For herds milked with robotics, the secrets to success may be in the palatability and quality of the pellets fed in the milking station and the consistent delivery of the remainder of the ration. Jim Salfer discussed how robotic milking dairies are feeding their cows during his presentation at the Four-State Dairy Nutrition and Management Conference held this summer in Dubuque, Iowa.

“The goal of every feeding program is to develop a low-cost diet that meets the nutritional requirements of cows while optimizing milk production and cow health.

In most conventional herds, this is accomplished by feeding a TMR where all ingredients are mixed together and delivered to the cow. For automated milking systems (AMS) herds, a partially mixed ration (PMR) is offered in the feedbunk with a portion of the concentrate being fed through the milking box,” Salfer said.

“One of the challenges facing nutritionists is to balance the nutrients supplied in the PMR and in the feed offered in the milking box to entice cows to visit the milking stall on a regular basis,” he explained. “Feeding management is one of the major factors for success in AMS. Feed offered in the AMS unit is the major motivating factor to attract cows to consistently visit the milking station.”

The sometimes complicated interactions among cow behavior, activity, diet, feed consumption, cow health and production can often cause frustration for producers and nutritionists alike, he said.

“Based on research, nutritionist surveys and farmer comments, the most important factors affecting feeding success include a high-quality, palatable pellet and excellent feed management,” he said.

Salfer said high-quality pellets are very hard and do not easily break apart. Poor-quality pellets are soft, break apart easily, and the cows cannot eat it as fast. The cows also do not like the fines (dust).

Salfer cited a study which showed that in a free-flow system, feeding a high-quality pellet versus a low-quality pellet, voluntary milkings increased from 1.72 to 2.06 per cow per day.

The percentage of cows that needed to be fetched was 16 percent with low-quality pellets versus 7.1 percent for high-quality pellets. Cows fed a low-quality pellet averaged 54.5 pounds of milk per day, and cows on a high-quality pellet averaged 55.6.

Salfer said many of the producers they surveyed had tried feeding a meal instead of a pellet in the milking box as a way to save money. “On every farm this proved unsuccessful and they reverted back to feeding a pellet,” he reported.

Pellets should be made from palatable ingredients, such as expeller soybean meal, distillers grains, corn and molasses or flavors, hard and free from fines. Cows also do not like pellets that contain a lot of fat or animal byproducts.

“It costs a little more for the more palatable ingredients, but it is worth it, not only because the cows milk more but also because they visit the milking station more regularly and you have fewer fetch cows,” he said.

Although finding the right pellet is important, he noted even minor changes in the PMR moisture, consistency of the mix (i.e., long hay that is difficult to process to a consistent length) and changes in forage quality can affect the number of milkings per day and overall milk production.

Salfer said very consistent feeding at the bunk is also very important. “If feed moisture changes and rations are not adjusted promptly, visits may drop. This drop in visits will result in a decrease in milk production and an increase in number of fetch cows.

The increase in fetch cows may disrupt other cow behaviors, resulting in an even bigger decrease in visits and decrease in milk production, leading to a downward spiral creating much frustration for the producer.”

A 2012 study showed just a $0.02 difference in the average total cost of feed for conventional milking setups than robotics: $7.21 per cow per day for parlor cows and $7.23 per cow per day for cows milked by robotics.

There is a much more significant difference in the daily cost of feeding high-production cows (120 pounds per day) though, about $9.40 in robotic herds versus $8.87. Feeding low-production cows (50 pounds per day) was cheaper in robotic herds, about $5.18 for parlor herds versus $5.63.

In summary, it is cheaper to feed the later-lactation, lower-producing cows and more expensive to feed early lactation, higher-producing cows in a robot, he said.

The benefits of feeding cows in a robotic herd include rewarding high-production cows with the energy they need, more cows will have a positive energy balance and gain weight faster after calving, and cows will not become overconditioned because they are being fed what they need.

Generally, guided-flow automated milking systems require less pelleted feed to draw the cows to the milking box. Salfer said the amount of pellets offered in the milking box in free-flow systems was 2 to 25 pounds per cow per day compared to 2 to 18 pounds per day in the guided-flow systems. “The average amount of pellets fed across all herds was 3 pounds per cow per day less with guided-flow barns,” he said.

Currently, the majority of systems are free-flow systems. If installing guided-flow systems, Salfer and his colleagues strongly recommend the milk-first system. In feed-first systems, cows fill up on the PMR and tend to stand in the feed alley or commitment pen and chew cud without entering the selection gate or visiting the AMS.

“It might work in Europe, where the cows are typically fed a low-energy diet in the bunk,” he said. “But we don’t feed those diets in the U.S. and we’ve heard a lot of complaints about these systems.”

The PMR in guided-flow systems tended to be slightly higher in energy and lower in neutral-detergent fiber than the PMR in free-flow systems. Salfer said these ration differences are primarily because of the lower amount of pellets fed through the milking box in guided-flow systems, so more energy must be fed through the PMR.

The PMR in a free-flow herd is typically balanced for milk production levels of 10 to 30 pounds less than the herd’s average milk production. The PMR in guided-flow systems was balanced for 9 to 20 pounds less than the average of the herd.

Salfer explained that “high energy density in the PMR in free-flow barns may lead to decreased milking frequency, resulting in less milk production per cow, whereas in guided-flow barns cows are guided to the robot through the selection gate.

“Both guided-flow systems and free-flow systems can be successful. In our study, we have herds that averaged more than 90 pounds per cow per day over an entire year of production with both free-flow and guided-flow systems,” he concluded. “The key is to manage the system well to optimize production.” PD

Kelli Boylen is a freelance writer in Waterville, Iowa.