If traced to industry, the problems would rank alongside Ireland's worst toxic pollution incident at Ballydine, Tipperary, in the 1980s when large numbers of cattle were poisoned by industrial emissions.
Attention has centred on three farms around the village of Askeaton. But animal health sources say the number of farms suffering unexplained abnormalities is around 20. Animal deaths linked to immune system failure are reported from as far as Rathkeale, four miles from Askeaton.
Residents in Askeaton and Ballysteen are concerned about acrid night- time emissions which sometimes force residents to cover mouths and noses when going outside. Ailments have been sufficiently serious for children of two neighbouring farmers to require specialist treatment.
No warning has been issued against people on other farms consuming local milk, though tests by an Irish Government laboratory showed above normal fluorine levels. Contamination of the human food would represent "the nightmare scenario," an Irish Farmers' Association spokesman warned.
Medical data is being collated for the inquiry by the Irish Environmental Protection Agency (EPA). But farmers fear it lacks resources, and want investigations extended to also examine reported birth defects, including foals born without eyes, across the Shannon in Co Clare.
Doctors are also concerned. Dr Mary Grey, of the Irish College of General Practitioners, said known health problems included a "particularly bad deformed birth, the like of which the obstetrician had never seen before". Rumours of an unusual number of women experiencing multiple miscarriages remain unconfirmed.
The local TD (MP), Michael Finucane, criticises long delays in starting comprehensive tests. Citing the Ballydine incident, he says that "the most fundamental lesson is that one cannot sit idly by".
Industrial sites on the southern Shannon shore include the giant Aughinish Alumina plant just three miles away. Tests by the British Agricultural Development Advisory Service (ADAS) found aluminium traces in dead cattle on the Ryan farm in Askeaton which were almost 20 times the levels considered safe.
ADAS confirmed to the farmer that high aluminium levels were present in bone ash from his animals. Three animals showed aluminium levels of 117 parts per million, 119 ppm and 790 ppm, many times greater than the danger levels.
Chris Livesey, a vet and head of toxicology and nutrition at Britain's Central Veterinary Laboratory, emphasised that aluminium is one of the most commonly found elements. Testing is easily contaminated by aluminium from other sources. Scientists admit to uncertainty over what levels of aluminium are toxic, but confirm it is linked to animal disorders involving secondary phosphate deficiency.
After aluminium sulphate accidentally contaminated water supplies in Camelford, Cornwall, in 1988, associated illnesses ranged from gastro- intestinal disturbances to rashes and mouth ulcers. A neuro-psychologist who tested 20 local people found some suffered minor brain damage causing loss of co-ordination.
Emissions also drift towards Askeaton from Moneypoint, the Irish Republic's only coal-fired power station 15 miles away. Critics complain it lacks basic "scrubber" filters and spews out thick smoke.
Initially, some investigators suspected iodine deficiency was a factor in the cattle deaths. A soil expert who helped investigate the Ballydine case says iodine levels "can be pivotal", affecting animal fertility, prolonging gestation and causing weak or "soft" calves.
Vets are wary, however. Iodine deficiencies, sometimes associated with goitrogens - naturally occurring chemicals in some clovers and other pasture plants that inhibit utilising of iodine - might explain animals' failure to thrive. But none could cite instances where it caused widespread cattle deaths.
The possibility that emissions from Aughinish or Moneypoint are involved is tempered by the fact that both are some distance from the worst-affected farms. Some investigators believe that had Aughinish's emissions affected cattle, those hit would most likely be "literally over the wall".
Both plants emit sulphur dioxide from their respective oil and coal fuels. If it were causing lethal animal health problems, enormous concentrations would have to be involved.
Aughinish Alumina strongly rejects suggestions that the company is contributing to health problems in the area.
Pat Lynch, corporate affairs director, points out that the plant is subject to 64 impositions "covering all aspects of emissions" laid down in county council planning permission, given after a public inquiry.
The firm pays for monitoring by a state agency from a ring of points around the plant. "There has never been a problem," he insists.
Aughinish processes more than 1 million tonnes of bauxite imported from west Africa into alumina for export to smelters abroad. Bauxite is crushed and ground, with alumina dissolved from "red mud" residue by the Bayer method, using caustic sodium hydroxide. Mr Lynch says the principal emission is sulphur dioxide from burning fuel oil. He discounts high aluminium traces in cattle bone ash as a cause for concern. The element is "universally present" and abnormal readings can easily occur, he says.
He attributes animal illness to imbalances in mineral trace elements in pasture and lack of supplements. Farming practice has changed radically in the last two decades, Mr Lynch claims, resulting in cattle "not getting a balanced input, leading over a number of years to deficiencies that border on the dangerous".
Nitrogen and copper levels in grassland have often not been properly tested. He says: "They [the farmers] have been playing with dynamite."Reuse content