1) General Zoological Data
This single member of the genus is widely distributed over the American west and northern Mexico. In the distant past, thirteen species of antilocapridae were found in North America, this is the only remaining species of this genus, with five recognized subspecies. They are well known for their speed and also difficulty in keeping healthy in zoological parks. Longevity in captivity is 12+ years. They are said to be the only animal with both horn and antler, having a hollow horn over a protrusion of bone. Their name derives from the short prong at the distal antler. Beintema et al. (2003) sought gene for ribonuclease gene sequences and were unable to detect the seminal-type ribonuclease in pronghorn, apparently having completely deleted in pronghorn, presenting difficulties for phylogenetic assignment. Indeed, Nowak (1999) summarized recent information on relationship to other taxa that suggests they be comprised with cervids under the superfamily Cervoidea. They weigh up to 70 kg, males being larger than females. Both have antlers. Neonates weigh from 3-5.78 kg (Hayssen et al.1993). A comprehensive review of all aspects of this species has been published by one the best experts on pronghorn, O'Gara (1978).
Aerial surveys of the population in Wyoming, for instance, were conducted by Johnson et al. (1991) with several herd sizes over 300 animals being detected. In Mexico, however, the three subspecies of pronghorn are considered to be significantly endangered with only a few thousand animals remaining (Ceballos & Navarro, 1991). This is especially true for the subspecies of Baja California.
General Gestational Data
Wislocki & Fawcett described four mid-pregnant uteri, but a more comprehensive study of female reproduction was undertaken by O'Gara (1969). He indicated that between three to seven ova developed into expanded blastocysts, twins resulted as a general rule. The expanding tip of the proximal, normally implanted gestational sac pierced by the necrotic tip of its membranes the distal embryonic sac, thus eliminating excess implantation. Gestation is around 250 days with singletons in the first pregnancy and twins born thereafter in more than 50% of pregnancies. Triplets have also been reported. Transuterine migration occurs. Neonates suffer high mortality from predation. Possible monozygotic twins occur (see section on pathology).
A few macroscopic descriptions of young implantations have been detailed by O'Gara (1969) but histology is needed. I have had available only one mid-pregnant uterus containing twins, made available by the Los Angeles zoo many years ago. The photographs come from that specimen.
4) General Characterization of the Placenta
This is a typical polycotyledonary, epithelio-chorial placenta, similar to most other ungulates. The placenta has are an average of 92 (flat) cotyledons and the membranes meet in midline around 50-75 mm length (O'Gara, 1969). Anastomoses between fetal circulations are most uncommon. The distal tip of the membranes is necrotic. There is, however great variation in the number of placentomes developing, from 46 to 180 (O'Gara, 1969). Weights are not available of placentas and only volumes of cotyledons have been ascertained by O'Gara (1969).
Details of fetal/maternal barrier
This is typically epitheliochorial with cuboidal trophoblast and a moderate number of binucleate trophoblast. Villi contain relatively little connective tissue. They are diffusely interposed between major uterine trabeculae.
The cord attaches nearer the cervix than the utero-tubal junction (Mossman, 1987), but there are no descriptions or measurements of umbilical cords in any of the descriptions listed here.
7) Uteroplacental circulation
No studies are found in the literature.
8) Extraplacental membranes
The peripheral tip towards to oviductal end of amnion/allantois usually becomes necrotic (yellow-cheesy) from lack of allantoic vasculature and "acts as a lethal weapon in intra-uterine competition" (O'Gara, 1969). Mossman (1987) described the allantois as a "long, narrow, tubular allantoic cavity".
Trophoblast external to barrier
There is no uterine invasion by trophoblast.
The uterus is bicornuate; a cervical mucus plug develops during gestation. (O'Gara, 1969). Normally four rows of caruncles develop, although O'Gara (1969) found five uteri without caruncles in his large series. There is no true decidua. Between cotyledons, the endometrial glands continue to be active.
There is neither a subplacenta nor other unusual features of placentation.
I have not been able to identify any studies on endocrinology of pronghorn.
Pronghorns have 58 acrocentric chromosomes (Wurster & Benirschke, 1967; Hsu & Benirschke, 1969). Hybrids are unknown. Dain (1977) studied the replication pattern of the sex chromosomes and found it to be larger than the "normal" 5% of genome; they detected late-labeling portions of both X and Y that were in excess of the 4.7% for the "regular" X chromosome. Gallagher et al. (1994) compared the band homologies of several Bovidae, including the pronghorn and found cattle and pronghorn to be most similar. A study of satellite DNA was undertaken by Denome et al. (1994). Murray et al. (1995) were able to use mitochondrial D-loop variation for the species identification among many different ungulates. Lee et al. (1994) were able to differentiate some subspecies by allozyme analysis in a large population from different areas; their study of mtDNA variation however was less informative.
The serological studies conducted are listed in the next section.
15) Pathological features
16) Physiologic data
18) Other remarks - What additional
Information is needed?
Beintema, J.J., Breukelman, H.J., Dubois, J.Y. and Warmels, H.W.: Phylogeny of ruminants secretory ribonuclease gene sequences of pronghorn (Antilocapra americana). Mol. Phylogenet. Evol. 26:18-25, 2003.
Brodie, S.J., Bardsley, K.D., Diem, K., Mecham, J.O., Norelius, S.E. and Wilson, W.C.: Epizootic hemorrhagic disease: analysis of tissues by amplification and in situ hybridization reveals widespread orbivirus infection at low copy numbers. J. Virol. 72:3863-3871, 1998.
Ceballos, G. and Navarro, L, D.: Diversity and conservation of Mexican mammals. Chapter 9 (pp. 167-198) in Biogeography and Biodiversity. M.A. Mares and D.J. Schmidly, eds. Univ. Oklahoma Press, Norman, Oklahoma, 1991.
Clark, G.G., Calisher, C.H., Crabbs, C.L., Canestorp, K.M., Tesh, R.B., Bowen, R.A. and Taylor, D.E.: Malpais spring virus: a new vesiculovirus from mosquitoes collected in New Mexico and evidence of infected indigenous and exotic ungulates. Amer. J. Trop. Med. Hyg. 39:586-592, 1988.
Clemens, E.T., Meyer, K.L., Carlson, M.P. and Schneider, N.R.: Hematology, blood chemistry and selenium values of captive pronghorn antelope, white-tailed deer and American bison. Comp. Biochem. Physiol. C 87:167-170, 1987.
Dain, A.: DNA replication in the sex chromosomes of the pronghorn and Rocky Mountain goat. Cytogenet. Cell Genet. 18:126-135, 1977.
Denome, R.M., O'Callaghan, B., Luitjens, C., Harper, E. and Bianco, R.: Characterization of a satellite DNA from Antilocapra americana. Gene 145:257-259, 1994.
Dhindsa, D.S., Cochran, T.H., Castro, A., Swanson, J.R. and Metcalfe, J.: Serum biochemical and electrophoretic values from four deer species and from pronghorn antelope. Amer. J. Vet. Res. 36:1455-1457, 1975.
Dubey, J.P.: Sarcocystis species in moose (Alces alces), bison (Bison bison), and pronghorn (Antilocapra americana) in Montana. Amer. J. Vet. Res. 41:2063-2065, 1980.
Dubey, J.P.: Isolation of encysted Toxoplasma gondii from musculature of moose and pronghorn in Montana. Amer. J. Vet. Res. 42:126-127, 1981.
Dunbar, M.R., Velarde, R., Gregg, M.A. and Bray, M.: Health evaluation of a pronghorn antelope population in Oregon. J. Wildl. Dis. 35:496-510, 1999.
Dunbar, M.R., Wolcott, M.J., Rimler, R.B. and Berlowski, B.M.: Septicemic pasteurellosis in free-ranging neonatal pronghorn in Oregon. J. Wildl. Dis. 36:383-388, 2000.
Edwards, J.F., Davis, D.S., Roffe, T.J., Ramiro-Ibanez, F. and Elzer, P.H.: Fusobacteriosis in captive wild-caught pronghorns (Antilocapra americana). Vet. Path. 38:549-552, 2001.
Elzer, P.H., Smith, J., Roffe, T., Kreeger, T., Edwards, J. and Davis, D.: Evaluation of Brucella abortus strain RB51 and strain 19 in pronghorn antelope. Ann. N.Y. Acad. Sci. 969:102-105, 2002.
Gallagher, D.S., Derr, J.N. and Womack, J.E.: Chromosome conservation among the advanced pecorans and determination of the primitive bovid karyotype. J. Hered. 85:204-210, 1994.
Griner, L.A.: Pathology of Zoo Animals. Zoological Society of San Diego, San Diego, California, 1983.
Hayssen, V., van Tienhoven, A. and van Tienhoven, A.: Asdell's Patterns of Mammalian Reproduction: a Compendium of Species-specific Data. Comstock/Cornell University Press, Ithaca, 1993.
Hsu, T.C. and Benirschke, K.: An Atlas of Mammalian Chromosomes. Vol. 3, Folio 136, 1969. Springer-Verlag, New York.
Jessup, D.A.: Epidemiology of two orbiviruses in California's native wild ruminants: preliminary report. Progr. Clin. Biol. Res. 178:53-65, 1985.
Johnson, B.K., Lindzey, F.G. and Guenzel, R.J.: Use of aerial line transect surveys to estimate pronghorn populations in Wyoming. Wildl. Soc. Bull. 19:315-321, 1991.
Kingston, N., Williams, E.S. and Thorne, E.T.: Invasive entamoebae in pronghorn (Antilocapra americana) from Wyoming. J. Wildl. Dis. 26:50-54, 1990.
Kuttler, K.L.: Anaplasma infections in wild and domestic ruminants: a review. J. Wildl. Dis. 20:12-20, 1984.
Lance, W.R., Hibler, C.P. and DeMartini, J.: Experimental contagious ecthyma in mule deer, white-tailed deer, pronghorn and wapiti. J. Wildl. Dis. 19:165-169, 1983.
Lee, T.E., Bickham, J.W. and Scott, M.D.: Mitochondrial DNA and allozyme analysis of North American pronghorn populations. J. Wildl. Manage. 58:307-318, 1994.
Li, H., Shen, D.T., Jessup, D.A., Knowles, D.P., Gorham, J.R., Thorne, T., O'Toole, D. and Crawford, T.B.: Prevalence of antibody to malignant catarrhal fever virus in wild and domestic ruminants by competitive-inhibition ELISA. J. Wildl. Dis. 32:437-443, 1996.
Miller, M., Amsel, S., Boehm, J. and Gonzales, B.: Presumptive copper deficiency in hand-reared captive pronghorn (Antilocapra americana). J. Zoo Wildl. Med. 32:373-378, 2001.
Mossman, H.W.: Vertebrate Fetal Membranes. MacMillan, Houndmills, 1987.
Mossman, H.W. and Duke, K.L.: Comparative Morphology of the Mammalian Ovary. University of Wisconsin Press, Madison, Wisconsin, 1973.
Murray, B.W., McClymont, R.A. and Strobeck, C.: Forensic identification of ungulate species using restriction digests of PCR-amplified mitochondrial DNA. J. Forensic Sci. 40:943-951, 1995.
Nowak, R.M.: Walker's Mammals of the World. 6th ed. The Johns Hopkins Press, Baltimore, 1999.
O'Gara, B.W.: Unique aspects of reproduction in the female pronghorn (Antilocapra americana Ord). Amer. J. Anat. 125:217-232, 1969.
O'Gara, B.W.: Antilocapra americana. Mamm. Species 90:1-7, 1978.
Pusateri, F.M., Hibler, C.P. and Pojar, T.M.: Oral administration of diazepam and promazine hydrochloride to immobilize pronghorn. J. Wildl. Dis. 18:9-16, 1982.
Raisbeck, M.F., O'Toole, D., Schamber, R.A., Belden, E.L. and Robinson, L.J.: Toxicologic evaluation of a high-selenium hay diet in captive pronghorn antelope (Antilocapra americana). J. Wildl. Dis. 32:9-16, 1996.
Schwartz, C.C., Nagy, J.G. and Kerr, S.M.: Rearing and training pronghorns for ecological studies. J. Wildl. Managem. 40:464-468, 1976.
Simmons, H.A., Steffen, D.J., Armstrong, D.L. and Rogers, D.G.: Parastrongylus tenuis in captive pronghorn antelope (Antilocapra americana) in Nebraska. J. Wildl., Dis. 38:822-825, 2002.
Stauber, E.H., Autenrieth, R., Markham, O.D. and Whitbeck, V.: A seroepidemiologic survey of three pronghorn (Antilocapra americana) populations in southeastern Idaho, 1975-1977. J. Wildl. Dis. 16:109-115, 1980.
Thorne, E.T., Williams, E.S., Spraker, T.R., Helms, W. and Segerstrom, T.: Bluetongue in free-ranging antelope (Antilocapra americana) in Wyoming: 1976 and 1984. J. Wildl. Dis. 24:113-119, 1988.
Wislocki, G.B. and Fawcett, D.W.: The placentation of the pronghorned antelope (Antilocapra americana). Bull. Museum Comp. Zool. Harvard College 101:548-558, 1949
Wobeser, G., Daoust, P.Y. and Hunt, H.M.: Polioencephalomalacia-like disease in pronghorns (Antilocapra americana). J. Wildl. Dis. 19:248-252, 1983.
Wurster, D.H. and
Benirschke, K.: Chromosome studies on some deer, the springbok, and the
pronghorn with notes on placentation in deer. Cytologia 32:273-285, 1967.
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