Cut and carry: Investigating the effects of increasing the proportion of grass in the diets of high yielding dairy cows

The increasing interest from farmers and nutritionists into the inclusion of fresh grass into dairy cow diets is confirmed in the latest report prepared by Scotland’s Rural College (SRUC) on behalf of DairyCo . 

The significant savings made from replacing expensive bought in feeds with grass and impact of the increased cost of silage making for TMR diets are the two of the elements considered.

KEY POINTS:

• Cows fed 50% of their diet as grass delivered the highest economic surplus under certain economic conditions. In the case of this system; a milk price of 32ppl or lower at a grass production cost of £15 per tonne. If milk prices decline then cut and carry systems become more attractive because of low production costs. If grass production costs were lower than £11 per tonne then 50% grass-fed cows delivered the highest economic surplus, regardless of milk price.

• Cows which were fed 25% of their diet as grass had approximately the same milk yields as those fed 50% grass, but with higher production costs. Under all economic scenarios the 25% grass-fed group delivered the lowest economic surplus, because feed costs remained high but without the benefits of high milk yields. It may not be beneficial to introduce smaller quantities of grass as part of a cut and carry system.

• TMR-only feeding delivered a higher economic surplus than both grass-fed groups at a TMR cost of £74 per tonne or lower, regardless of milk price. However, many farmers will produce grass at a lower cost than £15 per tonne, as used in this analysis. TMR-only feeding is particularly beneficial if milk prices are high due to high milk