Document 6477631

Definition
Acidosis
A
id i – Causes,
C
Prevention and
Treatment
Known also as grain poisoning,
poisoning grain
overload, engorgement
Geoff Duddy
Extension Officer (S&W)
Industry & Investment, NSW
Definition
VFA Percentages as pH Falls
Acetic acid
Butyric acid
70
With rapid carbohydrate fermentation
Propionic acid
Lactic acid
60
50
– rumen acid percentages change
– increasingly more lactic acid is produced
– rumen and
d bl
blood
d pH
Hd
drops
– rumen buffering capacity is weakened
– fermentation efficiency drops
40
%
30
20
10
0
7
6.5
6
5.5
5
4.5
pH
1
VFA Percentages as pH Falls
Normal rumen pH range
70
60
Grain
50
%
Fibre digesting bacteria
40
preferred range
30
Grain
Starch digesting
20
bacteria preferred
range
10
0
7
6.5
6
5.5
5
4.5
pH
Causes
Causes
Acidosis is generally associated with
– feeding grains or
– pellets but may also occur when
sheep consume
– by-product feeds (eg potatoes)
that are low in fibre, high in starch
‘Sugar’
Sugar acidosis may also occur :
• on rapidly growing pastures high
in sugar but low in effective fibre
• when feeding high quality, short
chop
h acidic
idi ((pH
H values
l
<4.5)
4 5) silage
il
2
Clinical
Engorgement and
acidosis leads to:
An inability to
remove gas and
foam
Clinical acidosis symptoms usually
develop within 6-8 hours.
Symptoms may include:
• dehydration,
• depression
• scouring,
• coma and death
Sub-Clinical
Sub-Clinical acidosis symptoms:
• dehydration,
d h d ti
• abdominal pain,
• scouring,
• lameness,,
• abscess’s,
• pneumonia
Pressure build up
Asphyxiation
Sub-Clinical
• reduced fibre digestion
• reduced
d
df
feed
d iintake
t k
• reduced feed conversion
efficiency
• reduced efficiency overall
Sub-clinical acidosis is generally of
greater economic importance
Sheep Characteristics
Sheep differ from cattle with feed
passing quicker through the rumen
Sheep tend to have a higher incidence
of gut issues
O pasture
On
t
sheep
h
spend
dh
half
lf th
the ti
time
eating compared to cattle, but almost
four times longer chewing
3
Indicators of ruminal acidosis
Indicators of ruminal acidosis
Chewing activity
– While resting 40 to 50% of a flock should be
‘ h i cud’
‘chewing
d’
Faeces (remember the 3 “C’s”)
– Colour, Consistency and Content
green when g
graze fresh pasture,
p
,
• dark g
• brown-olive with increasing hay intake,
• yellow-olive with increasing grain intake and
• grey generally indicates acidosis
Solid
Poor consistency
consistency, gas
Adequate fibre bubbles, intact grain, mucin
No acidosis
casts etc are signs of
acidosis
Feed characteristics
– acidosis risk g
greater when
• pasture is lush, leafy and growing
rapidly
• feeding high quality, low pH silages
• inadequate chop length (reduces
chewing rumination and saliva)
chewing,
• feeding processed grain
• high starch, low fibre by-products
Indicators of ruminal acidosis
Laminitis/lameness
4
Indicators of ruminal acidosis
Laminitis/lameness
Due to increasing blood and pressure in
extremities leading to blood vessel
damage and swelling
Prevention of ruminal acidosis
Effective fibre = formation of a ‘rumen mat’
• Adequate and ‘effective’ fibre
Lam na damage (hooves), infection
Lamina
nfect on and
increased temperature within affected
feet
Prevention of ruminal acidosis
• Gradual adaptation to starch-rich
feeds
• Do not crack or grind grains for
sheep
Bentonite



• Include one or more of following
within a ration:

Feed Additives
a clay
l that
th t sswells
lls in size
si when
h n in
contact with rumen fluid
binds acid ions and slows gut flow
negative affect on protozoa which
increases protein availability
some palatability and digestibility
concerns
Bicarb of Soda




Feed Additives
an
n alkali
lk li
naturally produced by lamb when
chewing (in saliva)
buffers against acid production
add 1-2%
1 2% on weight basis
5
Acid Buf





calcified seaweed
honeycombed with large surface area
that buffers for an extended period
absorbs 3X more acids at pH 5 than
bicarb of soda
releases
l
calcium
l i
and
d magnesium
i
within the rumen
add 1-2% on weight basis
Virginiamycin (Eskalin)



Feed Additives
Feed Additives
an antibiotic
b
prevents multiplication of lactic
acid producing bugs
require
q
veterinary
y approval
pp
(S4)
( )
Limestone




a calcium
l i m supplement
s ppl m nt
has some buffering action in small
intestine
may reduce intake
add 1-2%
1 2% on weight basis
Yeasts


Feed Additives
Feed Additives
may aid
id in
i the
h binding
bi di of
f ‘bad’
‘b d’
bacteria within the rumen, reducing
the risk of acidosis
and/or
stimulate rumen bugs, increasing
efficiency of digestion
Feed Additives
Ionophores (eg: Bovatec)





increases
in
s s propionic
p pi ni acid
id = energy
n
prevents coccidiosis
improve feed conversion efficiencies
may reduce intake
i l d d att 25
included
25-70g
70 per ttonne of
f feed
f d
Treatment of ruminal acidosis
– feeding hay to stimulate saliva flow
– antacids (magnesium hydroxide,
hydroxide
magnesium oxide or sodium bicarbonate)
at 1 g/kg body weight
– oral electrolyte solutions,
ght vegetable oil
o l may help sheep
– use of llight
to belch captured gases, reducing early
stage losses
6
Treatment of ruminal acidosis
– antibiotics may reduce liver damage
– drench with a 1:8 dishwashing
liquid/water solution (10 ml/kg)
– treat with activated charcoal (if
available) - 1-4 g/kg with 1g/50 ml
water
– Stale beer (rate unknown…..)
unknown )
Pre-Training Lambs
There are benefits associated with ‘prep
training’ lambs while with their dam or
experienced ewes to recognise grain and
feeders prior to weaning
Pre-Training Lambs
Training
g lambs
m to recognise
g
grain and
g
feeders
• improves future recognition and
intakes
• reduces shy feeders and
• may reduce acidosis risk
7
Percentage Eating (Days 1 and 5)
Pre-Training Lambs
100
90
Many store lambs may not have been
imprinted and are being introduced to
a feeding regime to which they are
not accustomed.
80
70
%
60
50
40
30
20
Day 5
Day 1
10
0
Control
No Dams
With Dams
This increases the risk of variable
intake, engorgement and acidosis
Green et al (1984)
8