Mineral Trial

Mineral Supplementation

I’ve been pondering mineral supplementation in recent years – especially after losing a couple of weaner heifers with Selenium (Se) deficiency in June 2018. Last year I submitted an application for a smart farms grant which would have enabled our Landcare Group to blood test cattle across a number of herds in the region. The grant application was not successful so I decided to jump straight into a response trial with Multimin and Cobalife B12 Se.

Multimin vs Cobalife VB12 + Se

I’m confident that Selenium (Se) is our biggest concern. Both Multimin and Cobalife deliver Se, as does (to a tiny extent) the fluke drench we use in June.

The obvious next question is: “Is there a benefit to providing other supplements?”

Zinc and Manganese

Respected veterinary consultant John Webb Ware suggested at the Bendigo Better Beef Conference 2019 that Zinc and Manganese are not deficient in North East Victoria. This is backed up anecdotally by local vets who’ve conducted blood testing in our area.


Copper often gets a mention as a potential problem. I haven’t seen rusty coated cattle and I’m led to believe copper deficiency is less likely to limit performance.


B12, if deficient, will limit performance.


So if we forget about Zinc and Manganese, I guess my trial can be simply summarised as Copper (Multimin) vs B12 (Cobalife).


All our steers and heifers were weighed and drenched at 10months of age with Flukazole C + Se. Animals with even tag numbers where given 4ml of Cobalife B12 + Se. Animals with odd tag numbers were given 5ml of Multimin.

There was no control (untreated) group as I wasn’t willing to let any animals miss the Se supplementation.


Results are in for the steers only. After 8 weeks (7/6/2020 to 25/7/2020), there is no difference in weight gain.

Sample (n)Avg daily gainAvg weight
Results of response trial

Unanswered Questions

Would untreated animals have been the same?

Having a control would have been great. Maybe I’ll try another response trial next year to answer this question.

Are there benefits to supplementation besides weight gain?

Fertility is the other big label claim to these products. I’ll have pregnancy test results for the heifers eventually but I imagine a supplement so far (5 months) prior to joining will not influence pregnancy rates. Feedback from the twittersphere suggests users have not seen Multimin make any difference to pregnancy rates when tested with an untreated control.

Is Selovin LA a better way to supplement Se?

Probably – for some cattle. The Se in Selovin is in a different form (barium selenate) to the Multimin and Cobalife (sodium selenate) which allows you to deliver a much bigger volume which releases slowly over 12 months. By comparison, the amount of Se delivered by Multimin and Cobalife lasts up to 3 months.

Selovin a more difficult injection to administer as it is important to inject behind the animals ear to avoid carcass damage. Barium residue at the injection site also has the potential to show up on export carcass X-ray tests. The cows I’ve needled with Selovin in the past all have a persistent large lump behind their ear.

Selovin may be worth considering for replacement heifers where we’d get the 12 month benefit.

How much Se do these products deliver?

Cost 500ml
(ex GST)
Se mg/ml*Rec Dose
Se/dose (mg)$/ml$/ dose$/mg Se
Cobalife VB12+Se$59.504416$0.12$0.48$0.03
Selovin LA$216.73507350$0.43$3.03$0.01
Flukazole /Flukare0.001350.035
* 350kg weaner

Where to from here?

I need more advice about critical timing of Se supplementation to decide if a long acting (Selovin) product should be in our mix or if short term winter coverage is all that we really need. We already have excellent conception rates so it’s really only weight gain that offers a return on investment for us.

Blood testing and liver biopsies are the other obvious considerations.

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