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Selection For Resistance To Fowl Typhoid In The Chicken With Reference To Its Inheritance, W. V. Lambert, C. W. Knox 2017 Iowa State College

Selection For Resistance To Fowl Typhoid In The Chicken With Reference To Its Inheritance, W. V. Lambert, C. W. Knox

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Experiments were planned to study the influence of selection upon natural resistance to fowl typhoid in the chicken, and to determine something about the genetic nature of differences in resistance.

Using a pathogen of constant virulence and a uniform method of infection, it was determined that degree of infection influenced the mortality in unselected chicks. Both total mortality and rate of mortality were increased by the heavier doses.

Four generations of selection for resistance to a standard dose of fowl typhoid bacteria resulted in a decided decrease in mortality in the selected population. The mortalities observed in the chicks of ...


Factors Influencing Egg Production Ill. The Association Of The Date Of Hatch With Date Of First Egg, Sexual Maturity And Egg Production In S. C. White Leghorns, C. W. Knox 2017 Iowa State College

Factors Influencing Egg Production Ill. The Association Of The Date Of Hatch With Date Of First Egg, Sexual Maturity And Egg Production In S. C. White Leghorns, C. W. Knox

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. The data show a positive rectilinear association between the date of hatch and the date of first egg.

2. The date of hatch seemed to have a very slight association with the age at first egg (sexual maturity).

3. A decided curvilinear association was found between the date of hatch and the number of eggs produced before March 1.

4. The data show a positive rectilinear correlation between the date of hatch and spring egg production (March, April, May and June).

5. The date of hatch has a curvilinear association with total annual egg yield.


Studies On The Changes In Nectar Concentration Produced By The Honeybee, Apis Mellifera Part I. Changes Which Occur Between The Flower And The Hive, O. W. Park 2017 Iowa State College

Studies On The Changes In Nectar Concentration Produced By The Honeybee, Apis Mellifera Part I. Changes Which Occur Between The Flower And The Hive, O. W. Park

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. The honeybee changes the concentration of nectar or sirup only very slightly while en route to the hive.

2. The change is a decrease instead of an increase as has been assumed by many heretofore.

3. The amount of decrease varies directly with the concentration of the nectar or sirup.

4. Observed mean decreases varied from one-fiftieth of 1 percent on a 13 percent sirup to 1.8 percent on a 64 percent sirup.

5. The average decrease for Iowa nectars commonly gathered by the honeybee is about 1 percent.

6. "Carry-over" from the previous load is relatively unimportant ...


Length And Floor Construction Of Dairy Stalls, Henry Giese, C. Y. Cannon 2017 Iowa State College

Length And Floor Construction Of Dairy Stalls, Henry Giese, C. Y. Cannon

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

One of the problems confronting the designer of a dairy barn is to determine the proper length of the stall platform. Cows vary considerably in length, and the stall length should vary to to meet the requirements of individual cows. Stalls that are too short make uncomfortable beds, force the cows to stand with one or both hind feet in the gutter and cause them, in reaching for hay in the manger, to carry manure to the stall floor. Long stalls are equally objectionable as the droppings fall on the platform rather than in the gutter. Adjustable stanchions are available ...


The Pathogenicity Of Fusarium Niveum (Efs.) And The Development Of Wilt Resistant Strains Of Citrullus Vulgaris (Schrad.), D. R. Porter, I. E. Melhus 2017 Iowa State College

The Pathogenicity Of Fusarium Niveum (Efs.) And The Development Of Wilt Resistant Strains Of Citrullus Vulgaris (Schrad.), D. R. Porter, I. E. Melhus

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Watermelon wilt, caused by Fusarium niveum EFS., is a serious disease in Iowa as well as in many other sections of the United States. The present Iowa acreage is 90 percent less than it was before wilt became a factor.

Infection may occur through the roots formed on a runner covered with infested soil. Injury induced by wind-blown sand seemed to favor wilt infection.

Comparative physiologic tests were made with 18 cultures of Fusarium niveum obtained from widely separated localities. These cultures seemed to differ in: (a) rate of growth on artificial media, (b) type of pigmentation, (c) rate of ...


Some Chemical And Bacteriological Effects Of Various Kinds And Amounts Of Lime On Certain Southern Iowa Soils, R. H. Walker, P. E. Brown, A. W. Young 2017 Iowa State College

Some Chemical And Bacteriological Effects Of Various Kinds And Amounts Of Lime On Certain Southern Iowa Soils, R. H. Walker, P. E. Brown, A. W. Young

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Extensive investigations have been conducted to determine the influence of lime on acid soils, but there is still much to be learned regarding the reactions involved and the effects of additions of various kinds and amounts of lime on different soils. Soils vary widely in physical, chemical and bacteriological properties, and hence lime rarely has the same effect on different types. It has been noted that soils with practically the same hydrogen ion concentration may require different amounts of lime to neutralize the acidity. The organic matter and colloidal content are quite variable and will affect not only the need ...


Methods For Determining Carbon Dioxide Production In Soils, F. B. Smith, P. E. Brown 2017 Iowa State College

Methods For Determining Carbon Dioxide Production In Soils, F. B. Smith, P. E. Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Many investigators have studied the organic matter in soils, in the attempt to determine its nature and composition, the rate and character of the decomposition which it undergoes, the products of decomposition, and especially the value of various kinds of organic materials which may be applied to soils, as indicated by decomposition studies.


Studies On The Development Of Butter Cultures From Mixtures Of Organisms, R. S. Farmer, B. W. Hammer 2017 Iowa State College

Studies On The Development Of Butter Cultures From Mixtures Of Organisms, R. S. Farmer, B. W. Hammer

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Studies on the bacteriology of butter cultures have shown that two types of bacteria are normally present, one which attacks primarily the lactose with the formation of large amounts of lactic acid, while the other is characterized by its production of volatile acid from citric acid. These findings suggest the development of butter cultures under carefully controlled conditions by making mixtures of the two types of organisms. While many satisfactory butter cultures have been secured with this procedure, mixtures made with organisms that appear typical on the basis of morphology, cultural characteristics and the usual biochemical tests, often fail to ...


Bacteriology Of Butter Iv. Bacteriological Studies On Surface Taint Butter, H. A. Derby, B. W. Hammer 2017 Iowa State College

Bacteriology Of Butter Iv. Bacteriological Studies On Surface Taint Butter, H. A. Derby, B. W. Hammer

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. The surface taint butter examined often contained large numbers of bacteria, as determined by the plate method, and with some of the samples the counts were very high; with a few samples the counts were comparatively low. The counts were higher on the surface portion of a sample than on the interior portion in all but 1 of 20 comparisons.

2. The surface taint butter examined usually contained large numbers of yeasts, with the surface portion of a sample commonly containing a larger number than the interior portion; the butter showed some mold counts that were high and a ...


Chemistry Of Butter And Butter Making I. A Comparison Of Four Methods For The Analysis Of Butter With An Explanation Of A Discrepancy Found To Exist In The Fat Determinations, E. W. Bird, D. F. Breazeale 2017 Iowa State College

Chemistry Of Butter And Butter Making I. A Comparison Of Four Methods For The Analysis Of Butter With An Explanation Of A Discrepancy Found To Exist In The Fat Determinations, E. W. Bird, D. F. Breazeale

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. A modification of the A. O. A. C. method for complete butter analysis is described. The method is considered applicable for use in control laboratories, in which eight or more samples are analyzed at a time.

2. This method, together with the Kohman and Mojonnier analyses for butter, was compared with the A. O. A. C. method as a standard. The modified official and the Kohman methods check closely with the A. O. A. C. method for all constituents of butter. With the 50 samples analyzed in duplicate the fat content was 0.22 percent lower by the Mojonnier ...


The Biology Of The Stalk Borer Papaipema Nebris (Gn.), George C. Decker 2017 Iowa State College

The Biology Of The Stalk Borer Papaipema Nebris (Gn.), George C. Decker

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. The stalk borer, Papaipema. nebris (Gn.), is a native American insect, normally feeding upon Ambrosia trifida but occasionally causing considerable damage to corn and other crops.

2. There is but one generation each year. The overwintering eggs hatch during late April or early May and after a growing period of from 9 to 18 weeks the larvae pupate. The moths emerge during August or September and begin at once to deposit eggs for the next year's brood upon the leaves of grass and weeds.

3. The number of larval instars required to complete development varied from seven to ...


Genetic Tests For Linkage Between Row Number Genes And Certain Qualitative Genes In Maize, E. W. Lindstrom 2017 Iowa State College

Genetic Tests For Linkage Between Row Number Genes And Certain Qualitative Genes In Maize, E. W. Lindstrom

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Tests on a large scale were devised to determine if the multiple genes for kernel row number on the maize ear would show genetic linkage with known genes on several of the maize chromosomes. The linkage groups tested involved P (pericarp and cob), R (aleurone), Su, (endosperm), and Y (endosperm color) chromosomes.

A very significant correlation between cob (and pericarp) color and row number was discovered in a large series of crosses. This was so pronounced that one is inclined very strongly to believe that one of the major row-number genes is located on the P chromosome.

The experiments involving ...


Bacteriology Of Butter Iii. A Method For Studying The Contamination From Churns, B. W. Hammer, H. C. Olson 2017 Iowa State College

Bacteriology Of Butter Iii. A Method For Studying The Contamination From Churns, B. W. Hammer, H. C. Olson

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

A method for the study of the contamination from churns is suggested. It consists of allowing a small amount of an agar medium containing 2.5 percent air-dried agar to solidify in contact with the surface to be studied, the transferring of the agar preparation thus formed to a sterile petri dish and finally the counting of the colonies that develop on incubation. With surfaces nearly horizontal the agar is poured on, while with surfaces not nearly horizontal the medium is poured behind a glass plate held a short distance from the surface by a gasket. The results are expressed ...


The Secular Movement Of Corn Prices, Geoffrey S. Shepherd 2017 Iowa State College

The Secular Movement Of Corn Prices, Geoffrey S. Shepherd

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

One of the problems of Corn Belt agriculture is the instability of its prices. This is especially true of its major products, corn, hogs and cattle.

Among these three, the price of corn deserves particular study. Its fluctuations are rapid and irregular, and at times become very great. On four different occasions since the world war, the price of No.3 yellow corn at Chicago has risen or fallen more than 25 cents in two months. The coefficient of variability of the series of monthly prices (the standard deviation of the prices divided by their mean) for the period November ...


The Measurement Of The Degree Of Saturation Of Soils With Bases, R. H. Walker, B. J. Firkins, P. E. Brown 2017 Iowa State College

The Measurement Of The Degree Of Saturation Of Soils With Bases, R. H. Walker, B. J. Firkins, P. E. Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. To determine the degree of saturation of a soil, data must be secured to show the amount of replaceable bases, replaceable hydrogen and base exchange capacity.

2. Experiments have been conducted to determine the accuracy of various methods for these determinations.

3. A study was first made of the electrodialysis method for replaceable bases, using both the Mattson and the Bradfield cells.

4. When 100 grams of soil were electlodialyzed in the Mattson cell for 45 hours, the results seemed satisfactory when compared with the data secured with other methods.

5. When a smaller amount of soil (10 grams ...


A Gene Influencing The Composition Of The Culm In Maize, Merle T. Jenkins, Fisk Gerhardt 2017 Iowa State College

A Gene Influencing The Composition Of The Culm In Maize, Merle T. Jenkins, Fisk Gerhardt

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. A gene influencing the strength of culm in maize has been isolated and found to behave as a simple Mendelian recessive. The character has been called lazy and the factor pail' involved has been degignated La la.

2. Lazy plants are distinguished from their normal sibs by their prostrate habit of growth. Their culms have a much lower breaking strength.

3. The culms of the lazy and normal plants have similar morphological structure, but differ histologically in the thickness of their cell walls.

4. The gene, lazy, exerts a marked influence on the composition of the culm. It greatly ...


Bacteriology Of Butter Ii. A Method For The Microscopic Examination Of Butter, B. W. Hammer, J. A. Nelson 2017 Iowa State College

Bacteriology Of Butter Ii. A Method For The Microscopic Examination Of Butter, B. W. Hammer, J. A. Nelson

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Routine determinations of the numbers of bacteria in market milk, market cream and ice cream are being used extensively in the control of the quality of these products. Comparable determinations are only occasionally employed with butter. One of the reasons for this is that many butter plants regularly add enormous numbers of bacteria in the form of butter culture to the cream that is to be churned, and, while a large percentage of these organisms is carried away in the buttermilk, the bacterial content of the butter is nevertheless greatly increased. The addition of butter culture in order to give ...


Supplements To A Milk Diet For Dairy Calves, C. Y. Cannon 2017 Iowa State College

Supplements To A Milk Diet For Dairy Calves, C. Y. Cannon

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The two factors probably responsible for the inability to raise calves on a ration of whole milk alone are the development of rickets and anemia. Tetanic convulsions in calves probably arise in association with rickets. None of the calves in the experiments reported in this bulletin developed tetany as they were protected against rickets by feeding cod-liver oil and bone meal.

Blood pictures of the calves on a milk diet disclosed an anemic condition as measured by a reduced quantity of hemoglobin, a subnormal erythrocyte count and a lower specific gravity of the blood. The calves also became dyspneic, showed ...


Nitrate Assimilation In Soils, F. B. Smith, P. E. Brown 2017 Iowa State College

Nitrate Assimilation In Soils, F. B. Smith, P. E. Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Preliminary work with solution cultures inoculated with soil showed that 20.83 mgm. of nitrate nitrogen disappeared in eight days, while the total nitrogen increased. The results obtained with soil cultures were very similar to those obtained with the solution cultures. Treating the soil with straw in the greenhouse brought about a complete utilization of the nitrates, while there was a small accumulation of nitrate in the soil treated with farm manure.

The nitrate-assimilating power of the soil was influenced by a number of factors, and, altho much information was secured by the methods employed, more work on the various ...


Bacteriology Of Butter I. Influence Of The Distribution Of The Non-Fatty Constituents On The Changes In Bacterial Content During Holding, B. W. Hammer, R. V. Hussong 2017 Iowa State College

Bacteriology Of Butter I. Influence Of The Distribution Of The Non-Fatty Constituents On The Changes In Bacterial Content During Holding, B. W. Hammer, R. V. Hussong

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. Unsalted butter held at 21°C. showed a rapid increase in the number of bacteria it contained, whether it was held in the normal physical condition or with the serum largely separated. In general, the multiplication of bacteria was much more rapid when the serum was separated than when it was not.

2. Unsalted butter held at 7°C. also showed an increase in the number of bacteria contained, whether it was held in the normal physical condition or with the serum largely separated, but the increase was much less rapid than at 21°C. The multiplication was, in ...


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