Experiment Station Record, Volume 92, January-June, 1945 Page: 268
xiii, 1010 p. ; 24 cm.View a full description of this book.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
268 EXPERIMENT STATION RECORD [Vol. 92
percentage, and increased the degree of shrinkage of the carcass on storage. The
wool from severely infected sheep was short and dry and showed breaks in the
fibers.
It is concluded that the debilitating effects of the disease are mainly due to interference
with normal intestinal functions produced by the nodular involvement of the
intestinal wall that follows penetration of the larval stage of the parasite.
Factors influencing embryonation and survival of eggs of the stomach worm,
Haemonchus contortus, D. A. SHORB. (U. S. D. A.). (Jour. Agr. Res. [U. S.],
69 (1944), No. 7, pp. 279-287).-Using feces of sheep experimentally infested
with H. contortus, the effect of lack of oxygen, drying, and adverse temperatures on
egg survival was tested at Beltsville, Md., from August 1936 to February 1940.
After culture jars were sealed so that no fresh air could enter, embryonation of
H. contortus eggs in the cultures ceased, and in less than 4 weeks but more than
3 weeks the viability of the eggs was destroyed. At temperatures below 55 F. no
development to infectivity of H. contortus took place, and death resulted if the
exposure was sufficiently long. Constant temperatures above 98 were deleterious to
the eggs. There was little difference in the number of larvae that developed from
eggs kept at temperatures of 90 to 96 and 93 to 99 and those kept at
70. The lethal effect observed increased with the deviation from the optimum
temperatures. Drying killed eggs rapidly, but a few survived several hours in apparently
dry feces. When the moisture content of the feces was lowered by drying
the feces at a relatively low humidity or by means of air currents at a relatively
high humidity, the death rate of eggs was raised.
The data are interpreted as indicating that in the western half of the United
States, where two-thirds of the sheep and lambs are raised, the climate is usually
too dry in the summer and too cold in the winter for the survival of eggs of
H. contortus, except on irrigated pastures. Nearly all the remaining third of the
sheep and lambs raised in this country are found where the winters are cold and
embryonation of eggs in normal years would be possible only from May to September,
inclusive. The experiments involving the effect of reduced oxygen supply on
the survival of H. contortus eggs "indicate that as a source of Haemonchus infection
swamps and ponds with much organic matter may have been overrated. Most H.
contortus eggs falling in such ponds or on swampy ground would die for lack of
sufficient oxygen."
The anthelmintic efficiency against sheep nematodes of copper-nicotine sulfate
alone and copper-nicotine sulfate in conjunction with phenothiazine in salt,
A. R. MARTIN. (Cornell Univ.). (Cornell Vet., 34 (1944), No. 3, pp. 241-247).
-Nineteen ewes and 19 of their lambs were given a copper-nicotine sulfate drench
monthly while on pasture, with access to pure salt, while 39 ewes and 40 of their
lambs were handled in the same way on another pasture and received similar
drenches, with free access to phenothiazine with salt (1 : 15). The phenothiazine
group suffered no apparent deleterious effects from the administration of the drug
in the manner described. Scours and diarrhea, certain nematodes (medium-sized
stomach worms, trichostrongyles, and nodular worms), and the incidence of nodules
in the intestinal tracts were significantly reduced in the phenothiazine-treated lambs
as compared with the group getting pure salt only.
Shikles syringe with the Whitlock nozzle for administering anthelmintics to
sheep, D. F. EVELETH and J. O. Foss. (N. Dak. Expt. Sta.). (Vet. Med.,
39 (1944), No. 10, p. 388, illus. 1).-This apparatus is found useful for most liquid
anthelmintics, although certain precautions must be observed.
Diseases of pigs before and after weaning, J. S. KOEN. (U. S. D. A.).
(North Amer. Vet., 25 (1944), No. 6, pp. 339-347).-An address discussing losses
due to abortion, anemia, scours, cholera, erysipelas, enteritis, and parasitism.
Upcoming Pages
Here’s what’s next.
Search Inside
This book can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Book.
U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc5064/m1/281/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.