Darren Sutton: On your marks, get set…calve

It's time to start calving.

Well we blinked and we are on the cusp of another calving.

While many farms are wetter than we would like, most have good covers, good BCS and the promise of getting paid a fair reward for the effort that goes into dairy farming.
This month I want to touch on a few points about how to best transition your dry cows into high performing milkers.

Feed intakes

Ideally we want to reduce cow intakes to about 90 per cent of maintenance about 10 days prior to calving. This helps prime her metabolism to make the jump from dry to lactating cow. While this may be feasible when cows are fully housed and fed a TMR, in NZ with our weather conditions, this is highly impractical.

All you can attempt to do is in fine weather get cows to graze to 1100-1200 after thre or four hours.

As a milker, to strike the right balance of good feed intakes and ensuring the second round of grazing is also high quality pasture, graze to 1500-1600. This will ensure both good milk production and a manageable rate of cow condition. With or without supplements being fed, these target residuals remain constant.

Feed types

As a springer cow there are some better feeds than others. To help reduce their energy intakes and reduce the amount of calcium in their diet, feeding maize and/or hay or the longest and rankest paddocks help to achieve this. We are wanting to reduce their calcium and potassium intakes where possible. This allows for better absorption of magnesium and primes the cow to mobilise her own calcium stores.

Cow condition

This is a tricky one. Leading up to the PSC you are trying to get cows to 5.0 for MA cows and 5.5 for R2s and R3s, but once we move past the PSC you need to ensure that the late calvers are not becoming too fat.

The R2s and R3s will generally not be an issue if well grown and become 5.5 to 6.0 (hard to do), but the older and latest calvers when they turn into the 5.5+ BCS cows have much higher risk of becoming a down cow. These late calvers do need to be tightly fed through late spring and fed more low energy feed like hay or straw to reduce this risk.

Minerals

Dry cows and milking cows need about 20g of elemental Mg supplemented per day. This is about 40g of Mg oxide per cow per day. If dusting, then the losses can be high, so doubling this rate is typically required. If fed via a feed pad, then still make an allowance for some wastage.

Also adding magnesium chloride or sulphate through the drinking water will help reduce milk fever. These chloride and sulphate forms of Mg are absorbed better than oxides, but cannot be used to fully replace Mg oxide due to their bitterness.

It is important to start Mg supplements three to four weeks prior to calving.

Dry cows should not get any calcium supplemented to them four weeks prior to calving. Once milking, most cows, if fed mainly pasture, will have enough calcium supplied to meet their daily demands.

However if feeding higher rates of supplements like PK and maize, you may need to add in some Limeflour to account for some feeds that have a low Ca content. Often 100g /cow/day via the feed pad will cover most maize feeding deficiencies (2-4kg of maize/c/day).

Colostrums often benefit with Limeflour dusted at 200g/cow/day over their pasture even if not being supplemented with maize. This is due to their metabolism making the change and low pasture intakes in the first few days post-calving.

Avoid calving cows on effluent paddocks. Milkers are the safest mob to be grazing any long effluent paddocks.

Think through your transition plans and make sure you can set your cows up to succeed this spring and avoid metabolic issues. Planning now will save you time later.