COMPARATIVE LEUKOTOXICITIES OF PASTEURELLA HAEMOLYTICA ISOLATES FROM DOMESTIC SHEEP AND FREE-RANGING BIGHORN SHEEP (OVIS CANADENSIS)

1994 ◽  
Vol 30 (4) ◽  
pp. 523-528 ◽  
Author(s):  
Steven J. Sweeney ◽  
Ronald M. Silflow ◽  
William J. Foreyt
1979 ◽  
Vol 57 (10) ◽  
pp. 2010-2021 ◽  
Author(s):  
Robert A. MacArthur ◽  
Ronald H. Johnston ◽  
Valerius Geist

The telemetered heart rates (HR) of unrestrained female bighorn sheep (Ovis canadensis canadensis) were recorded under various behavioral and environmental circumstances. In all ewes HR varied positively with activity level and inversely with distance to a road traversing the study area. The HR recorded from animals moving at night or through timber by day were higher than during daytime movement across open slopes.Responses to transient stimuli varied greatly. The appearance of free-ranging canids evoked maximal increases in HR in all ewes. Vehicular traffic and aircraft elicited HR responses only at close range (< 200 m). Most (78.1%) HR responses to disturbing stimuli preceded or occurred in the absence of overt behavioral reactions. The HR usually peaked within 60 s of the onset of the response and recovered to predisturbance base line in less than 200 s. The appearance and continued presence (1–10 min) of a human within 50 m of the sheep resulted in a 20% rise in mean HR. The significance of these findings is discussed in relation to the behavior, ecology, and bioenergetics of bighorn sheep.


Author(s):  
Margaret A. Highland ◽  
David A. Schneider ◽  
Stephen N. White ◽  
Sally A. Madsen-Bouterse ◽  
Donald P. Knowles ◽  
...  

2001 ◽  
Vol 79 (8) ◽  
pp. 1423-1432 ◽  
Author(s):  
Ryan J Monello ◽  
Dennis L Murray ◽  
E Frances Cassirer

Bighorn sheep (Ovis canadensis) populations commonly experience pneumonia outbreaks caused by Pasteurella spp. that result in a partial or complete dieoff. Although several factors can contribute to Pasteurella spp. transmission or infectivity in bighorn sheep, to date the importance of such factors in population declines has not been rigorously examined. We evaluated the relationship between pneumonia-induced dieoffs in bighorn sheep and environmental and biological factors by analyzing demographic information for 99 herds across the species' geographic range. Our analysis revealed that 88% of pneumonia-induced dieoffs occurred at or within 3 years of peak population numbers, which implies that density-dependent forces such as food shortage or stress contribute to bighorns' susceptibility to pneumonia. There were few differences in the growth rates of dieoff and non-dieoff populations, suggesting that pneumonia did not manifest itself demographically prior to an outbreak. On average, abundance of lambs was most dramatically reduced post outbreak (–66%) relative to that of either rams (–35%) or ewes (–42%). Deviations in normal precipitation and temperature regimes were not associated with the onset of pneumonia outbreaks, but herds found in proximity to domestic sheep tended to be more susceptible to dieoff. Our results suggest that bighorn sheep herds are rendered vulnerable to pneumonia principally through density-dependent factors, as well as through horizontal transmission of Pasteurella spp. from domestic sheep serving as reservoir hosts.


1987 ◽  
Vol 65 (8) ◽  
pp. 2028-2034 ◽  
Author(s):  
Henry J. Harlow ◽  
E. Tom Thorne ◽  
Elizabeth S. Williams ◽  
E. Lee Belden ◽  
William A. Gern

It was the purpose of this study to investigate methods of assessing responses to stress by free-ranging bighorn sheep (Ovis canadensis canadensis). The adrenal response test on wild-caught bighorn sheep maintained in captivity did not demonstrate either adrenal exhaustion or hypersensitivity during chronic stress. To study physiological responses to acute stress, hand-reared bighorn sheep were habituated to living in stalls and fitted with electrocardiogram leads and jugular cannulas for remote monitoring of cardiac frequency and blood cortisol changes. A radioimmunoassay was validated on bighorn sheep plasma which was a modification of the procedure used for domestic sheep. A linear relationship between heart rate and blood cortisol was obtained for individual animals suggesting that remote monitoring of cardiac frequency can be used as a predictor of adrenal function and, therefore, the potential immunologic condition of an animal during stress.


1989 ◽  
Vol 1 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Anthony E. Castro ◽  
Steven R. Montague ◽  
Jill F. Dotson ◽  
David A. Jessup ◽  
James R. DeForge

A cell line (BHFTE) was derived from a tongue explant of a bighorn sheep fetus (Ovis canadensis nelsoni). The cells have been maintained through 23 serial passages, and the modal number of chromosomes was calculated to be 55. Monolayer cultures were shown to be susceptible to various viruses, including bluetongue virus (BTV). Of 5 BTV serotypes (2, 10, 11, 13, and 17) tested, each produced a cytopathic effect (CPE) on initial passage at 33 C. A field isolate (serotype 10) of BTV from a black-tailed deer (Odocoileus hemionus columbianus) in its second passage in Vero-M cells also produced CPE when inoculated into BHFTE cells. Antigens of BTV were demonstrated by direct immunofluorescence in the cytoplasm of BHFTE cells inoculated with homogenates of chicken embryos injected with clinical specimens from a domestic sheep and an Arabian oryx (Oryx gazella leucoryx). A suspension of BTV-infected gnats (Culicoides spp.) produced CPE and BTV-specific fluorescence on the first passage in cells inoculated with a suspension of blood from sheep experimentally infected with BTV. Additionally, selected bovine viruses induced CPE in the cells. The cell line, which is free of mycoplasma and bovine viral diarrhea virus contamination, may be useful in diagnostic medicine and research involving the ruminant species.


1965 ◽  
Vol 43 (5) ◽  
pp. 885-888 ◽  
Author(s):  
E. C. H. Chen ◽  
D. A. Blood ◽  
B. E. Baker

Milk was obtained from five Rocky Mountain bighorn sheep living in the Jasper Park area of Alberta. The milk was collected at [Formula: see text] and 3 months post partum. The gross composition and milk fat fatty acids of the milk samples and of a sample of domestic sheep milk (Suffolk, 1 month post partum) were determined.


2012 ◽  
Vol 92 (3) ◽  
pp. 275-283 ◽  
Author(s):  
M. Palma-Irizarry ◽  
P. Damian-Matsumura ◽  
M. Betancourt ◽  
S. Romo ◽  
G. Perales ◽  
...  

Palma-Irizarry, M., Damian-Matsumura, P., Betancourt, M., Romo, S., Perales, G., Lagunas-Martínez, A., Madrid-Marina, M. V., Mejía, O. and Ducolomb, Y. 2012. Identification of novel variants of interferon-tau gene in Bighorn sheep ( Ovis canadensis mexicana ), Pelibuey sheep ( Ovis aries ) and its expression in hybrid blastocysts ( Ovis canadensis×Ovis aries ). Can. J. Anim. Sci. 92: 275–283. The major signal for maternal recognition of pregnancy (MRP) in ruminants is interferon-tau (IFNT). Four novel sequences of the IFNT gene were isolated from genomic DNA obtained from blood samples of Bighorn, Pelibuey or the hybrid ewes. The deduced amino acid sequence of the hybrid ewe showed 100% identity with one Bighorn sheep IFNT sequence, suggesting that this sequence was inherited from Bighorn sheep. The high degree of identity between Pelibuey and Bighorn sheep sequences could be a possible explanation for the successful MRP in some Bighorn hybrid pregnancies. In vivo and in vitro domestic sheep (Ovis aries) and hybrid sheep (Ovis aries×Ovis canadensis) blastocysts were obtained, and IFNT expression was measured by semiquantitative RT-PCR. In vivo and in vitro hybrid blastocysts showed lower expression of IFNT when compared with domestic blastocysts. In conclusion this study showed that there exists an effect of hybridization on IFNT expression and this can affect the MRP.


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