How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep ( Ovis canadensis ) Herd.
We evaluated bighorn sheep ( Ovis canadensis ) ewes and their lambs in captivity to examine the sources and roles of respiratory pathogens causing lamb mortality in a poorly performing herd. After seven consecutive years of observed December recruitments of <10%, 13 adult female bighorn sheep from the remnant Gribbles Park herd in Colorado, US were captured and transported to the Thorne-Williams Wildlife Research Center in Wyoming in March 2013. Ewes were sampled repeatedly over 16 mo. In April 2014, ewes were separated into individual pens prior to lambing. Upon death, lambs were necropsied and tested for respiratory pathogens. Six lambs developed clinical respiratory disease and one lamb was abandoned. Pathology from an additional six lambs born in 2013 was also evaluated. Mycoplasma ovipneumoniae , leukotoxigenic Mannheimia spp., leukotoxigenic Bibersteinia trehalosi , and Pasteurella multocida all contributed to lamb pneumonia. Histopathology suggested a continuum of disease, with lesions typical of pasteurellosis predominating in younger lambs and lesions typical of mycoplasmosis predominating in older lambs. Mixed pathology was observed in lambs dying between these timeframes. We suspected that all the ewes in our study were persistently infected and chronically shedding the bacteria that contributed to summer lamb mortality.
1 Wyoming Game and Fish Department, 528 S Adams, Laramie, Wyoming 82070, USA.
Mary E
ME
Wood
2 Colorado Division of Parks and Wildlife, Wildlife Health Program, 4330 Laporte Avenue, Fort Collins, Colorado 80521-2153, USA.
Karen A
KA
Fox
3 Wyoming Game and Fish Department, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA.
Jessica
J
Jennings-Gaines
3 Wyoming Game and Fish Department, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA.
Halcyon J
HJ
Killion
4 Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 Hwy. 34, Wheatland, Wyoming 82201, USA.
Sierra
S
Amundson
2 Colorado Division of Parks and Wildlife, Wildlife Health Program, 4330 Laporte Avenue, Fort Collins, Colorado 80521-2153, USA.
Michael W
MW
Miller
3 Wyoming Game and Fish Department, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA.
William H
WH
Edwards
D000818:Animals; D003120:Colorado; D005260:Female; D045802:Mycoplasma ovipneumoniae / Q000472:pathogenicity; D011019:Pneumonia, Mycoplasma / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology / Q000401:mortality*; D034581:Sheep, Bighorn; D014959:Wyoming
Bibersteinia trehalosi; Bighorn sheep; Mannheimia; Mycoplasma ovipneumoniae; Ovis canadensis; Pasteurella multocida; pneumonia; respiratory disease