Assessing the Occurrence and Severity of “Lumpy Jaw” in Wild Sheep (Ovis sp.)

Amanda Williams¹ B.A., Alexis Berger¹ B.A., Dave Dyer² M.S., Emily Graslie³ B.A., Victoria Swenson¹ M.A.¹ University of Montana, Dept. of Anthropology

² University of Montana, Philip L Wright Zoological Museum, Div. of Biological Sciences³ Johns Hopkins University, Dept. of Museum Studies

Abstract“Lumpy jaw”, or chronic mandibular osteolyelitis, is an infectious disease caused most commonly by the bacteria in the genus Actinomyces. Other causes of the disease may be the bacteria Arcanobacterium pyogenes and Fusobacterium

necrophorum.” It is a chronic infection that often becomes established in the bones of the oral cavity (Hoefs and Bunch, 2001). It is found frequently in domestic cattle, and is also found in wild ungulates. Using Ovis canadensis and O. dalli specimens from the Philip L. Wright Zoological Museum at The University of Montana, this study aims to examine the occurrence and create a scale that measures the severity of “lumpy jaw.” Previous research has suggested that there is a higher rate in O. canadesnsis than in O. dalli; however the severity of “lumpy jaw” is greater in O. dalli. We assessed 42 O. dalli and 168 O. canadensis from the Philip L. Wright Zoological Museum. Only the mandibles were examined, and

elements were assessed for: presence of lumpy jaw, dental abnormalities, tooth wear, and sex and age of the specimens. A scale was created from zero to five to assess the severity. Zero represents lumpy jaw was not present while a level of five is described as having at least four fistulous tracts present on the mandible. This study found that of the specimens examined lumpy jaw occurred in 11.9 percent of O. dalli and 14.3 percent in O. canadensis. “Lumpy jaw” could be explained

by the breaks in the oral mucosa, from either coarseness in diet or tooth eruption. This research also has implications in other disciplines such as zooarchaeology, skeletal biology, wildlife management, anthropology, and paleopathology. There is very little research that assesses the prevalence of “lumpy jaw” in wild sheep populations in an archaeological context.

Materials and MethodsThe researchers examined 210 Ovis sp. specimens from the Philip L Wright Museum ‘s skeletal collection. Only mandibles were analyzed for the presence of “lumpy jaw” in both O. canadensis (Bighorn Sheep) and O. dalli (Dall Sheep). Both the left and right sides were examined for the presence of food, porosity, and other abnormalities were noted along with age and sex when known. All data was entered into a spreadsheet for easier comparisons and sorting. Specimens found to exhibit some severity of “lumpy jaw” were pulled and further examined and photographed. An initial assessment was made using the scale developed by Konjević et al. (2011) for roe deer. A six stage method was developed using Konjević et al.’s (2011) method that can be applied to Northwestern United States Ovis sp. with a Stage 0 being not present and a Stage V scored as an extreme case.

ResultsOut of the 210 specimens, 168 were Bighorn Sheep and 42 were Dall Sheep. A total of 30 mandibles from the sample set showed some evidence of “lumpy jaw” and scored with a number from our scale (0-5), which is a frequency of 14.3%. Of the 30 specimens that had “lumpy jaw,” five came from the Dall sample. Lumpy jaw was found in 11.9% of the Dall sample. The Dall Sheep “lumpy jaw” sample contained only three specimens with known ages. Of these three specimens, two were 5½ years old and the other was 2½ years old. Sex was known for all five of the “lumpy jaw” samples with three being female and two male. Overall, the occurrence of “lumpy jaw” appears to more frequent in female specimens for Dall Sheep, which is consistent with Hoeffs and Bunch’s (2001) finding. Four of the five Dall Sheep exhibited this pathology on the right side with only one of them exhibiting the pathology on the left mandible. The five “lumpy jaw” mandibles all scored at Stage I.

The other twenty-five “lumpy jaw” specimens came from Bighorn Sheep, which equals a frequency of 14.88%. Of the 25 Bighorn Sheep specimens, there were eleven with known ages. The ages ranged from 25 months to nine years old. Almost all of the Bighorn Sheep specimens, 24 of 25, had known sexes. There were fifteen males and nine females. These results indicate an opposite trend from that observed in Dall Sheep. Overall, the Bighorn Sheep exhibited this pathology more frequently (52%) on the right mandible than compared to the left (40%). The other 8% were too fragmented to correctly side. The Bighorn “lumpy jaw” mandibles scored at all stages.

Stage 0 Normal mandible.

Stage IThickening of mandible in area of 1-2 teeth

Some Porosity of cortex.May be bone loss at gumline.

Stage II

Thickening of mandible in area of 2 – 3 teeth.

Moderate porosity of cortex; may be small cloaca.

Bone loss at gumline more pronounced.

Stage III

Thickening of mandible in 3-4 teeth; loss of contour of ventral surface of mandible.

Severe porosity of cortex; multiple cloaca forming.

Pronounced bone loss at gumline may be present.

Stage IV

Thickening of mandible in area of approximately 4 teeth; loss of contour of

ventral surface of mandible. Severe porosity of cortex; multiple cloaca

present. Pronounced bone loss at gumline may be

present.

Stage V

Thickening of mandible affecting entire toothrow; pronounced loss of normal

contour of mandible. Severe porosity of cortex; multiple cloaca

present.Pronounced bone loss at gumline over

multiple teeth.

Stages in Mandibular Bacterial Infection in Wild Sheep (Ovis sp.)

Discussion/ConclusionThere exists some literature concerning the relationship between “lumpy jaw” and members of the Order Ungulata (Bronner and Bronner 1971; Tillett 1997; Bunch et al. 1999; Hoef and Bunch 2001; Konjević et al. 2011). The main contributor to “lumpy jaw” is the consumption of sharp vegetation (Hoef and Bunch 2001; Konjević et al. 2011). Due to the build up of impacted food, the pathological condition can take root. In our sample, both the occurrence and the severity of “lumpy jaw” appears to be more prevalent in Bighorn Sheep compared to Dall. This finding is not consistent with Hoef and Bunch’s (2001) finding. The discrepancies between the two studies, could be due to our small sample size. Hoef and Bunch (2001) noted that environment, climate, and adaptation contribute to a higher rate among Bighorn Sheep. Bunch et al. (1999) also state that competition among wild sheep species and a loss of habitat can be responsible for the occurrence of “lumpy jaw.” Higher rates among females can be due to differing foraging patterns among males and females. “A possible explanation for the sex specific discrepancy of lumpy jaw is the difference in range use strategies between the sexes” (Hoef and Bunch 2001: 46). Overall, the difference in occurrence of “lumpy jaw” could be due to sample size, environment, and foraging patterns. The environments for Bighorn Sheep range from Montana to Nevada while Dall Sheep have a range in the drier ranges of Alaska and Brooks mountain ranges (Shackleton et al. 1997).

AcknowledgmentsWe would like to thank the Philip L. Wright Zoological Museum for allowing us to use their specimens. We would also like to thank the Associated Students of the University of Montana.

ReferencesBronner M, Bronner M. 1971. Actinomycosis. John Wright and Sons Ltd Publishing. Toronto, Canada. P. 1-355.

Bunch T, Boyce W., Hibler C., Lance W, Spraker T., Williams E. 1999. Diseases of North American Wild Sheep. In Valdez and Krausman: Mountain Sheep of North America. The University of Arizona Press. Tucson, Arizona. p.209-237.

Hoef M., Bunch T.D. 2001. “Lumpy Jaw in Wild Sheep and Its Evolutionary Implications”. Journal of Wildlife Diseases. 37(1):39-48.

Konjević D., Jelenko I., Seberin K., Poliƈnik H., Janicki Z., Salvica A. Njemirobskij V. Stanin D., Pokorny B. 2011. “Prevelance of Mandibular Osteomyelitis in Roe Deer (Capreolus capreolus) in Slovenia. Journal of Wildlife Diseases. 47(2) 393-400.

Shackleton D.M. Barichelloa N., Gunn A., Hubert D.H., Harper F. 1997. North America. In Shackleton D.M editor. Status Survey and Conservation Action Plan for Caprinae: Wild Sheep and Goats and their Relatives. IUCN the World Conservation Union. Cambridge, UK. P. 296-318.

Tillett G. 1997. OVIS: North American Wild Sheep. Roadhouse Publishing Group. Oxford, United Kingdom. P. 5-74.