News & Advice

Is Maize filling your feed gap?

Mar 2, 2021 | Dairy, Farm systems, Minerals

Alise Inger, Veterinarian, Anexa Vets Maramarua

Maize silage is a useful and high quality supplement that many dairy farmers use to fill feed gaps. Maize is most cost efficient when used to fill a deficit like a summer dry or to extend lactation rather than replace pasture. With the summer dry upon us, maize being harvested now will provide a welcome feed supply to many Waikato dairy farms.

Maize silage has the potential to benefit your system in the following ways:

  • Additional supplement can assist in building pasture covers as cows leave higher post grazing covers. This can help you stay 1st pasture targets.
  • Allow a longer lactation giving more days in milk
  • Lower FEI risk than PKE
  • Highly palatable feed that is a good vehicle for carrying minerals
  • Assist in maintaining or gaining cow body condition in order to hit calving BCS targets.

Maize silage is a high starch, low protein feed that is very palatable. Therefore, care needs to be taken when introducing maize into the diet. Introduction of maize silage should occur over a few days to allow rumen bugs to adapt. For example start on 2kg DM/cow per day then after 5 days increase by 1kg DM/cow every 2-3 days. Ensure that you ask the contractors what DM% your maize is, or get it tested independently, so that you know how much maize you are actually feeding.

Like all feed supplements maize is not completely balanced. Maize has low levels of potassium, magnesium, calcium, sodium and phosphorus. Sometimes these imbalances can be balanced out partially by other feeds (e.g. PKE which is high in phosphorus), but they sometimes can exacerbate the mineral deficiencies if other feeds are also low in the same minerals (e.g. PKE which is low in calcium).

Maize mineral balancer should be considered when feeding more than 2 kg DM of maize silage per day or at lower levels if other supplements that are low in minerals are already being fed. These mineral supplements need to be mixed well into the maize silage to ensure that there is even uptake of minerals and silage.
Anexa Veterinary Services has a ready to use Maize Balancer which can be easily added to maize silage and is suitable for late lactation, however depending on what other supplements are being fed you may need to tweak the minerals. A good rule of thumb for a home-made recipe is for late lactation (not freshly calved autumn) cows:

  • 10g limeflour per kgDM per cow of supplement offered
  • 5g causmag per kgDM per cow of supplement offered
  • 5g salt per kgDM per cow of supplement offered. In addition to this sometimes when grass is limiting (like now) and no PKE is being used, phosphorus may also need to be added, which can be done with dicalcium phosphate.


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