Dairy farmers in west Wales are reporting an upsurge in a condition that causes cattle to eat large quantities of soil, stones and other objects.

Exceptional winter rainfall, which leached nutrients from soil, followed by a lengthy dry spell are believed to have caused the spike in cases of pica.

Some cows have died because they have ingested so much material that their gut has become blocked.

Carmarthenshire dairy farmer Iwan Francis lost two cows to the condition while two others needed emergency surgery.

Mr Francis, who farms at Nantglas, Talog, has experienced low levels of pica in previous grazing seasons but says the problem is much worse this year.

“It started sooner, in the second week of April, and we still have it,’’ says Mr Francis, whose milking cows have access to rock salt throughout the year.

As the problem has progressed he has noticed it is more of a problem in his spring calving cows than in his autumn calvers.

Introducing oyster shell powder in feed troughs has previously helped but not this year.

Mr Francis has since added phosphorous to water and, when this didn’t help, doubled the quantity of the mineral in in-parlour concentrates, but none of these eased the problem.

While dietary interventions have not yet helped, Mr Francis has taken steps to prevent his 200-cow herd accessing stones.

“Where there is a cow track in a paddock, I have put up temporary fencing and I am also pushing them into the yard sooner at milking.’’

Cattle with pica have a depraved appetite, licking, chewing and eating unexpected objects such as plastic matting, string and urine and burrowing into earth banks to eat soil.

Pica is difficult to treat because it can have multiple underlying causes including phosphorous, sodium and fibre deficiencies as well as other factors such as acidosis, fluke and parasite burdens.

Pica can also be a result of learned behaviour from animals copying each other, although this doesn’t rule out an underlying deficiency.

Anecdotal evidence suggests there are herds that are very badly affected.

Some farmers have lost cows because they have ingested so much material that their gut has become blocked.

Vet Kate Burnby said this was unusual. “Some will not have noticed anything beyond cows licking the side of the cow track but then when they go to AI cows they will pull out a handful of gravel.’’

She describes pica as a complex condition and urges farmers with affected herds to seek veterinary advice promptly.

Ms Burnby warns against over-feeding phosphorous.

“In intensive systems some have been overfeeding phosphorous because of studies which purported to show that high levels can enhance intakes but we now know there is no benefit in over-feeding, supplement only to the appropriate levels.’’

Cattle are at risk in all systems and in all age groups but Ms Burnby says the pica being seen this year is largely affecting lactating cows.

She recommends farmers work with their vet to evaluate the ration and animal health.