The grass uptake of grazing cows is still a great unknown in dairy cattle nutrition and grassland management on dairy farms. A pilot was conducted in 2019 in which the developed grass uptake model, based on sensor data, was tested in practice. This pilot within the Amazing Grazing project shows that the need for more control over grassland use is high and that this bottleneck figure can make an important contribution to this.
In 2019, a practical test was started on five dairy farms to estimate the daily grass intake of cows. The participants were able to view an estimate of the grass intake and grazing behavior daily. The purpose of this was to test in practice whether the daily data flow for this could be generated from various digital sources, such as sensors and cow data from management systems. The next step was to link these and calculate a daily grass intake at flock level from this data. This information is then fed back online to the participating farmer.
Reliability rating in practice
In addition to testing the technical possibilities, the second spearhead in the pilot was testing the grass intake rate among these participants themselves. How reliable is the figure and how can this indicator fit into business operations, looking at ease of use and availability. Grass uptake was calculated daily at five practice farms and fed back to the farmer. Three farms were milked in a traditional milking parlor and two farms used an automatic milking system (AMS). Parlor farms had all the data from one supplier (Nedap), which made collecting, calculating and providing feedback relatively easy. Nedap had developed a platform (internet site) especially for the participants, on which the participants could log in and view the daily grass intake. At the companies with AMS, Wageningen Livestock Research took more effort to link the data flows (more data suppliers).
All participants were very satisfied with the new key figure "Grass intake" and certainly see added value for applying this figure in their business operations. The participants were more aware of grassland use and the place of fresh grass in the total ration. The model still has some points for improvement, such as the way of availability and the time at which the farmer can consult the figure. For example, the participants wish to see the result as soon as they prepare or weigh the (rough) feed that they wish to provide to their animals in the barn. A further development of this index and the technical application is therefore desirable.