation and production level.
In summary, with the ability to milk and feed each cow individually in the AMS, there are associated challenges with maintaining adequate milking frequencies and managing cow health and welfare. Not only are housing design, milking and nutritional management important in AMS herds for encouraging voluntary milking; bedding and hygiene must be also be optimally managed to maintain good hoof and udder health, body condition and overall cow welfare. 
Meagan King is a post-doctoral researcher at the University of Guelph.
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Trevor DeVries
- Professor
- University of Guelph
- Email Trevor DeVries
