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.