Balancing Maize silage

Balancing Maize silage
By Margaret Perry, Veterinarian, Anexa Vets

Driving around the district in the current summer dry, we are seeing some really healthy maize crops, which will be a welcome supplemental feed source following harvest. Maize silage provides high quality forage supplement that many of our dairy farmers incorporate into the ration to fill the feed gap. Maize silage has the potential to:
  • Allow cows to milk on longer in the season,
  • Minimise FEI risk,
  • Help lactating cows to maintain and gain body condition during lactating (and dry period),
  • Assist in building pasture covers during late lactation into the early dry period – with an end goal of target pasture covers come June 1st.
Maize silage has low levels of potassium, calcium, magnesium, sodium and phosphorus. Therefore feeding maize silage can exacerbate mineral deficiencies such as magnesium and calcium deficiency if other feeds which are low in these minerals are also being fed. Sometimes supplementary feeds compliment each other nicely such as PKE (high in phosphorus) and maize silage (low in phosphorus).

Dietary mineral supplementation should be considered when feeding more than 2 to 3 kg DM maize silage per cow per day. Mineral supplementation will decrease the likelihood of metabolic cows during the pre-dry off period. Maize is a low protein, high starch feed that is very palatable. Therefore, when introducing (and increasing) maize in the diet it should be done over a few days in order to allow the rumen microflora to adapt to the new nutrients. For example start at 2kgDM/cow per day of maize silage and after 5 days increase 1kDM/cow/day every 2-3 days. Introducing mineral supplements before the maize starts (if possible) and leaving them in the diet for a few days after maize has finished will reduce the risk of clinical mineral deficiencies at these higher risk times.

As with any mineral supplements, the products need to be well-mixed into the maize silage, to ensure even intakes of silage and minerals. Causmag and limeflour are not palatable, therefore if they are not mixed well, cows will miss out.
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, if you wish to make your own, then a good rule of thumb (when feeding PKE with the maize which accounts for the P) is:
  • 10g limeflour per kgDM per cow of supplement offered
  • 5g causmag per kgDM per cow maize silage offered
  • 5g salt per kgDM per cow maize silage offered.
If you want to make sure your diet is adequately balanced, speak to your vet or one of our TSR reps.

Date Added: Friday, 7th February 2020