Progress 08/01/05 to 08/01/11
Outputs
OUTPUTS: The project was initiated through a cooperative agreement with Dr. Dave Taylor, Research Entomologist, USDA-ARS Agroecosystem Research Unit. In the initial years of the project research projects established research methods combining the expertise of scientists with backgrounds in entomology and animal science. The initial outputs of the projects were experiments to develop methods to look at the effects of stable flies on physiological variables; such as feed intake, behavior, stress hormone levels on individual animals in controlled experimental conditions with controlled stable fly populations. Over the lifetime of the project the major output has been the development of experiments to discover research methods combining entomology and animal science. These experiments provide a foundation for future research projects. The two experiments conducted in the current reporting period our evidence of the potential for additional outputs enhanced by the cooperative efforts. The design and treatments for the two experiments conducted during the current reporting period are described below. Design and Treatments of Experiment #1: Eighty cow / calf pairs of similar age and breeding will be weighed prior to the study. Based upon pre-study cow and calf weights and calving dates, cow / calf pairs were divided into 2 balanced experimental treatment groups. For group 1, fly repellent was applied via 3-D Quick Hand sprayer units located at the water source to both cow and calf entering the unit. Group 2, served as the control group and water was applied to cows via the 3-D Quick Hand sprayer units located at the water source. Permethrin applied at label rates was used as the repellent. To avoid confounding effects of horn flies, cows will be treated with Y-Tex YP 820 ear-tags. Previous research (Campbell 1976) indicates that the primary effect of horn flies on calves is maternal, hence calves were not be ear tagged. Cows and calves were weighed every 28 days. Stable fly leg counts were conducted on all animals 2 times per week to document stable fly biting pressure and repellent efficacy. Design and Treatments of Experiment #2: GPS collars were placed on 6 heifers in a herd of 40 heifers in a single pasture. The herd was rotated to additional pastures as forage supply required from May 27, 2011 to October 1, 2011. Position coordinates from the collars were recorded every 10 minutes from 5:00 a.m. to 9:00 p.m. then every 20 minutes from 9:00 p.m. to 5:00 a.m. Emergence traps were used to estimate the stable fly population. PARTICIPANTS: Major Research Partner Dave Taylor, Research Entomologist, USDA-ARS Agroecosystem Research Unit, Kathy Hanford, Department of Statistics University of Nebraska Lincoln, Additional individuals, position and participation as related training provided in all case was in experimental design and research techniques related to both entomology and animal science. The project provided a unique opportunity for the cross-discipline experience and training. Darko Aleus Visiting student from Croatia, Karl Moline, Cow/Calf Manager University of Nebraska Agricultural Research & Development Center, Kelly Brink, Research Technologist Range and Forage, Doug Brinkerhoff, Research Technician - Entomolgy, Lisa Schole, MS Graduate Student, Kelsey Rolfe, Research Technician - Ruminant Nutrition, Coleman Outhet, Student Intern. The project was partially funded by an intial cooperative agreement and a subsequent addition by Dept of Agriculture-ARS. Additional cooperators have been colleagues in the the ruminant nutrition and physiology faculty. TARGET AUDIENCES: The target audiences are scientists in the field of study, entomology and animal science and beef cattle producers. The audience will be informed through peer reviewed publications, especially the Professional Animal Scientist for the animal science audience. Publications will also be prepared for the entomology field by Dr. Taylor. In addition, the results will be shared through interactions of scientists, research technicians, students and interns. The Nebraska Beef Report will provide a means of delivery for extension specialists in both fields to become aware of the results and incorporate in their extension programming. PROJECT MODIFICATIONS: As this is a termination report there are no specific major changes to the project. It is anticipated that future project development will be significantly influenced by the results of this project.
Impacts
Over the lifetime of the project the major outcomes are the evaluations of new methods to study the effects of stable flies on cattle. The techniques reported in the MS thesis (Schole 2007) provided basis for additional controlled experiments and the importance of energy expenditure for behavioral responses to stable fly bites. Studies in subsequent years evaluated the use pens developed as cages to house specific a number of stable flies, monitor individual animal feed intake and heart rate throughout the 24 hour period for 5-7 consecutive days intake. The overall outcome and impact of these experiments is the magnitude of the effect on feed intake and heart rate is extremely variable and the large amount of data that can be collected must be closely refined and subjected to new methods of statistical evaluation. The outcomes of these experiments will be reported in publications currently in preparation. When the complete analyses and publication of the results of the two major experiments from previous years and the current reporting period of the project are available it is anticipated that the research community will have additional and very useful information regarding methods to study the impact of stable flies on the physiology of calves. The project should produce additional publications in the 2012 and additional cooperative experiments in the next two years.
Publications
- Schole L.A., Taylor, D.B., D. R. Brink, Hanford, K.J. 2011. Use of modified cages attached to growing calves to measure the effect of stable flies on dry matter intake and digestibility, and defensive movements. Professional Animal Scientist April 2011 vol. 27 no. 2 133-140.
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: A study was initiated to determine the effect of stable flies on weaning weights of calves and the efficacy of repellants to reduce this impact. The approach for this study was based upon that used by Campbell et al. (2001) to determine the effects of stable flies on weight gain in grazing steers. Cow / calf pairs of similar age and breeding were weighed prior to the study. Based upon pre-study cow and calf weights and calving dates, cow / calf pairs were divided into 4 balanced experimental treatment groups. For group 1, fly repellant were applied to both cow and calf; group 2, repellant was applied to calves and water was applied to cows; group 3, repellant was applied to cows and water to calves; group 4 water was applied to both cows and calves. Animals were treated in squeeze-chutes 2 times per week from mid-May through weaning in mid-September. The repellant was applied at label rates. To avoid confounding effects of horn flies, cows were treated with Y-Tex YP 820 ear-tags. Previous research (Campbell 1976) indicates that the primary effect of horn flies on calves is maternal, hence calves were not ear tagged. Cows and calves were weighed every 28 days. Experimental animals were be co-mingled in a single pasture. Stable fly leg counts were conducted on all animals 2 times per week to document stable fly biting pressure and repellant efficacy. PARTICIPANTS: D. Brinkerhoff (USDA-ARS), J. Hradec, and N. Meyer, B. Voelker (USDA-ARS), and T. Weinhold (USDA-ARS) for technical and animal care support. This project was supported by USDA Specific Cooperative Agreement 58-5440-5-321. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The analyses and interpretation intake and heart rate data of the study described in 2009 are still in progress. The data collected in the study above is also being analyzed.
Publications
- Schole,L., Taylor, D., Brink, D., and Hadford, K.(2010).Utilization of Modified Cages Attached to Growing Calves to Measure Effect of Stable Flies on Dry matter Intake and Digestibility, and Defensive Movements. Professional Animal Scientist. (Pending)
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: An new experiment was conducted to support the findings in a previous trial for publication of the data and confirm the conclusions. The experiment was conducted in the Metabolism Area, Animal Science Building Lincoln, NE in accordance with IACUC Number 382. Objectives of the experiment were to quantify the effects of stable fly population on feed intake patterns, heart rate and behavior. The experiment was conducted as a completely randomized design with 4 replications. The treatments were: control (no flies); low population (equivalent of 5 flies/leg) and higher population (equivalent of 50 flies/leg). In each replication 6 650-750 lb steers were housed in 6 pens covered with net material to create a cage for the flies. Flies were added to the cages as needed to maintain the treatment populations. Feed intake (computer records of feedbunks attached to load cells), heart rate (Polar Equine Belt) and animal behavior (video recording cammeras) were recorded for 10 consecutive days following an adaptation to the pens. PARTICIPANTS: Individuals working on this project include Dr. David Taylor, Research Entomologist USDA-ARS,Agroecosystem Management Research Unit; Tami M Brown Brandl,Fnvironmental Management Research,Agricultural Engineer and Carol G. Chitko Mckown, Research Microbiologist,U.S. MEAT ANIMAL RESEARCH CENTER. The partner organization for the project is U.S. Department of Agriculture - ARS in conjunction with the specific cooperative agreement, 58-5440-5-321. A graduate student, Kelsey Rolfe and undergraduate student Lance Dahlquist gained significant training and professional development from the participation in data collection. TARGET AUDIENCES: Dr. David Taylor presented a seminar to the Ruminant Nutrition faculty and graduate students to advance their knowledge of the impact of various species of flies on beef and dairy cattle. PROJECT MODIFICATIONS: In order to identify physiological stess heart monitors have been added and blood samples were analyzed for neutrophil changes.
Impacts
The data are currently being analyzed.
Publications
- No publications reported this period
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Results of 2007 study conducted by Schole were used to design a field study conducted during the summer of 2008. The results of the field study were not conclusive, because of low stable fly populations. PARTICIPANTS: Dr. David B. Taylor of the USDA-ARS Agroecosystem Management Research Unit, UNL, Lincoln, NE is the major collaborator in the project. The project has provided for one individual to complete a Masters of Science degree and an independent study project for one undergraduate student. TARGET AUDIENCES: The target audience is the beef and dairy producer and the goal is to provide information for their decisions related to stable fly control. PROJECT MODIFICATIONS: The major change in the approach is to develop screened pens for individual animals in the metabolism room of the UNL Animal Science Complex and to control the exposure of individual calves to populations of stable flies in the screened pen rather than in cages on their back or before conducting additional studies in the field.
Impacts
The results of the field study in conjunction with the results of Schole (2007) indicate to clearly establish the impact of various stable fly populations on growing calves another controlled metabolism study is needed. Plans for conducting the study in 2009 are being developed.
Publications
- No publications reported this period
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Progress 10/01/06 to 09/30/07
Outputs
The results have been published in the M.S. thesis, Response of Growing Calves to Stable Flies, of Lisa A. Schole. Discussions of the results and copies of the thesis were shared with Research Entomologist of USDA-ARS and entomology, dairy and beef cattle extension specialists of the University of Nebraska-Lincoln to use in their programs.
Impacts
Nine Holstein steer calves with an average weight of 187 kg were used to determine the effects of stable flies on growing calves. The calves were individually housed on 3 x 3 m pens with slotted floors. Calves were exposed to three treatment levels of stable flies (0, 10,100) applied for 3 (900, 1200,1500) 30 min intervals. The study consisted of a 4 period crossover design, with each period being 17 d long. Each period had a 5 d adaptation, 7 d treatment, and 5 d adaptation period. Calf weights were collected on 1 d, and while in the chute their backs were clipped and Velcro was glued on. The clipped spot on the calves back allowed an area for the stable flies to feed and the Velcro provided a spot to attach the cages. Fecal samples were collected on d 5, 6, 7, 12, 13 and 14 at 900,1200 and 1500 and used to determine digestibility. Saliva samples were collected from each calf on d 12 beginning at 1530, to be analyzed for cortisol concentrations. Defensive movements
such as head throws, kicks, tail movement or circling due to stable flies varied (P< 0.0001) on the individual calves. The number stable flies and the time of day the calf was exposed to had a direct impact on the amount of defensive movements the calf exhibited (P= 0.0200). Defensive movements by calves increased with stable fly numbers regardless of successful stable fly feeding. Stable flies affected dry matter intake, number of meals consumed, time spent eating, meal length or size of meal. Dry matter digestibility and cortisol levels did not differ between the different treatment levels of stable flies. Stable flies caused behavior changes in calves regardless of feeding, but do not appear to affect digestibility, intake, or stress levels. An energy based model was created and predicted a loss in ADG of 0.11 kg/d (10.0%) due to defensive movement associated with stable fly activity.
Publications
- No publications reported this period
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Progress 10/01/05 to 09/30/06
Outputs
The most significant accomplishments to date are key techniques were established and Exp. #1 was completed. In regard to techniques, preliminary trials conducted prior to Exp. #1 provided significantly improved techniques to be used in the project. Cage design, feeding of fly populations, and exposure times were adjusted based on two preliminary trials. Preliminary data from Exp. #1 indicates the incorporation of the modifications insured treatment differences in full blood feedings were experienced by the cattle. Experiment #1 was conducted from May 3, 2006 to July 9, 2006. Three replicates of a four period cross over design with 3 levels of fly exposure were completed. Data was collected for the following variables: o Animal activity o Salivary cortisol o Feed consumption patterns o Feed dry matter digestibility
Impacts
The publication of results of Exp. #1 will provide scientists in the field of study refined and tested new techniques for determining effects of stable fly exposure levels on calves. Specific recommendations for cattle producers should be available following the publication of the experimental results.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Currently Exp. #1 is in progress. Treatments are exposure level of stable flies equivalent to 0, 5, or 50 flies/animal. The exposure time will be 15 minutes for 3 times (0900-0915; 1200-1215; and 1500-1515 hours). The design for Experiment #1 will be a completely balanced 4 period crossover design utilizing a Digram-Balanced Latin square. A fourth period will be conducted so each treatment follows itself to increase the efficiency of the study to separate out the treatment and carryover effects.
Impacts
The expected impact of Exp. #1 is the foundation for further experiments will be established as research procedures for fly exposure, data collection methods and potential carryover effects of fly exposure will be established.
Publications
- No publications reported this period
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