Seasonality of reproduction in Asian elephants Elephas maximus and African elephants Loxodonta africana: underlying photoperiodic cueing?

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Predicting feed intake and feed efficiency in lactating dairy cows using digesta marker techniques

Direct measurement of individual animal dry matter intake (DMI) remains a fundamental challenge to assessing dairy feed efficiency (FE). Digesta marker, is currently the most used indirect technique for estimating DMI in production animals. In this meta-analysis we evaluated the performance of marker-based estimates against direct or observed measurements and developed equations for the prediction of FE (g energy-corrected milk (ECM)/kg DMI). Data were taken from 29 change-over studies consisting of 416 cow-within period observations. Most studies used more than one digesta marker. So, for each observed measurement of DMI, faecal dry matter output (FDMO) and apparent total tract dry matter digestibility (DMD), there was one or more corresponding marker estimate. There were 924, 409 and 846 observations for estimated FDMO (eFDMO), estimated apparent total tract DMD (eDMD) and estimated DMI (eDMI), respectively. The experimental diets were based mainly on grass silage, with soya bean or rapeseed meal as protein supplements and cereal grains or by-products as energy supplements. Across all diets, average forage to concentrate ratio on a dry matter (DM) basis was 59 : 41. Variance component and repeatability estimates of observed and marker estimations were determined using random factors in mixed procedures of SAS. Between-cow CV in observed FDMO, DMD and DMI was, 10.3, 1.69 and 8.04, respectively. Overall, the repeatability estimates of observed variables were greater than their corresponding marker-based estimates of repeatability. Regression of observed measurements on marker-based estimates gave good relationships (R²=0.87, 0.68, 0.74 and 0.74, relative prediction error =10.9%, 6.5%, 15.4% and 18.7%for FDMO, DMD, DMI and FE predictions, respectively). Despite this, the mean and slope biases were statistically significant (P<0.001) for all regressions. More than half of the errors in all regressions were due to mean and slope biases (52.4% 87.4%, 82.9% and 85.8% for FDMO, DMD, DMI and FE, respectively), whereas the contributions of random errors were small. Based on residual variance, the best model for predicting FE developed from the dataset was FE (g ECM/kg DMI)=1179(±54.1) +38.2(±2.05)×ECM(kg/day)−0.64(±0.051)×BW (kg)−75.6(±4.39)×eFDMO (kg/day). Although eDMD was positively related to FE, it only showed a tendency to reduce the residual variance. Despite inaccuracy in marker procedures, eFDMO from external markers provided a reliable determination for FE measurement. However, DMD estimated by internal markers did not improve prediction of FE, probably reflecting small variability.     

Examination of the interrelationships of behavior,dominance status,and ovarian activity in captive Asian and African elephants

Ovarian inactivity has been identified in captive African (Loxodonta africana) and Asian (Elephas maximus) elephants and is thought to be mediated in part by social influences. Thus, a survey was conducted to determine how behavior and dominance status relate to each other and to ovarian cyclicity. For both Asian and African elephants, dominance status was positively correlated with relative size, age, temperament, disciplinary nature, and willingness to share novel objects. Relative size and temperament were also related to disciplinary nature toward herdmates. Behavior toward keepers was a good indicator of the willingness of elephants to follow commands, whereas sharing novel objects was positively correlated with object curiosity. Finally, dominance status, temperament, and disciplinary nature were all correlated with willingness to share. Comparisons of ovarian cyclicity status with behavior rankings were conducted only for African elephants because of the low number of noncycling Asian elephants surveyed. Overall, social status appeared to be the best predictor of ovarian activity in African elephants. Noncycling African elephant females ranked higher in the dominance hierarchy and gave more discipline to herdmates than cycling cohorts. It remains to be determined whether these are cause or effect relationships, but clearly it is important to understand how physical and social attributes impact physiological processes, such as reproduction. Captive management now needs to focus on optimizing social and environmental conditions to maximize reproductive potential in elephants. Zoo Biol 23:431–448, 2004. © 2004 Wiley‐Liss, Inc.     

Circulating levels of α‐tocopherol and retinol in free‐ranging African elephants (Loxodonta africana)

To date, there are no detailed reports of circulating levels of plasma α‐tocopherol and retinol for large samples of free‐ranging African elephants (Loxodonta africana). This survey study measured natural circulating levels of α‐tocopherol as a measure of vitamin E activity and retinol as an indicator of vitamin A activity, in 70 free‐ranging African elephants captured at Kruger National Park as part of a translocation program. Mean levels of α‐tocopherol and retinol were found to be 0.613 ± 0.271 μg/mL and 0.039± 0.007 μg/mL, respectively, and did not vary significantly across sex or age class. Elephants appear to normally have low circulating levels of both these nutrients compared with domestic herbivore species; values from healthy, free‐ranging elephant populations may provide useful data for assessing nutrient status of captive animals. Zoo Biol 18:319–323, 1999.© 1999 Wiley‐Liss, Inc.     

Personality Assessment and Its Association With Genetic Factors in Captive Asian and African Elephants

Elephants live in a complex society based on matrilineal groups. Management of captive elephants is difficult, partly because each elephant has a unique personality. For a better understanding of elephant well being in captivity, it would be helpful to systematically evaluate elephants' personalities and their underlying biological basis. We sent elephant' personality questionnaires to keepers of 75 elephants. We also used 196 elephant DNA samples to search for genetic polymorphisms in genes expressed in the brain that have been suggested to be related to personality traits. Three genes, androgen receptor (AR), fragile X related mental retardation protein interacting protein (NUFIP2), and acheate‐scute homologs 1 (ASH1) contained polymorphic regions. We examined the association of personality with intraspecific genetic variation in 17 Asian and 28 African elephants. The results suggest that the ASH1 genotype was associated with neuroticism in Asian elephants. Subjects with short alleles had lower scores of neuroticism than those with long alleles. This is the first report of an association between a genetic polymorphism and personality in elephants. Zoo Biol. 32:70‐78, 2013. © 2012 Wiley Periodicals, Inc.     

Long‐term administration of α‐tocopherol in captive Asian elephants (Elephas maximus)

After the loss of an African elephant (Loxodonta africana) in February 1989 at the Denver Zoological Gardens (DZG) with very low circulating serum α‐tocopherol, a long‐term study was initiated with three Asian elephants (Elephas maximus) to evaluate the effect of an oral micellized, water‐soluble, natural source d‐α‐tocopherol supplement. Baseline α‐tocopherol levels were evaluated and found to be approximately 3.75‐fold less than those reported for semi‐free‐ranging Asian Nepalese work camp and free‐ranging African elephants. The DZG elephants were then administered a liquid d‐α‐tocopherol (Emcelle^®) at 2.2 IU/kg body weight orally once daily. Serum samples were obtained and analyzed at 1, 2, 8, and 12 months and then annually for 96 months. The oral vitamin E supplement significantly elevated serum levels above baseline and were found to be comparable with levels reported for semi–free‐ranging and free‐ranging elephants. Zoo Biol 20:245–250, 2001. © 2001 Wiley‐Liss, Inc.     

Assessment of testicular endocrine function in captive African elephants by measurement of urinary and fecal androgens

Androgen measurements in urine and/or feces represent a potentially important tool for monitoring testicular endocrine function in the African elephant. To assess the feasibility of this approach, the aims of the present study were to: 1) examine the presence and relative abundance of immunoreactive testosterone (iT) and its 5α‐reduced 17‐oxometabolite epiandrosterone (iEA) in African elephant excreta, and 2) compare urine and fecal androgen profiles in animals of different ages and during the musth and non‐musth condition. Urine and fecal samples were collected over periods of up to 3 years from five bulls (ages 7–24 years) living in three mixed social groups. In parallel, indications of musth were recorded by keeper staff as an independent marker of male androgen status. Measurements of iT and iEA were carried out by enzymeimmunoassay (EIA) following methanolic extraction of hydrolyzed urine and lyophilized fecal powder. High‐pressure liquid chromatography (HPLC) of musth phase samples confirmed the presence of substantial quantities of testosterone (T) and epiandrosterone (EA) in both urine and feces. EA was predominant in feces, whereas T was more abundant in urine. In each male, the two androgen measures were significantly correlated (feces, r = 0.71–0.93, P < 0.0001; urine, r = 0.86–0.91, P < 0.0001), as were fecal and urinary concentrations of each of the two androgens measured (r = 0.35–0.77, P < 0.0001). Moreover, in the two oldest males that showed clear signs of musth, levels of iEA and iT were markedly elevated during musth compared to non‐musth periods (differences were significant for feces in both animals, but in urine only for one). Collectively, the data show that measurement of urinary and fecal androgens generates useful information on gonadal status in male African elephants, and as such should provide new opportunities to improve the management and welfare of bulls maintained in captivity, as well as to examine physiological correlates of reproductive function in free‐ranging animals. Zoo Biol 21:27–36, 2002. © 2002 Wiley‐Liss, Inc.     

Skewed birth sex ratio and premature mortality in elephants

Sex allocation theories predict equal offspring number of both sexes unless differential investment is required or some competition exists. Left undisturbed, elephants reproduce well and in approximately even numbers in the wild. We report an excess of males are born and substantial juvenile mortality occurs, perinatally, in captivity. Studbook data on captive births (CB, n = 487) and premature deaths (PD, <5 years of age; n = 164) in Asian and African elephants in Europe and North America were compared with data on Myanmar timber (Asian) elephants (CB, n = 3070; PD, n = 738). Growth in CB was found in three of the captive populations. A significant excess of male births occurred in European Asian elephants (ratio: 0.61, P = 0.044) and in births following artificial insemination (0.83, P = 0.003), and a numerical inclination in North American African elephants (0.6). While juvenile mortality in European African and Myanmar populations was 21–23%, it was almost double (40–45%) in all other captive populations. In zoo populations, 68–91% of PD were within 1 month of birth with stillbirth and infanticide being major causes. In Myanmar, 62% of juvenile deaths were at >6 months with maternal insufficient milk production, natural hazards and accidents being the main causes. European Asian and Myanmar elephants PD was biased towards males (0.71, P = 0.024 and 0.56, P < 0.001, respectively). The skewed birth sex ratio and high juvenile mortality hinder efforts to help captive populations become self-sustaining. Efforts should be invested to identify the mechanism behind these trends and seek solutions for them.     

Prediction of total fecal output in sheep fed silage using the Captec chrome controlled-release capsule

Six Finnish wethers (average weight, 52.3 kg) were used to determine the effectiveness of a controlled-release Cr₂O₃ bolus and the internal marker acid insoluble ash (AIA) for predicting fecal output. Wethers were fed grass silage for ad libitum intake. Each wether was dosed orally with one continuous-release Cr₂O₃ bolus (CRC) on the first day of the experiment. Chronology of the trial was as follows: Day 0 to 14, marker adaptation period; Day 15 to 21, total fecal collection; Day 22 to 23, fecal grab sampling every 4 h; Day 25 to 35, once-daily fecal grab sampling. Accuracy of marker-estimated fecal output derived from each method was compared within a marker with total fecal collection values using a paired t-test. Concentrations of AIA and Cr varied (P < 0.10) between sampling times. Accuracy of fecal output estimates was better with the controlled-release Cr₂O₃ bolus (r = 0.97; P = 0.03) than with AIA (r = −0.08; P = 0.89). Grab samples taken once produced reliable (r = 0.96; P = 0.02) estimates of fecal output of silage-fed wethers using the controlled-release Cr₂O₃ bolus. The controlled-release Cr₂O₃ bolus is a better marker than acid-insoluble ash for predicting fecal output of silage-fed wethers.     

Survey of the reproductive cyclicity status of Asian and African elephants in North America

The Asian and African elephant populations in North America are not self‐sustaining, and reproductive rates remain low. One problem identified from routine progestagen analyses is that some elephant females do not exhibit normal ovarian cycles. To better understand the extent of this problem, the Elephant TAG/SSP conducted a survey to determine the reproductive status of the captive population based on hormone and ultrasound evaluations. The survey response rates for facilities with Asian and African elephants were 81% and 71%, respectively, for the studbook populations, and nearly 100% for the SSP facilities. Of the elephants surveyed, 49% of Asian and 62% of African elephant females were being monitored for ovarian cyclicity via serum or urinary progestagen analyses on a weekly basis. Of these, 14% of Asian and 29% of African elephants either were not cycling at all or exhibited irregular cycles. For both species, ovarian inactivity was more prevalent in the older age categories (>30 years); however, acyclicity was found in all age groups of African elephants. Fewer elephant females (～30%) had been examined by transrectal ultrasound to assess reproductive‐tract integrity, and corresponding hormonal data were available for about three‐quarters of these females. Within this subset, most (～75%) cycling females had normal reproductive‐tract morphologies, whereas at least 70% of noncycling females exhibited some type of ovarian or uterine pathology. In summary, the survey results suggest that ovarian inactivity is a significant reproductive problem for elephants held in zoos, especially African elephants. To increase the fecundity of captive elephants, females should be bred at a young age, before reproductive pathologies occur. However, a significant number of older Asian elephants are still not being reproductively monitored. More significantly, many prime reproductive‐age (10–30 years) African females are not being monitored. This lack of information makes it difficult to determine what factors affect the reproductive health of elephants, and to develop mitigating treatments to reinitiate reproductive cyclicity. Zoo Biol 23:309–321, 2004. © 2004 Wiley‐Liss, Inc.     

Variation in stereotypic behavior related to restraint in circus elephants

The purpose of this study was to determine the effect of penning and chaining on circus elephant behavior. The behaviors of 10 Asian elephants (Elephas maximus) and three African elephants (Loxodonta africana) were videotaped for at least 24 hours at each of six performance locations. At four of these locations, the elephants were restrained in electric‐wire pens on turf and at two locations the elephants were restrained via leg chains on macadam. Instantaneous scan sampling at 5‐minute intervals during each observation period was conducted to determine the frequency of occurrence of seven behavior categories: aggression, comfort, ingestion, locomotion, resting, social, and stereotypy. Stereotypies and social interaction (P < 0.0008) were more likely with chained restraint; comfort, ingestion, and locomotion activities were less likely (P < 0.0037) with chained restraint, whereas aggression and resting activities were not affected by type of restraint (P > 0.6254). Variation in stereotypic activity was related to age (P = 0.0001), with younger elephants more likely to show stereotypic activity than older elephants. Zoo Biol 19:209–221, 2000. © 2000 Wiley‐Liss, Inc.     

A comparison of total collection and marker technique for the measurement of apparent digestibility of diets for growing pigs

Use of markers for the measurement of digestibility is a less labour intensive method than total faecal collection. The objectives of the present study were: (1) to evaluate chromic oxide (Cr₂O₃), titanium dioxide (TiO₂) and acid-insoluble ash (AIA) markers for the calculation of digestibility and (2) to examine the reliability of grab sampling as a technique for measuring digestibility in group-housed animals. For marker comparison, eight entire males were housed in individual metabolism crates and offered a cereal-based diet. Pigs were randomly allotted to treatments for total collection period one, four to the diet with 1 g chromic oxide and 1 g titanium dioxide added per kilogram (Treatment A) and four to the same the diet without marker (Treatment B). During total collection period two, the treatments were reversed. AIA was measured for all animals in crates. For grab sampling study, grouped-housed animals (13–14 per pen) were fed the same cereal-based diet as for marker comparison above and AIA marker was used. Faecal samples were taken from a representative number of animals (minimum eight) in a pen while held in a weighing scales. All feed and faeces samples were analysed for marker content and digestibility. Feed analysis showed 0.93 g/kg of Cr₂O₃ and 1.02 g/kg of TiO₂ added to the diet. Faecal marker recovery was 96, 92.3 and 99.9% (S.E. 2.27) for Cr₂O₃, TiO₂ and AIA, respectively. Mean energy digestibility values were 0.858, 0.848, 0.844 and 0.855 (S.E. 0.003, P<0.01) for total collection, Cr₂O₃, TiO₂, AIA, respectively. Energy digestibility coefficients were 0.852 and 0.861 (S.E. 0.004, P>0.10) for total collection (as measured in marker comparison) and grab sampled animals, respectively. In conclusion, acid-insoluble is a reliable marker for the measurement of digestibility and grab sampling offers a rapid and reliable alternative to the labour intensive metabolism crate method.     

Evaluation of nutrient digestibility and fecal characteristics of exotic felids fed horse‐ or beef‐based diets: use of the domestic cat as a model for exotic felids

The objective of this study was to determine the effects of feeding commercially available beef‐ and horse‐based diets on nutrient digestibility and fecal characteristics of large captive exotic felids and domestic cats. Four species of large exotic felids including cheetahs, Malayan tigers, jaguars, and Amur tigers, and domestic cats were utilized in a crossover design. Raw meat diets included a beef‐based diet (57% protein; 28% fat) and a horse‐based diet (51% protein; 30% fat). All cats were acclimated to the diet for 16 days followed by a 4 day collection period, where total feces, including one fresh sample, were collected. All feces were scored on collection. Intake did not differ due to diet, but fecal output was greater when cats consumed the horse‐based diet. Total tract apparent dry matter (DM) digestibility was higher (P<0.05) and organic matter (OM) and crude protein (CP) digestibilities were lower (P<0.05) when cats were fed the beef‐based diet compared with the horse‐based diet. CP digestibility was similar in domestic cats and cheetahs, and greater (P<0.05) than Amur tigers. Fecal scores were lower and fecal DM was greater (P<0.05) when cats consumed the horse‐based diet compared with the beef‐based diet. Domestic cats had lower (P<0.05) fecal ammonia concentrations compared with all other species. Fecal ammonia concentrations were lowest (P<0.05) when cats were fed the horse‐based diet. Fecal total short‐chain fatty acid (SCFA), branched‐chain fatty acid (BCFA), and butyrate concentrations were higher (P<0.05) when cats consumed the beef‐based diet. Our results suggest that the domestic cat serves as an appropriate model for large exotic felid species, but differences among the species exist. Decreased nutrient digestibility by tigers and jaguars should be considered when developing feeding recommendations for these species based on domestic cat data. Zoo Biol 29:432–448, 2010. © 2009 Wiley‐Liss, Inc.     

Nutrient digestibility and fecal characteristics are different among captive exotic felids fed a beef‐based raw diet

Nutrient digestibility has not been well characterized in exotic felids. The objective of this experiment was to evaluate differences in nutrient digestibility and fecal characteristics in five large exotic captive felid species, including bobcats, jaguars, cheetahs, Indochinese tigers, and Siberian tigers. All animals were individually housed and adapted to a beef‐based raw diet (Nebraska Brand^® Special Beef Feline, North Platte, NE) for 16 d. Total fecal collections were conducted from days 17 to 20. Fecal samples were weighed and scored on collection. Diet and fecal samples were evaluated for dry matter, organic matter, protein, fat, and energy to determine total tract digestibility. Fresh fecal samples were collected to determine fecal pH, ammonia, phenol, indole, short‐chain fatty acid, and branched‐chain fatty acid concentrations. Fecal scores were greater (P<0.01) in Indochinese tigers when compared with all other species, and cheetahs had greater (P<0.01) fecal scores than jaguars and bobcats. Fat digestibility was greater (P<0.01) in Siberian tigers, Indochinese tigers, and bobcats (96%) compared with cheetahs and jaguars (94%). Digestible energy was greater (P<0.05) in bobcats and Indochinese tigers at 93.5 and 92.9%, respectively, compared with cheetahs and jaguars, 91.6%. Fecal pH was greater (P<0.01) in bobcats compared with all other species evaluated. Indole concentrations were greater (P<0.05) in cheetahs and jaguars compared with bobcats and Indochinese tigers. Fecal ammonia concentrations were increased (P<0.05) in cheetahs compared with all other species. The beef‐based raw diet was highly digestible; however, differences in fat and digestible energy suggest that species should be considered when determining caloric needs of exotic felids. Zoo Biol 27:126–136, 2008. © 2008 Wiley‐Liss, Inc.     

A case study of apparent conflict between molecular phylogenies: the interrelationships of African elephants

Recent molecular phylogenies of the African elephants suggest that there is an evolutionary structure within Loxodonta africana. Some nuclear results ( Roca et al., 2001 ) support the separation of the forest African elephant subspecies L. a. cyclotis as a species distinct from the savannah elephant L. a. africana, on the basis of the recognition of both forming highly divergent (reciprocally monophyletic) clades. Conversely, a mitochondrial survey ( Eggert et al., 2002 ), while admitting a geographic partitioning of the genetic structure within African elephants, suggests retaining the status quo. They recognize three diagnosible entities (western, central and south‐eastern Africa) with non‐overlapping ranges within L. africana sensu lato. In order to address these conflicting views (historical fragmentation and speciation or isolation by distance, respectively), we have sequenced two datasets of 1961 bp (for 50 elephants) and about 3700 bp, respectively (for 20 elephants) of the mitochondrial DNA for both forms of elephants (cyclotis and africana). They span the cytochrome b gene, the control region and several RNAs. When compared with former mtDNA data, they provide the most comprehensive view of the African elephant phylogeny (78 mtDNA haplotypes, of which 44 are new) and provide the first insight into populations from the Democratic Republic of Congo. The genetic diversity of mtDNA was appraised and the stability of alternative phylogenetic trees was investigated. Our results are inconsistent with both those prior studies. They revealed two highly divergent molecular clades referred to as F and S, that do not conform to the morphological delineations of cyclotis and africana. A non‐negligible proportion of specimens of L. a. africana display haplotypes prevailing in forest elephant populations (clade F). The geographic distribution of clades and areas of their co‐occurrence support the hypothesis of incomplete isolation between forest and savannah African elephant populations, followed by recurrent interbreeding between the two forms. We state that the conclusions of prior studies resulted from insufficient character and/or geographic sampling. We conclude that there is no satisfying argument which can recognize two or more species of African elephants. We briefly comment on the meaning of such an attitude in a conservation viewpoint. © The Willi Hennig Society 2005.     

Initial findings on visual acuity thresholds in an African elephant (Loxodonta africana)

There are only a few published examinations of elephant visual acuity. All involved Asian elephants (Elephas maximus) and found visual acuity to be between 8′ and 11′ of arc for a stimulus near the tip of the trunk, equivalent to a 0.50 cm gap, at a distance of about 2 m from the eyes. We predicted that African elephants (Loxodonta africana) would have similarly high visual acuity, necessary to facilitate eye‐trunk coordination for feeding, drinking and social interactions. When tested on a discrimination task using Landolt‐C stimuli, one African elephant cow demonstrated a visual acuity of 48′ of arc. This represents the ability to discriminate a gap as small as 2.75 cm in a stimulus 196 cm from the eye. This single‐subject study provides a preliminary estimate of the visual acuity of African elephants. Zoo Biol 29:30–35, 2010. © 2009 Wiley‐Liss, Inc.     

Estimating age of immobilized elephants from teeth impressions using dental silicon

High precision condensation dental silicon, Zetalabor^TM, was used to create moulds of the lower jaw molars from 22 immobilized African elephants (Loxodonta africana Blumenback) during radio collaring operations. These moulds were used to determine the elephant's age using Laws and Jachmann's molar aging criteria. The technique proved easy and fast and produced useful imprints in 90% of the cases. We found our age estimates, based on physical appearance, made prior to immobilizations were relatively accurate, with 75% within ±3 years and 95% within ±5 years from the age indicated from molar evaluation. When re‐collaring the same individuals in 2–3 years, new moulds will be made to compare a known time period with the degree of tooth wear. This will provide verification of Laws age estimates from free‐ranging elephants.     

Public Attitudes in India and Australia toward Elephants in Zoos

ABSTRACT

We surveyed the attitudes of people toward captive elephants in australia, where importation into zoos has been controversial recently, compared with India, where elephants are indigenous. Both australian (AR, n = 101) and Indian (IR, n = 101) respondents rated conservation as the most important reason for the role of zoos and sanctuaries. Australian respondents were more concerned about the husbandry conditions for keeping wild animals in zoos and sanctuaries than Indian respondents (p = 0.02). This concern for captive animals increased with the higher educational level of the respondents. Female australian respondents were more concerned about the practice of keeping elephants in captivity than australian men. More australian respondents were prepared to pay extra to visit a zoo with elephants (AR 42.6%, IR 7.9%, p < 0.001). Indian respondents believed more than their australian counterparts that it was important for any zoo to display elephants, and wanted to interact with elephants by feeding, touching, and riding on them. While australian respondents? perceptions of captive elephants acknowledged their scientific value, Indian respondents viewed elephants primarily of religious, cultural, and historical significance. We conclude that australians and Indians have different requirements for keeping elephants in zoos, which should inform zoo directors about the best way to present them to the public.     

Development of an enzyme‐linked immunosorbent assay (ELISA) for Luteinizing Hormone (LH) in the elephant (Loxodonta africana and Elephas maximus)

A simple, rapid enzyme‐linked immunosorbent assay (ELISA) for the measurement of LH in plasma and serum of elephants (Loxodonta africana and Elephas maximus) has been developed, validated, and used for comparative studies. Purified elephant LH (eleLH) diluted in elephant plasma was used as standards (0.78–50 ng/ml). A monoclonal antibody against the β‐subunit of bovine LH (518B₇) was used as the capture antibody. The second antibody (a polyclonal rabbit anti‐human LH antibody), conjugated to horseradish peroxidase, cleaved a substrate (tetramethyl benzidine), resulting in a color change. The total assay time was approximately 2½ hr, with incubations at room temperature. Sensitivity was found to be 1.56 ng/ml. Cross‐reactivities to elephant FSH and TSH were low: 0.9% and 0.15%, respectively. The accuracy of the assay was demonstrated by comparing the ELISA with a validated eleLH radioimmunoassay (RIA), progesterone data, and ultrasound observations. Blood samples from 18 Asian and African elephant cows were analyzed with the ELISA and RIA, and an additional 11 cows were used to describe endocrine parameters for LH and progesterone using only RIA. No difference was found in LH peak concentrations between the ELISA and RIA. The time from the progesterone decline to the first LH peak, and the time between the two peaks were similar between species. Asian cows had higher LH peaks than African cows. Ultrasound confirmed the time of ovulation occurring with the second LH peak. Three cows were inseminated and confirmed to be pregnant using this ELISA as a timing device. Instrumentation is not always required, as LH peaks approximating 3 ng/ml can be visually observed. In conclusion, this ELISA can be used as a field test to determine time of ovulation for artificial insemination (AI) or natural breeding of both species of elephants, and thus is an important tool for the preservation of captive populations worldwide. Zoo Biol 23:65–78, 2004. © 2004 Wiley‐Liss, Inc.     

Non‐invasive fecal hormone analysis and behavioral observations for monitoring stress responses in captive western lowland gorillas (Gorilla gorilla gorilla)

Non‐invasive techniques for monitoring the stress response in captive western lowland gorillas (Gorilla gorilla gorilla) were investigated. Fecal samples for cortisol measurement and concurrent behavioral data were collected from six individuals in a socially housed gorilla group (one adult male, three adult females and their three offspring) over a 7‐month period. Despite inter‐individual variation in the dynamics of fecal cortisol concentrations over time, several major secretory peaks coincided across individuals. High cortisol concentrations in feces were correlated with induced stressors or behavioral observations indicating high social tension, with a 1–2 day lag period. Entry progression order of the gorillas into a den complex and a supplant‐based dominance index were suitable indicators of overall dominance hierarchies, and fluctuations over time reflected periods of instability. Diurnal variation in fecal cortisol was not apparent when comparing afternoon and morning samples, however the sample collection interval was relatively short (3–5 hr). These results demonstrate the feasibility of monitoring stress responses based on the dynamics of both fecal cortisol excretion and behavior. This non‐invasive approach may be used for gauging responses to changes in husbandry, environment and group structure of captive gorillas. Zoo Biol 0:1–15, 2005. © 2005 Wiley‐Liss, Inc.