Agricultural Science Commons^™

Mosquito And Fly Control Research By The Usda-Ars Center For Medical, Agriculture And Veterinary Entomology (Cmave) In The Deployed War-Fighter Protection (Dwfp) Program, Kenneth J. Linthicum, Sandra A. Allan, Donald Barnard, James Becnel, Ulrich R. Bernier, Seth Britch, Gary Clark, Miriam Cooperband, Chris Geden, Jerome Hogsette, Daniel Kline, Roberto Pereira, Julia Pridgeon, Brian Quinn, Craig Welch, Liming Zhao

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

Despite existing measures to prevent and control arthropod-borne diseases in military units, these diseases continue to be serious threats to deployed troops. Due to a shrinking list of safe, cost-effective pesticides for control of disease vectors, new and improved toxicants and methods for delivery are needed by the armed forces. Since 2004, the USDA Agricultural Research Service (ARS) has participated in the Department of Defense (DOD) - sponsored Deployed War-Fighter Protection (DWFP) program to identify and develop new tools for combating pest and vector species that impact deployed war-fighters. Ongoing research at the USDA-ARS Center for Medical, Agricultural and Veterinary …

Isolation Of Salmonella Enterica And Shiga-Toxigenic Escherichia Coli O157 From Feces Of Animals In Public Contact Areas Of United States Zoological Parks, James E. Keen, Lisa M. Durso, Thomas P. Meehan

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

The fecal prevalence of subclinical Salmonella enterica and Shiga-toxigenic Escherichia coli O157 among animals in human-animal contact exhibits at institutions in the United States accredited by the Association of Zoos and Aquariums was estimated to assess public health risk. The prevalence was less than 0.6% for both zoonotic pathogens among 997 animals sampled at 36 exhibits.

A Cellulose Fiber-Based Diet For Screwworm (Diptera: Calliphoridae) Larvae, M. F. Chaudhury, Steven R. Skoda

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

A highly absorbent cellulose fiber from recycled paper was tested and compared with a polyacrylate gelling agent, Aquatain, normally used for bulking and solidifying larval rearing medium of screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae). The absorbent fiber, when mixed with water and dietary ingredients, produced a diet medium of homogeneous texture that supported larval growth and development comparable with the standard gelled diet. Larval and pupal weights from two concentrations of cellulose fiber-based diet were significantly higher than those obtained using gelled diet. The number of pupae per tray, percentage of adult emergence, oviposition, percentage of egg hatch, and adult …

Lixus Cardui, A Biological Control Agent For Scotch Thistle (Onopordum Acanthium): Safe For Australia, But Not The Usa?, Joe Balciunas

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

Invasive exotic plants are often weeds in more than one country. After a biological control agent for a weed has been developed for use in one country, it is reasonable to consider using the same agent against the same weed in another country. ‘Transfer Projects’ can save considerable time and money, and they have been popular around the world. Lixus cardui Olivier (Coleoptera: Curculionidae), a weevil from Europe, was first used by Australian researchers to control Scotch thistle, Onopordum acanthium L. (Asteraceae). There are few close relatives of Scotch thistle in Australia, but that is not the case in North …

Physiological Host Range Of Ceratapion Basicorne, A Prospective Biological Control Agent Of Centaurea Solstitialis (Asteraceae), Lincoln Smith

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

Ceratapion basicorne (Coleoptera: Apionidae) is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Host plant specificity of the insect was evaluated in no-choice oviposition experiments. Feeding on leaf tissue by adult females was highly correlated to oviposition rate, both of which occurred primarily on plants in the tribe Cardueae, and especially those in the monophyletic subtribe Centaureinae. The highest rates of larval development occurred on Ce. solstitialis and Centaurea cyanus (bachelor’s button, garden cornflower), and there was significant development on …

The Cercospora Nicotianae Gene Encoding Dual O-Methyltransferase And Fad-Dependent Monooxygenase Domains Mediates Cercosporin Toxin Biosynthesis, Katherine L. Dekkers, Bang-Jau You, Vivek S. Gowda, Hui-Ling Liao, Miin-Huey Lee, Huey-Jiunn Bau, Peter P. Ueng, Kuang-Ren Chung

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

Cercosporin, a photo-activated, non-host-selective phytotoxin produced by many species of the plant pathogenic fungus Cercospora, causes peroxidation of plant cell membranes by generating reactive oxygen species and is an important virulence determinant. Here we report a new gene, CTB3 that is involved in cercosporin biosynthesis in Cercospora nicotianae. CTB3 is adjacent to a previously identified CTB1 encoding a polyketide synthase which is also required for cercosporin production. CTB3 contains a putative O-methyltransferase domain in the N-terminus and a putative flavin adenine dinucleotide (FAD)-dependent monooxygenase domain in the C-terminus. The N-terminal amino acid sequence also is similar to …

Genetic Diversity In Laboratory Colonies Of Western Corn Rootworm (Coleoptera: Chrysomelidae), Including A Nondiapause Colony, Kyung Seok Kim, B. Wade French, Douglas V. Sumerford, Thomas W. Sappington

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

Laboratory-reared western corn rootworms, Diabrotica virgifera virgifera, from colonies maintained at the North Central Agricultural Research Laboratory (NCARL) in Brookings, SD, are used extensively by many researchers in studies of the biology, ecology, behavior, and genetics of this major insect pest. A nondiapause colony developed through artificial selection in the early 1970s is particularly attractive for many studies because its generation time is much shorter than that of typical diapause colonies. However, the nondiapause colony has been in culture for ≈190 generations without out-crossing. We compared variation at six microsatellite loci among individuals from the NCARL nondiapause colony (≈190 …

The Influence Of Oscillating Dietary Protein Concentrations On Finishing Cattle. Ii. Nutrient Retention And Ammonia Emissions, S. L. Archibeque, H. C. Freetly, N. A. Cole, Calvin Ferrell

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

We hypothesized that oscillation of the dietary CP concentrations would improve efficiency of N use and reduce N loss to the environment. Charolais-cross steers (n = 8; 315 ± 21 kg of BW) were used in a replicated 4 × 4 Latin square design. The steers were allowed ad libitum access to the following diets: 1) 9.1% CP (low), 2) 11.8% CP (medium), 3) 13.9% CP (high), or 4) low and high oscillated on a 48-h interval on each diet (oscillating). Dry matter intake did not differ among treatments (P = 0.46), but N intake differed (P < 0.01) from 94 (low) to 131 (medium), 142 (high), and 133 g/d (oscillating), as designed. Dry matter digestibility increased (P < 0.01) from 71.8% (low) to 75.8% (medium), 77.7% (high), and 77.5% (oscillating). Nitrogen digestibility increased (P < 0.01) from 62.2% (low) to 67.2% (medium) to 70.1% (high) and 70.9% (oscillating). Nitrogen retention was greater (P < 0.01) in steers fed oscillating (55.0 g/d) than in the steers fed low (34.8 g/ d) or high (40.2 g/d), but N retention of steers fed medium (49.8 g/d) differed (P = 0.02) only from that of steers fed low. Urinary urea N did not differ between steers fed medium (19.5 g/d) or oscillating (21.3 g/d) but was lowest (P < 0.01) for those fed low (8.2 g/d) and greatest for those fed high (39.2 g/d). Daily heat production (kcal/BW^0.75) tended …

Early Investments In Soil Conservation Research Continues To Provide Dividends, J. E. Gilley, D. C. Flanagan

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

Current soil conservation programs are built upon an established research legacy. Hugh H. Bennett, chief of the USDA Soil Conservation Service from 1935 to 1951, was instrumental in the establishment of a network of 35 soil conservation experiment stations (SCES). Research projects were initiated at the SCES in the 1930s to investigate the principal factors causing erosion and to identify the most effective and practical methods of controlling soil loss from agricultural areas. Information obtained from the SCES, and selected other locations, was assembled at the National Runoff and Soil Loss Data Center (NRSLDC) established on the campus of Purdue …

Transient Expression Of The Ectodomain Of Matrix Protein 2 (M2e) Of Avian Influenza A Virus In Plants, Lev G. Nemchinov, Angela Natilla

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

We have previously reported an expression system based on the capsid protein gene (CP) of cucumber mosaic virus (CMV) placed under transcriptional control of a potato virus X (PVX)-based vector. PVX-expressed CMV CP formed virus-like particles, which served as carriers for heterologous antigens of the Newcastle disease virus (NDV).
In this work, we applied our expression tool toward the development of plant-derived vaccine candidate against avian influenza A virus. Twenty-three amino acid-long extracellular domain of the viral M2 protein (M2e) was engineered into the internal motif 5 of CMV CP and the recombinant gene then was transiently expressed in plants …

Environmental Abundance Of Anopheles (Diptera: Culicidae) Larval Habitats On Land Cover Change Sites In Karima Village, Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Ephantus Muturi, Patrick Halbig, Joseph Mwangangi, R. K. Wanjogu, Enock Mpanga, Jose Funes, Josephat Shililu, John Githure, James L. Regens, Robert J. Novak

All Peer-Reviewed Publications

A study was carried out at Karima Village in the Mwea Rice Irrigation Scheme in Kenya to assess the impact of rice husbandry and associated land cover change for mosquito larval abundance. A multi-temporal, land use land cover (LULC) classification dataset incorporating distributions of Anopheles arabiensis aquatic larval habitats was produced in ERDAS Imagine version 8.7 using combined images from IKONOS at 4m spatial resolution from 2005 and Landsat Thematic Mapper (TM)™ classification data at 30-meters spatial resolution from 1988 for Karima. Of 207 larval habitats sampled, most were either canals (53.4%) or paddies (45.9%), and only one habitat was …

Larval Habitat Dynamics And Diversity Of Culex Mosquitoes In Rice Agro-Ecosystem In Mwea, Kenya, Ephantus J. Muturi, Josephat I. Shililu, Weidong Gu, Benjamin G. Jacob, John I. Githure, Robert J. Novak

All Peer-Reviewed Publications

Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter …

Distribution And Relative Importance Of Lepidopteran Cereal Stemborers And Their Parasitoids In Uganda, T. Matama-Kauma, F. Schulthess, J. A. Ogwang, J. M. Mueke, C. O. Omwega

All Peer-Reviewed Publications

Infestation levels and parasitism of lepidopteran stemborers on maize were assessed in four agroecological zones (AEZ) in Uganda. The indigenous noctuid Busseola fusca Fuller (Noctuidae) and the invasive Chilo partellus Swinhoe (Crambidae) were the most important stemborers recorded. C. partellus represented 77% of the stemborers in the Eastern AEZ while B. fusca was dominant in the other AEZs, accounting for 60-79%. The proportion of infested plants was between 16% and 45% and borer density between 0.2 and 1.0 borers per plant. There was no clear relationship between damage and stem tunneling, which is often used to estimate yield loss. Telenomus …

Antibacterial Activity Of Apis Mellifera L. Propolis Collected In Three Regions Of Kenya, Elliud M. Muli, J. M. Maingi

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The present study aimed at investigating the susceptibility of the microorganisms Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis to ethanolic extracts of propolis (EEP) from three regions of Kenya (Taita, Tana and Samburu). Propolis was extracted using four different concentrations of ethanol: pure, 70%, 50%, and 30%. Ethanol (70%) and Streptomycin were used as controls. The agar diffusion method using filter paper disks was employed. Antibacterial activity was determined as an equivalent of the inhibition zones diameters (in millimeters) after incubation at 37°C for 24h. Significant differences in the antibacterial activities of propolis were observed among …

Switchgrass For Biomass Feedstock In The Usa, Matt Sanderson, Paul Adler, Akwasi Boateng, Michael Casler, Gautam Sarath

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

Switchgrass has received much study for biomass feedstock production and conversion through research funded by the US-DOE and USDA during the past two decades. We have an improved understanding of the adaptation of existing cultivars and new cultivars with yield and adaptation improvements are now appearing. We also have a good understanding of the agronomics of switchgrass production, mainly from its use as a forage crop. There remain several constraints to switchgrass use in bioenergy cropping systems, including reliable establishment methods to obtain productive stands in the first year, targeted fertilization and nutrient management techniques to efficiently use nitrogen fertilizer, …

Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams

All Peer-Reviewed Publications

A survey was conducted in Tororo, Bugiri and Kapchorwa districts in eastern and northeastern Uganda on farmers' perceptions of constraints in maize production. Farmers in Tororo and Bugiri consistently ranked stemborers and striga as the major production constraints in maize growing, while those in Kapchorwa ranked stemborers and lack of capital as the most important. Approximately 35 and 40% of the farmers in Tororo and Bugiri, respectively, identified stemborers as the 'caterpillar' that destroys their maize. In Kapchorwa, 50% of the farmers identified stemborers. Pesticide application was the most common control measure while the use of indigenous and cultural control …

Intsormil’S Global Impact: A Revolution In West African Sorghum Production, Intsormil

INTSORMIL Impacts and Bulletins

Sorghum and pearl millet are the staple grains for millions of people around the world, especially those residing in the semiarid margins of agricultural sustainability. For this reason, INTSORMIL has been working in the semiarid regions of Africa and Central America where it has been helping sorghum and millet farmers achieve the status of surplus grain production and the economic, social and health benefits thus provided. What impact has INTSORMIL had on the lives of these sorghum and millet farmers?

To determine the global impact of the USAID funded INTSORMIL program, Battelle, an independent agency, was chosen to conduct an …

Bovine Immune Response To Shiga-Toxigenic Escherichia Coli O157:H7, Mark A. Hoffman, Christian Menge, Thomas A. Casey, William Laegreid, Brad T. Bosworth, Evelyn A. Dean-Nystrom

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

Although cattle develop humoral immune responses to Shiga-toxigenic (Stx⁺) Escherichia coli O157:H7, infections often result in long-term shedding of these human pathogenic bacteria. The objective of this study was to compare humoral and cellular immune responses to Stx⁺ and Stx^- E. coli O157:H7. Three groups of calves were inoculated intrarumenally, twice in a 3-week interval, with different strains of E. coli: a Stx2- producing E. coli O157:H7 strain (Stx2⁺O157), a Shiga toxin-negative E. coli O157:H7 strain (Stx^-O157), or a nonpathogenic E. coli strain (control). Fecal shedding of Stx2⁺O157 was …

Agronomic And Quality Effects In Winter Wheat Of A Gene Conditioning Resistance To Wheat Streak Mosaic Virus, L. A. Divis, R. A. Graybosch, C. J. Peterson, P. Stephen Baenziger, G. L. Hein, B. B. Beecher, T. J. Martin

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

Wheat streak mosaic virus (WSMV) is one of the most important diseases limiting winter wheat (Triticum aestivum L.) production in the western Great Plains of North America. There is no known effective WSMV resistance within the primary gene pool of wheat. However, a resistance gene (Wsm1) has been transferred to wheat from a perennial relative, intermediate wheat-grass [Thinopyrum intermedium (Host) Barkworth & DR Dewey]. Nebraska-adapted winter wheat lines carrying Wsm1 were used to characterize the effects of this alien introgression on agronomic and quality traits. Sister-lines from six breeding populations were evaluated under virus-free conditions, …

Survival Of Immature Anopheles Arabiensis (Diptera: Culicidae) In Aquatic Habitats In Mwea Rice Irrigation Scheme, Central Kenya, Joseph M. Mwangangi, Ephantus J. Muturi, Josephat Shililu, Simon M. Muriu, Benjamin Jacob, Ephantus W. Kabiru, Charles M. Mbogo, John Githure, Robert Novak

All Peer-Reviewed Publications

Background: The survivorship and distribution of Anopheles arabiensis larvae and pupae was examined in a rice agroecosystem in Mwea Irrigation Scheme, central Kenya, from August 2005 to April 2006, prior to implementation of larval control programme. Methods: Horizontal life tables were constructed for immatures in semi-field condition. The time spent in the various immature stages was determined and survival established. Vertical life tables were obtained from five paddies sampled by standard dipping technique. Results: Pre-adult developmental time for An. arabiensis in the trays in the experimental set up in the screen house was 11.85 days from eclosion to emergence. The …

The Circuitous Path To The Comparison Of Simulated Values From Crop Models With Field Observations, Albert Weiss, Wally Wilhelm

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

The Journal of Agricultural Science, Cambridge has been a fixture in dissemination of crop simulation models and the concepts and data upon which they are built since the inception of computers and computer modeling in the mid-20th century. To quantify the performance of a crop simulation model, model outputs are compared with observed values using statistical measures of bias, i.e. the difference between simulated and observed values. While applying these statistical measures is unambiguous for the experienced user, the same cannot always be said of determining the observed or simulated values. For example, differences in accessing crop development can be …

University Research Program Sees Drop In Funding, Zach Pluhacek

INTSORMIL Impacts and Bulletins

A program headquartered at the University of Nebraska-Lincoln that uses science to assist economically stressed nations will receive $9 million throughout five years through a cooperative agreement with the U.S. Agency for International Development.

The agreement, announced Friday morning by the UNL Office of Research and Graduate Studies, will significantly decrease the annual funding the International Sorghum and Millet Collaborative Research Support Program, or INTSORMIL, has received in recent years.

Sorghum Flour In The El Salvador Baking Industry, Intsormil

INTSORMIL Impacts and Bulletins

The El Salvador baking industry is dependent on imported wheat which results in a loss of valuable foreign exchange. In response, CENTA (Centro Nacional de Tecnologia Agropecuaria y Forestal) scientists with support from INTSORMIL have produced sorghum varieties which have the physical and chemical qualities making them suitable for flour which can be used as a partial substitute for wheat flour in the baking industry, thus decreasing the cost of baked goods. CENTA food technician, Fidelia Herrera pioneered the use of sorghum flour in El Salvador and began helping village bakers utilize sorghum flour back in the 70’s.

To test …

Harina De Sorgo En La Industria Panificadora De El Salvador, Intsormil

INTSORMIL Impacts and Bulletins

La industria panificadora de El Salvador depende de las importaciones de trigo, lo cual ocasiona una pérdida considerable de divisas. En respuesta a esto, los investigadores del Centro Nacional de Tecnología Agropecuaria y Forestal (CENTA) con ayuda del INTSORMIL han venido produciendo variedades de sorgo con cualidades físicas y químicas adecuadas para sustituir parcialmente la harina de trigo, reduciendo de esta manera los costos de producción de las panaderías. La Señora Fidelia Herrera, técnologa del CENTA fue la primera en tomar el liderazgo sobre la necesidad del uso de la harina de sorgo en El Salvador, al ayudar durante los …

Grazing Management Effects On Sediment And Phosphorus In Surface Runoff, Matthew M. Haan, James R. Russell, Wendy J. Powers, John L. Kovar, Jamie L. Benning

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

Sediment and phosphorus (P) in runoff from pastures are potential non–point-source pollutants in surface waters that may be influenced by surface cover, sward height, treading damage, surface slope, soil moisture, and soil P. The objectives of the current study were to quantify sediment and total P loads in runoff produced during simulated rainfall from pastures and to evaluate their relationships with the physical and chemical characteristics of the soil and sward. Five forage management treatments— ungrazed (U), hay harvest/fall stockpile grazing (HS), continuous stocking to a sward height of 5 cm (5C), and rotational stocking to sward heights of 5 …

Convergence Of Agriculture And Energy: Implications For Research And Policy, Kenneth Cassman, Vernon Eidman, Eugene Simpson, Larry Berger, Robert Loomis, Marie Walsh, Todd A. Peterson, Edward Runge

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

Access to an adequate energy supply at reasonable cost is crucial for sustained economic growth. Unfortunately, oil prices and the need to import from politically unstable countries lowers the reliability of the U.S. energy supply and hinders economic development. Although biofuels have been identified as an important component of the national strategy to decrease U.S. dependence on imported oil, the ability to sustain a rapid expansion of biofuel production capacity raises new research and policy issues. This document seeks to identify the most critical of these issues to help inform the policy development process. The goal is to enhance the …

Development Of Pcr-Based Chloroplast Dna Markers That Characterize Domesticated Cowpea (Vigna Unguiculata Ssp. Unguiculata Var. Unguiculata) And Highlight Its Crop-Weed Complex, Y. Feleke, R. S. Pasquet, P. Gepts

All Peer-Reviewed Publications

In 1992, Vaillancourt and Weeden discovered a very important mutation for studying cowpea evolution and domestication. A loss of a BamHI restriction site in chloroplast DNA characterized all domesticated accessions and a few wild (Vigna unguiculata ssp. unguiculata var. spontanea) accessions. In order to screen a larger number of accessions, primers were designed to check this mutation using PCR RFLP or direct PCR methods. Using these new primers, 54 domesticated cowpea accessions and 130 accessions from the wild progenitor were screened. The absence of haplotype 0 was confirmed within domesticated accessions, including primitive landraces from cultivar-groups Biflora and Textilis, suggesting …

Electrophysiological Responses Of The Lepidopterous Stemborers Chilo Partellus And Busseola Fusca To Volatiles From Wild And Cultivated Host Plants, M. A. Birkett, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams, C. M. Woodcock

All Peer-Reviewed Publications

The stemborers Chilo partellus and Busseola fusca are major pests of subsistence cereal farming in Africa. Volatiles released by two cultivated hosts, sorghum and maize (Sorghum bicolor and Zea mays), and two wild grass hosts, Pennisetum purpureum and Hyparrhenia tamba, were collected by air entrainment. Electrophysiologically active components in these samples were detected by coupled gas chromatography-electroantennography (GC-EAG), and the active peaks identified by gas chromatography-mass spectrometry. A total of 41 compounds were identified from the four plant species, all of which, as well as two unidentified compounds, elicited an electrophysiological response from one or both of the stemborers. The …

Heat Stress Risk Factors Of Feedlot Heifers, Tami M. Brown-Brandl, Roger A. Eigenberg, John A. Nienaber

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

Heat stress in cattle results in millions of dollars in lost revenue each year due to production losses, and in extreme cases, death. Death losses are more likely to result from animals vulnerable to heat stress. A study was conducted to determine risk factors for heat stress in feedlot heifers. Over two consecutive summers, a total of 256 feedlot heifers (32/ breed/ year) of four breeds were observed. As a measure of stress, respiration rates and panting scores were taken twice daily (morning and afternoon) on a random sample of 10 heifers/ breed. Weights, condition scores, and temperament scores were …

Comparison Of Heat Tolerance Of Feedlot Heifers Of Different Breeds, T. M. Brown-Brandl, J. A. Nienaber, Roger A. Eigenberg, Terry L. Mader, J. L. Morrow, J. W. Dailey

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

Heat stress in cattle causes decreases in feed intake and feed efficiency; in extreme cases, it can cause death. These losses amount to millions of dollars each year. A study was designed to determine severity of heat stress among four breeds of cattle. Throughout two summers, 256 feedlot heifers of four different breeds were observed. Respiration rates, panting scores, and surface temperatures were taken twice each day on 10 animals/breed for several weeks during the summers of 2002 and 2003. Twenty-four-hour behavior measurements were recorded for four heat-stress and four thermoneutral days. Results showed during the afternoon, Angus cattle (black) …