Many livestock regions across Victoria have experienced one of the best winters and the lead in to spring for some time.
The plethora of green feed available has brought to attention an increased chance of trace mineral deficiencies such as iodine, selenium, copper and cobalt, in livestock.
District Veterinary Officer at Wodonga, Jeff Cave, said given the conditions, trace mineral deficiencies could be an issue for producers this year.
He said goitre, or iodine deficiency, had been reported in sheep flocks at a couple of locations in hilly areas of the north-east, east of the Hume Freeway.
Dr Cave said the early winter growth meant that ewes may not have been ingesting sufficient iodine from the soil.
He said iodine was required by the thyroid gland to enable the newborn lamb to "thermo-regulate".
A lamb or kid with goitre was often undersized or stillborn with a reduced wool cover and weak and die of exposure more easily.
Sheep ingest several essential trace minerals from soil intake as ewes grazed short pastures after a dry summer and before the autumn break.
He said that this year with a lot of early season pasture growth the intake of trace minerals via the soil was less likely to have occurred.
In regions where there was an iodine deficiency in the soil, wet conditions meant what iodine was present was leached out of the soils.
Dr Cave said the lack of iodine did not harm the ewe but resulted in the ewe producing lambs with goitre.
He said it was difficult to treat lambs born with iodine deficiency.
Prevention was the best strategy by way of supplementing the ewes with a drench with potassium iodide in mid pregnancy. The alternative was to provide iodised salt blacks.
He said the drench was effective in ensuring all ewes received a reasonable dose.
Rapidly growing pasture was also lower in trace minerals and growing lambs had a higher demand for trace minerals and were more likely to suffer a dietary deficiency, he said.
He said producers in areas with known deficiencies should review their trace mineral supplement strategies.
Trace mineral deficiencies also affected calves.
Dr Cave said producers needed to be aware of what deficiencies they had in their area and the anticipated seasonal conditions.
Selenium supplementation could be achieved in vaccinations with added selenium at marking time for a shorter form of supplementation, or injections.
Copper deficiency presented most dramatically as enzootic ataxia (or 'swayback'), a condition causing paralysis of the hind limbs of newborn or very young lambs.
Dr Cave said special care must be taken when supplementing ewes with copper as sheep could be easily killed with relatively small amounts.
Cobalt deficiency was an ill-thrift disease of reduced appetite and growth, decreased wool production, anaemia and poor reproductive performance. Affected animals often had 'white liver' disease.
Diagnosis was based on vitamin B12 levels (vitamin B12 contains cobalt), and treatment is with vitamin B12.