Seasonal foraging behavioural compensation in reproductive wapiti hinds (Cervus elaphus canadensis)

Captive wapiti hinds were observed during seven periods between June 1996 and November 1997. We investigated their activity and foraging behaviour on two pastures, heavily and lightly grazed, during four phases of the reproductive cycle (early gestation, late gestation, peak lactation, and late lactation). Within season, differences in forage availability between pastures had little apparent effect on wapiti feeding behaviour (p0.05). However, within each pasture, hinds tended to select locations of higher phytomass than the pasture average. Among seasons, effects of forage availability on feeding behaviour were pronounced. Hinds grazed longest in late lactation (12.8 h/day), when they spent 94% of their active time foraging, whereas during early gestation they foraged fewer hours (8.2 h/day) and less intensively (66% of active time). The longest foraging bouts also occurred in late lactation (100 min) and decreased linearly as the number of bouts per day increased (R(2)=0.88). The annual peak bite rate (BR) was in late lactation (62 bites/min), whereas the annual nadir occurred in early gestation (37 bites/min). Smallest bite sizes (BS) (mg) were recorded in late gestation (127 mg), and increased linearly with forage availability (R(2)=0.46), with largest BS occurring during peak lactation (280 mg). This study demonstrated how seasonal modifications in activity and foraging behaviour enabled gestating and lactating wapiti hinds to satisfy their changing nutritional requirements on seasonal pastures. Knowledge of behavioural compensation in response to nutritional demand and pasture conditions will be useful in designing supplementation program for farmed wapiti.     

The gestation length of wapiti (Cervus elaphus) revisited

As an ancillary activity to an artificial insemination program in farmed wapiti, the length of gestation of 28 wapiti hinds that delivered single calves of established parentage was calculated. Estrus was synchronized in 47 wapiti using progesterone impregnated devices (controlled internal drug release, CIDR) and an injection of PMSG. All hinds were artificially inseminated between 60 and 63h after CIDR removal. Pregnancy was determined between 45 and 65 days by ultrasound. A verifiable figure for gestation length was obtained based both upon timed-artificial insemination, date of parturition, and confirmation of sire identity through microsatellite DNA technology. The calculated gestational length of 247 +/- 5 days was significantly (P < 0.0001) shorter than the generally quoted figure of 255 +/- 7 days.     

Forage quality and patch choice by wapiti (Cervus elaphus)

Recent models suggest that herbivores might optimize energygain by selecting patches of intermediate vegetation biomass.We tested this hypothesis in wapiti (Cervus elaphus) by estimatingdaily rates of energy gain in relation to grass biomass andby measuring patch choice in experimental pastures in whichgrass biomass was manipulated by mowing. The digestible energycontent of grasses declined with increasing biomass due to maturationalchanges in fiber and lignin content. Daily rates of dry matterintake by wapiti increased with grass biomass at a deceleratingrate, implying a Type II functional response. Linking thesevalues to published ad libitum energy intake and energy expenditureparameters, Fryxell's (1991) model predicted that the dailyrate of energy gain should be highest when wapiti feed in grasslandswith 1000–1100 kg/ha. In trials in which grass biomasswithin a mosaic of patches was manipulated experimentally between800–2900 kg/ha, wapiti preferred patches of 1200 kg/ha,close to the value predicted by the energy gain model. Our resultssuggest that the rate of energy gain by wapiti is constrainedby both grass biomass and grass fiber content, the latter ofwhich varies inversely with grass biomass. Behavioral preferencefor grass patches of intermediate biomass and fiber contentcould help explain patterns of aggregation and seasonal migrationreported previously for wapiti.     

Induction of ovarian follicular wave emergence in wapiti (Cervus elaphus)

Two experiments were done to test the effects of treatments designed to electively induce ovarian follicular wave emergence in wapiti for the purpose of group synchronization. In Experiment 1, hinds were assigned randomly to three groups and given saline im (controls; n=5), 5mg of estadiol-17ss im (n=4), or 5mg estradiol-17ss plus 100mg progesterone im (n=5). In Experiment 2, hinds were assigned randomly to two groups and given no treatment (controls; n=6), or transvaginal ultrasound-guided follicle ablation (n=7). In both experiments, ovarian follicular dynamics were monitored by daily transrectal ultrasonography from Day 0 (day of treatment) to Day 9. In Experiment 1, blood samples were collected at each examination for measurement of serum concentrations of progesterone and FSH. Both experiments were conducted during the late anestrous period (July and August). The mean (+/-S.E.M.) day of wave emergence did not differ between the control and estradiol alone groups, but tended to be later in the estradiol plus progesterone group Day 4.0+/-0.7, Day 3.5+/-0.3, and Day 5.2+/-0.2, respectively; P=0.06). The interval from treatment to wave emergence was less variable in the estradiol plus progesterone group (P<0.05) and tended to be less variable in the estradiol-alone group (P=0.07) than in the control group. The day of wave emergence was more variable (P<0.05) and tended to be later (P=0.10) in the control group compared to the ablation group (Day 2.5+/-0.8 versus Day 1.4+/-0.2). All three treatments were effective in synchronizing ovarian follicular wave emergence among a group of wapiti hinds. Follicle ablation may be an alternative method for synchronization of follicular waves in estrus synchronization and superstimulatory protocols.     

Artificial insemination of red deer (Cervus elaphus) with frozen-thawed wapiti semen

Semen collected from wapiti (Cervus elaphus) in Canada in 1983 was frozen in two extenders. In 1988, the semen was used to inseminate 200 red deer hinds on 2 farms in New Zealand. Oestrus was synchronized in the hinds with progesterone-impregnated intravaginal devices (CIDR); 200 iu pregnant mares' serum gonadotrophin was given to each hind on Day 11. The CIDRs were removed on Day 12 at 20/h, as the numbers of the hinds were recorded. On Day 14, 54-56 h after CIDR removal, the hinds were brought into the yards in the same batches and laparoscopically inseminated. Semen from three sires was used. The overall conception rate was 51%. Gestation length ranged from 239 to 247 days. One hind was lost at calving, 3 calves had to be hand raised and there were 2 neonatal calf deaths.     

Characterization of 11 polymorphic tetranucleotide microsatellites for forensic applications in California elk (Cervus elaphus canadensis)

Eleven polymorphic tetranucleotide microsatellite loci have been developed for forensic use in the protection of California elk. Based on a reference sample of elk taken from three races throughout California, the loci consist of 4–9 alleles (average 6.125). Probabilities of identity ( Paetkau et al. 1995 ) range from 0.079 to 0.288, with an overall probability of identity of 1.3 × 10^?9 (one in 7.8 × 10⁸).     

Psoroptic scabies in Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from Wyoming

Thirteen Rocky Mountain bighorn sheep (Ovis canadensis canadensis) with clinical signs of psoroptic scabies were captured in Wyoming. Signs included droopy ears, depilation on the head and neck, and exudate in the ears. Mites were identified as either Psoroptes cervinus or P. equi. Two ewes with scabies at the time of original capture had no clinical signs of mite infection 1 and 2 yr later.     

Ectoparasites from elk (Cervus elaphus nelsoni) from Wyoming

Hides of nine elk, collected during the winter of 1986-1987 from the National Elk Refuge, Wyoming (USA) were examined for ectoparasites. Parasites recovered were mites, Psoroptes sp. (five elk); lice, Solenopotes ferrisi and Bovicola (Bovicola) longicornis (seven elk); and winter ticks, Dermacentor albipictus (nine elk). Three elk with severe scabies had an estimated 0.6 x 10(6), 3.8 x 10(6) and 6.5 x 10(6) mites, respectively. Densities of mites were much higher in skin regions with severe dermatitis. Skin lesions on elk with scabies consisted of dense, often moist, scabs extending along the dorsal and lateral thoracic regions of the body. Lesions attributed to winter ticks consisted of broken hair and alopecia on the dorsal portion of the lower neck, often extending in a "collar" around the neck.     

Enumeration and antibiotic resistance patterns of fecal indicator organisms isolated from migratory Canada geese (Branta canadensis)

Thermotolerant fecal indicator organisms carried by migratory waterfowl may serve as reservoirs of antibiotic resistance. To determine the extent to which such antibiotic resistance markers were present in migratory Canada geese (Branta canadensis) on the Maryland Eastern Shore, we isolated Enterococcus spp. and Escherichia coli from fresh feces and examined the antibiotic resistance profiles of these bacteria. Samples were obtained in October 2002, January 2003, and March 2003. Thermotolerant E. coli counts ranged from 0 to 1.0x10(7) colony forming units (CFU)/0.1g (g-1) wet weight of feces, whereas Enterococcus spp. counts ranged from 1.0x10(2)-1.0x10(7) CFU g-1 wet weight of feces. Primary isolates of each indicator organism were tested against a panel of 10 antibiotics. Greater than 95% of E. coli isolates were resistant to penicillin G, ampicillin, cephalothin, and sulfathiazole; no E. coli were resistant to ciprofloxacin. Enterococcal isolates showed highest resistance to cephalothin, streptomycin, and sulfathiazole; no enterococci were resistant to chloramphenicol. The tetracyclines, streptomycin, and gentamycin provided the greatest discrimination among E. coli isolates; chlortetracycline, cephalothin, and gentamycin resistance patterns provided the greatest discrimination between enterococcal strains. Multiple antibiotic resistance (MAR) profiles were calculated: fall (E. coli=0.499; enterococci=0.234), winter (E. coli=0.487; enterococci=0.389), and spring (E. coli=0.489; enterococci=0.348). E. faecalis and E. faecium, which are recognized human nosocomial pathogens, were cultured from winter (44 and 56%, respectively) and spring (13 and 31%, respectively) fecal samples.     

Somatic embryogenesis from immature embryos of redbud (Cercis canadensis)

Somatic embryos developed directly from 96 and 110 day post-anthesis Cercis canadensis L. (redbud) zygotic embryos from one of two trees sampled that were explanted onto modified Schenk and Hildebrandt medium amended with either 1, 2, 3 or 5 mg/1 2,4-D in combination with either 7.6 or 12. 6 mM ammonium ion. Although somatic embryogenesis was expressed on most media, the number of explants that produced somatic embryos and the mean number of embryos formed per explant were greatest on media that contained either 2 or 3 mg/1 2,4-D; 12.6 mM ammonium ion inhibited embryogenesis from 96 day post-anthesis explants. Zygotic embryos explanted 117 days after anthesis produced only callus and roots. Somatic embryos that were bottle-shaped or had distinct cotyledons organized roots on germination media, but only one embryo formed a shoot. No additional development occurred. Histological examination of somatic embryos showed that shoot apical meristems were poorly developed.Abbreviations 2,4-D 2, 4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - BAP 6-benzylaminopurine - FPA Formalin-propionic acid-ethanol (50%)     

Teratological pollen of Circaea canadensis ssp. canadensis (Onagraceae: Circaeeae)

Pollen morphology of Circaea canadensis (L.) Hill ssp. canadensis collected from sites in Oklahoma differs from that described in earlier reports on this taxon. The samples we observed had poorly developed viscin threads, many with slender connecting points. In the equatorial zones between apertures there were randomly dispersed and elevated tectal components. These features may be due to arrested development since they are present in early stages of development in related taxa.     

Isolation of Actinobacillus suis from a Canada goose (Branta canadensis)

Blindness from conjunctivitis caused by Actinobacillus suis was found in a Canada goose (Branta canadensis) from a wildlife refuge in Kentucky. Lesions were not observed elsewhere and other body organs were grossly normal. Actinobacillus spp. in birds is rare and this is apparently the first report of conjunctivitis resulting from this infection in waterfowl.     

Giardia in beaver (Castor canadensis) and nutria (Myocastor coypus) from east Texas

We examined the prevalence of Giardia sp. infection in nuisance beaver (Castor canadensis) and nutria (Myocastor coypus) in east Texas. From October 1992 through September 1993, 100 beaver and 30 nutria were collected in routine wildlife management activities conducted by the U.S. Department of Agriculture-Animal and Plant Health Inspection Service-Texas Animal Damage Control Service. Fecal and duodenal mucoid samples were preserved from each animal. Fecal samples were examined for the occurrence of Giardia sp. cysts using the Merifluor immunoassay detection kit: 30 beaver (30.0%) and 20 nutria (66.7%) were positive for Giardia sp. Duodenal mucoid samples were examined for Giardia sp. trophozoites using trichrome staining. with 26 beaver (26.0%) and 20 nutria (73.3%) testing positive. Combining both techniques resulted in 33 beaver (33.0%) and 22 nutria (73.3%) testing positive for Giardia sp. We found no relationship between Giardia sp. and host age, sex, river system, habitat, county, or season in beaver. However, a relationship was found when season and habitat were considered together. No relationship was found between Giardia sp. and age, river system, habitat, county, or season in nutria: however, more males (87.5%) were infected than females (46.4%).     

Reproductive performance of pubertal red deer (Cervus elaphus) hinds: effects of genetic introgression of wapiti subspecies on pregnancy rates at 18 months of age

Low reproductive productivity of young red deer (Cervus elaphus) hinds on New Zealand deer farms appears to reflect high incidences of puberty failure at 16 months of age. This is despite the general attainment of average liveweights 15–25 kg in excess of the accepted minimum threshold for puberty in subspecies of western European origin (scoticus, elaphus and hippelaphus) that form the basis of the national herd. The present study tests the hypotheses that introgression of the larger North American wapiti subspecies (nelsoni, manitobensis and roosevelti) into breeding herds (1) can be assessed from morphological features of individuals, (2) that there is a relationship between the level of wapiti parentage and non-pregnancy rate at 18 months of age (a proxy for puberty failure) and (3) that minimum liveweight thresholds for puberty increase with increasing levels of wapiti parentage.

A total of 4329 18-month-old hinds across four “red” deer farms in southern New Zealand were scanned for pregnancy status. Each hind was assigned a wapiti score (WS) as a subjective assessment of the obviousness of wapiti features. Various body measurements were additionally recorded for each hind. A hair sample was collected for DNA analysis (14 markers) to objectively assign subspecies pedigree (i.e. “Elkmeter”) on a subset of 1258 individuals. A total of 506 (11.7%) hinds were not pregnant at 18 months of age with rates varying between 4.1 and 37.3% between farms and years. Mean WS differed significantly between farms and reflected the genetic management policy of each farm. WS was positively correlated to Elkmeter for each farm/year (<0.05) although regression slopes varied significantly. WS was able to be adjusted for these differences to assign a corrected WS (CWS) for all 4329 individuals that estimated the proportion wapiti parentage. Discriminant analysis of morphological variables relative to Elkmeter supported the first hypothesis and showed that shoulder height and body length were good indicators of the degree of wapiti parentage within individuals. This enabled the development of an objective estimate of wapiti parentage (EWP). The actual level of such parentage within herds ranged from <5 to >55%. There was a significant negative association between wapiti parentage and pregnancy, which was strongly influenced by liveweight, supporting the second and third hypotheses. This was manifest as marked displacement of pregnancy probability curves in relation to liveweight between genotype groups, particularly for those groups with >20% wapiti parentage. For example, predicted threshold liveweights required to achieve a 90% pregnancy rate for EWP values that represent 0, 10, 20, 30, 40 and 50% wapiti parentage were 81, 81, 85, 106, 127 and 137 kg, respectively. Within the study herds, the majority of hinds of 0–20% wapiti parentage exceeded the predicted 90% threshold liveweights for their genotype cohort. However, hinds with higher levels of wapiti parentage generally fell below the predicted threshold for their genotype group. The data strongly suggest that under liveweight performance levels measured for red deer, hinds with >20% wapiti parentage are at high risk of puberty failure.     

Isolation and characterization of proteoglycans from growing antlers of wapiti (Cervus elaphus)

Proteoglycans were extracted with 4 M guanidine–HCl from the zone of maturing chondrocytes, the site of endochondral ossification of growing antlers of wapiti (Cervus elaphus). Proteoglycans were isolated by DEAE-Sephacel chromatography and separated by Sepharose CL-4B chromatography into three fractions. Fraction I contained a high molecular mass (>1000 kDa) chondroitin sulfate proteoglycan capable of interacting with hyaluronic acid. Its amino acid composition resembled that of the cartilage proteoglycan, aggrecan. Fraction II contained proteoglycans with intermediate molecular weight which were recognized by monoclonal antibodies specific to chondroitin sulfate and keratan sulfate. Fraction III contained a low molecular mass (<160 kDa) proteoglycan, decorin, with a glucuronate-rich glycosaminoglycan chain.     

The attraction of the known: the importance of spatial familiarity in habitat selection in wapiti Cervus elaphus

Most studies of habitat selection by large herbivores focus on the resource availability and interactions with other species, but neglect the importance of an animal being familiar with an area due to past use. Yet, studies of the establishment and retention of territories, home ranges, birth sites, and feeding site choices in experimental settings have shown the importance of spatial familiarity at these scales. We used GPS locations of translocated wapiti Cervus elaphus , resource selection functions (RSF), and time-to-return to examine whether previous site use was important for selection of sites by wapiti in west-central Alberta. To construct RSFs, we used logistic regression that included spatial familiarity (presence of a previous GPS location within a 50-m radius) as well as estimates of herbaceous and shrub biomass, elevation, aspect, slope, and predation risk to wapiti from wolf predation, as dependent variables. We found that previous use had a strong positive relationship with subsequent site use, indicating that wapiti were not avoiding previously visited locations, as would be expected if memory of forage depletion (which we did not measure) determined response to familiar locations. Revisited sites were of higher quality, i.e. had more moderate terrain, higher forage, and lower predation risk, than sites that were not revisited, indicating that the selection of familiar locations was likely not the result of avoidance of unfamiliar locations. Finally, animals demonstrated preference for familiar locations that it had visited most recently, indicating that memory (which would decline with time) of higher site quality, rather than high quality alone, influenced selection for familiar locations. We conclude that spatial familiarity is important not only for large scale processes such as selection of home range and territory, but for smaller scale habitat selection and foraging as well.