NorFor's milk responses to changes in silage quality is accurate!

Recently, a new response function showing the change in ECM (energy corrected milk) production with changes in organic matter digestibility (OMD) of forage was introduced. This function was created based on a collection of data from different trials (Weisbjerg, Aarhus University (AU), pers-com).

This response function was compared to results from the NorFor system when simulating similar conditions..

A fixed ration consisting of 5 kg DM of rapeseed meal, 4 kg DM barley and 14 kg DM silage (20%clover) with OMD varying from 73 to 79% was used to compare ECM-responses according to the AU-function and the NorFor system. Responses can be seen in Table 1

Table 1: AU function and NorFor ECM responses with different silage quality.

Table 1 shows that when OMD of the silage is increased by 3 percentage units (from 70% to 73%), there is an increase on 1,3 kg ECM/cow/day in the data. When the simulation was performed in NorFor Feed Ration Optimizer (NFRO), there was a predicted increase by 1,4 kg ECM. When the increase of OMD was from 76% to 79% there was only 0,22 kg ECM of difference between the data and NorFor`s output. Concluding that NFRO prediction is similar to data findings.


NorFor also has the advantage to optimize economically different rations. The effect of forage quality on milk income minus feed cost (MMF) simulated with NFRO is shown in the following example. The feed ration used is the same as in Table 1.

Table 2. Effect of forage quality on MMF (milk production goal 35.5 kg ECM).

*Price of the silages was assumed the same.
**Results based on DK prices for milk and feed.

When comparing the rations for a certain milk production goal, Norfor suggests that higher OMD of silages will lead to a cheaper ration, as it will decrease the use of grains while only a slight increase in silage intake. One major assumption is that the costs of the different silages are the same. This might not be the case on many farms as higher quality is followed by more cuts, e.g. 5 cuts instead of 4 cuts and the last cut will in some cases lead to higher costs of the silage.

NorFor predicts accurately the milk production with changes in silage digestibility. Also, according to NFRO higher digestibility of silages will result in cheaper rations and higher profit.

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If you are a Cattle Nutritionist, a cattle organisation, a veterinarian, a scientist, a farm consultant or anyone else with an interest in dairy cow and cattle feeding, don´t hesitate to contact us. It might be of mutual benefit.

Best regards
Patrik Nordgren, CEO