Measurements, Weights, and Carcass Yields of Pronghorns in Alberta

Abstract

Standard body measurements (117 specimens), whole weights (216 specimens), hog-dressed weights (1,210 specimens), and dressed weights (40 specimens) obtained from pronghorn antelopes (Antilocapra americana americana) in southern Alberta were analyzed and compared with data published for specimens of the americana, mexicana, and oregona subspecies in other regions. The average total lengths of pronghorns in this study are longer than those of pronghorns for all regions except California. Alberta pronghorns have the shortest ear lengths. Mean shoulder heights are equivalent to those for Montana pronghorns but are shorter than for pronghorns in other regions. The maximum whole weight attained by a mature male (155 lb) in late summer in Alberta exceeds the maximum weight previously reported. Although pronghorns in this study are heavier than those in most regions, their mean body weights are similar to amerwana specimens in Wyoming, and oregona animals in Oregon and California. The relatively lighter winter body weight in Alberta probably reflects the severe conditions on that northern range. Ee physical features of the pronghorn appear to comply with both Allen's Rule and Bergmann's Rule. Mean hog-dressed weights in this study exceed those for Idaho, Montana, and Wyoming, but are smaller than those reported for California and North Dakota. They range from 66 to 75 percent of whole weights. Mean dressed carcass yields range from 51 to 57 percent and correspond closely to the yield values reported for other wild ungulates. Whole weights can be estimated by applying the conversion factors 1.36 and 1.51 to the hog-dressed weights of mature males and females, respectively, and 1.78 and 1.95 to the dressed weights. Also, the linear regressions between whole and hog-dressed weight for yearling and mature males (y = 16.7496 + 1.1732x) and females (y = 38.7119 + 0.9501x), and the linear regressions between whole vveight and heart girth for immature and older males and females (y = 0.3043x 179.4817), mature males and females (y = 0.2S4Sx 126.68S3), and submature males and females (y = 0.2484x 136.6747), can be used to provide useful esffmates of whole weights. acterized by a mean annual precipitation of less than 14 inches, high rates of evaporation, prolonged periods of drought, and great extremes in temperature. Most soils are classed as Brown Soil Group (Chernozems) by Bowser et al. ( 1963 ) and support a mixed prairie vegetation (Coupland 1950, 1961 ) . Needle-and-thread ( Stipa comata ), blue grama (Bouteloua gracilis), western wheatgrass (Agropyron smithii), Junegrass (Koeler?a cristata), pasture sagewort (Artem?sia frigida ), and sagebrush ( Artemisia cana) are dominant on many upland sites (Clarke et al. 1942, Coupland 1950, 1961, Smoliak 1956). Most pronghorns examined in this study were shot or trapped in plant communities classified as Stipa comataAgropyron smithii / Bouteloua gracilis, and Stipa comata /Bouteloua eracilis habittlt types (Mitchell 1965). This paper reports on ageand sexspecific body measurements and seasonal weights of pronghorns in Alberta at the northern limit of their continental distibution. Body measurements and weights, carcass yields, and the percentage of whole weights comprised by internal and external offal are considered. The relationships between various body weights are compared with data from other regionsn and criteria are established for estimating whole weights using hog-dressed and dressed weights and heart girths. This study was conducted on the western extremity of the Canadian Great Plains in Alberta between lat 49° and 51° N. The steppe of this region is a relatively uniform, undulating to gently rolling till plain char1 Present address: Biology Department, University of Saskatchewan, Regina Campus, Regina.