Agriculture Reference
In-Depth Information
“cockle” by leather dealers and at one time were thought to be caused by
nutritional problems.)
The keds produce irritation and itching, causing the sheep to rub, scratch,
and injure their wool. Some sheep bite at themselves to relieve the suffering
and occasionally become habitual wool chewers. Wool chewers may get an
impacted rumen from eating their own wool.
Keds reduce weight gain by causing anemia and by impairing the quality
and yield of the meat. Their feces diminish the value of the wool by caus-
ing stains that do not readily come out. Wool stained by ticks is sometimes
referred to as “dingy.”
Sheep keds can be easily eradicated with systematic treatment. Mature
keds lay only one egg per week, for a total of a dozen or so in their lifetime.
The eggshells become attached to the wool ½ to 1 inch (1.3 to 2.5 cm) from
the skin. Therefore, most of them are removed in shearing, making them easy
to eliminate. Newly hatched keds die within an hour unless they can obtain
blood from a sheep. A mature ked cannot survive more than 4 days away from
the sheep.
To be effective, the whole fl ock must be treated for keds at one time; oth-
erwise the untreated sheep pass the keds back to the treated sheep. Examine a
KED TREATMENT:
A HISTORICAL PERSPECTIVE
In the nineteenth century, adult sheep were seldom treated for
ticks. Since the shearing was done later in the spring than is
common now, the heat of the sun and the scratching of the sheep
drove most of the keds onto the nicely wooled lambs. Herders
waited a few weeks after shearing, then dipped the lambs in a
liquid tobacco dip, sometimes with soap added. The vat used was
a narrow box, with a slatted, grooved shelf at one side. A lamb
was lifted out and laid on the shelf. Then the workmen squeezed
the fl eece, letting the dip run back into the box. By reusing the
dip, 5 or 6 pounds (2.3 or 2.7 kg) of cheap plug tobacco could
treat 100 lambs and was quite effective on the keds, although the
mature sheep still had enough ticks left to get a good start on the
next infestation.
