Formation of calculi
(stones or crystals) within the urinary tract of sheep and goats is common and
primarily a metabolic disease. The most
common calculi found in lambs and kids on high-concentrate diets
is the struvite type, which contains calcium, magnesium and ammonium phosphates.
The mineral composition of drinking water, in conjunction with mineral
imbalances in the diet, probably contributes more to the initiation of calculi
formation than does the lack of water itself.
Castration
of young kids and lambs removes the hormonal influence necessary for full
development of the urinary tract. Consequently, the problem most frequently
occurs in lambs/kids being managed for livestock shows. The sigmoid flexure and
urethral process of lambs and kids are the most common sites for calculi to
lodge. Irritation of delicate urethral lining at the calculi lodging site causes
inflammation and restriction, thus blocking urine flow through the urethra. Retention of
urine, abdominal pain and distention and rupture of the urethra or bladder are
associated with this condition. A significant number of cases result in death of
the animal.
What to
look for if you suspect Urinary Calculi:
1. Abdominal discomfort.
Wethers are restless, kick at their belly and make frequent attempts to urinate.
If hand fed, animals may not charge the trough with the group at feeding
time.
2. Attempts to
urinate are often accompanied by rapid twitching of the tail. Animals may also
groan or bleat while attempting to urinate. Grinding or gritting the teeth while
resting is also an indication of pain.
3. Before
complete occlusion of the urinary tract, urine may dribble from the urethra, dry
on the preputial hair, and leave mineral deposits.
4. Palpation of
the penis and urethral process may reveal significant hypersensitivity,
distension and/or swelling.
Prevention
As is the case with many
health problems, prevention of this condition is much easier and more effective
than attempts at treatment. The following are offered for consideration in the
development of a urinary calculi prevention program:
1. Delay
castration of young lambs/kids as long as possible.
2. Clean, cool
water is a must. Clean enough that you would drink from the trough.
3. A ration with
at least a 2:1 calcium to phosphorus ratio greatly reduces the incidence in
feeder animals.
4. Addition of
3-4% salt in the ration stimulates water intake and has thereby proved
beneficial.
5. Ammonium
chloride should be added to the feed at the rate of 0.5-1.5% see Table 1).
Ammonium sulfate can be substituted for ammonium chloride. However, results may
be less satisfactory.
Table 1.
Ammonium Chloride as a Feed Additive (Preventative) |
Ammonium
Chloride |
To mix, add lb/ton |
For topdress, add g/lb feed |
0.50% |
10 |
2.27 |
1.00% |
20 |
4.54 |
1.50% |
30 |
6.81 |
6. The diet
should provide ample amounts of Vitamin A.
7. Haphazard
addition of "supplements" to balanced rations can result in a mineral imbalance
in the total diet.
Treatment
1. If urine flow is
completely blocked, consult a veterinarian. Surgical removal of the
urethral process may provide beneficial if the blockage is at or near the end of
the penis. However, in lambs and kids, the occlusion is frequently associated
with the sigmoid flexure of the penis located inside the abdominal
cavity.
2. If obstruction of
urine flow is not complete (animal still passing
small amounts of urine):
a. Smooth muscle
relaxants in combination with anti-inflammatory agents may be helpful. Such
treatment must be done under the supervision of a veterinarian, could prove to
be expensive and is not practical on a large scale.
b. Withholding
feed for 24 hours in conjunction with oral dosing of ammonium chloride
(0.20-0.33 g/kg body weight) can acidify the urine and thereby dissolve struvite
crystals associated with high-grain rations (Table 2). Acidification of the
urine should be maintained for > 1 week due to the probable
presence of multiple calculi in the bladder.
Table 2.
Mixing Instructions for Ammonium Chloride Solutions (Oral
Drench) |
Ammonium
Chloride
Dose,
g/kg
BW |
Animal
Weight
lb |
Volume of
Dose, cc |
20 |
40 |
60 |
mix _lb NH4CL/gal.
H2O |
0.20 |
30 |
1.20 |
0.60 |
0.40 |
|
45 |
1.80 |
0.90 |
0.60 |
|
60 |
2.40 |
1.20 |
0.80 |
0.26 |
30 |
1.56 |
0.78 |
0.52 |
|
45 |
2.34 |
1.17 |
0.78 |
|
60 |
3.12 |
1.56 |
1.04 |
0.33 |
30 |
1.98 |
0.99 |
0.66 |
|
45 |
2.97 |
1.49 |
0.99 |
|
60 |
3.96 |
1.98 |
1.32 |
Might experience
difficulty in dissolving this amount of ammonium chloride per gal. of
water. Will depend on salinity of water being used (shaded cells).
Doses were
selected assuming a 20 cc drench gun would be used to administer the
ammonium chloride solution.
Caution: Ammonia
toxicity could be a potential problem if the higher doses of
NH4Cl are
chosen. However, treatment of urinary calculi is a desperation effort.
Therefore, the risk of ammonia complications may be tolerable in light of
impending death if urine flow is not re-established. |
|