Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of Kentucky (5145)
- University of Nebraska - Lincoln (2933)
- Department of Primary Industries and Regional Development, Western Australia (866)
- Utah State University (796)
- Brigham Young University (569)
-
- University of Arkansas, Fayetteville (527)
- South Dakota State University (299)
- TÜBİTAK (268)
- Western Kentucky University (211)
- Michigan Technological University (198)
- Louisiana State University (129)
- Claremont Colleges (125)
- International Centre of Insect Physiology and Ecology (125)
- University of Texas Rio Grande Valley (70)
- Clemson University (67)
- University of Dar es Salaam (62)
- Eastern Illinois University (61)
- Purdue University (60)
- California Polytechnic State University, San Luis Obispo (59)
- Old Dominion University (57)
- Tennessee State University (57)
- Cal Poly Humboldt (48)
- University of Northern Iowa (48)
- Portland State University (46)
- Connecticut College (45)
- SIT Graduate Institute/SIT Study Abroad (41)
- University of the Philippines Los Baños (41)
- Missouri State University (37)
- Universitas Padjadjaran (37)
- University of Minnesota Morris Digital Well (37)
- Keyword
-
- Western Australia (524)
- Grazing (344)
- Sheep (195)
- Cattle (163)
- Forage (163)
-
- Nitrogen (156)
- Climate change (146)
- Alfalfa (145)
- Biodiversity (142)
- Utah (140)
- Pasture (131)
- Grains and field crops (119)
- Yield (118)
- Livestock (117)
- Horticulture (113)
- Soil (106)
- Wheat (106)
- Agriculture (97)
- Silage (97)
- Grassland (96)
- Tall fescue (96)
- Digestibility (94)
- Plants (94)
- Stocking rate (93)
- Biological sciences (92)
- Intake (92)
- Forage quality (91)
- Pastures (90)
- Sustainability (90)
- Management (88)
- Publication Year
- Publication
-
- IGC Proceedings (1977-2023) (4103)
- United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications (576)
- Department of Agronomy and Horticulture: Faculty Publications (501)
- NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County (362)
- Journal of the Department of Agriculture, Western Australia, Series 4 (310)
-
- Turkish Journal of Botany (268)
- Brigham Young University Science Bulletin, Biological Series (260)
- The Prairie Naturalist (251)
- Forage News (244)
- Department of Plant Pathology: Faculty Publications (215)
- Theses and Dissertations (198)
- UAES Bulletins (197)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (193)
- Graduate Theses and Dissertations (189)
- Electronic Theses and Dissertations (176)
- Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences (166)
- Agricultural Research Magazine (165)
- Bryophyte Ecology Subchapters (150)
- Kentucky Alfalfa and Stored Forage Conference (148)
- Mammoth Cave Research Symposia (133)
- Kentucky Grazing Conference (129)
- All Peer-Reviewed Publications (125)
- Aliso: A Journal of Systematic and Floristic Botany (110)
- Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research (110)
- Center for Plant Science Innovation: Faculty Publications (106)
- Bulletins 4000 - (96)
- Forage Symposium at the Kentucky Cattlemen’s Convention (88)
- Experimental Summaries - Plant Research (84)
- All Archived Publications (80)
- Great Basin Naturalist Memoirs (80)
- Publication Type
- File Type
Articles 12871 - 12900 of 14327
Full-Text Articles in Entire DC Network
An Analysis Of Cadmium And Lead Uptake In Hydroponically Grown Corn Seedlings, Julie Jones Medlin
An Analysis Of Cadmium And Lead Uptake In Hydroponically Grown Corn Seedlings, Julie Jones Medlin
Dissertations
The purpose of this study was to analyze selected growth parameters of hydroponically grown corn seedlings (Zea mays) in relation to the uptake of the heavy metals, lead and cadmium. The corn seedlings were treated with various concentrations of lead and cadmium at different levels of pH, and phosphate and ferric ion concentrations. Root and shoot lengths were measured before and after heavy metal treatment to determine the relative growth in the different treatment solutions. Wet and dry weights were also obtained. The plant material was digested with nitric and perchloric acids in preparation for analysis for heavy metal content …
Challenges Facing The Family Farm - Proceedings Of A Seminar, Tom Sweeney, Peter Hackett, Tim Martella, Ron Punch, Max Trenorden, Ric Collins, David Berryman, Peter Westlund, Kevin Goss, Merle Henning, Pat Smeeton, Eileen Lanahan, Ivy Hall, Derek White, Kingsley Waterhouse, Frank Holland, David Rice, Graham Cooper, Mel Mason, Chris Henschke, John Holmes, Bill Woods, Mike Ewing, Bob Steggle, John Peirce, Peter Stallwood, Kevin Lynch, John Suiter, John Johnston, Peter Mckenzie, Leon English, Jack Ripley
Challenges Facing The Family Farm - Proceedings Of A Seminar, Tom Sweeney, Peter Hackett, Tim Martella, Ron Punch, Max Trenorden, Ric Collins, David Berryman, Peter Westlund, Kevin Goss, Merle Henning, Pat Smeeton, Eileen Lanahan, Ivy Hall, Derek White, Kingsley Waterhouse, Frank Holland, David Rice, Graham Cooper, Mel Mason, Chris Henschke, John Holmes, Bill Woods, Mike Ewing, Bob Steggle, John Peirce, Peter Stallwood, Kevin Lynch, John Suiter, John Johnston, Peter Mckenzie, Leon English, Jack Ripley
Journal articles
The papers put forward should be valuable reference to all farmers in the wheatbelt. to bridge the gap between experts and farmers. My aim in organising this seminar was an attempt to bridge the gap between experts and farmers.
Mineral Compostition Of Atriplex Hymenelytra Growing In The Northern Mojave Desert, A. Wallace, E. M. Romney, R. B. Hunter, J. E. Kinnear, G. V. Alexander
Mineral Compostition Of Atriplex Hymenelytra Growing In The Northern Mojave Desert, A. Wallace, E. M. Romney, R. B. Hunter, J. E. Kinnear, G. V. Alexander
Great Basin Naturalist Memoirs
Fifty samples of Atriplex hymenelytra (Torr.) S. Wats, were collected from several different locations in southern Nevada and California to test variability in mineral composition. Only Na, V, P. Ca, Mg, Mn, and Sr in the samples appeared to represent a uniform population resulting in normal curves for frequency distribution. Even so, about 40 percent of the variance for these elements was due to location. All elements differed enough with location so that no element really represented a uniform population. The coefficient of variation for most elements was over 40 percent and one was over 100 percent. The proportion of …
Parent Material Which Produces Saline Outcrops As A Factor In Differential Distribution Of Perennial Plants In The Northern Mojave Desert, A. Wallace, E. M. Romney, R. A. Wood, A. A. El-Ghonemy, S. A. Bamberg
Parent Material Which Produces Saline Outcrops As A Factor In Differential Distribution Of Perennial Plants In The Northern Mojave Desert, A. Wallace, E. M. Romney, R. A. Wood, A. A. El-Ghonemy, S. A. Bamberg
Great Basin Naturalist Memoirs
An area of 0.46 km2 divided into six zones in the northern Mojave Desert transitional with the Great Basin Desert has been studied. Diversity is high among the perennial plant species within the 0.46 km2 area. Common species for the two deserts that are present in the area studied are Atriplex confertifolia (Torr. & Frem.) S.Wats., Ceratoides lanata (Pursh) J. T. Howell, Grayia spinosa (Hook.) Moq., Ephedra nevadensis S. Wats. Some other species present include Lycium andersonii A. Gray, Lycium pallidum Miers, Ambrosia dumosa (A. Gray) Payne., Larrea tridentata (Sesse & Moc. ex DC) Cov., Acamptopappus shockleyi A. …
The Prairie Naturalist Volume 12, Numbers 3 And 4. September–December 1980
The Prairie Naturalist Volume 12, Numbers 3 And 4. September–December 1980
The Prairie Naturalist
THE FLORA AND SANDHILLS PRAIRIE COMMUNITIES OF ARAPAHO PRAIRIE, ARTHUR COUNTY, NEBRASKA ▪ K. H. Keeler, A. T. Harrison and L. S. Vescio
USE OF ULTRASONIC SOUND TO ESTIMATE BODY FAT DEPOTS IN THE MALLARD ▪ G. A. Baldassarre, R. J. Whyte and E. G. Bolen
NORTHERN MOCKINGBIRD BREEDING IN NORTH DAKOTA ▪ D. Child, J. Fontaine, T. Gatz, M. Johnson and J. Oswald
SPRING ARRIVAL OF BIRDS AT WOODWORTH, NORTH DAKOTA ▪ K. F. Higgins, L. M. Kirsch, and J. M. Callow
HYBRIDIZATION AND TAXONOMIC STATUS OF GREATER PRAIRIE CHICKENS AND SHARP-TAILED GROUSE (HYBRIDIZATION IN GROUSE) ▪ D. W. …
Transpiration And Co2 Fixation Of Selected Desert Shrubs As Related To Soil-Water Potential, S. B. Clark, J. Letey Jr., O. R. Lunt, A. Wallace, G. E. Kleinkopf, E. M. Romney
Transpiration And Co2 Fixation Of Selected Desert Shrubs As Related To Soil-Water Potential, S. B. Clark, J. Letey Jr., O. R. Lunt, A. Wallace, G. E. Kleinkopf, E. M. Romney
Great Basin Naturalist Memoirs
In desert plants, transpiration rates decreased before photosynthetic rates when plants were entering a period of water stress. This may have adaptive consequences. A difference of -5 bars in the soil-moisture potential had considerable importance in reducing the rate of transpiration. In Helianthus annuus L. (sunflower) the photosynthetic rate decreased before the transpiration rate in contrast to Great Basin-Mojave Desert plants, and the changes occurred with a -1 bar difference in soil-moisture potential. Morphological changes in three desert plant species [Artemisia tridentata Nutt., Ambrosia dumosa (Gray) Payne, Larrea tridentata (Ses. Moc. ex DC) Cov.] as the soil-moisture potential decreased …
Litter Production And Nutrient Content Of Litter In The Seasonally Flooded Dismal Swamp, Marta M. Gomez
Litter Production And Nutrient Content Of Litter In The Seasonally Flooded Dismal Swamp, Marta M. Gomez
Biological Sciences Theses & Dissertations
Litter production was studied in four plant communities in the Great Dismal Swamp, Virginia, that differ primarily in species composition and flooding regime. Greatest leaf deposition occurred in the more flooded communities, maple-gum (Acer-Nyssa) with 536 g m-2 yr-1 and cypress (Taxodium distichum (L.) Richard) with 528 g m-2 yr-1, followed by the cedar (Chamaecyparis thyoides (L.) BSP) and mixed hardwood (Quercus-Acer-Nyssa-Liquidambar) communities with 506 g m-2 yr-1 and 455 g m-2 yr-1, respectively. Litter nutrient concentrations were generally higher in the cypress and maple-gum stands, indicating greater nutrient availability …
The Flora And Sandhills Prairie Communities Of Arapaho Prairie, Arthur County, Nebraska, Kathleen H. Keeler, A. T. Harrison, L.S. Vescio
The Flora And Sandhills Prairie Communities Of Arapaho Prairie, Arthur County, Nebraska, Kathleen H. Keeler, A. T. Harrison, L.S. Vescio
School of Biological Sciences: Faculty Publications
The Arapaho Prairie is a 526-hectare (two-section) tract of upland Sandhills prairie located approximately nine miles southwest of the town of Arthur in Arthur Co., Nebraska (Sec. 31, 32 T18N R39W). The Prairie is at the extreme southwest edge of the 52,000-km2 Nebraska Sandhills (see Kaul 1975) and is floristically and ecologically typical of the slightly drier, western part of this vegetation type. Sandhills prairie which stretches across much of north central Nebraska is a unique type of "mixed" grassland (Pool 1914, Rydberg 1931, Tolstead 1942, Weaver 1965) created by impact of the dry, continental climate on the extensive …
Germination And Haustorial Development In Orobanche Minor Smith (Orobanchaceae), David L. Spelce
Germination And Haustorial Development In Orobanche Minor Smith (Orobanchaceae), David L. Spelce
Biological Sciences Theses & Dissertations
Orobanche minor Smith is an introduced root parasite that is known to attack some commercial crops. Germination occurs only after a preconditioning period involving moisture which must be followed by a chemical stimulant produced by the host root. Strigol and strigol analogs (GR-compounds} have been reported to germinate some species of Orobanche. Statistical tests indicate a significant difference between the effectiveness of strigol, GR-7 and GR-45 (P = 0.001).
The embryo is an undifferentiated mass of cells. During germination, the radicular pole of the embryo differentiates into the radicle, while the plumular pole remains undifferentiated. The radicle forms the primary …
The Prairie Naturalist Volume 12, Number 2. June 1980
The Prairie Naturalist Volume 12, Number 2. June 1980
The Prairie Naturalist
COMPOSITION OF BEAVER CACHES ON THE TONGUE RIVER IN MONTANA ▪ J. E. Swenson and S. J. Knapp
GRAY PARTRIDGE WINTER MOVEMENTS AND HABITAT USE IN NORTH DAKOTA ▪ J. W. Schulz
ANNOTATED CHECKLIST OF MAMMALS OF NEBRASKA ▪ J. K. Jones, Jr. and J. R. Choate
OBSERVATIONS OF SEVERAL ARCTIC GULLS IN NORTH DAKOTA ▪ C. A. Faanes and T. A. Gatz
WINTER FOOD HABITS OF NEBRASKA BOBCATS (Felis rufus) C. J Mahan
NOTE
The Meadow Jumping Mouse in Southeastern Montana ▪ W. L. Matthews
The Ferns Of The Rancho Del Cielo Region, Lawrence Victor Lof
The Ferns Of The Rancho Del Cielo Region, Lawrence Victor Lof
Theses and Dissertations - UTB/UTPA
This paper contains a key to the fifty-seven fern species found on the eastern slope of the Sierra de Guatemala in southern Tamaulipas Mexico. Included are descriptions and drawings of each of the species In addition, the climate and its relation to the unique flora of the area is discussed.
Effects Of Host Plant Patch Size And Surrounding Plant Type On Insect Population Dynamics, Lynn A. Maguire
Effects Of Host Plant Patch Size And Surrounding Plant Type On Insect Population Dynamics, Lynn A. Maguire
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The purpose of the present study was to investigate how plant spatial patterns and insect behavior interact to influence the population dynamics of insects using the plants. The study included three phases: l) field experiments using collards (Brassica oleracea) and the crucifer insect fauna; 2) simulation models representing the population dynamics of an insect herbivore as functions of insect dispersal behavior and host plant patch size; and 3) model-field syntheses integrating model predictions and field variability estimates to choose an appropriate spatial scale for future field experiments or applications.
In field experiments on surrounding plant type, collards were …
Ultrastructural Localization Of Solanidine In Potato Tubers, Shau-Ron Han
Ultrastructural Localization Of Solanidine In Potato Tubers, Shau-Ron Han
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Solanine, the green substance in potato, Solanum tuberosum L., tubers, is a toxic glycoalkaloid that is a potential human health hazard. To control the formation of this glycoalkaloid a greater understanding of its site of synthesis is needed. Labelling of solanidine, a direct precursor in the biosynthesis of solanine, with digitonin may indirectly locate the site of solanine synthesis in tubers. A study using ultrastructural cytochemical techniques was initiated to explore this possibility.
Sprouted tips and peridermal complex (periderm and cortex) tissue were fixed three different ways: (1) glutaraldehyde only, (2) osmium tetroxide and glutaraldehyde, and (3) glutaraldehyde-osmium tetroxide-digitonin mixture. …
The Prairie Naturalist Volume 12, Number 1. March, 1980
The Prairie Naturalist Volume 12, Number 1. March, 1980
The Prairie Naturalist
RESIDUAL SEEDS AS POTENTIAL SPRING WATERFOWL FOODS IN SMALL, MAN-MADE IMPOUNDMENTS ▪ G. A. Baldassarre
NOTES ON THE NATURAL HISTORY OF BATS FROM BADLANDS NATIONAL MONUMENT, SOUTH DAKOTA ▪ J. P. Farney and J. K. Jones, Jr.
PRAIRIE CHICKEN DOMINATED SHARP-TAILED GROUSE INTERACTION ▪ R. A. Schmidt
CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA— 1979 ▪ R. N. Randall
THIRD NESTING OF CATTLE EGRET IN NORTH DAKOTA ▪ R. A. Schmidt
FIRST BREEDING RECORDS OF THE WHITE-FACED IBIS IN NORTH DAKOTA ▪ R. A. Schmidt
NOTES
Pinon Jay in North Dakota ▪ R. N Randall, J. Swanick and O. Swanick
Gray-crowned …
The Extrafloral Nectaries Of Ipomoea Leptophylla (Convolvulaceae), Kathleen H. Keeler
The Extrafloral Nectaries Of Ipomoea Leptophylla (Convolvulaceae), Kathleen H. Keeler
School of Biological Sciences: Faculty Publications
Ipomoea leptophylla Torr. (Convolvulaceae) is a sprawling dry-site morning glory with two types of extrafloral nectaries: foliar nectaries and nectaries on the outside of the sepals. Both are shown to greatly increase insect visitation to the plant. Ants visiting sepal-surface nectaries significantly decrease flower damage caused by grasshoppers and seed losses caused by bruchids. These results are similar to those for I. carnea and other plants whose extrafloral nectary-ant interactions have been studied, but differ in detail. This is the first demonstration of antiherbivore defense of a prairie plant by nectary visitors.
Fisheries Report No 39 - The Wildlife Of The Proposed Toolonga Nature Reserve, Shark Bay Shire, Western Australia, A. A. Burbidge, P. J. Fuller, K. Cashin
Fisheries Report No 39 - The Wildlife Of The Proposed Toolonga Nature Reserve, Shark Bay Shire, Western Australia, A. A. Burbidge, P. J. Fuller, K. Cashin
Fisheries Research Reports
Following a Cabinet endorsed recommendation by the Environmental Protection Authority in 1975, an area of vacant Crown Zand (the Toolonga Area) was examined during April and September, 1978.
The geology, soils and vegetation of the area are described and annotated lists of mammals, birds, amphibians and reptiles are presented. A small part of the area lies in the South West Botanical Province (Irwin District) but most is in the Eremaean Botanical Province (Carnarvon District). The vertebrate fauna is a mixture of south-western, Shark Bay and arid zone species, but the last predominate.
The Toolonga Area provides an opportunity to protect …
Nongame Birds Of The Rocky Mountain Spruce- Fir Forests And Their Management, Kimberly G. Smith
Nongame Birds Of The Rocky Mountain Spruce- Fir Forests And Their Management, Kimberly G. Smith
T.W. "Doc" Daniel Experimental Forest
Spruce-fir forests in the Rocky Mountains consist mainly of Engelmann spruce and subalpine fir. The breeding avifaunas in these forests show remarkable consistency in composition along a latitudinal gradient from Montana to Arizona and New Mexico, and with avian communities in the Hudsonian life zone in Washington, Oregon, and California. Woodpeckers, corvids, and seed-eating finches are the most common components. Only the Golden Eagle and a few other raptors are threatened or endangered. Few species winter in these high mountain forests. The distribution of many species is controlled primarily by the vegetation physiognomy, a variable under the control of the …
Polyphenal Oxidase Activity And Dark Pigment Of Oospore Walls In Chara Globularis, Michael F. Glinternick
Polyphenal Oxidase Activity And Dark Pigment Of Oospore Walls In Chara Globularis, Michael F. Glinternick
Theses Digitization Project
No abstract provided.
Productivity, Depletion, And Natural Selection Of Salvia Columbariae Seeds, Robert D. Brayton, Brian Capon
Productivity, Depletion, And Natural Selection Of Salvia Columbariae Seeds, Robert D. Brayton, Brian Capon
Aliso: A Journal of Systematic and Floristic Botany
No abstract provided.
(1) Powdery Mildew Control Of Grapes With Fungicides. (2) Black Spot And Downy Mildew Of Processing Peas: 80al32. (3) Facial Eczema Investigation., A Bokor
Experimental Summaries - Plant Research
Powdery mildew control of grapes with fungicides. Location: Mount Barker Research Station. Black spot and downy mildew of processing peas - 80AL32. Facial eczema investigation. Facial eczema is a recognised myco-toxic disease of grazing stock in New Zealand. It is caused by a fungus Pithomyces chartarum growing on dead litter part of the pasture. The disease has become recognised as a risk to sheep in the Albany Region following reported losses in 1978. A pasture paddock at Cape Riche was sampled weekly by the Animal Division to determine fluctuations in spore numbers of P. chartarum. Comments: The fungus could readily …
Sulphur Nutrition Of Pastures And Crops Phosphorus And Potassium Nutrition Of Pastures On Deep Sands In The High Rainfall Areas, J S. Yeates, M F. Clarke
Sulphur Nutrition Of Pastures And Crops Phosphorus And Potassium Nutrition Of Pastures On Deep Sands In The High Rainfall Areas, J S. Yeates, M F. Clarke
Experimental Summaries - Plant Research
CONTENTS A. SULPHUR 1. Sources, rates, time of application of sulphur to legume pastures (high rainfall) - 80AL1, 80AL4, 80MA1, 80KE1. 2. Sulphur soil test on pastures (high rainfall) - 80AL12, 80AL13, 80AL14, 80BY2, 80KE2. 3. Sulphur rundown on sulphur absorbing soils of the high rainfall areas - 80BY1. 4. Sulphur requirements of pasture in low rainfall areas - 80JE17, 80M020. 5. Residual value of 1979 applied sulphur. Rates of fine gypsum applied 1980 - 79AL2, 79AL18, 79AL22, 79AL23, 79AL25, 79AL41, 78BA8 B, 79BY3, 79BY4, 79HA2, 79KE3, 79KE7, 79M020. 6. Sulphur requirements of wheat - 80JE16, 80M09. B. PHOSPHORUS 7. …
Horse Pasture, Garry D. Lacefield, J. Kenneth Evans, John P. Baker
Horse Pasture, Garry D. Lacefield, J. Kenneth Evans, John P. Baker
Agriculture and Natural Resources Publications
Pastures for horses should be more than mere exercise lots. High quality pasture can supply enough protein, vitamins, and minerals to meet the nutritional needs of most pleasure horses at relatively low cost. Although pastures furnish substantial amounts of energy, working horses will likely need additional energy supplementation. In addition, pasture will help to maintain healthy animals by furnishing the bulk needed in horse rations, as well as exercise areas, sunshine, and fresh air.
The pasture should be enclosed by a safe, strong fence. Fresh water and shade should also be provided. The pasture should be large enough to encourage …
Analyses Of Illinois Wild Turkey Habitat And April Foods, Kim D. Price
Analyses Of Illinois Wild Turkey Habitat And April Foods, Kim D. Price
Masters Theses
A vegetative analysis of turkey habitat was conducted in Alexander, Jackson, Union, and Calhoun Counties, Illinois. From these studies it was determined that turkeys inhabit relatively open stands of timber with agricultural fields and forest clearings in close proximity. Species of Quercus comprise approximately 40% or more of the tree species sampled, with Q. alba, Q. rubra, and Q. velutina being the most dominant. Found growing in association with Quercus are species of Carya, Cornus florida, Acer saccharum, Sassafras albidum, Fraxinus americana, and Ulmus rubra, in varying concentrations. The examination of food …
A Test Of The Fertilizing Value And Inhibitory Qualities Of Sewage Sludge, Gregory D. Kugler
A Test Of The Fertilizing Value And Inhibitory Qualities Of Sewage Sludge, Gregory D. Kugler
Masters Theses
Three sludges - aerobic, anaerobic, Milorganite, and peat moss were tested for fertilizing ability, seed inhibition, and chemical composition. Using green bean (Phaseolus sp.) and rye grass (Lolium perenne) seeds in two sludge amended soils, a greenhouse study indicated growth enhancement for the rye grass and variable results for the green beans. Algal and fungal contaminations were problems. Seeds germinated in sludge extract were inhibited, but no correlation with the chemical analyses could be established. Only Milorganite had a heavy metal content significantly higher than the soils tested.
Growth And Performance Of Growing-Finishing Lambs Exposed To Long Or Short Photoperiods, B. D. Schanbacher, J. D. Crouse
Growth And Performance Of Growing-Finishing Lambs Exposed To Long Or Short Photoperiods, B. D. Schanbacher, J. D. Crouse
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The effects of photoperiod (8 hr light: 16 hr dark [8L:16D] or 16L:8D) on performance of growing-finishing lambs were evaluated in an experiment with 24 rams and 24 wethers. All lambs were caged in groups of two in a controlled environment and fed a pelleted diet ad libitum for the duration of the study (10 to 22 weeks of age). Performance and carcass data showed that both photoperiod and sex of lamb affected growth rate (P<.01) and feed efficiency (P<.05) but that only sex of lamb affected carcass quality (P<.05) and yield (P<.10). A sex by photoperiod interaction was not observed for any of the traits measured. Average daily gain (grams/per day) and feed efficiency (feed/gain) for lambs in the four treatment groups tested were: rams (16L:8D), 410 and 4.3; rams (8L:16D), 340 and 4.5; wethers (16L:8D), 345 and 4.6, and wethers (8L:16D), 300 and 4.8, respectively. Carcass weight, like slaughter weight, was affected by photoperiod (P<.01) and sex of lamb (P<.05); both rams and wethers exposed to long photoperiods had the heaviest carcasses. Ram carcasses were leaner, had better yield grades and were heavier than wether carcasses, yet both ram and wether carcasses graded Choice. Testosterone concentrations in serum were undetectable (<.2 ng/ml) at 22 weeks of age in wethers but were elevated (P<.O1) in ram lambs exposed to short (3.4 ± 1.4 ng/ml) or long (.8 ± .2 ng/ml) photoperiods. Prolactin concentrations, on the other hand, were not influenced by sex of lamb but were influenced (P<.01) by photoperiod; i.e., prolactin concentrations were high in rams (190 ± 34 ng/ml) and wethers (178 ± 28 ng/ml) exposed to long photoperiods and low in rams (43 ± 9 ng/ml) and wethers (27 ± 11 ng/ml) exposed to short photoperiods. These results suggest that testosterone and prolactin may independently affect growth and performance of growing-finishing lambs.
Fertilizing Capacity And Morphology Of Fowl And Turkey Spermatozoa In Hypotonic Extender, M. R. Bakst
Fertilizing Capacity And Morphology Of Fowl And Turkey Spermatozoa In Hypotonic Extender, M. R. Bakst
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The effects of graduated increments of hypotonic Beltsville Poultry Semen Extender (BPSE) on fowl and turkey sperm morphology, motility, percentage dead
and fertility were examined. The morphology of fowl and turkey spermatozoa was
adversely affected by decreases in BPSE osmolarity; a reduction of osmolarity of
BPSE to below 200 and 140 mosmol adversely affected the fertility of fowl and
turkey spermatozoa, respectively. The addition of Ficoll to the extender allowed
direct observation of the effects of hypotonic BPSE on the sperm plasmalemma.
Plasmalemmal swelling, due to the uptake of water, was noted initially at the
midpiece. Such plasmalemmal swelling may …