80 Farmers’ Bulletin 1150. 
head. is often carried to one side and the animal may become blind 
or appear to be blind. 
Unless surgical treatment or accident frees the sheep from its 
parasite, the animal will die, usually in the ninth month. When ex- 
amined after death, the brain or spinal cord will be found to have on 
or in it a bladderworm, or more than one, and an equal amount of 
brain or cord tissue will be found to have disappeared or been 
crowded aside by the growth of the cyst. The skull adjacent to the 
parasite is often softened or even absorbed to the point where it has 
a hole or several holes through it. In the late stages sheep are so 
emaciated that the meat is unfit for food. 
Treatment.—The treatment for gid is surgical. This is satis- 
factory only when the cyst is on the surface of the brain. Operation 
may be performed with a trocar and cannula or with a trephine. In 
the trocar and cannula operation the wool is sheared over the affected 
area, as determined by the symptoms and by palpation to find a soft 
spot or one where the sheep reacts violently to pressure. Under local 
anesthesia the trocar and cannula are driven through the skull and 
the trocar withdrawn from the cannula. If the cyst is struck, a 
watery fluid will issue from the cannula. This fluid is syringed out 
and the cannula withdrawn. Suitable cannulas are provided with a 
cleft to catch the bladder membrane and pull it out. If this fails, 
it is necessary to remove the membrane with forceps or by some other 
means. This operation, like operations generally, should be con- 
ducted under aseptic conditions: The median line of the skull 
should be avoided. 
With the trephine outfit the wool is sheared over the proper area 
and under local anesthesia and aseptic conditions a V-shaped incision 
is made through the skin and the skin dissected back. A piece of 
skull is then cut out with a five-eighths-inch trephine and the hard 
membrane covering the brain is cut with bent scissors. The parasite 
will usually push out and may be grasped with forceps and removed. 
If it does not appear, it may be necessary to explore for it with the 
finger. After removing the parasite and controlling the hemorrhage, 
the skin flap may be sewed back along one side of the tip of the V, 
and the wound covered with a pledget soaked in some antiseptic. 
The animal should be kept quiet in a dark shed for several days 
after operation. 
Some sheepmen cut the skull with a pocket knife or puncture the 
cyst with a knife. In such cases the sheep is apt to die of infection, 
even if the worm is removed. The operation for gid calls for care 
and should be performed by a competent veterinarian. If operation 
does not seem to be feasible, it is advisable to kill giddy sheep for 
mutton or send them to market before they become emaciated and 
unfit for food. 
