Trace minerals and your herd

Getting the right balance and level of trace minerals is an important part of animal health and production, and a sensible trace mineral supplementation program requires information.

Getting them wrong can adversely affect cow health, with sub-optimal levels leading to reduced performance and excessive levels, as well as being a waste of your hard-earned income, leading to ill-health or death.

Going into winter is a good time to be testing your herd’s mineral status. Typically, this testing would cover off selenium (Se), copper (Cu) and cobalt (Co) levels but may also include additional elements such as Iodine (tested as T4) and zinc. There are essentially three options available for doing this testing each with their own advantages and disadvantages.


Blood Tests

Testing mineral status on collected bloods is quick, easy and relatively cheap. Blood sampling is generally done on four to ten animals, gives excellent information on selenium and cobalt levels, but is limited in its use for Cu. Blood copper levels will give an indication of present copper status but are not particularly useful at assessing Cu reserves into the future. The liver is the storage organ for Cu so as far as assessing reserves, liver analysis will give you a better answer.


Liver testing on cull cows

Liver samples from cull animals (usually four to six) are a good method of assessing Cu, Se and Co levels in cattle.  If you are sending livestock to slaughter, now is a good time to get valuable information from cull-cow liver samples.  We can supply you with a liver sample request form. Two key steps are required:

Fax a fully completed copy of the liver request form to the Asurequality office of your chosen slaughter premises.  The number can be found on the back of the request form.  We can fax a copy through for you, ideally at least ONE day’s notice is required before your stock arrive for slaughter.

A copy MUST also go with the stock truck driver. Make sure it is attached to your Animal Status Declaration.

You do have to be mindful that the line of cull cows is only indicative of the rest of the herd. If these animals have had a long convalescence, have been grazing a separate area of the farm (such as a location that has not had selenium prills added), then they may not be good indicators of the rest of the herd.


Liver testing on live animals

This sounds very invasive but is a routine part of what we as large animal vets do. This requires a small incision on the right-hand side of the cow into which we pass a sterile tube that collects a small sample of liver. This does take longer than simply collecting blood and is hence slightly more expensive, but it does circumvent the limitations mentioned above.


Our preferred testing strategy:

Testing strategy

Call your vet to discuss what would be the best way of doing this job to suit you and your farm’s requirements.


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