Agricultural Science Commons^™

Diurnal Rhythm In Serum Testosterone Levels And Thymidine Uptake By Testes In The Domestic Fowl, B. D. Schanbacher, W. R. Gomes, N. L. Vandemark

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Serum testosterone levels were measured by radioimmunoassay at 3-hr. intervals in a total of 80 mature Dwarf Leghorn cocks, and incorporation of thymidine-³H in testes was measured by radioautography in an additional 24 birds. Serum testosterone was higher at night (P< 0.02), averaging 7.14 ± 0.55 ng/ml during light hours (0900-1800 hr.), and 9.42 ± 0.73 ng/ml (P < 0.02) during darkness (2100-0600 hr.). In a second experiment to determine the rate of incorporation of thymidine into testes, birds were inadvertently subject to continuous artificial light during the 24-hr. study period; uptake of thyrnidine-³H did not differ between day and nighttime periods, averaging 174 ± 5 and 177 ± 4 tritium-labeled cells per mm², respectively. These data suggest that, during the Ohio spring season, testosterone production is favored at night. Spermatogenic DNA production may not vary diurnally, but the unusual lighting scheme involved may have altered the …

Morphological And Physiological Factors Related To Yield Of Alfalfa, A. L. Foutz, Wallace Wilhelm, A. K. Dobrenz

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Several morphological and physiological factors were measured on clones of alfalfa (Medicago sativa L. ‘Mesa- Sirsa’) which displayed a wide range in SLW, leaflet weight and leaflet area. Apparent photosynthesis, dark respiration and post-illumination burst expressed as mg C0₂ dm^-2hr^-1 were not related to yield. However, when the rate of each factor was expressed on a whole plant basis (rate x leaf area per plant) , significant relationships were found with yield. Correlation coefficients between total apparent photosynthesis, total dark respiration, total post-illumination C0₂ burst and yield were r = .71*, r = .77* …

Potential Insect-Control Applications For Microwaves, Stuart Nelson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The idea of using radiofrequency (RF) electric energy for controlling insects is not new. Experiments in the United States to control insects with high-frequency electric fields date back at least 45 years, and reports indicate development of similar interests in Europe during the same period. Many researchers have explored the possibilities since then, and their findings have been reviewed in several publications (Thomas, 1952; Frings, 1952; Peredel'skii, 1956; van den Bruel et al., 1960; Watters, 1962; Nelson, 1966, 1967, 1972, 1973). The purposes in preparing this paper are to summarize these findings in a general way, to discuss some of …

Ovulation, Fertility And Prenatal Mortality In Heifers Treated With Pmsg Or Porcine Fsh, D. B. Laster

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Ovulation rate, fertilization rate and prenatal mortality were studied in yearling beef heifers treated with PMSG or FSH and in non-treated controls. Oestrus was synchronized in 50% of the animals in each treatment with an oral progestagen. The gonadotrophin injections were given during the normal oestrous cycle or during the progestagen-administration period. All heifers were inseminated 6 to 10 hr after observation of standing oestrus.

Ovulation rate and percentage fertility were determined in approximately a third of the animals in each treatment group. The reproductive tracts of the remaining animals were examined 81 to 104 days after insemination for number …

Follicular Development In Heifers Infused With Follicle-Stimulating Hormone, D. B. Laster

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Follicle-stimulating hormone from different species has been used to increase ovulation and calving rates in cattle, injections proving to be most successful when given during the late follicular phase of the oestrous cycle or in combination with progestagens (Willett & Buckner, 1953; Bellows, Anderson & Short 1969). Some investigations have resulted in substantial increases in ovulation and calving rates, but there is usually a high degree of variation in ovarian response. Patterns of follicular growth and atresia have been studied in cattle (Rajakoski, 1960) and hypotheses have been suggested to explain how exogenous FSH stimulates follicle growth in relation to …

Disappearance And Uptake Of [125I]Fsh In The Rat, Rabbit, Ewe And Cow, D. B. Laster

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Follicle-stimulating hormone (_NIH-FSH-S8) was labelled with ¹²⁵I to determine its disappearance rate after a single intravenous injection and to determine the level of circulating [¹²⁵I]fsh in the blood after a single intramuscular or subcutaneous injection in the rat, rabbit, ewe and cow. There was a difference in the disappearance and uptake rates among the four species, but the shape of the curve for rate of loss and uptake of labelled fsh was similar in all species. The disappearance of radioactivity occurred at two rates; the first from 1 to 8 min and the second from …

Penstemon In Your Garden [Revised], Roger D. Uhlinger, Glenn Viehmeyer

Department of Agronomy and Horticulture: Faculty Publications

The Genus Penstemon

Penstemon Breeding: Emasculation • Pollen Collection • Pollination • Keeping Records

Selection of ParentaI MateriaIs

Species Crosses

Breeding Behavior

Sources of Breeding Material

Penstemon Propagation: Propagation by Seed • Propagation by Division and Layering • Propagation by Cuttings • Tip Cuttings • Single Node and Single Eye Cuttings • Striking the Cuttings • Rooting Mediums • Setting the Cuttings

Penstemon Diseases : Leaf Diseases • Soil Borne Diseases • Virus Diseases

Insects that Affect Penstemon: Aphids • Cutworms • False Plant Bug • Flea Beetle • Grasshoppers • Leaf hoppers • Slugs • Red Spider Mites • …

Effect Of Temperature On Food And Water Intake And Rumen Fermentation, W. R. Gengler, F. A. Martz, H. D. Johnson, G. F. Krause, Leroy Hahn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The purpose was to determine volatile fatty acid concentrations at normal (18 C) and high (35 C) ambient temperature, and to determine the effect of increasing the rumen temperature with an intra-ruminal heating coil in an 18 C ambient temperature.

Penicillium Urticae Bainier Enumeration In Soils, Fred A. Norstadt, T. M. Mccalla

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Studies of stubble-mulched soils from three locations in Nebraska showed larger total counts (bacteria and actinomycetes) and fungi than in plowed soils. Penicilliurn urticae Bainier numbers increased in subtilled soil compared with either plowed soil or subtilled soil with crop residues removed.** P. urticae B. produces patulin, a phytotoxic substance. This organism is regarded as one of the possible sources of the toxicity problem arising in stubble mulching. Penicillium expansum Link and patulin were studied in the apple replant problem.

The purpose of this paper is to present methods to estimate P. urticae B. numbers in soils and demonstrate patulin …

Rollins Adams Emerson (1873-1947) Horticulturist Pioneer Plant Geneticist Administrator Inspiring Student Adviser, Rosalind Morris

Department of Agronomy and Horticulture: Faculty Publications

The vigorous and highly productive life of Professor R. A. Emerson spanned 74 years and 7 months. His birth and death took place In New York State, but Nebraska nurtured his early development and schooling. He spent 15 years of his professional career at the University of Nebraska, followed by 33 years at Cornell University.

Rollins Adams Emerson, son of Charles David and Mary C. Adams Emerson (a direct descendant of Henry Adams), was born May 5, 1873 at Pillar Point, New York State on the eastern shore of Lake Ontario. In 1880 his family moved to Nebraska and settled …

Predicted Versus Measured Production Differences Using Summer Air Conditioning For Lactating Dairy Cows, Leroy Hahn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Predicted summer production losses were made for Holstein cows in three widely separated locations in the United States where field investigations of air conditioning for dairy barns have been completed. These losses, based on a functional relationship developed from Missouri Climatic Laboratory data and local climatological data, were compared to the measured losses at each location. Correlation of losses for Holstein cows varied from excellent in northern Ohio to good in southern Louisiana and central Missouri. Variations due to hotter- or cooler-than-normal summer seasons and level of production were reasonable at all locations.

Ponds And Marshes For Wild Ducks On Farms And Ranches In The Northern Plains, Wade H. Hamor, Hans G. Uhlig, Lawrence V. Compton

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

REGARDLESS of where you live in the , northern Plains, chances are good that you can attract wild ducks to your farm or ranch. To do so you may need to build a pond or marsh or improve the ones you now have. The center of wild-duck production in the United States is in the northern Plains and includes parts of North Dakota, South Dakota, Minnesota, Montana, Wyoming, Colorado, Nebraska, and Iowa. The numerous natural and manmade ponds and marshes along with fertile soil and favorable climate make this a region of ideal duck habitat. Many of these ponds and …

Seminal Vesiculectomy In Bulls, L. C. Faulkner, M. L. Hopwood, J. N. Wiltbank

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Semen was evaluated before and after seminal vesiculectomy in seven bulls. Volume, motility, percentage of live cells and primary abnormalities decreased, while cell concentration and secondary morphological abnormalities increased. Five of the bulls were mated with heifers and had acceptable fertility. The vesicular glands influence certain seminal characteristics but are not essential to fertility.

Response Of Sheep And Swine To Treatments For Control Of Ovulation, P. J. Dziuk

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Control of the estrous cycle is essential to precise research in gamete and zygote physiology and could be useful in animal husbandry. The conception rate in sheep during the breeding season following treatments to control ovulation has varied from about normal (Dauzier, 4; Robinson, 20; Evans et al., 9; Lamond and Bindon, 17; Brunner et al., 3; Hinds et al., 15), to distressingly low levels in other cases (Braden et al., 2; Davies, 5; Lamond, 16). Treatments during the anestrous season have given a variable response but usually only 30 to 50 percent of ewes lamb (Gordon, 13; 14).

Evaluation Of Some Methods For Controlling The Bovine Estrous Cycle, R. G. Zimbelman

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

This paper will deal primarily with the evaluation of various methods to control the estrous cycle in cattle. Consideration will be given to four methods of altering the normal estrual cycle. (A) The inhibition of ovulation as a means of altering the estrual cycle appears to be receiving most attention in recent years. The bulk of this paper will deal with ovulation inhibition by progestogens; thus, it would seem appropriate to give a brief evaluation of the other three methods.

Factors Influencing The Regression Of Corpora Lutea In The Ewe, Rabbit And Rat, H. G. Spies

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Stages in the life of corpora lutea may be divided logically into formation, function and regression. Mechanisms controlling each stage may be independent or overlapping depending on the species. Anderson et al.,(4) have pointed to lack of current evidence to allow a clear distinction between luteinizing hormone (LH) and luteotropic hormone (LTH) in farm animals. Initial LTH release is probably sufficient to form and maintain the corpora lutea for the normal estrous cycle (Aldred et al., 1). Maintenance of corpora lutea for the normal duration of an estrous cycle in hypophysectomized ewes (Denamur and Mauleon, 6) and sows (du Mesnil …

Mechanisms Controlling The Formation And Persistence Of The Corpus Luteum, L. L. Anderson, R. M. Melampy

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Mechanisms which control formation of corpora lutea during the estrous cycle, and particularly factors affecting their persistence and regression in various reproductive stages, have been of considerable interest to physiologists concerned with developing methods for control of the estrous cycle in domestic animals. Some recent reviews on control of ovarian function are those by Chester Jones and Ball (30), Anderson et al. (9) and Short (121).

The Role Of Light In The Regulation Of Cyclical Estrous Activity In Sheep, M. T. Clegg, H. H. Cole, W. F. Ganong

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The widespread existence of biological clocks among animals is documented by a considerable body of evidence. Recently Farner (13) has reviewed this subject covering information on a large variety of animals. In this paper an attempt will be made to restrict most of the discussion to sheep. Experimental data from other species, however, will be cited when it can be usefully related to an understanding of the mechanisms controlling seasonal breeding activity in this species. As far as present knowledge is concerned, the factors regulating or at least monitoring annual physiologic cycles appear to depend greatly upon the influence of …

Comments And Conclusions Concerning Studies On Estrous Control In Domestic Animals, H. H. Cole

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Let me allay at once any apprehension you may have that I am about to recapitulate all that has been said during the past two days. Redundancy at this time would merely accentuate your current soporific state. Thus I shall take advantage of the prerogative of seniority to modify the title of my talk to "Comments and conclusions concerning studies on estrous control in domestic animals."

The Lifespan Of Corpora Lutea Induced During The Luteal Phase Of The Estrous Cycle In Swine., B. N. Day

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A more complete understanding of the mechanisms involved in the function and maintenance of the corpus luteum would be very useful in developing more effective methods of controlling the estrous cycle in farm animals. Various types and classes of experimental animals have been utilized in an effort to define the factors causing the persistence of the corpus luteum. In swine, several different experimental approaches have been made in an attempt to extend, experimentally, the functional lifespan of the corpus luteum in non-pregnant animals. Less frequently, attempts have been made to induce premature regression. In general, the procedures used to induce …

Evaluation Of Methods For Controlling The Estrous Cycle, William Hansel

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Truly effective estrous cycle synchronization techniques are of great potential value to commercial producers of beef and dairy cattle, sheep, and swine. Many commercial beef cattlemen recognize the merits of using outstanding sires through artificial insemination (AI) to produce greater numbers of faster gaining cattle having the most desirable carcass characteristics. The relatively high heritability of feedlot gains makes this idea particularly attractive. Nevertheless, progress in attaining this goal has been rather slow, mainly because of the practical problems involved in breeding range cattle artificially and the low conception rates frequently obtained. Methods for cycle regulation compatible with the most …

Contents For Proceedings: Conference On Estrous Cycle Control In Domestic Animals, July 9-10, 1964

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

This publication is a record of the papers presented at a conference on estrous cycle control in domestic animals, held July 10-14, 1964 at the University of Nebraska. Objectives of the conference were to review the status quo of research on this problem, to provide a forum for exchange of ideas and experiences, and to point up the direction of future research.

Some Side-Effects And After-Effects Of Experimental Endocrine Treatments Used To Modify The Natural Estrual Rhythm, L. E. Casida

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The side-effects and after-effects to be considered in this discussion are those which grow out of experimental attempts to modify the natural estrual rhythm, and which have a bearing on the subsequent fertility ofthe animal. They are the effects that at one-and-the-same- time are the despair and the hope of workers on technological control of reproduction. They are the despair in that they detract from our immediate ability to control reproduction; they are the hope in that we may be able to learn more about the reproductive process in our attempts to analyze and understand them.

Roles Of Hypothalamus And Hypophysis In The Control Of The Estrous Cycle, A. V. Nalbandov

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The interrelation between the hypothalamus and the anterior pituitary gland has been firmly established. It is not the intention of this report to review the literature on this extensive subject. Such reviews are available in "Advances in Neuroendocrinology" (Nalbandov, 2), and since the time of this publication many papers on this subject have appeared in current journals. For the purposes of the present discussion a few fundamental facts will be restated, but the major part of my presentation will deal with my own views of the research areas which should be of special interest to animal scientists concerned with phenomena …

Hormonal Control Of Reproductive Activity In The Ewe, J. F. Wagner

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

There are many advantages which result from synchronizing the estrous period in a ewe flock. In situations where the ewes are not hand bred to the ram, the synchronization of estrus makes the application of artificial insemination (AI) techniques more efficient. Detection of estrus usually is more reliable in a synchronized flock. Only 3 to 4 days are needed to detect estrus in 90 percent of a synchronized flock, whereas 16 to 18 days are normally required. This allows the AI technician to plan the number of breedings and have semen available. When hormones are given in the feed, an …

The Variance Of Intraclass Correlation Involving Groups With One Observation, L.A. Swiger, W.R. Harvey, D.E. Everson, K.E. Gregory

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

An approximate formula is derived for the variance of intraclass correlation when unequal numbers of observations per group occur. The effect on the variance of t of adding groups with single observations is examined using the formula and results obtained by empirically generating data on a computer. The empirical results indicate that the approximate formula is satisfactory over the range of numbers used.

Adding a group with fewer than the average number of observations per group tends to reduce Vt by increasing the degrees of freedom for groups by one, but tends to increase Vt by decreasing the average precision …

Phytotoxic Substances From Soil Microorganisms And Crop Residues, T.M. Mccalla, F.A. Haskins

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The role of organic matter in the growth of plants has been a subject of much investigation and controversy since the sixteenth century. During the early era, decomposition of plant residues and green and animal manures provided a primary source of minerals for plant growth. In addition, beneficial effects on soil structure and water-holding capacity were attribute to the presence of organic matter. With the development of agricultural chemistry culminating in the work of Liebig in the nineteenth century, it was discovered that plants could make satisfactory growth in the absence of added organic matter if suitable kinds and amounts …

The Inhibition Of Seedling Growth By Crop Residues In Soil Inoculated Wlth Penicillium Urticae Bainer, D. E. Behmer, T. M. Mccalla

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In the Great Plains area of the United States, stubble-mulch practices have been widely used in the control of soil erosion by wind or water. Although this method of leaving crop residue on the surface has been very effective in combating erosion, depressed plant growth and reduced grain yield have often occurred in wet years. Similar growth problems have been observed during unseasonably cool, wet springs in field experiments at Lincoln, Nebraska. Because increased numbers of certain micro-organisms occur immediately beneath a decomposing surface mulch, the production of phytotoxic compounds under these conditions may well have been associated with the …

Microorganisms And Soil Structure, T. M. Mccalla, F. A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

SUMMARY

Good stable soil structure is valuable for promoting the growth of plants and micro-organisms by permitting enhanced aeration and water penetration and by decreasing erosion under some conditions.

Micro-organisms influence water percolation through the soil. They may plug up soil pores with byproducts of growth and reduce water percolation. On the other hand, if a soil containing a large amount of microbial products is stirred and allowed to dry, then the percolation may be high.

Micro-organisms are involved in stabilizing soil structure by their products of decomposition and their cellular binding material, such as mycelia. Microorganisms differ greatly in …

Pensternon In Your Garden, Glenn Viehmeyer

Department of Agronomy and Horticulture: Faculty Publications

A new race of hardy perennials is beginning to appear in American gardens. These are the penstemons, a genus of plants closely related to the familiar snapdragon, which may become important ornamentals as they become better known to gardeners. The purpose of this bulletin is to show the possibility of the genus as an ornamental and to suggest species and species hybrids of possible value to Great Plains gardeners; to provide information about propagation and culture; and to encourage gardeners to engage in penstemon breeding as an avocation.