Feeding livestock today is not just about dumping hay or silage into the barn and hoping it works.
It is a carefully controlled process to ensure animal health, optimize production and protect the environment.
Feeding dairy cows presents unique challenges. Milking is increasingly being done by robots. But these robots are more than just milking machines: they also provide what Sophia Cattleya Donde calls the cows’ “dessert”: tasty, nutritious pellets.
“The robot is a complete system,” explains Donde, a doctoral student in USask’s School of Agriculture and Bioresources (AgBio), “and it runs 24/7. It’s a voluntary system, so the cows voluntarily go to the robot whenever they want to be milked.”
“The pellets are an attraction. If you feed them in the robot, they will want to go to the robot more often.”
But do pellets actually affect milk production? Donde decided to find out.
The diet of cows milked with robotic systems consists of partial mixed rations (PMR), which are high-quality feed-based ingredients that cows ingest in addition to pellets, meaning that pellet feeding can affect when and how much PMR a cow ingests.
Specifically, Donde studied whether the combination of starch concentration in pellets and the amount of pellets provided affected lactating cows’ performance and the nutrients consumed at any point in the production cycle.
Donde noted that there is a gap in the literature on this topic, which is important to fill.
“We find that people usually only focus on the pellets and don’t realise that the majority of a cow’s nutrition is in the barn feed,” she said.
“Most studies haven’t focused on the intake of PMR. They tend to focus on the amount of pellets that are in the robot.”
But as the robot’s pellet intake increases, the cow’s PMR intake decreases, she says. Here’s where the parallels between human and cow desserts come in.
“I might not eat the whole meal. Hmm, I’m not going to eat that much rice or vegetables… because I really want to eat cake.”
“You start replacing the main meal with dessert. It’s pretty much what cows do. They don’t eat everything from the barn that they should be eating. They eat pellets, so they eat that instead.”
