Pica (depraved
Appetite) & Slurry/Urine
drinking in Cattle
Phil Rogers MRCVS
<philrogers@eircom.net>
Grange Research Centre,
Dunsany, Co. Meath, Ireland
21-Mar-2001
PICA (DEPRAVED OR ABNORMAL
APPETITE)
Pica includes persistent licking, chewing or eating
of wood (fence posts, tree-bark, sticks, wood partitions), soil (dirt, clay,
stones), rags, bones etc. Pica can occur in all types of cattle and is mainly an
outdoor problem. However, housed calves may develop navel-sucking, hair-licking
or may lick plaster off the walls.
CAUSES
SPORADIC CASES (in only a few animals in a large group) may indicate primary or
secondary BRAIN DISORDER (encephalitis, encephalopathy (as in liver disease, CCN
etc), toxicity (CNS poisons, ragwort, Pb etc), metabolic disease (nervous
ketosis, hypomagnesaemia etc) etc)).
HERD OUTBREAKS (in many animals in the group)
may arise in herd problems of parasitism, obesity, mineral deficiency (p, na,
cu, co etc), undernutrition (protein-energy deficit) and with low-roughage
feeds. Cattle in certain paddocks may eat clay or tree-bark in those paddocks
but not in adjoining paddocks. That problem often arises on lush grass (heavily
fertilised and low in fibre) and the cattle seek out the stemmier grass under
fences or on headlands. Grass in those areas may be grazed to the
ground.
REMEDIAL ACTIONS: IDENTIFY AND CORRECT THE
CAUSES
- If shortage of fibre is suspected, extra
roughage (some straw or hay) may be provided.
- If mineral deficiency (P, Na, Cu, or Co
etc) is confirmed on blood and/or feed tests, increased supplementation with
those minerals may be tried (see mineral supplements, below). However, pica
often occurs in cattle which are otherwise healthy and thriving and mineral
supplements may fail to control it.
- Some outbreaks have no known cause and may
not be solved by laboratory tests on blood or feed.
SLURRY/URINE DRINKING
Persistent drinking of slurry or urine (sometimes
drunk directly from other animals) occurs mainly as a herd problem in calved
cows wintered indoors or in yards. The problem is more aesthetic than economic,
as general herd health and productivity is usually normal. However, as infected
urine or slurry can spread infectious agents (such as TB, Salmonella,
Leptospira, BVD etc), the vice is undesirable.
CAUSES
- The causes are largely unknown. Suggested
causes include: metabolic disorders associated with high milk
yield and low roughage intake (high quality silage (high DMD) and
dairy ration); subclinical ketosis; subclinical acidosis (with
craving for alkaline material); mineral deficiency (P, Mg, Na,
trace-minerals).
- Investigation usually is futile. It has
aspects of a learned vice, associated with boredom: once it starts, it
usually spreads rapidly through the group. Poor yard drainage, or poor
concrete (allowing pooling of effluent, slurry or urine) is usual.
Otherwise, there appear to be few etiological factors in common.
- One can test blood and/or feed for mineral
deficiency (Na, Cu, Co, P, Mg etc) but many cases investigated by us over
the past 20 years have failed to confirm any specific deficiency as a main
cause.
REMEDIAL ACTIONS: IDENTIFY AND CORRECT THE
CAUSES
- If detected early (when only a few animals are
affected), removal of the culprits to a separate area may prevent the
vice from spreading to the rest of the group.
- Provision of extra roughage (some straw or
hay) and 30% inclusion of pulp (beet- or citrus-) in the concentrate feed,
improvement of yard drainage and resurfacing of pitted concrete occasionally
helps.
- If blood or silage tests indicate Na, P, Mg or
trace mineral deficiency, feeding of salt or a high-quality mineral
(see below) may be tried. However, salt or high quality mineral mixes,
even at high levels, often fail to control the problem.
See the Teagasc Manual on the Control of Mineral
Imbalances in Cattle & Sheep, or shorter Web articles on minerals
for Cows &
Other Cattle, and for Beef
Herds.
In spite of the above attempts, it may be
difficult or impossible to control slurry/urine drinking until
the cows are let out to pasture, when it usually self-cures within
days.