Using Fecal Hormonal and Behavioral Analyses to Evaluate the Introduction of Two Sable Antelope at Lincoln Park Zoo

Journal of Applied Animal Welfare Science

ISSN: 1088-8705 (Print) 1532-7604 (Online) Journal homepage: http://www.tandfonline.com/loi/haaw20

Erin Loeding , Jeanette Thomas , Dave Bernier & Rachel Santymire

To cite this article: Erin Loeding , Jeanette Thomas , Dave Bernier & Rachel Santymire (2011) Using Fecal Hormonal and Behavioral Analyses to Evaluate the Introduction of Two Sable Antelope at Lincoln Park Zoo, Journal of Applied Animal Welfare Science, 14:3, 220-246, DOI: 10.1080/10888705.2011.576968

To link to this article: http://dx.doi.org/10.1080/10888705.2011.576968

Published online: 17 Jun 2011.

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Download by: [Dr Kenneth Shapiro] Date: 02 November 2015, At: 13:35 JOURNAL OF APPLIED ANIMAL WELFARE SCIENCE, 14:220–246, 2011 Copyright © Taylor & Francis Group, LLC ISSN: 1088-8705 print/1532-7604 online DOI: 10.1080/10888705.2011.576968

Using Fecal Hormonal and Behavioral Analyses to Evaluate the Introduction of Two Sable Antelope at Lincoln Park Zoo

Erin Loeding,1 Jeanette Thomas,1 Dave Bernier,2 and Rachel Santymire3

1Department of Biological Science, Western Illinois University– Quad Cities, Moline 2Department of Animal Care, Lincoln Park Zoo, Chicago, Illinois 3Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, Illinois

Introductions of sable antelope (Hippotragus niger) can be difﬁcult due to the potential ensuing aggression compoundedby their large horns. The goal was to use hormonal assays and behavioral analyses to evaluate the success of an introduction of 2 adult females at Lincoln Park Zoo. The objectives were to (a) document behavioral and hormonal changes in 2 female sable antelope during the introduction, (b) compare fecal glucocorticoid metabolites (FGM) in each individual during the introduction stages, (c) measure fecal androgen metabolites (FAM) during introduction and compare with dominance rank and observed aggression, and (d) monitor estrous cycle synchronization. Results demonstrate that FGM

Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 were higher before than during and after the introduction. Behavioral observations indicated limited aggression between females, although the keeper survey results revealed that the new female was more dominant and had higher mean FGM and FAM than the resident. Both sable antelope were reproductively active throughout the year. Results indicate that fecal hormone analysis can provide zoo management with valuable information to minimize the risk of aggression, injury, and stress during introductions of nonhuman animals.

Erin Loeding is now at The University of Chicago. Correspondenceshould be sent to Erin Loeding, The University of Chicago, 940 East 57th Street, Chicago, IL 60660. Email: [email protected]

220 SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 221

Sable antelope (Hippotragus niger) are indigenous to the wooded savannahs of southeastern Africa, where they forage on grasses and shrubs (International Union for Conservation of Nature [IUCN] Species Survival Commission Ante- lope Specialist Group, 2008). Sable antelope live in matriarchal herds of 40 to 50 females, with their young and a single dominant adult male, with female territories overlapping with male territories; however, neighboring herds are isolated with little interaction (Thompson, 1993). Young males at 3–4 years of age form bachelor groups of 2–12 individuals and become solitary to establish territories at 5–6 years (Nowak, 1999). With a population in the wild of around 54,000 individuals, sable antelope are classified as Lower Risk with major threats from habitat loss, overharvesting, and human disturbance (IUCN, 2008). However, the rare subspecies, the giant sable antelope (Hippotragus niger variani), is listed as Critically Endangered and has a population in the wild of fewer than 500 individuals (IUCN, 2008). The North American captive population of sable antelope is comprised of 140 individuals (56 males, 83 females, and 1 unreported sex) living in 17 institutions; no giant sable antelope are maintained in North America (International Species Information System, 2010). Information gathered from research on welfare and behavior of the sable antelope is potentially useful for application to the endangered counterpart. The complexity of wildlife social structures and hierarchies make introductions of new individuals into an existing group in captivity challenging. In sable antelope, introductions of a new individual to a herd of conspecifics have proven difficult because of increased aggression and serious injury from their large horns, which are found in both sexes (Read & Noble, 1984; Thompson, 1993). Typically, the introduced female encounters aggression from conspecifics by pursuit, which leads to exclusion from the herd (Thompson, 1993). Excluded individuals may need to be moved to a separate exhibit for the individual’s safety. To monitor the physiological responses of introducing a new individual to a group of conspecifics, fecal hormonal analysis is a noninvasive method of monitoring the well being of zoo-housed individuals and permits examination of gonadal (reproductive) and adrenocortical (stress) activity for some species. Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 Using feces is favored over using blood because samples can be collected during routine cleaning of the nonhuman animal’s enclosure and without sedation or restraint to confound glucocorticoid values (Moestl & Palme, 2002). Moreover, feces represent a cumulative value of hormonal activity instead of the point- in-time blood sample; the ease of fecal collection provides the opportunity for longitudinal hormonal assessment of individual animals (Brown, Wasser, Wildt, & Graham, 1994). If small changes after specific events are desired, however, fecal hormone assessment cannot detect acute changes in hormonal activity. In sable antelope, fecal progestin metabolites (FPM) are well correlated with serum progesterone (Thompson & Monfort, 1999). 222 LOEDING, THOMAS, BERNIER, SANTYMIRE

Quantitative physiological measurements of aggression have not been documented in the sable antelope. Aggression has been correlated with increased androgen metabolites and high social rank of individuals in a group of ungulates. For example, in male bighorn sheep (Ovis canadensis), a correlation was determined between high social rank and aggression exerted (Pelletier, Bauman, & Festa-Bianchet, 2003). In sable antelope, dominance rank was correlated with aggressive behaviors and age, with the more aggressive and oldest individuals possessing the highest rank (Thompson, 1993). Mature females of the herd establish a stable linear dominance hierarchy through extensive fighting (Nowak, 1999; Thompson, 1993). Fecal androgen metabolites (FAM) with behavioral observations may be a potential indicator of dominance rank and provide zoo management with a method to predict problems during introductions. However, FAM have not been measured in Hippotragine antelope, and relationships between FAM and aggression in females have been very limitedly investigated. Also undocumented in sable antelope, fecal glucocorticoid metabolites (FGM) can be useful in measuring the stress response during a specific event. Although stress can be described many different ways, it is defined as the actual or anticipated threat to homeostasis, anticipated threat to well being, or a physiological response to a real or perceived stressor (Ulrich-Lai & Herman, 2009). When a stressful situation or stressor is perceived, the hypothalamus secretes corticotropin-releasing hormone to act on the anterior pituitary, thus releasing adrenocorticotropic hormone. Consequently, glucocorticoids (including cortisol and corticosterone) are released by the adrenal cortex to act on various parts of the body, such as increasing glucose productionin the liver and reserving glucose for the brain and heart (Moberg, 1991; Palme, 2005; Touma & Palme, 2005). Fecal glucocorticoid metabolites have been used to quantify adrenocortical activity in a wide variety of species, including carnivores, primates, and ungulates (Beehner & McCann, 2008; Boissy & Le Neindre, 1997; Young et al., 2004). For example, FGM have been demonstrated to increase in cattle heifers (Bos taurus) tethered after a grazing period (Redbo, 1993). In addition, glucocorticoid metabolites have a direct inhibitory effect on estrogen secretion of granulosa cells in cattle (Kawate, Inaba, & Mori, 1993). In other mammalian species, adreno- Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 cortical activity has been quantified in a wide variety of situations, such as an indicator of the effects of (a) environmental enrichment—giant panda, Ailuropoda melanoleuca (Liu et al., 2006); (b) stereotypical behavior—clouded leopard, Ne- ofelis nebulosa (Wielebnowski, Fletchall, Carlstead, Busso, & Brown, 2002); and (c) separation and reunion of conspecifics, and ambient temperature changes— cattle (Boissy & Le Neindre, 1997; Redbo, 1993; Rhynes & Ewing, 1973). Estrous cycle synchronization is often an important antipredation strategy to maximize fitness in herd species such as the sable antelope (Rutberg, 1987; Thompson, 1995). Benefits include coordinating birth when environmental conditions are most advantageous and optimizing social growth through interactions SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 223

with conspecifics. A study of college female humans living with or close to each other synchronized their menstrual cycles over 6 months (McClintock, 1971). Norway rats (Rattus norvegicus) synchronized their estrous cycles over time when housed in groups compared with individuals living alone in similar conditions and are mediated by airborne chemical communication (McClintock, 1978). With females attaining sexual maturity at 2 years, female sable antelope may use the flehmen behavior to detect fluctuations in the urinary hormone metabolites of conspecifics to alter their own ovarian activity, thus coordinating parturition with herdmates to facilitate a 2-month birth peak (Thompson, 1991, 1995). Flehmen behavior is often directed at multiparous females when estrous cycling resumes after parturition with high-ranking females exhibiting the highest rate of flehmen (Thompson, 1991, 1995). Environmental cues like daylight are utilized by species with gestation periods less than 12 months; however, daylight and temperature near the equator do not vary much because food availability is associated with rainfall (Sekulic, 1978). In the wild, sable antelope reproduction is dependent on precipitation, with populations in areas with rainy seasons calving during the seasonal precipitation and areas without rainy seasons calving year-round (Thompson, Mashburn, & Monfort, 1998). Whether it is physiological or a response to environmental cues, the cause of these reproductive differences remains unknown (Thompson et al., 1998). The overall goal of this project was to assess the introduction of two adult female sable antelope at Lincoln Park Zoo (LPZ) by monitoring behavior and quantifying hormonal values related to adrenocortical activity, reproduction, and dominance rank. The specific objectives of this study were to (a) document behavioral and hormonal changes in the two female sable antelope during the introduction; (b) measure FAM concentration during the introduction and compare values with dominance rank and observed incidences of aggression; (c) compare FGM values in each individual before, during, and after the introduction; and (d) determine if estrous cycle synchronization occurred. The anticipated results were (a) the dominant, more aggressive female will have higher FAM concentration; (b) estrous cycle synchronization will occur; and (c) overall adrenocortical activity will decrease after the introduction. Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

METHOD

Animal and Housing The introduction of 2 unacquainted adult, female sable antelope was planned by LPZ in Chicago, Illinois. Born at LPZ, the resident female was 13 years old. Solitary for several years, the new female was 12 years-old, born at Mesker Park Zoo (MPZ) in Evansville, Indiana, and transported to LPZ on March 24, 2006. 224 LOEDING, THOMAS, BERNIER, SANTYMIRE

Both females were mother-reared and had never bred. The newly acquainted sable antelope were housed at LPZ’s Antelope/Zebra area, which is located near a zoo entrance. The zoo is open year-round to the public. The sable antelope were fed a diet of grass, hay, and Mazuri® Herbivore diet. Water was available ad libitum. The lights in the indoor stalls were turned on from 0630 to 1830 hr year- round. When the overnight temperature was above 4.4ıC (40ıF), the antelope were given access to the outdoor exhibit and their respective indoor stalls; at lower temperatures, the females were locked inside at night. If the daytime temperature was below 0ıC (32ıF), the females were given limited outdoor access during the short cleaning period. When the daytime temperature was between 0ıC and 37.8ıC (100ıF), the sable antelope were locked outside all day. During air temperatures above 37.8ıC and any precipitation, the antelope had access to their own stall. While the zookeepers cleaned the outdoor exhibit, the antelope were separated into their respective stalls. When the new sable antelope arrived at LPZ, she tested positive for internal parasites and was held in quarantine until she tested negative from March 24, 2006, until April 29, 2006. From April 29, 2006, until May 19, 2006, the new antelope was housed in an exhibit immediately adjacent to the resident female, with limited visual and olfactory contact through a large and tall timber wall and no physical contact. This period hereafter is referred to as the “howdy” period. On May 19, 2006, the new female was introduced to the resident female in the outdoor enclosure. As a precaution, keepers were stationed around the enclosure with ﬁre extinguishers and a water hose in the event a ﬁght ensued.

Behavioral Observations Behavioral observations were collected by the hoofstock keepers and students (n D 14) after passing an interobserver reliability test and achieving greater than 90% compliance with other observers (Crockett, 1996). An ethogram of 22 behavioral categories (Table 1) was derived from observations on other captive sable antelope (Thompson, 1993) and Sichuan takin (Budorcas taxicolor; D. Bernier, personal communication, April 18, 2006). Sichuan takin observations Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 were used to develop the sable antelope ethogram because both species exhibit comparable behaviors and undergo similar behavioral observations (L. Scanlon, personal communication, April 18, 2006). Observations occurred between 1000 and 1400 hr every day or as often as time and weather allowed. A 10-min sample was collected using an instantaneous-scan sampling of each female at 30-s intervals once per hour. At each sample, the resident female’s behavior was scored as 1 of 22 mutually exclusive behavioral categories; then the new female’s behavior was immediately documented. The proximity of both females was recorded as less than 2.4 m apart or greater than 2.4 m apart or about a body length. To record behaviors potentially missed during the scans, any SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 225

TABLE 1 Ethogram Categories for Sable Antelope Introduction at Lincoln Park Zoo

Aggressive Behaviors

Spar (SSP) Entwine horns with the other antelope. Shove(SP) Usebodypart(exceptheadandhorns)topush/bump the other antelope. Presshorns(PHP) Usethetipsofhornstopokeorjabtheother antelope. Horn dominance display Stand in head-to-tail orientation and mutually assert dominance (HDD) over other antelope by maintaining an erect posture. Chase/Supplant (CSD) Antelope pursues or follows the other antelope at a rapid pace. Horn aggression display Lower horns facing the other antelope in a medial horn (HAD) presentation. Head shake, other display Shake head in the direction of the other antelope. (HSD) Paw/Dig(PDD) Disruptgroundwithfronthooves.

Submissive Behaviors

Fendoff(FO) Stoptheapproachofanotherantelopewithhorns or body. Avoid/Move away (AMD) Move away from another antelope. Squat/Urinate, other Urinate at the approach of another antelope. submissive (OS) Head low posture(HL) Turn headto the side and lower horns. Vocal-buzz (VO-B) Force air out of the nostrils with the mouth closed to produce a snorting sound.

Other Behaviors

Social affiliative (SA) Contact with conspecific, excluding horn contact. Following conspecifics (FC) Move behind the other antelope, in the same path. Attention to conspecific (AC) Alert with head and eyes directed at another antelope. Self-play(SPl) Jumpinplace,gambolaroundenclosure,frolic, or leap over objects (not in response to a chase), independent of another antelope. Object manipulate (OM) Investigateor interact with object. Maintenance(MA) Scratch,lick, orrub ownbody. Locomotion(LC) Moveatleast2 stepsforward,independentof the other antelope. Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 Inactive/Other (IN) Stand or lie at rest, including full body shake; yawn; snort; sneeze; stretch; defecate; feed/drink; or chew cud. Notvisible(NV) Antelopecannotbeseenbytheobserver. Social proximity Contact Bothantelopetouchsomebodypart. Proximate Antelopearewithin3mofeachother. Distant Antelopearegreaterthan3mapart.

All Occurrences

Any aggressive and submissive behaviors were recorded as all occurrences between scans. 226 LOEDING, THOMAS, BERNIER, SANTYMIRE

TABLE 2 Questionnaire Used to Survey Keepers About Sable Antelope Behavior on a Scale of 1 to 5 (Low to High)

1. How often each individual shifts in or out of the indoor enclosure 2. How difﬁcult it is to shift each individual 3. How frequent the following behaviors occur for each individual (Shove, Press Horns, Horn Dominance Display, Head Shake, Horn Aggression Display) 4. How many times one sable antelope displaces the other sable 5. How often interactions between the sable are initiated by each individual 6. How many wounds, on average, are observed on each sable on a weekly basis 7. The average social proximity between the sables inside and outside 8. The overall dominance of both individuals

aggressive or submissive behaviors observed between scans were recorded using all occurrence behavioral sampling; however, the type of aggressive/submissive category was not noted, only whether it occurred. At the end of the entire study, ﬁve Antelope/Zebra keepers ﬁlled out a survey of eight questions (Table 2) about the dominance rank and aggressive behaviors they observed in each female during their daily interactions with the animals. The keepers used a 1–5 scale to record their responses; higher scores indicated a more dominant rank.

Fecal Sample Collection and Processing Fecal samples were collected at approximately the same time during daily routine cleaning from both females before the howdy period, including the new female’s preshipment samples collected at MPZ (March 13, 2006–April 28, 2006), during the howdy period (April 29, 2006–May 18, 2006), and after the introduction (May 19, 2006–April 12, 2007). Fecal samples were placed into a labeled, sealed plastic bag and stored in a freezer at 20ıC until analyzed. Hormones were extracted in batches of 88 using methods described by Brown et al. (1994). Briefly, 5.0 mL of 90% ethanol (100% ethanol:distilled water) was added to 0.5 g of wet feces, vortexed eight tubes at a time (Daigger, Vernon Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 Hills, IL); entire extraction batch was mixed (Glas-Col, Terre Haute, IN) on a setting of 60 for 30 min. The tubes were then centrifuged (1500 rpm; 20 min) and the supernatants recovered into a second set of clean, glass test tubes. The fecal pellets were resuspended in 5.0 mL of 90% ethanol, vortexed in batches of 8 for 30 s, and centrifuged (1500 rpm; 15 min). The supernatant was recovered, combined with the first set, and air-dried in a warm water-bath (60ıC). The extracts were reconstituted in 1.0 mL of methanol with three to five glass beads added and briefly vortexed. The reconstituted samples were mixed at a setting of 60 for 20 min and then placed in a sonicator (Fisher Scientific, Waltham, MA) for 20 min. SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 227

Enzyme Immunoassays (EIA) Fecal androgen metabolites were analyzed by testosterone EIA previously described by Young et al. (2004). The testosterone horseradish peroxidase (HRP) ligands and polyclonal antiserum (R156/7; University of California, Davis, CA) were used at dilutions of 1:30,000 and 1:10,000, respectively. Antiserum cross- reactivities for testosterone were as follows: testosterone, 100%; 5a-dihydro- testosterone, 57.37%; androstenedione, 0.27%; androsteron and DHEA, 0.4%; and cholesterol, 0.03%. Cross-reactivity was 0.02% for the following: ˇ-estradiol, progesterone, pregnenolone, hydrocortisone, cholic acid, chenodeoxycholic acid, cholic acid methyl ester, dehydrocholic acid, deoxycholic acid, lithocholic acid, glycholic acid, taurodeoxycholic acid, taurocholic acid, taurochendeoxycholic acid, and glycochenodeoxycholic acid (Dloniak et al., 2004). The testosterone EIA was validated by demonstrating (a) parallelism between binding inhibition curves of fecal extract dilutions (1:2–1:2,048) and (b) significant recovery (>90%) of exogenous testosterone added to fecal extracts (1:2,500; ˆy D 0.869x 0.554, R2 D 0.994). Assay sensitivity was 2.3 pg/well, and intra- and interassay coefficients of variation were <10%. Using a cortisol EIA, FGM were analyzed for sable antelope. Cortisol polyclonal antiserum and HRP (R4866; University of California, Davis, CA) were used at a 1:8,500 and 1:20,000 dilution, respectively. Cross-reactivity to the cortisol antiserum was cortisol, 100%; prednisolone, 9.9%; prednisone, 6.3%; corti- sone, 5%; corticosterone, 0.7%; deoxycorticosterone, 0.3%; 21-deoxycortisone, 0.5%; 11-deoxycortisol, 0.2%; progesterone, 0.2%; 17˛-hydroxyprogesterone, 0.2%; and pregnenolone, 17˛-hydroxypregnenolon, anderostenedione, testosterone, androsterone, dehydroepiandrosterone, dehydroisoandrosterone-3-sulfate, aldosterone, estradiol-17ˇ, estrone, estriol, spironolactone, and cholesterol, 0.1% (Young et al., 2004). The cortisol EIA was validated by demonstrating the following: (a) parallelism between binding inhibition curves of fecal extract dilutions (1:2–1:2, 048), (b) significant recovery (>90%) of exogenous cortisol added to fecal extracts (1:200; ˆy D 0.854x 11.884, R2 D 0.9982), and (c) biological validation using a veterinary procedure as an acute stressor (Touma

Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 & Palme, 2005). Assay sensitivity was 3.9 pg/well, and intra- and interassay coefﬁcients of variation were <10%. For the biological validation, the new female was anesthetized for a physical examination on April 4, 2007, and the fecal samples were collected for the next week. FPM were analyzed using enzyme immunoassay. Progesterone polyclonal antiserum (CL425; University of California, Davis, CA) and HRP were used at a dilution of 1:10,000 and 1:40,000, respectively. Cross-reactivities of the progesterone antibody were as follows: progesterone, 100%; 4-pregnen-3˛-ol-20-one, 188%; 4-pregnen-3ˇ-ol-20-one, 172%; 4-pregnen-11˛-ol-3,20-dione, 147%; 5˛-pregnan-3ˇ-ol-20-one, 94%; 5˛-pregnan-3˛-ol-20-one, 64%; 5˛-pregnan- 228 LOEDING, THOMAS, BERNIER, SANTYMIRE

3,20-dione, 55%; 5ˇ-pregnan-3ˇ-ol-20-one, 12.5%; 5ˇ-pregnan-3,20-dione, 8%; 4-pregnen-11ˇ-ol-3,20-dione, 2.7%; 5ˇ-pregnan-3˛-ol-20-one, 2.5%; and preg- nanediol, 5˛-pregnan-3˛,20ˇ-diol, androstenedione, and corticosterone, <0.1% (Graham, Schwarzenberger, Mostl, Galama, & Savage, 2001). The progesterone EIA was validated by demonstrating the following: (a) parallelism between binding inhibition curves of fecal extract dilutions (1:64 1:32,768) and (b) sig- niﬁcant recovery (>90%) of exogenous pregnane added to fecal extracts (1:1000; ˆy D 0.857x 0.304, R2 D 0.995). Assay sensitivity was 0.78 pg/well, and intra- and interassay coefﬁcients of variation were <10%.

Statistical Analysis All statistical analyses were performed using Microsoft Excel (MS Office 2003); SYSTAT Version 11.0 (SPSS Inc., Chicago, IL); and, for FGM and FAM analyses, Sigma Stat Version 3.0 (SPSS Inc., Chicago, IL) at a p D .05 level of significance. Values were reported as the mean ˙ standard error (SE). Daily FPM, FGM, and FAM values were tested for normality using the Shapiro-Wilk test. From the ethogram (Table 1), the defined behavioral observation data were used to determine the amount of time each female spent performing each behavioral category out of the total observations. Responses to the zookeeper survey were analyzed using a Mann-Whitney U test. Mean FAM were calculated for each individual antelope. Elevated FAM values were any samples above the mean plus 1 standard deviation (SD). A two- way analysis of variance (ANOVA) test and a Bonferroni’s pairwise comparison were used to calculate if there was a difference in FAM between the females by the three stages of the introduction. The baseline value of FGM for each sable antelope was calculated using an iterative process (Brown et al., 1994; Moriera et al., 2001). Briefly, the mean plus 1.5 SD FPM value was calculated for all samples. All values greater than the mean plus 1.5 SD were removed, and the mean plus 1.5 SD was recalculated until no values exceeded the mean plus 1.5 SD—at which point the mean became Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 the baseline. An elevated FGM value was defined as any sample with a value greater than 2 SD of this baseline value. A two-way ANOVA and a Bonferroni’s pairwise comparison were performed to determine if there was difference in the FGM value between the females by the three stages of introduction. Determining the baseline FPM values followed the same iterative process as the FGM, except the mean plus 1.25 SD was used (Moriera et al., 2001). A complete estrous cycle length was determined by taking the date of the first elevated FPM value and counting the number of days until the first elevated value of the next cycle. To be considered a different ovarian cycle phase, hormone values needed to be below or above baseline for greater than 1 day. SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 229

The luteal phase was calculated by counting the number of days that FPM was continuously elevated within a cycle, excluding all the single-day rise or drop in hormone levels. The follicular phase was calculated by counting the number of days FPM was not elevated. The luteal phase length plus the follicular phase lengths equaled the total estrous cycle length. To determine if estrus synchronized, four random days were chosen to determine if the females were in the same point of their cycle. Synchronization would occur if the females were matched in their cycle and remained matched for the remainder of the study.

RESULTS

Behavior and Dominance During the 1 year of behavioral observations (n D 13,472), only 42 incidences of aggression occurred—too few for meaningful statistical analysis. The ﬁrst aggressive display occurred 12 days after the sable antelopes’ introduction on May 19, 2006, and the second display was 95 days after the introduction. The behavioral category inactive/other (n D 11,960) accounted for the majority (89%) of the observed behaviors, followed by maintenance behaviors (n D 639; 5%), locomotion (n D 443; 3%), and females not visible to the observer (n D 363; 3%; Figure 1). Given that the behavioral results did not indicate a dominant individual, hoofstock keepers answered a survey about aggression and dominance rank in both females (Table 2). The new female had a greater level of aggression/dominance rank from all survey questions (U0:05.2/5;5 D 25, p < .05). Among keepers, the new female received a mean dominance rank score of 33.0 ˙ 2.2 (range, 27–39). The resident female was ranked with a mean dominance rank score of 18.4 ˙ 1.9 (range, 15–25).

Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 Fecal Androgen Metabolites

When comparing baseline FAM, the new female had higher (F1;529 D 4.58, p D .03) concentrations than the resident female, with mean values of 161.4 ˙ 3.8 ng/g wet feces (range, 60.0–252.4 ng/g wet feces) and 129.4 ˙ 3.6 ng/g wet feces (range, 39.2–184.4 ng/g wet feces), respectively (Figure 2a & b). Mean elevated FAM values for the new and resident female were 296.7 ˙ 9.5 ng/g wet feces (range, 256.5–468.0 ng/g wet feces) and 185.8 ˙ 7.7 ng/g wet feces (range, 186.1–336.1 ng/g wet feces), respectively (Figure 2a & b). Fecal androgen metabolite concentration for each female differed (F2;529 D 14, p < .001) by the three stages of the introduction (Figure 2a & b). However, (a) Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

(b)

FIGURE 1 Percentage of total behaviors (a) scored by an observer for two female sable antelope at Lincoln Park Zoo from March 2006 to March 2007 and percentage of total behaviors excluding the inactive/other category (b).

230 SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 231 Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

FIGURE 2 Daily fecal androgen metabolites (FAM) of the resident (a) and the new female (b) sable antelope at Lincoln Park Zoo from March 2006 to April 2007. The dashed line on the vertical axis indicates elevated FAM values, whereas the solid line indicates the baseline value for FAM. On the horizontal axis, the solid line is the starting date of the howdy period, and the dashed line is the date of the introduction. 232 LOEDING, THOMAS, BERNIER, SANTYMIRE

the individual sable antelope and the introduction stage had an interaction (F2;529 D 6.55, p D .002; Figure 2a & b). For the resident female, the mean FAM concentration before the introduction was 152.5 ˙ 3.0 ng/g wet feces and for the new female the mean was 174.8 ˙ 4.8 ng/g wet feces. During the introduction, the resident female’s FAM concentration was 219.9 ˙ 6.0 ng/g wet feces, whereas the new female’s concentration was 176.1 ˙ 6.6 ng/g wet feces. Mean FAM concentration after the introduction was 119.3 ˙ 4.5 ng/g wet feces and 161.4 ˙ 5.9 ng/g wet feces for the resident and new female, respectively.

Fecal Glucocorticoid Metabolites For the biological relevance, elevated FGM values were observed 24 hr postvet- erinary procedure, thus validating our analyses (Figure 3). Overall, the FGM values of the 2 females (Figure 4a & b) were different (F1;535 D 35.9, p < .001). Speciﬁcally, the resident female’s baseline FGM was 28.0 ˙ 0.4 ng/g wet feces (range, 12.7–34.9 ng/g wet feces), and the mean elevated FGM value was 37.5 ˙ 1.2 ng/g wet feces (range, 36.0–101.3 ng/g wet feces). The new female’s baseline FGM was 38.4 ˙ 0.4 ng/g wet feces (range, 20.1–46.1 ng/g Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

FIGURE 3 Fecal glucocorticoid metabolites (FGM) values from the new female sable antelope from March 1 to April 12, 2007, at Lincoln Park Zoo. The dashed line on the vertical axis indicates elevated FGM values, whereas the solid line indicates the baseline value for FGM. The rise in FGM on April 5, 2007, served as a biological validation that cortisol was the appropriate hormone for stress hormonal analysis. SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 233 Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

FIGURE 4 Daily fecal glucocorticoid metabolites (FGM) for the resident (a) and the new female (b) sable antelope at Lincoln Park Zoo from March 2006 to April 2007. The line on the horizontal axis indicates the dates of the howdy period and the actual cohousing of the females, respectively. The dashed circle indicates days when the new female tested positive for parasites, whereas the solid circle indicates negative test results. The dashed line on the vertical axis indicates elevated FGM values, whereas the solid line indicates the baseline value for FGM. 234 LOEDING, THOMAS, BERNIER, SANTYMIRE

wet feces), and the mean elevated FGM was 48.8 ˙ 1.6 ng/g wet feces (range, 46.7–124.9 ng/g wet feces). During the three stages of introduction, FGM values differed (F2;535 D 25.3, p < .001) between females (Figure 4a & b). Before the introduction, the resident female’s mean FGM values were lower (p < .001; 53.9 ˙ 3.5 ng/g wet feces) compared with the new female’s mean FGM value of 72.2 ˙ 2.9 ng/g wet feces (Figure 4). During the introduction the resident female’s mean FGM (40.2 ˙ 3.0 ng/g wet feces) was lower (p < .001) than the new female’s mean FGM value at 45.7 ˙ 4.7 ng/g wet feces (Figure 4a & b). After the introduction, the resident female’s mean FGM values were lower (p < .001; 40.2 ˙ 3.0 ng/g wet feces) compared with the new female’s mean value at 45.7 ˙ 4.7 ng/g wet feces (Figure 4a & b). For both females, the FGM values decreased (p < .001) during and after the introduction compared with before the introduction (Figure 4a & b). From July 23 to November 12, 2006, the new female’s FGM values were consistently elevated. The resident female also experienced a similar elevation with a shorter duration. To determine the reason for the increase in FGM, several factors were examined including: temperature plus heat index, number of zoo visitors arriving by bus, and internal parasites. Using a Pearson’s correlation analysis, the new female’s mean weekly FGM values were compared with the mean weekly air temperature (adjusted for heat index above 65ıF [18ıC]) and the mean weekly number of bused visitors (Figure 5b). For the new female, the adjusted air temperature was positively correlated (r D 0.390, df D 56, p < .05) to the FGM values; however, the number of visitors was not correlated with FGM values (Figure 5a & b). The months with the greatest number of visitors (in 2006 April, May, and June—135,303 visitors) was threefold higher than in July, August, September, and October when the FGM values were elevated for the new female (42,951 visitors; Figure 5a). However, the FGM values for the new female were not correlated with the number of visitors, even during the months with the greatest number. For the resident female, the FGM values were not correlated with air temperature or visitors. When the new female arrived at LPZ, she tested positive for internal Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 strongylids parasites. The resident female did not test positive for parasites and, therefore, could not be compared. Using a one-way ANOVA, the FGM values from dates when internal parasites were in the feces were compared with FGM values during dates when parasites were absent. The dates for internal parasites included a 20-day prepatent period for strongyles detection until the end of medical treatment (August 17–November 24, 2006). No parasites (including the 20-day, prepatent period) were detected from December 2, 2006–March 3, 2007. The FGM values were elevated (F1;139 D 121.5, p < .001) when the new female tested positive for strongyle parasites compared with when she tested negative for parasites (Figure 4b). SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 235 Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

FIGURE 5 Mean weekly fecal glucocorticoid metabolites (FGM) for the resident and new female sable antelope compared with mean weekly number of visitors (a) and the mean weekly adjusted air temperature (b) from March 2006 to April 2007 at Lincoln Park Zoo. 236 LOEDING, THOMAS, BERNIER, SANTYMIRE

Reproductive Activity Mean FPM (resident female, 1679.5 ˙ 54.5 ng/g wet feces; new female, 2058.4 ˙ 78.2 ng/g wet feces) from the 2 sable antelopes were similar (p > .05). The FPM baseline was 460.1 ˙ 23.6 ng/g wet feces (range, 181.7–641.2 ng/g wet feces) for the resident and 423.2 ˙ 16.7 ng/g wet feces (range, 263.5–524.1 ng/g wet feces; Figure 6a & b) for the new female. The resident female’s mean elevated FPM concentration was 751.5 ˙ 43.5 ng/g wet feces (range, 668.4– 4453.1 ng/g wet feces), and the new female’s FPM was 586.5 ˙ 136.9 ng/g wet feces (range, 558.4–6521.2 ng/g wet feces). Mean estrous cycle length for the resident female (n D 10) was 35.8 ˙ 2.0 days (range, 28–46 days) with a mean follicular phase length of 9.5 ˙ 1.3 days (range, 2–18 days) and a mean luteal phase length of 26.3 ˙ 1.7 days (range, 17–36 days). For the new female, the mean estrous cycle length (n D 12) was 30.0 ˙ 3.3 days (range, 17–58 days) with a mean follicular phase length of 6.1 ˙ 0.6 days (range, 3–11 days) and a mean luteal phase length of 23.9 ˙ 3.1 days (range, 9– 47 days). Estrous synchronization was evaluated by matching FPM of the 2 females on four random days during the study to determine if they were in the same point in their estrous cycle. However, as illustrated by Figure 6a and b, no synchronization was observed.

DISCUSSION

Introductions of new individuals in a zoo setting can be difficult, especially with species in the wild about whose natural social structure little is known. In this study, fecal hormonal analysis was used to document the impact on the welfare of 2 adult female sable antelope during their introduction at LPZ, thus providing zoo management staff with valuable information about the amount and changes in adrenocortical activity in these animals. For sable antelope, this is the first time hormones associated with adrenocortical activity and dominance rank were quantified. Using a 1-month-long howdy Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 period minimized the risk of potential aggression and elevated adrenocortical activity. Although not observed behaviorally, the new female had higher FAM and also scored higher on a dominance rank survey completed by the keeper staff. The resident female had lower FAM pre- and post introduction in the howdy period, possibly indicated as a submissive rank. Adrenocortical activity decreased in both individuals when housed as a pair compared to solitary housing; however, their estrous cycles did not synchronize as they may in the wild. Previous hormonal studies on the sable antelope analyzed FPM in attempts to characterize reproduction in this species (Thompson et al., 1998). However, the present study was the first to measure FGM and FAM in sable antelope. SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 237 Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015

FIGURE 6 Fecal progestin metabolites (FPM) by date for the resident (a) and new female (b) sable antelope from March 2006 to April 2007 at Lincoln Park Zoo. The dashed line on the vertical axis indicates elevated FPM values, whereas the solid line indicates the baseline value for FPM. The short, solid lines indicate estrous cycles for each individual. 238 LOEDING, THOMAS, BERNIER, SANTYMIRE

The FGM analysis has been related to adrenocortical activity for other species, including the clouded leopard, in whom it was determined that height of the enclosure, the number of keepers, being kept on public display, and the presence of predators influenced adrenocortical activity (Wielebnowski et al., 2002). Moreover, FGM were used to determine if stereotypical behaviors were decreased by environmental enrichment in captive giant pandas during different mating periods (Liu et al., 2006). Though stereotypical behaviors did not change with environmental enrichment, stereotypies were correlated with elevated FGM, suggesting that stereotypic behavior during estrus may be a response to elevated FGM (Liu et al., 2006). Because hormonal indictors of adrenocortical activity and dominance rank have not been analyzed, information gathered from this study can be applied to sable antelope and other exotic species to assist with their welfare assessment, breeding, and management in zoos. Using a howdy and slow acquaintance period facilitated an introduction of these 2 females at LPZ with minimal aggression. Buechner, Stroman, and Xanten (1974) documented a female sable antelope introduction where the introduced female was chased into a moat and was butted each time she rose from the moat. After 2 days, the introduced female was able to leave the security of the moat but was eventually removed from the group for safety. During an introduction at the Saint Louis Zoo, a male sable antelope had full visual and olfactory contact with a herd of females through a chain-link gate, and the dominant female displayed the most aggression by charging toward the male and hitting the chain-link gate. Nevertheless, these aggressive displays diminished over 2 months and the male was introduced without injuries (Read & Noble, 1984). In the present study, the new and resident females had limited visual and olfactory contact with each other during the howdy period, when the resident female spent much time near the timber wall of the adjacent enclosure where the new female was located. Consequently, they familiarized themselves with each other and had an uneventful introduction without aggressive displays or injuries. The first aggressive display occurred 2 weeks after the introduction and the second display about three months afterward; unfortunatelythe specific trigger of these incidents, if any, was undocumented. However, it is important to note that Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 the social dynamic of introducing two adults does not reflect possible behaviors and adrenocortical activity associated with an individual being introduced into a herd, as Thompson (1993) indicated; introduction to a herd can be very difficult. The introduction method is particularly useful for social species because it allows the hierarchy to gradually adjust to the new member without causing too much instability. Unfortunately, most introductions at zoos are not documented. Publishing the triumphs and tribulations of introducing new individuals to a social group is important to assist zoo staff in managing their collections. For sable antelope, data on dominance rank and FAM were valuable for determining if the introduction was successful. In hybrid baboons (Papio sp.), SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 239

female dominance rank and FAM values were positively correlated. The most aggressive, higher ranking females had higher FAM values; however, when rank was excluded from analysis, FAM values and aggression had no obvious relationship (Beehner, Phillip-Conroy, & Whitten, 2005). Research on female FAM and dominance rank is very limited and mostly on primates (Beehner et al., 2005): talapoin monkeys (Miopithecus talapoin) and ring-tailed lemurs (Lemur catta). In a study of male dama gazelles (Gazella dama mhorr), Cassinello and Pieters (2000) determined that bachelor groups in small enclosures received an increased rate of aggression from higher ranking individuals. Criteria for assessing a successful introduction, particularly in sable antelope, should include low rates of aggression and a decrease or return of FAM and FGM to baseline values. Animal keepers observe the behaviors of the animals in their care daily and are often relied on to detect changes in behavior important to veterinary staff. Whitham and Wielebnowski (2009) stated that many zookeepers have decades of experience with a particular species and the opportunity to observe individuals over a long time and in a variety of contexts. Over time, keepers integrate and interpret observations of how the animals in their care interact with the environment and may be better at assessing the dynamic behavior qualities than a short-term direct observer (Carlstead, Mellen, & Kleiman, 1999). In scores of rhinoceros behavioral traits, Carlstead et al. (1999) found that keeper ratings of animal behavior were valid in cross-institutional descriptions of individual behavioral differences, including dominance to conspeciﬁcs. Keeper evaluations of certain behaviors, such as pacing and hiding in clouded leopards, were associated with increased FGM (Wielebnowski et al., 2002). From the keeper survey of the 2 LPZ sable antelope, the new female was more dominant than the resident female, demonstrating a simple linear hierarchy, albeit with only two animals. Monitoring FAM may be useful to assist with determining if introductions are likely to be successful by comparing the relative FAM values of the individual to be introduced with those of resident individuals and the dominance hierarchy of Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 the herd or previous hierarchy status. New individuals with high FAM relative to the individuals of the herd may exhibit high rates of aggression, thus hindering the introduction. Thompson (1993) warned that introductions of adult sable antelope are likely to be unsuccessful because of the aggressive nature of sable antelope; however, using a slow and gradual introduction method with FAM and dominance rank data analysis may increase the likelihood of success. In this study, the new female was more dominant and had higher FGM than the resident female. In cooperative breeders, dominant individuals have greater FGM values than subordinates (Creel, 2001), as is the case for the sable antelope at LPZ. Looking at three social species—dwarf mongoose (Helogale parvula), 240 LOEDING, THOMAS, BERNIER, SANTYMIRE

African wild dogs (Lycaon pictus), and gray wolves (Canis lupus)—Creel (2005) found that basal glucocorticoids were higher in dominant individuals than subordinates and argued that elevated glucocorticoids and their consequences may be a cost of social dominance. Monitoring dominance and FGM in a herd would contribute to understanding how dominance and subordination influence the physiological response to stress. Monitoring adrenocortical activity can assist zoo staff with the identification of potential problems before they manifest in an animal’s behavior. Knowledge of behavior and adrenocortical activity during the howdy period allows zoo management the opportunity to decide whether to extend the howdy period or abandon the introduction. Recent developments have worked out fecal extrac- tions and EIA plates to be processed quickly in the field (Freeman, Abbondanza, Meyer, Schulte, & Brown, 2010; Santymire & Armstrong, 2009). Fecal samples can be extracted in the field the same day they are collected, using a battery- operated homogenizer and filter paper (Santymire & Armstrong, 2009). Freeman et al. (2010) modified an FPM EIA for use in the field, where results can be obtained in as little as 36 hr. Plasma glucocorticoid values in domestic cattle were compared when heifers were isolated from the herd, then reunited with familiar and unfamiliar conspecifics (Boissy & Le Neindre, 1997). In domestic sheep (Ovis aries), social separation increased plasma glucocorticoid values (Adeyemo & Heath, 1982; Parrott, Houpt, & Mission, 1998). In domestic chickens (Gallus gallus), the gradual reduction of brood size increased the stress hormone values (Bryan-Jones & Harvey, 1987). These studies indicate that social species have lower adrenocortical activity when housed with conspecifics; nevertheless, FGM may be influenced by the quality of the social situation. Like cattle, female sable antelope are a herd species—although it is unknown how their adrenocortical activity and welfare are affected by long-term solitary housing. For the new female, transportation and acclimation to a new facility likely presented a stressful situation and could account for the higher FGM before the howdy; however, both females demonstrated the same trend in lower FGM once they had limited visual contact compared with their solitary condition. Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 Once the sable antelope females at LPZ had visual and olfactory contact, the adrenocortical activity decreased about 30%. Monitoring FGM during the introduction to another sable antelope will help evaluate the physiological impact on each individual. Despite having an extended period of elevated FGM values, the new female’s FGM baseline after the introduction was lower than before the introduction. Accordingly, housing female sable antelope in at least a pair seemingly is less stressful than solitary housing in this study with only 2 individuals. Nonetheless, further research is needed to determine how adrenocortical activity is affected by introductions to a herd situation, especially when a bull is present. Longitudinal FGM monitoring of a new individual and the herd SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 241

would investigate dynamics of stress as the hierarchy of the herd is potentially challenged. Accounting for the sable antelope’s history of difficult introductions ex situ (Thompson, 1993), measuring adrenocortical activity and dominance rank will assist with the evaluation of the effectiveness of the introduction and provide valuable welfare information to assist zoo management decisions for future introductions in this species. During this study, an extended period of elevated FGM was observed in the new female 2 months postintroduction and lasted for about three months. The number of visitors was not correlated with adrenocortical activity during these months. Considering the sable antelope’s enclosure at LPZ is near the visitor’s bus stop where 4,033 buses dropped off around 187,836 visitors during the study, it is important to document whether the visitors’ presence disturbs the sable antelope. Because chronic adrenocortical activity may cause physiological problems without behavioral indicators and influence welfare, animals may need to be moved if visitors are too disruptive, although this was not the case in this study as higher FGM was associated with a parasitic infection. In African bovids, strongyle nematodes were the most common parasite identified (Ezenwa, 2003) and occurred in free-ranging sable antelope on ranches in Texas (Craig, 1993). Strongyle nematodes are worms with a direct life cycle, and the host becomes infected when it ingests the third-stage larvae from soil and vegetation (Davidson & Nettles, 1988; Hoberg, Kocan, & Rickard, 2001). However, strongyle infections are not necessarily pathogenic (Hoberg et al., 2001). The specific strongyle species in the sable antelope at LPZ was unknown. For the new female, the continued elevated FGM coincided with a period of parasite infestation and warm summer temperatures. Although FGM values and air temperature were correlated, this may be an indirect relationship that actually reflects the increased opportunity for acquiring parasites; the sable antelope were potentially exposed to parasites on both warm days and nights when they were allowed to graze outside all the time, and the parasites became more proliferate in the soil. Strongyle parasites were present in the new female sable antelope and, rather than pathology, perhaps resulted in physiological stress response. Because the resident female did not test positive for parasites, a relationship Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 between parasitic infection and FGM could not be evaluated. However, because her FGM elevation occurred during a period similar to that of the new female, she may have had a parasitic infection but was tested during the prepatent period; nevertheless, zoo staff treated the resident female prophylactically. Moreover, temperature and FGM were not correlated with the resident female. Further research is needed to determine whether the parasite elevated FGM or high FGM suppressed the immune system and increased susceptibility to parasites and infections. In cattle, prolonged stress has delayed, shortened, and inhibited estrus (All- rich, 1994; Moberg, 1975, 1991; Tilbrook, Turner, & Clarke, 2000). When the 242 LOEDING, THOMAS, BERNIER, SANTYMIRE

hypothalamus-pituitary-adrenal axis is activated, gonadotrophins are suppressed, consequently inhibiting reproduction (Tilbrook et al., 2000) and being potentially problematic if trying to breed animals. Despite over 3 months of elevated FGM, the new female’s estrous cycle was not affected. However, not statistically different, the sable antelope’s FPM concentration decreased and the estrous cycle length shortened during the summer months; this same trend was observed in Thompson et al. (1998). Furthermore, this decrease occurred during the elevated FGM for the new female. When trying to breed animals, it is important to monitor FGM to ensure that elevated periods are not influencing or inhibiting reproduction. Without a bull, the sable antelope in this study were not in a breeding situation; however, these data gathered about the elevated FGM and estrus were vital to ensure welfare was not compromised. If the elevated FGM resulted in reproductive suppression for either sable antelope, it may be an indicator that chronically high FGM may be having other physiological problems associated with chronic stress, such as immune suppression and loss of muscle mass (Creel, 2005). Estrous cycle length in the new and resident females was similar to Thompson et al. (1998) and other Hippotragine antelopes (Asa et al., 1996; Morrow, Wildt, & Monfort, 1999). The female sable antelope in this study remained reproductively active throughout the year. Previous reports have found that captive sable antelope demonstrate the ability to breed year-round (Thompson et al., 1998). Wild sable antelope breeding is determined by seasonal wet/dry cycles (Nowak, 1999; Sekulic, 1978). Coordinating calving periods among females is an important biological function to ensure calves are born at approximately the same time of year to coincide with optimum resources. However, it is unknown if wild sable antelope are reproductively active throughout the year or experience anovulatory periods, as in the scimitar-horned oryx (Morrow, Wildt, & Monfort, 1999). Field studies are needed to determine if wild sable antelope are reproductively active year-round. Considering all sable antelope in this study and at the National Zoological Park’s Conservation and Research Center (NZP-CRC) were born in North America, it is unknown if the lack of reproductive seasonality is an artifact of housing or a seasonal difference from living in the northern Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 hemisphere. Sable antelope at LPZ and NZP-CRC have constant resources and do not experience wet/dry seasons; therefore, reproductive seasonality may not be required to maximize fitness as it would in the wild. In addition to a lack of seasonality, the sable antelope did not exhibit estrous synchronization. In the wild, sable antelope give birth within a 2-month window, which suggests reproductive synchrony. Although the LPZ females had periods of synchrony, the overall hormone profile was not synchronized. It is unclear in the wild if synchronization occurs at estrus or parturition. Scimitar-horned oryx (Oryx dammah) show a synchronized anovulatory period in captivity during the North American spring months but not in sable antelope maintained at the SABLE ANTELOPE BEHAVIORAL ENDOCRINOLOGY 243

same facility (Morrow et al., 1999). Therefore, reproductive physiology among Hippotragine antelope may differ signiﬁcantly among species (Morrow et al., 1999).

CONCLUSION

This study laid the framework for a positive introduction of a complicated species despite reports of difficult past introductions. Sable antelope have lower FGM when housed with a companion, but choosing a compatible individual is difficult. Using FAM and dominance rank scoring methods may be useful in determining the appropriate individual for introductions to a solitary animal or to a new herd. Zoological institutions have the important task of evaluating a solitary individual’s welfare and deciding if bringing in a species-appropriate companion will be beneficial. Further research with greater sample sizes is needed to determine not only the androgen metabolite/dominant relationship in herd situations but also the impact of prolonged FGM and internal parasites. Perhaps the most useful information for zoo management from this study is the behavioral and hormonal documentation of a successful introduction of a species that historically has been problematic.

ACKNOWLEDGMENTS

We thank Lincoln Park Zoo and the Davee Center for Epidemiology and Endocrinology, especially Diana Armstrong, Dr. Eric Lonsdorf, and Michelle Rafacz. We are grateful to hoofstock keepers at Lincoln Park Zoo, including Lisa Scanlon, Angie Adkin, Penny Reidy, and Jon Miot. At Mesker Park Zoo, we are particularly appreciative to Erik Beck and the keeper staff. We acknowledge Susan Meiers and Jeff Engel at Western Illinois University for their help with this article. This study was approved by Lincoln Park Zoo’s Research Committee

Downloaded by [Dr Kenneth Shapiro] at 13:35 02 November 2015 and Western Illinois University’s Institutional Animal Care and Use Committee. For their helpful comments, we thank Katie Brooks, Matt Heinz, and three anonymous reviewers.

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