Despite New Zealand’s relatively benign climate lending itself so well to pastoral farming, its soils can hide some
chronic mineral deficiencies that can undo the efforts of the best farm managers as they try to get the most out of
Richard Sides, Boehringer Ingelheim Animal Health NZ technical veterinarian is urging farmers to look harder at what may
be holding their stock’s performance back, and says the answer may be easier to find than they first thought.
“It could be easy to spend five seasons and a lot of money chasing the wrong solution to the problem you see in your
stock, when spending just a few hundred dollars on some advice and blood tests could reveal a simple trace element
Typically in New Zealand selenium and cobalt can be the two most common deficient minerals, thanks to this country’s
relatively young, ash type soils predominating.
Both these trace elements play a critical role in animal health and production performance.
Selenium is responsible for maintaining a healthy immune system, fertility and muscular development and about 30% of New
Zealand’s grassland area provides insufficient selenium levels.
Cobalt is critical for the synthesis of vitamin B12, important for energy and protein metabolism (and therefore healthy
growth rates). A deficiency in cobalt is typified by poor growth rates, a loss of appetite and higher death rates in
The Volcanic Plateau has the greatest natural deficiencies in these vital trace elements, and the “bush sickness” that
afflicted sheep in the first half of the 20th century prompted the mass plantings of pine trees as an option to pastoral
farming. While this area is famed for deficiency, many other pockets of NZ are almost as low.
Testing for deficiencies can be as simple as taking blood tests to detect levels of both minerals or, going one step
further, liver biopsy from several live animals can provide an even more accurate indicator of selenium levels.
“The results in a mob are very consistent for selenium, so you only need about four animals in your sample for an
Richard says it can also be surprising the outcomes from the relatively simple tests.
“We have had cases where one year the copper levels were low and selenium was high, and the following year they had
completely reversed - had my client assumed this year was the same as last he would have not only wasted money on the
copper treatment, but missed out with lower production thanks to the compromised selenium levels.
“It is worth testing each year to see where your stock are at, and to build up something of a history to learn from, and
see where your money is best spent.”
The link between trace element deficiencies and parasites is also better understood now, and failing to address one can
put stock on a slippery health slope to be afflicted by the other.
“Selenium plays a key role in helping maintain the animal’s immune system and if it is deficient in it then it is more
vulnerable to worms’ effects. In turn, the gut becomes inflamed by parasites, reducing its ability to absorb trace
elements, and so it becomes a vicious circle of infection and deficiency.”
Conducting blood/liver tests with faecal egg counts (FEC)s to get a handle on the level of worm infections will
integrate the two big challenges of worms and minerals, ensuring one is working with the other, rather than expecting
one to deal with the symptoms of the other.
“The beauty is that you can pursue this integrated approach, once you have identified the deficiencies, through the use
of a mineralised drench treatment. Eclipse with vitamin B12 and selenium is a good example of a twin active drench
delivering both minerals in an easily administered product to cover your bases.”
Richard points to the relatively low information cost that goes with acquiring blood tests, as opposed to the high cost
business of trying to boost lowered stock productivity through crops and supplements.
“That is a lot of money to spend, over what may often be an already stressful time for the animal, when the solution may
be far closer to home, and fixed far more cost effectively, with positive ongoing benefits into the following season.”