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J.B. DeWitt

Publications and source records attributed to J.B. DeWitt.

46 records · Page 3Linked to original sources
USGS1950

Rodent repellency

In the course of studies involving more than 2,500 chemical repellents, it has been found that certain groups of- compounds containing nitrogen or sulfur are repellent to rats under the , test conditions and it appears probable that some of these compounds might be used for the protection of packaged goods against rodent attacks. Additional tests to determine optimum methods of application will be necessary before final evaluation of these compounds will be possible and extensive field trials will be required to establish the degree of protection which may be afforded by the use of these materials. Pending such final evaluation, it may be assumed that the results,to date offer a means of selecting the most promising types of'materials for further trial....On the basis of the test data, it appears that some amine derivative, such as a salt of some organic, acid, or a complex with trinitrobenzene or with a metallic salt of a dialkyl dithiocarbamic acid might offer promise of protection of packaging materials against rodent attacks....Protection might be obtained through the use of certain 'physical deterrents' such as plastics, waxes or drying oils.

Modern Packaging↗
USGS1949

Rodent-repellent studies. I. Method for the evaluation of chemical repellents

A biological assay procedure and a method for the numerical expression of results have been devised for the determination of the repellency to rodents of different chemical compounds. The procedure is based upon the degree of acceptability of foods containing the candidate repellents, and has been shown to offer a rapid, reliable measure of repellent activity.

Journal of the American Pharmaceutical Association↗
USGS1949

Rodent-repellent studies. III. Advanced studies in the evaluation of chemical repellents

In order to bridge the gap between preliminary screening of chemicals for potential rodent repellency and the application of these compounds to paper cartons, more advanced studies in the evaluation of promising materials have been carried out. These studies have resulted in: (1) a modification of the food acceptance technique which eliminates doubtful compounds and also provides a closer analogy to the ultimate goal, and (2) a method for rapidly testing chemicals incorporated in paper. When the results of these latter tests are expressed as a function of time, it can be shown that a distinct correlation exists between the deterrency exhibited by treated paper and the repellency of treated food.

Journal of the American Pharmaceutical Association↗
USGS1949

Calcium and phosphorus requirements of breeding bobwhite quail

In the course of studies designed to determine the calcium and phosphorus requirements of breeding bobwhite quail, it was found that best results were obtained when the Ca/P ratio in the diet was approximately 2.3:1. Variations in the Ca/P ratio produced significant differences in results when the level of phosphorus in the diet was 0.75%, but the differences were less marked when the level of phosphorus was increased to 1.00%. Although diets containing 0.75% phosphorus and 1.8% calcium appeared adequate for reproduction, as judged by the criteria of the maintenance of satisfactory condition in the breeders, egg production, fertility, hatchability and survival of offspring during the first 5 days after hatching, it was found that the winter mortality of the offspring of birds fed such a diet was much greater than that occurring in the offspring of birds fed on diets containing 1.00 or 1.25% phosphorus. It is concluded that breeding bobwhite quail require diets furnishing approximately 1.00% phosphorus and 2.3% calcium.

Journal of Nutrition↗
USGS1948

Storage by bobwhite quail of vitamin A fed in various forms

According to studies conducted with 236 bobwhite quail chicks at Patuxent Research Refuge, crystalline carotene in cottonseed oil fed at levels of 3000 I.U. (the requirement for optimum growth), 5000 I.U., and 25,000 I.U. per pound of feed, was utilized only ⅓ to 1/7 as efficiently as vitamin A alcohol; ½; to 1/10 as natural vitamin A ester; and ¼ to 1/17 as vitamin A acetate, based on the storage of vitamin A in the liver. The carotene in the natural carrier, alfalfa leaf meal, was assimilated as effectively as was crystalline carotene in cottonseed oil, when both were fed at 5000 I.U. per pound of feed. Crystalline carotene when fed at a level over 8 times the requirement of the quail for maximum growth, or 25,000 I.U. per pound of feed, was stored as vitamin A in the livers of pen-reared quail to an extent comparable to the levels found in certain young wild quail. Vitamin A acetate was utilized more efficiently by quail than either vitamin A alcohol or the natural vitamin A ester. There was considerable individual variation in storage of vitamin A by quail on the same diet, and with the same or similar parental background.

Journal of Nutrition↗