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Large Animal - Transition Cow Management

The three weeks before and after calving is the critical time period.

Pregnancy testing as soon as possible after bulls are removed from the herd (six weeks) will give good information on late calving dates (foetal ages).
For accurate calving dates for the AB cows as well, pregnancy test six weeks after AB finishes.

The Aim for the transition period is to have the cows prepared for as many of the possible changes they will face going from a dry cow to a milking cow before they calve.


Because of the space the calf takes up springers cannot eat large amounts at any one time. They need to have feed available all day to make sure they get enough energy. It is ideal to give them the same types of feed as the milkers will get so they are used to it before they calve. They will however need adjusting to a high starch supplement to avoid acidosis (e.g. maize).

Ideally, there should be enough grass in the breaks where the springers and colostrums are, that it looks like some grass is being wasted. If the cows are cleaning up the breaks well, they need to be getting silage or they will have to work too hard. Residuals should be above 1600kgDM/Ha, you can worry about quality control in late spring.


Maize can be fed up to 12kg (wet weight) per cow per day. At the higher feeding levels, there are increased risks of acidosis, (diarrhoea, poor production, death). This happens when the cows either eat lots of an easily digested feed that they are not used to or if there is not enough fibre in the diet.

The amount and type of the other parts of the diet have a big effect. It takes about three weeks for the cows gut to get used to a news feed.

Ideally, start maize silage three weeks prior to calving.

Extra fibre may be necessary. E.g. Hay, grass silage.

Maize is low in minerals. There is one mix available with Magnesium, Calcium and Salt premixed.


Depending on the quality of grass silage it can suit different times of the year.

Grass silage is a “safer” feed than maize silage. The cows do not need as much time to adapt to grass silage.

Good quality grass silage is well suited to being fed with maize silage. The Maize has low protein and high carbohydrate, while the grass silage has the reverse. In the summer/autumn protein can be low in the grass. If maize is fed at this time the levels of protein in the diet can become too low. Protein determines the level of milk production. This is why cows will often put weight on with maize silage, but will not milk very well.

The poorer quality silage, made from older grass, is an excellent dry cow feed and can be a good source of fibre to balance out the Maize and Early spring grass growth. Because it is quite bulky and comparatively low in energy it can decrease milk production if too much is fed unaccompanied by energy dense food. Not a good summer milking feed.


Check copper and selenium levels at drying off to see what supplementation is needed over the winter.
Selenium prills in the fertiliser are very effective and economical for increasing selenium levels. Selenium can be added to the drench or can be injected with a B12/Selenium supplement.

Magnesium should be started at least three weeks pre calving. Magnesium Oxide either dusted or on feed is effective. Magnesium sulphate / chloride can be put in the water but it is difficult to get it to effective levels and still be palatable.

Milking Cows and springers need 10g magnesium per cow per day.
Magnesium Chloride and Magnesium Sulphate have less magnesium than Magnesium oxide. To get the same amount of magnesium as magnesium oxide about 5 times the amount is required.

The amount given depends on how the magnesium is being given as there are different levels of wastage.

Magnesium oxide

  • Drenching - 20g/cow/day
  • On Silage - 40-80g/cow/day
    (Lower end dose rate is for in bins, higher end for in paddock)
  • Dusting - 70-150g/cow/day
    (Higher end for wet weather and large areas per cow)

Other minerals

  • Calcium, Magnesium, Salt mix for maize. 
  • 25g lime flour per kg maize (Do not give lime flour to springers)
  • Selenium - as required from blood tests
  • Copper - as required from blood tests
  • B12 (Cobalt) - as required from blood tests


Acts to modify the bacteria in the cow’s rumen so there is more energy available to the cow. On average there is 7% more energy.

It can be given as a powder on feed, as a drench or via an inline water dispenser. Due to potential problems with spreading a small amount of powder over the maize, it is recommended to mix the Rumensin in with the magnesium before spreading it onto the silage. This makes it easier to spread it evenly.

Early Pregnancy testing will give the best information on calving dates and allow for good springer management.

Dry the cows off in good condition, with a BCS of 5. (It is far more efficient to put condition on in autumn to late lactation, NOT the dry period). Cows can’t eat enough due to calf size.

  • Run different dry mobs to avoid over fat cows.
  • Test cows near drying off to see what minerals are necessary over the winter.
  • Start magnesium 3 weeks pre-calving.
  • Do not graze springers on paddocks that have been effluent treated or that have high potash levels.
  • Start maize silage 3 weeks before calving, or as soon as possible.
  • Increase maize feeding amounts over 3 weeks.
  • Offer springers and colostrums cows as much feed as possible.

Order of importance

  1. Colostrum cows
  2. Springers
  3. Milkers
  4. Drys

Please contact us for any further information or clarification.

Kamo Veterinary Limited

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