Automatic feed pushing in dairy barns: Considerations of TMR leftovers particle size

Dairy cows are typically fed a total mixed ration (TMR), which includes a blend of forage, cereals, by-products, supplements, vitamins, and mineral salts tailored to each farm's specific needs. Providing a quality ration is crucial for the production cycle, but optimizing feed bunk management is equally important to maximize TMR's nutritional benefits. Consistent feeding times, high-quality components, and frequent replenishment of the TMR near the feeding bunk ensure cows have a regular, high-quality diet 24 hours a day, every day of the week. The study involves monitoring the TMR leftovers from four dairy farms and one fattening bull farm in Northern Italy. These farms utilized automatic feeding systems (AFS) and mixing wagons for TMR processing, while leftover feed pushing occurred both manually (twice a day) and automatically using a rotary drum feed pusher and AFS. TMR leftover samples, collected just before the administering of fresh feed, underwent particle size analysis using a Penn State Particle Separator with screens of 19, 8, and 1.18 mm and a bottom pan. Data processing has pointed out that leftover particle size composition varies depending on feed-pushing techniques. The pushing-up action of the AFS results in a leftover particle size like the operator-based one and contains a high percentage of particles higher than 8 mm. On the other hand, pushing back the feed with a drum feed pusher results in leftover particle size with a high percentage of long fibres in the 19 mm and 8 mm screens, which results from the animal sorting activity against longer particles. These results indicate that the way feed is pushed back to the feeding trough affects the innate feed-sorting behaviour of the animals, interacting with the other factors resulting from the housing characteristics.