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Vol 56, No 2
March 2017
Pages 210–213
Journal of the American Association for Laboratory Animal Science
Copyright 2017
by the American Association for Laboratory Animal Science
210
Black-tailed prairie dogs are ground-dwelling squirrel-like
rodents (Rodentia: Sciuridae).2 In addition to squirrels, known
members of this family include chipmunks and woodchucks
(groundhogs, marmots). Of the 5 prairie dog species, black-
tailed prairie dogs are the most common, both in the wild
and in captivity. Ecologically, prairie dogs are considered a
keystone species in prairie ecology.3 Prairie dogs are a useful
animal model for human gallbladder disease and infectious
diseases caused by Clostridium difcile, Yersinia pestis, Franci-
sella tularensis, and Orthopoxvirus.5 Because blood collection is
required for the study and health monitoring of this species,5
we here describe several nonterminal methods useful in black-
tailed prairie dogs.
All animals were handled in a humane and appropriate
manner in accordance with Kansas State University humane
care and use policies. The College of Veterinary Medicine of
Kansas State University endorses and abides by the American
Veterinary Medical Association policy on Animal Welfare as
formulated by the AVMA Animal Welfare Committee.4
Blood Sample Volume
No studies are available currently that report the total blood
volume of prairie dogs. A taxonomically related rodent species,
an active (nonhibernating) ground squirrel (Citellus parryi ab-
lusis), has a total blood volume of 59 mL (approximately 7% to
8% of body weight),10 similar to that of other rodent species.6,8
Ideally, only healthy and mature animals are sampled. Black-
tailed prairie dogs older than 6 mo typically have reached their
adult size (female, approximately 850 g; male, 850 to 1200 g).3
In general, the recommended maximal proportions of the total
blood volume that can be collected with a minimal likelihood
of adverse side effects are 0.5% daily, 5% weekly, 7.5% biweekly,
and 10% monthly.1
Collecting more than 15% of the total blood volume as a single
sample may result in hypovolemic shock, whereas dividing
the total collection volume into multiple, smaller samples over
time may prevent such acute effects.1 Therefore, the maximal
volume of blood that can be withdrawn safely and appropriate
recovery times between collections should be considered before
beginning the procedure.
Blood samples of 1 mL or larger can be obtained from the
jugular vein, femoral vein, or the cranial vena cava of black-
tailed prairie dogs. In addition, peripheral sites such as the
cephalic vein, saphenous vein, and tarsal vein, are useful for
smaller blood samples, but collection from these sites is de-
pendent on local perfusion, which can be inuenced greatly by
hydration status, body temperature, blood pressure, peripheral
vascular resistance secondary to anesthetic drugs, and ambient
temperatures.
Anesthesia and Handling
General anesthesia is commonly required in prairie dogs to
facilitate collection of the blood sample as well as to perform
other procedures, such as thorough physical examination.7,9
Because this species is refractory to handling and can bite, an-
esthesia reduces the risk of handling-associated stress, which
can affect physiologic blood parameters.7 In addition, anesthesia
increases the safety of both animals and handlers. Handlers
should take appropriate measures when working with wild
prairie dogs and be aware of the potential for the transmission
of zoonotic pathogens, including Yersinia pestis, Francisella tu-
larensis, Bartonella spp., and Rickettsia spp.5 Chamber induction
with isourane is recommended for prairie dogs; and anesthesia
can then be maintained by using a tight-tting mask connected
to a nonrebreathing system.2,11
Tips Regarding Blood Collection
Blood samples should be collected immediately after an-
esthetic induction to avoid decreases in body temperature,
isourane-mediated hypotension (both of which increase the
difculty of blood collection from peripheral venipuncture
sites), and isourane-associated effects on the results. To
facilitate the visualization of landmarks and vessels, blood
collection sites should be clipped and free of fur and prepared
aseptically by using a routine protocol. Peripheral veins can be
preheated and locally occluded with a tourniquet—a rubber
band clamped with a hemostat works well—to enhance their
visualization. Preheating typically is unnecessary if ambient
temperatures are maintained and the animal is not hypo-
Techniques for Nonterminal Blood Sampling in
Black-Tailed Prairie Dogs (Cynomys ludovicianus)
Valerie Head,* David Eshar, and Melissa R Nau
Black-tailed prairie dogs (Cynomys ludovicianus) are used as an animal model for research on gallbladder stones and
several infectious diseases. A comprehensive, instructive resource regarding the appropriate techniques for venipuncture
and collection of nonterminal blood samples in this species has not yet been published. Blood samples (1 mL or larger) were
readily obtained from the jugular vein, femoral vein, or cranial vena cava, whereas peripheral sites, such as the cephalic vein,
saphenous vein, and tarsal vein, mainly were useful for obtaining smaller volumes. The detailed and illustrated informa-
tion presented here can aid clinicians and researchers in performing venipuncture, anesthesia, and handling of this species.
Received: 14 Aug 2016. Revision requested: 01 Sep 2016. Accepted: 14 Sep 2016
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University,
Manhattan, Kansas
*Corresponding author. Email: valeriehead@vet.ksu.edu
jaalas16000110.indd 210 3/9/2017 2:05:45 PM
211
Blood-sampling techniques in black-tailed prairie dogs
distal limb. Once the sample has been obtained, apply digital
pressure for hemostasis and remove the tourniquet.
Tarsal vein. Minimal-volume blood samples (100 μL or less)
can be obtained from the tarsal vein of prairie dogs by using
a 27-gauge needle and an insulin syringe or a capillary tube
(Figure 7). Place the prairie dog in lateral recumbency, preheat
the tarsal vein, and occlude it by using tourniquet. After the
needle is introduced, blood can be collected into a syringe;
alternatively, a capillary tube and associated blood-collection
tube can be used to collect blood from the skin surface. After
sample collection, apply digital pressure at the needle exit site
for hemostasis, and remove the tourniquet.
thermic; however, when needed, a single-use heat pack (for
example, Hood Thermopad, Summerland, British Columbia,
Canada) can be placed over the peripheral vein for 2 to 5 min.
When consistent with the intended use of the sample, syringes
for peripheral venipuncture of prairie dogs can be heparinized,
to decrease clot formation.
Sites for Blood Collection
Jugular vein. Blood samples as large as 6 mL can be collected
from the jugular vein of prairie dogs by using a 23- to 25-gauge
needle on a 1- to 6-mL syringe. This method of blood collection
requires 2 people: one to restrain the prairie dog and the other
to obtain the sample. The animal can either be placed in dorsal
recumbency, with its forelimbs extended caudally (Figure 1),
or positioned upright over the edge of a table, with forelimbs
pointed toward the oor (Figure 2), in a similar manner as for
domestic cats. During the procedure, use nger pressure to oc-
clude the jugular vein at the level of the shoulder. Because the
vein may not be visible, the venipuncture site can be imagined
to lie along a line drawn from the angle of the mandible to the
thoracic inlet. Apply digital pressure at the needle exit site for
hemostasis.
Femoral (medial saphenous) vein. Blood samples (1 to 3
mL) can be obtained from the femoral vein of prairie dogs
by using a 25- to 27-gauge needle on a 1- to 3-mL syringe.
This collection technique requires local occlusion through
the use of either a tourniquet or another handler to apply
pressure in the inguinal region. Place the prairie dog in either
lateral or dorsal recumbency (Figure 3). The femoral vein is
located centrally on the medial aspect of the thigh, and the
medial saphenous vein is a minor branch of the femoral vein
that lies on the medial side of the distal limb. Apply digital
pressure at the needle exit site for hemostasis, and remove
the tourniquet.
Cranial vena cava. Blood samples as large as 6 mL can be
collected from the vena cava, bilaterally from the thoracic in-
let, by using a 25- to 27-gauge needle on a 1- to 6-mL syringe.
Sample collection from this site requires one person to collect
the sample and 1 or 2 handlers to stabilize the prairie dog in
dorsal recumbency, with the head extended cranially and the
forelimbs extended distally. Palpate the manubrium and clavi-
cle and introduce the needle just lateral to the manubrium and
into the clavicular notch at a 45° angle (Figure 4). Minimize
lateral movement of the needle once the thoracic cavity has
been entered, to prevent laceration of the cranial vena cava.
Apply gentle traction on the syringe plunger after entering the
skin, because both the jugular vein and cranial vena cava can
be encountered here.
Cephalic vein. Small blood samples (1 mL or less) can be
obtained from the cephalic vein of prairie dogs by using a
25- to 27-gauge needle and a 1-mL syringe. This peripheral
vein should be preheated and occluded with a tourniquet. The
collection technique is similar to that for domestic animals,
and the cephalic vein may accommodate an intravenous
catheter in prairie dogs older than 6 mo or weighing more
than 700 g (Figure 5). After sample collection, apply digital
pressure at the needle exit site for hemostasis, and remove
the tourniquet.
Lateral saphenous vein. The lateral saphenous vein of prairie
dogs accommodates blood samples of no more than 1 mL,
which are collected by using a 25- to 27-gauge needle on a 1-mL
syringe. Place the subject in lateral recumbency, apply a tourni-
quet, and preheat the vein (Figure 6). The lateral saphenous vein
courses diagonally over the tarsus on the lateral aspect of the
Figure 1. The prairie dog is restrained in extended dorsal recumbency
for blood collection from the jugular vein (red dotted line) as the col-
lector occludes the vein at the level of the shoulder.
Figure 2. For upright jugular-vein blood collection, the prairie dog
restrained over the edge of a table, with the vein (red dotted line) oc-
cluded at the level of the shoulder.
jaalas16000110.indd 211 3/9/2017 2:05:48 PM
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Vol 56, No 2
Journal of the American Association for Laboratory Animal Science
March 2017
Recovery after Blood Collection
Because prairie dogs tend to develop acidosis and azotemia
under isourane anesthesia,2 we recommend that each animal
receives a 40-mL subcutaneous bolus of lactated Ringer solution
at the end of the anesthetic procedure. In addition, this treatment
provides uid replacement in cases where large-volume blood
samples were collected.8 Allow prairie dogs to recover from
anesthesia in a quiet, secure environment until they regain the
righting reex. Animals should then be placed in a carrier or
observation cage and monitored visually until full recovery and
return to regular behavior. Side effects of severe hemorrhage
are rare,12 but blood sampling is not without risk.
References
1. Diehl KH, Hull R, Morton D, Pster R, Rabemampianina Y,
Smith D, Vidal JM, Vorstenbosch C, European Federation of
Pharmaceutical Industries Association and European Centre
for the Validation of Alternative Methods. 2001. A good-practice
guide to the administration of substances and removal of blood,
including routes and volumes. J Appl Toxicol 21:15–23.
2. Gardhouse SM, Eshar D, Bello N, Mason D. 2015. Venous blood
gas analytes during isourane anesthesia in black-tailed prairie
dogs (Cynomys ludovicianus). J Am Vet Med Assoc 247:404–408.
3. Hoogland JL. 1996. Cynomys ludovicianus.Mammalian species
535:1–10.
4. Kansas State University, College of Veterinary Medicine.
[Internet]. 2016. Animal use policy: statement on animals used
in research, testing, and teaching. [Cited 10 September 2016].
Available at: http://www.vet.k-state.edu/research/support/
animal-use-policy/.
Figure 3. Using a tourniquet (a rubber band and hemostat) and pre-
heating the vein facilitate blood collection from the femoral vein of
a prairie dog. The animal’s distal limb is to the left and the proximal
limb and body are to the right, with the tail at the bottom of the gure
and the head at the top.
Figure 4. The cranial vena cava is accessed by introducing the needle
at an approximate 45° angle lateral to the manubrium in the clavicular
notch (sternum, black line; clavicles, green line). Take care to avoid
lateral movement of the needle.
Figure 5. The cephalic vein of prairie dogs provides blood samples
smaller than 1 mL and is a useful site for intravenous catheterization.
Figure 7. Minimal-volume blood samples can be collected from the tar-
sal vein (dotted red line) of prairie dogs by using a hematocrit tube at
the needle exit site after applying a tourniquet and preheating the vein.
Figure 6. Blood samples of less than 1 mL can be obtained from the
saphenous vein of prairie dogs after preheating the vein and applying
a tourniquet.
jaalas16000110.indd 212 3/9/2017 2:05:53 PM
213
Blood-sampling techniques in black-tailed prairie dogs
5. Keckler MS, Gallardo-Romero NF, Langham GL, Damon IK,
Karem KL, Carroll DS. 2010. Physiologic reference ranges for
captive black-tailed prairie dogs (Cynomys ludovicianus). J Am
Assoc Lab Anim Sci 49:274–281.
6. Lindstrom NM, Moore DM, Zimmerman K, Smith SA. 2015.
Hematologic assessment in pet rats, mice, hamsters, and gerbils:
blood sample collection and blood cell identication. Clin Lab
Med 35:629–640.
7. Ott Joslin J. 2009. Blood collection techniques in exotic small
mammals. J Exot Pet Med:117–139.
8. Parasuraman S, Raveendran R, Kesavan R. 2010. Blood sample collec-
tion in small laboratory animals. J Pharmacol Pharmacother 1:87–93.
9. Pilny AA, Hess L. 2004. Prairie dog care and husbandry. Vet Clin
North Am Exot Anim Pract 7:269–282.
10. Svihla A, Bowman HC. 1952. Oxygen carrying capacity of the
blood of dormant ground squirrels. Am J Physiol 171:479–481.
11. Wenger S. 2012. Anesthesia and analgesia in rabbits and rodents.
J Exot Pet Med 21:7–16.
12. Williams WR, Kendall LV. 2015. Blood collection in the guinea
pig (Cavia porcellus). Lab Anim (NY) 44:207–208.
jaalas16000110.indd 213 3/9/2017 2:05:53 PM
