19 December 2022

3 minute read

By: Emily Bourdeau

Robotic milking systems, also known as automatic milking systems (AMS), were first introduced to the U.S. in 2000. Although this technology was initially slowly adopted, it‘s recently become more appealing to farmers. Labor, specifically consistent labor, is hard to find and keep for many farms, and adopting an AMS can decrease labor and labor costs, which is one of the greatest expenses on the farm. Other benefits of AMS include decreased cow handling, increased and more consistent milkings and often higher milk production.

Robotic milking systems can be a great tool for farms, but they must be properly managed to be cost-effective. For example, if AMS aren’t managed properly farmers may end up spending more on feed then they really need, making the greatest on-farm expense even pricier. At the 2022 Cornell Nutrition Conference Dr. Trevor DeVries from the University of Guelph had a great talk about opportunities and challenges with the nutritional management of cows milked robotically. Dr. DeVries noted that two main goals of feeding cows in AMS are to formulate and provide a diet that meets the nutrient needs of both maintenance and production of cows, and then motivate cows to voluntarily enter the robot by dispensing pellets. The total diet for a cow milked in AMS is the partial mixed ration (PMR) fed at the bunk, plus the pellets dispensed individually to cows in the AMS, with the PMR providing the majority of dry matter intake (DMI).

With the diet being split into a PMR and AMS concentrate pellets, there is some opportunity to feed cows individually in a pen. This can be done by adjusting the amount of AMS pellets delivered to each cow or adding an additional supplement based on that cow’s stage of lactation, milk production, body weight, etc. A study at the University of Guelph supplemented early lactation cows milked in AMS with a molasses liquid feed supplement in addition to their AMS concentrate. This study found that those cows supplemented with molasses had improvements in energy balance and had minimal body condition loss during early lactation.

In addition to considering stage of lactation and milk yield for cows in AMS, it’s important to consider the behavioral aspects of the cow. A common claim about AMS feeding strategies is that increasing the amount of pellets delivered will encourage voluntary visits and milk yield; however, cows are physically limited to how much they can consume per minute. This means that there is a chance that cows are not able to consume all the pellets delivered in a typical seven-to-eight-minute milking. 

Eating rates will vary depending on the type of feed offered, but the average cow can consume concentrate at around 250 g/minute according to Dr. DeVries. Therefore, an average cow can be expected to consume about 1.8 kg (4 lb.) of concentrate in a seven minute milking. With a goal of three milkings per day this equates to an average of 5.4 kg/cow/day (12 lb/cow/ day) of concentrate. Consumption of concentrate can of course vary from cow to cow depending on how comfortable they are in the robot, but this behavioral aspect of the cow is important to think about. You might think that by providing more pellets you will be able to better encourage voluntary visits, but to be cost eff ective you must keep in mind how much the cows can physically consume during their milking times to avoid wasting pellets and potentially money.

When it comes to managing cows in AMS there also must be critical management of the PMR, as PMR feeding activity is linked to milking activity. It is heavily cited that more frequent feed push-ups can lead to cows having continuous access to feed which will positively affects milk production.

Dr. DeVries noted two observational studies that found an increase in milk production for cows in AMS when there were more frequent feed push-ups, once again reiterating how important feed access is no matter the system. Feeding cows in AMS is unique, but to keep AMS cost effective there needs to be thorough feed management across all elements.