Milk yield and economy when feeding fresh grass in the parlour

The performance level of organic dairy farms that use fresh grass in the barn does not differ from that of farms without grass.

By Irene Fisker, Linda Rosager Duve

Disclaimer: Please note that this text has been translated from Danish to English automatically and may contain errors.

The production results of dairy farms that use fresh grass in the barn have been compared with the production results of farms that do not use fresh grass in the barn. We followed 11 organic and conventional farms for 1-2 years. On the organic farms, the fresh grass is always a supplement to grazing.

The following figures and tables show the results for three groups of farms:

"Control" are farms without the use of fresh grass in the stable. For conventional farms, also without grazing, as this makes it possible to separate the effect of fresh stable grass from the effect of grazing.
"Barn grass" are farms that, based on feed codes and naming of feed materials, are assumed to use fresh grass in the barn.
"Project" are farms that use fresh grass in the barn and have participated in the project "Barn feeding with fresh grass in the barn".

There are only a few farms in the latter two groups, and in the statistical analysis, the groups "Barn grass" and "Project" have been combined. April and October are excluded from the calculations to avoid transition periods.

Lower milk yield in summer

Performance drops in the summer for all types of herds (see description of groups in the section above), and it seems that the drop is greatest for herds that feed fresh grass in the barn. However, the variation between farms means that this is not statistically significant.

Organic farms that use fresh grass in summer are numerically 1-2 kg per cow lower in milk yield all year round than organic farms that do not. However, the difference is not statistically significant. On the other hand, there is a difference between conventional farms with and without fresh grass.

Conventional farms that use fresh grass in summer have a lower average milk yield all year round than conventional farms that do not, see figure 1. The correlation may be that farms with a lower yield strategy choose to feed fresh grass.

Figure 1: Daily milk yield in organic and conventional large breed herds. Average of 2022/23 and 2023/24.

Tendency towards greater decrease in fat percentage

Both protein and fat percentages (see figure 2) are lower in summer for all types of farms. The use of fresh pasture grass has no effect on how much the protein percentage decreases, while there is a trend towards greater decrease in fat percentage for farms with pasture grass.