Which is the better feed for dairy cows?
Grains (wheat, barley, maize) and PKE are all very different feeds and decisions about which feed will best suit a lactating dairy herd depends on what cows require at any given time during the season as well as practical issues, such as ways that you can deliver these feeds to the cow.
How can we compare each feed with what a cow needs?
Feeding a cow well means balancing the diet with the range of feeds available, to provide a diet as close to the ideal requirements as you can. A general description on each of the feed components is as follows:
Dry Matter (DM) %
Spring pasture is lush and contains relatively low levels of dry matter. This can be an issue particularly when grazing time is limited by the time in the shed and walking to and from the paddock. On lush spring pasture a cow may have to harvest up to 200kg of wet grass to meet its daily energy requirements. The preferred type of supplements are high DM% because every bite of supplement delivers more dry matter than spring pasture which contains a lot of water. Wheat, barley, maize and PKE are all helpful here because they contain only small quantities of water.
How can we compare these different feeds with each other?
Comparing feeds on a dry matter basis is of limited value because DM does not acknowledge the diversity of quality across the various feeds. MJME comparisons are of greater value than DM but remain limited because MJME doesn’t factor in the differences in protein, fibre, water soluble carbohydrates and starch levels between feeds. Always compare wheat, barley and maize grain with other feeds on a starch-equivalent and NDF basis, not just based on cents per kg of DM or cents per MJME. PKE can be more directly compared with higher NDF forage supplements such as silage or hay.