Report on the Agricultural Experiment Stations, 1953 Page: 32
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32 REPORT ON EXPERIMENT STATIONS, 1953
Swine kidney worm
Up to the present time there is no known drug that will safely and
effectively destroy kidney worms in swine. Studies were therefore
conducted at the stations in Hawaii and South Carolina to determine
the efficacy of certain chemicals in killing the larvae in soil. Results
of the study at the Hawaii station strongly suggest that "Polybor-3"
a combination of sodium pentaborate tetrahydrate and sodium tetraborate
pentahydrate, will enable hog raisers to make an already infected
hog lot comparatively free of kidney worm larvae, and by frequent
application to reduce materially the level of kidney worm larvae
in soil on which infected animals are kept. The station notes that this
chemical combination is injurious to plants and, therefore, should
not be used where vegetation is to be maintained. The South Carolina
station reports that soil treatment with delta isomer benzenehexachloride
will reduce kidney worm infection in young swine if
the infected pens or lots are treated once weekly until the pigs are
weaned and they are transferred to kidney-worm-free lots.
Resistance of sheep and goats to stomach worms
Experiments aimed at raising the natural resistance of sheep and
goats to the common stomach worm Haemochus contortus have been
in progress at the Texas station for many years. Early selections of
surviving animals raised without anthelmintic treatment on intensive
exposure pastures have resulted in a flock of each species able to withstand
this parasite. The survival rate in lambs has been raised from
11 to 85 percent in a 9-year period. This high survival occurred only
when both parents were tested, as lambs with only one tested resistant
parent were little different from unselected controls. When goats that
had survived the exposure test were bred to individuals that were selected
for stomach worm resistance or to unselected controls, the survival
rate was high (above 75 percent), evidence that goats are more
resistant to this parasite than sheep. In both species it is possible to
raise the level of natural resistance to the point where it will be economically
feasible to use parasite-resistant breeding stock for commercial
The New York (Cornell) station has studied a disease of lambs
characterized clinically by lameness or paralysis originating in the central
nervous system. Affected lambs came from widely separated
areas of the State. When examined at the station they had a nearly
complete motor paralysis of neck, trunks, and front and hind limbs.
A new species of filaria, Neurofilaria cornellensis, was found in the
brain and spinal cord of two sheep.
Sheep parasites also persist on pastures
A special plot at the Missouri station that was heavily contaminated
with parasite eggs and larvae was withheld from sheep for two winters
and the intervening season. When parasite-free lambs were placed on
this plot, it was proven from the subsequent infection of the animals
that eggs from at least eight different parasite species had survived.
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United States. Office of Experiment Stations. Report on the Agricultural Experiment Stations, 1953, book, 1953; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5989/m1/34/: accessed March 25, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.