Brassica Feeding over the Dry Period – The Good, the Bad and the Ugly

Next to fodder beet, brassicas (rape, kale, turnips and swedes), are the other mainstay of the winter diet. It helps to understand some of their properties to get the best from them.

The Good

• In kale, the upper 2/3rd of the plant has quite good ME – being about 12.5MJ. The lower part of the plant (the stalk) will be lower and is only about 7ME close to the ground. The overall ME is about 11-11.5MJ/kgDM. The ME of all other brassicas are closer to 12MJME.

• Generally speaking, brassicas have good levels of crude protein for a dry cow – 14-18%. This makes it quite a good crop to finish the winter on if you have had cows on a low crude protein fodder beet through the early part of the dry period.

• Kale/Rape have high levels of calcium – about 3 times what is in grass and 9 times what is in fodder beet bulbs. This makes it handy for replenishing bone stores in dairy cows.

• A tall grazing face can form good shelter for cows if being grazed in a southern direction.

The Bad

• Kale crops often have bad utilisation in bad weather – it can be as low as 50%. Make sure you allow for this.

• Best practice is to work on 80% utilisation in good conditions. If it is higher than this, cows are probably being underfed. Make sure you factor this in on your daily allocation.

• All brassicas are low in effective fibre (and yes that includes those chewy looking stalks). This is the reason that as a minimum 25% of the diet needs to have a long fibre source – e.g. straw, hay or baleage.

• Animals often ingest quite a bit of mud while on crop – this will deplete copper stores. Selenium is also consumed/depleted soaking up ‘free radicals’ created by a high content of poly-unsaturated fatty acids.

• Swedes can be quite hard, making it tough for calves and heifers to eat. It can tend to be lower in crude protein as well.

The Ugly

• The lack of effective fibre and if fed frozen can make cattle prone to frost bloat (a free gas bloat). The cold temperature shocks the rumen disabling the ability to belch. Wait for the frost to come off before feeding.

• Brassicas will bind up Iodine which can result in still births in calves – particularly out of heifers. Dosing a trough with stock iodine on a daily basis in the last month of gestation may reduce this risk.

• Nitrate poisoning is a real danger - particularly in rape followed next by kale. Its most likely to occur after periods of cold, low light conditions, where leaf loss has occurred from previous breakouts, and when animals go onto a frozen crop with an empty belly.

• Like fodder beet, swedes can cause acidosis. A transition period is also important.

Achieving an Optimal Outcome at Drying-Off

1. Reducing Milk Production Before Dry-Off

Lower milk production reduces udder pressure and leakage post-dry off, minimizing mastitis risk.

• Gradually reduce feed intake to about 150 MJME/day and less than 16% crude protein in the week before dry-off week.

• For 3 days before and after dry-off, provide a diet of about 90 MJME/day and 12% crude protein.

• Remove top 10% ISCC cows from supply in the last 3 days before dry-off to avoid BMSCC grades

• Feed cows straw for 2 days before dry-off to firm up faeces and reduce splatter.

• In preparation for dry-off, identify and leave some rough residual paddocks (ie. 1700-1800kg DM/ha) to return cows to on the days before and including dry-off, to minimise grass intake and keep the cows environment clean.

2. Avoid giving antibiotic DCT to low volume cows

Low volume cows have a higher risk of causing Inhibitory substance grades the next spring if treated with DCAT.

• Do not treat cows with DCAT if they were producing <5L a day in the week before dry-off. These cows should receive ITS only.

3. Identifying Cows Unsuitable for Internal Teat Sealant (ITS) Only

Certain cows are at higher risk of losing the sealant or developing mastitis.

• Avoid ITS-only treatment for older cows (≥4 years) producing more than 15L at last herd test, cows with teat end lesions, poor udder conformation, or recent clinical mastitis. These may be better suited to combination therapy.

4. Keeping Cows Calm on Dry-off Day

Calm cows are easier to handle, reducing stress and contamination risk when inserting DCT.

• Supplement calcium and magnesium in the week before dry-off (avoid oversupplementing magnesium).

• Provide plenty of a low energy, high fibre diet to keep cows satiated on dry-off days. Use straw or other high dry matter high fibre feeds

5. Ensuring Clean Teat and Udder Skin

Clean skin reduces the chance of introducing bacteria during dry-off procedures.

• Trim tails at least a month before dry-off and keep them free of dags.

• Firm up faeces through diet and avoid muddy grazing conditions.

• Apply teat spray by hand-wand to every teat at every milking for the last five days before dry-off.

• Avoid walking cows on mucky laneways on the last day.

6. Correct Teatseal Insertion Technique

Proper placement ensures the sealant stays in place and is effective.

• Hold off the top of the teat during insertion to trap it at the base of the teat.

• Do not overheat the product as it may float up into the udder (20°C is optimal).

• Insert ITS or DCAT soon after cup removal to minimize contamination risk.

7. Reducing Risk of Teatseal Loss After Administration

Loss of sealant increases mastitis risk.

• Do not let cows run immediately after treatment; walk them slowly to a clean, close paddock.

• If moving cows to a run-off, do so within 2-24 hours or wait at least 7 days.

• Continue low energy, low protein feeding for 3 days post dry-off.

Transport of Cull Cows

We all have to do our bit to ensure that cull cows are transported in such a way as to maintain animal welfare, so they arrive at the other end fit and healthy.

• Only select animals that are fit for transport.

• A BCS of at least 3.0, ideally more.

• No signs of ill health.

• No visible signs of wounds, bleeding disease or deformity.

• Can bear weight evenly on all 4 legs.

• Horns: Not ingrown or recently removed. They must be inside the ears and not sharp enough to damage each other in the truck.

  • If you are unsure have them assessed to see if they can qualify for a transport certificate by a vet. When we write a transport certificate we can only certify them for 7 days and it must be to the nearest works. Make sure you have this all organised prior to booking us in to see them.

  • Download the Fit for Transport app from MPI for more information.

Massey University has done research looking at what caused cows to go down when they went to works. They found:

1. 80% of down cows had milk fever (low blood calcium levels).

2. Most cows that went down were still lactating.

3. The further cows were transported the greater the risk of going down.

What can you do to reduce the risk of cows going down?

• Where possible, fully dry cows off before transporting to slaughter. Transporting in full milk is high risk. Milk any lactating cows as close to transport as possible.

• Cull cows should be transported for the shortest time possible and ideally processed at the nearest works. Discuss options with your stock agent. The risk of injury or going down increases with travel time and distance.

• Supplement with extra calcium and magnesium

  • Lime flour 250- 300g per cow

  • Magnesium 60- 70 gm Mag Chloride or Mag Sulphate in water and 30gm Mg Oxide mixed with hay or straw.

• Take cows off green feed (lush pasture) for a minimum of 4 hours and a maximum of 6 hours if they are still lactating, (12 hours if dry) prior to pick-up time.

• Provide ad-lib roughage and water until loading with the calcium and magnesium added.

• A grazed-out paddock is recommended to give cows the opportunity to rest before the journey. Don’t stand them on concrete.

• Cows may be held in yards overnight at the processing plant, so the total time off feed is longer than just the journey time.

2025-26 Mating Commentary

The district six-week-in-calf rates for this season has jumped to be the best we have ever recorded. The average was at 72% and the median 73% (last season this was 69% and 70% respectively). In total we had 77 farms (as at end of February) achieving a 75% or greater 6 week in-calf rate which is a massive increase on the 42 farms that achieved this last season.

Three-week submission rate remains a massive driver of six week in-calf rate. This has increased by 2% this season to finish at 85%. About 31% of farms are achieving the 3-week SR target of >90%. This is a tremendous lift on just 15% of farms achieving this target last year. Proactive steps are required throughout the season to makes this happen!

Growing conditions were cool this season, which meant most farms remained on a knife edge throughout the early/mid parts of the season (surplus pasture cut for silage/baleage from the dairy platforms is well down). The positive spin-off was that pasture quality remained excellent. A buoyant industry meant that farmers were prepared to fill deficits with in-shed feeds at higher rates and longer periods. Feed blends containing DDG have now become the normal and certainly help balance the cow diet. A feature of farms with a large increase in reproductive performance is that they are also well up on production. Well fed cows get back in-calf – both submission and conception will improve.

Now is a great time to get in contact with your Prime Vet to review this season’s results and identify work-on’s and an appropriate plan to get there.

Mastitis Multiplex PCR – A big advance in milk quality management

Many of you will be aware of the highly convenient, Staph aureus PCR test that LIC has had an available for use on herd test samples for the last 10 years.

This season the test has got better. As well as a much improved sensitivity (improved chance of detecting Staph aureus if the cow is infected with it), the test will also simultaneously detect Strep uberis, Strep dysgalactia and will look for the presence of the BLAZ gene.

Cows detected with Staph aureus can be managed separately over the season to minimise spread to other cows. At the end of the season, these cows may be considered for culling (particularly if they possess the BLAZ gene, have been chronically high SCC or are greater than 6-7 years old.

The finding of either Strep species at a high incidence provides some certainty of the main cause of high somatic cell count cows and gives a greater confidence in the retention of younger infected cows when treated with DCAT as cure rates should be high.

The BLAZ gene is found in bacteria that are resistant to beta lactam antibiotics - e.g. penicillin. Cow milk found to contain this gene have bacteria on board which are less likely to cure with antibiotics and pose a risk to the development of herd level antibiotic resistance. Cows with Staph aureus and the BLAZ gene should definitely not be retained.

Testing of herd test samples must be booked with LIC in advance via our vet clinic. Talk to your Prime Vet. Once the herd test results are through, your Prime Vet will screen the HSSC cows and select those for testing. Typically these will be cows that are chronically high or with a SCC over 250-400,000 at the most recent herd test.

Cost of testing is $19 per cow (excluding GST). This is very good value. A minimum of 25 cows must be sampled.