INVESTIGATION OF MULE DEER USE OF ALFALFA FIELDS IN HUMBOLDT COUNTY NEVADA AND THE POTENTIAL ROLE OF COPPER DEFICIENCY

• Sponsoring Institution: State Agricultural Experiment Station
• Project Status: TERMINATED
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 0217829
• Project No.: NEV052UE
• Project Start Date: Feb 25, 2009
• Project End Date: Jan 31, 2010

Project Director
Stewart, K.

Recipient Organization
UNIVERSITY OF NEVADA
(N/A)
RENO,NV 89557

Performing Department
Natural Resources & Environmental Sciences

Non Technical Summary
Mule deer (Odocoileus hemionus) and pronghorn (Antilocapra americana) have been observed to exhibit lameness, diarrhea, emaciation and death on two ranches in Humboldt County, Nevada since 1997. Mule deer in this area appear to feed exclusively on the alfalfa fields of these two ranches and prior investigations have focused on determining an infectious cause of this disease without success. The objective of this study is to determine the cause of this syndrome in mule deer and to determine if mule deer are using those alfalfa fields to the exclusion of native forages.

Animal Health Component

(N/A)

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
311	3899	1060	100%

Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
3899 - Other animals, general;

Field Of Science
1060 - Biology (whole systems);

Keywords

mule deer

alfalfa

copper deficiency

Goals / Objectives
The objective of this study is to determine the cause of this syndrome in mule deer and to determine if mule deer are using those alfalfa fields to the exclusion of native forages. After careful review of previous reports, necropsy findings, and laboratory results collected by the Nevada Department of Wildlife, Nevada Department of Agriculture, and University of Nevada Reno, we hypothesize 1.Cause of the generalized unthriftiness is due to primary or secondary copper (or possibly selenium) deficiency. 2.Chronic diarrhea may result directly from these deficiencies 3.Infectious agents are not likely to be significant contributors to mortality.

Project Methods
This pilot study will collect water, plants, deer tissue, and serum samples from both live and dead animals as well as forage locations and movement patterns data from deer fitted with GPS collars. Mule deer are thought to occur on these alfalfa fields year around, but they likely also use surrounding sagebrush-steppe habitat. If this syndrome results from deficiency of copper or selenium in forage, or from heavy metals preventing uptake of those trace minerals, understanding the movement patterns and habitat use of these mule deer may help explain why these animals are exhibiting this syndrome. If use of native plants or water sources away from the alfalfa fields contributes to this syndrome, then understanding habitat use and movement patterns in relation to alfalfa fields and surrounding habitat will be important for identifying the cause of this syndrome. We will perform necropsies on 12 mule deer, males, females, and juveniles from two ranches in Humboldt County Nevada. We will examine blood, tissues (muscle, liver, lung etc) and serum for copper, selenium, heavy metals, and potential pathogens. In addition we will place GPS radio collars on 10 adult female mule deer (5 on each ranch). Radio collars will collected detailed information (~ 7 locations / day) on movement patterns and habitat use by those individuals.

Progress 02/25/09 to 01/31/10

Outputs
OUTPUTS: This study has two main objectives. The first is to identify source of disease symptoms expressed by deer concentrated on alfalfa fields and if these symptoms are a result of primary or secondary mineral deficiency. The second object of this study is to determine habitat use of deer in this region. We are particularly interested in residency time and seasonal use of alfalfa fields. This information along with timing of disease symptoms will allow us to understand if these symptoms are a result of high use of the alfalfa fields or related to mineral deficiencies in the region in general. To asses nutrient levels in the deer population we are gathering liver and blood samples from health individuals (6 hunter kill buck samples, 26 females from capture) as well as opportunistically remove sick animals. This past season saw unusually low occurrences of symptomatic individuals and we were able to sample one animal. Vegetation samples have been gathered on a monthly basis throughout the growing season in the uplands as well as on the alfalfa fields to identify if there are mineral deficiencies in the soil and forage. Fecal samples were collected on a monthly basis to compare diet of deer using alfalfa fields with those relying on upland habitat. During the months of June through October, bi-weekly deer counts were conducted on the alfalfa fields to determine use as well as identify symptomatic individuals. Deer numbers increased slightly from the beginning of summer through fall, however remained relatively constant. To more accurately identify timing and duration of use we radio marked 29 adult female deer this winter (December of 2011). Fifteen VHF collars and 7 GPS collars were hung on females thought to be associated with the alfalfa fields and an additional 7 GPS collars on females thought to be associated with upland habitat. Deer will be monitored bi-weekly and locations will be obtained through triangulation. This will allow us to determine fine scale habitat movements and compare upland populations with those relying mainly on the fields. PARTICIPANTS: Dr. Kelley Stewart and Dr. David Thain are the principle investigators on this project. There is also a PhD level graduate student, Sabrina Morano conducting the field work for this project. There has been a great deal of collaboration with the Nevada Department of Wildlife, in particular Mule Deer Staff Specialist Tony Wasley, State veterinarian Peregrine Wolff, regional wildlife biologists Ed Partee and Supervising Biologist Mike Doble. There has also been enormous cooperation from private landowner Giovanni Giordano. TARGET AUDIENCES: The target audience for this project would be state and federal biologists, the ranching community, and sportsman. This study was initiated to determine the cause of disease symptoms expressed by deer using alfalfa fields, along with identifying duration and timing of use. As landscapes change throughout the west whether as a result of increased development, rising temperature or senescence and shifts in vegetation patterns we may expect to see greater reliance on artificial food sources such as alfalfa. If this dependency results in increased mortality through reduced heath or depressed reproduction this may lead to a decrease in deer populations. Information gathered from this study will be useful for state and federal land managers and wildlife agencies, as well as landowners in dealing with these issues. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Plant, blood and liver samples are in the process of being sent out for analysis. A necropsy was conducting on the symptomatic individual, a male fawn, finding no disease agents present however the individual was severely emaciated even though rumen was filled with hay. This lack of a disease agent coupled with no body fat would support the hypothesis of a nutrient imbalance. Further analysis of trace minerals in the blood and livers of sick and healthy individuals will help to pinpoint the cause of this imbalance.

Publications

• No publications reported this period

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: These funds were used to support a graduate student on the project. The student was funded from September - December 2009. That student has begun to write a detailed project proposal and should begin field collection of data on deer and forage during spring and summer 2010. To date we have collected some baseline data on healthy mule deer observed on the alfalfa fields. During 2009, no sick deer were collected from the fields, a few unthrifty looking animals were observed, but biologists form Nevada Department of Wildlife were unable to relocate those animals for analysis of disease or indicators of mineral deficiency. We will capture mule deer during 2010 to collect data on health status and to apply radio collars to deer on alfalfa fields and neighboring uplands. We applied for a grant through United States Department of Agriculture that was funded, that funding begins February 2010, for further support of this project. PARTICIPANTS: Collaborators on this project include Dr. Kelley M. Stewart and Dr. David Thain from the University of Nevada Reno, Dr. Peregrine Wolff, Ed Partee, and Tony Wasley from Nevada Department of Wildlife, and Dr. Anette Rink from Nevada Department of Agriculture. Dr. Mark Atkinson was a collaborator from NDOW on this project, but he has recently left NDOW to work for Wildlife Conservation Society and is no longer working on this project. TARGET AUDIENCES: Target audiences include ranchers, biologists, and sportsman from Humboldt county and other parts of Nevada. In addition, researchers and managers working on effects of mineral deficiency in wild populations and on mule deer that use agricultural fields will be aided by data from this project. The effects of mineral deficiency or diseases in wild populations are difficult to document because little is known about mineral requirements in wild populations. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
No data has been reported yet. We collected 4 mule deer for baseline data from this study area to look for signs of chronic mineral deficiency, we are awaiting the results of those laboratory analysis on tissues collected.

Publications

• No publications reported this period