Advice for supplementary feeding dairy calves at grass
© Debbie James Supplementary feeding can be key to achieving efficient growth rates when grazing heifer calves.
It can also provide protection against coccidiosis if decoquinate, prescribed by a vet, is added to the pellet.
Below, we speak to James Chapman, of Devon-based Chapman Machinery, and Tim Potter, senior clinical director at Westpoint Farm Vets, to get advice on using snackers at grass.
See also: What is the value of leader-follower systems for dairy calves?
Pros and cons
Although troughs can do the job, there are advantages to using a snacker feeder – more commonly associated with sheep systems – because it allows for a more even feed distribution.
Drops of feed are deposited around the grazing break, which can help reduce bullying and poaching associated with trough feeding.
As with all outdoor feeding systems, there is a risk of TB-infected wildlife contaminating feed, but by using a snacker, only the concentrates required for a single feed are deposited.
Therefore, it is mostly eaten before other animals have access to it.
But one of the faults associated with this system is inaccurate feed allocation, caused by the machine being incorrectly calibrated.
If calibration isn’t done, calf performance can be affected by underfeeding. Conversely, feed costs will escalate if too much feed is allocated.
Calibration
Mr Chapman says calibration should be done each time the feed type or composition is changed.
Once the feeder is calibrated to a specific feed type, he suggests making a permanent pen mark on the graduated scale on the feeder as a reference for that feed.
“This allows for quick and easy setup at a later date,” he explains.
Tips for calibration:
- Connect the feeder to the battery of the towing vehicle before calibrating and keep the engine running – on ATVs with smaller batteries, the voltage drops when the vehicle is switched off and this will affect the output rate
- The feeder should be at least half-filled with feed
- Find a suitable catching device – a bucket is ideal – and zero the weigh scales (bathroom scales will do the job)
- Deposit 10 drops of feed into the bucket, weigh it, and then divide the weight by the number of drops – to give a weight per drop
- Aim for a simple multiple, for example, 1kg or 2kg/drop. This makes it is easy to calculate in your head the number of drops required for different groups of animals when feeding
- Repeat the process if you need to adjust the drop size
Protecting against coccidiosis
Turning dairy calves out to graze from three weeks of age can put them at risk of coccidiosis, but there are steps farmers can take to prevent this, says Dr Potter.
In trailed feeder systems, the quinolone coccidiostat, decoquinate, can be used for in-feed prevention, but it can only be provided with a prescription supplied by the farm vet, he adds.
Decoquinate halts a stage in the lifecycle of the coccidia parasite, allowing the calf to build immunity in a controlled way.
“The vet will need to confirm the requirements for it with the feed mill and advise on inclusion rates,” Dr Potter explains.
Pros and cons of dosing feed
There are advantages to providing coccidiostats in feed rather than dosing orally, not least owing to the fact it is easier and requires no labour over and above feeding.
But one downside is that administration relies totally on the intakes of calves.
“You can’t 100% guarantee that every animal is getting the required intake,” warns Dr Potter.
Importance of counts
He says farmers should work alongside their vet to develop a robust plan. This should include taking dung samples, carrying out oocyst speciation counts to identify pathogenic species, and observing clinical signs.
“It is important to remember that if the disease challenge is too great, it is possible that clinical disease will occur despite decoquinate in the feed, so always look out for signs of disease and carry out faecal oocyst counts (FOCs) to monitor coccidial oocyst levels,’’ advises Dr Potter.
These oocysts are much smaller than worm eggs, so a sample might reveal thousands of them even though this is no clinical sign of infection.
The stage at which treatment is required will vary depending on the clinical scenario, but in situations where there are clinical signs of coccidiosis, farmers should seek advice from their vet and target with a drench, says Dr Potter.
Review
In systems where decoquinate is used routinely in calf feed, the health status of calves should be reviewed intermittently to determine if medication is still necessary.
“There are many farmers who have built decoquinate into their feed system and it becomes a habit to give it year-on-year, so it is worthwhile revisiting with FOCs to see if it’s still necessary.
“We haven’t got to the stage where we are seeing resistance, but it is about making the most economic decisions for a farm business, being much more targeted with medication, and understanding disease changes on your unit,” he adds.
The review should form part of an integrated parasite control programme agreed by the farmer and vet.
Dr Potter says farmers can also go a long way to controlling coccidiosis by improving hygiene and grazing low-risk fields.
Concentrate feeding at grass
A dairy heifer calf needs an overall ration of 12.5 metabolisable energy (ME) for effective growth. The grass might be 11% ME or higher, but if it is only 18% dry matter (DM) the animal must eat large quantities to sustain growth.
To fill that nutritional gap, Chris Coxon, of Tiller Farm Consultancy, recommends feeding low quantities of 18% crude protein concentrates, rationed correctly to match the protein and energy quality of grass.
He suggests feeding 1kg a head, increasing to 1.5kg a head if conditions are very wet and cold.
Farmers should slowly reduce this to 0.5kg before cutting out supplementary feed completely by six months if heifers are thriving and are at target body condition and height against weight, Mr Coxon adds.