Quantifying male-biased dispersal among social groups in the collared peccary (Pecari tajacu) using analyses based on mtDNA variation.

Recent advances in the statistical analysis of microsatellite data permit calculation of sex-specific dispersal rates through sex- and age-specific comparisons of genetic variation. This approach, developed for the analysis of data derived from co-dominant autosomal markers, should be applicable to a sex-specific marker such as mitochondrial DNA. To test this premise, we amplified a 449 bp control region DNA sequence from the mitochondrial genome of the collared peccary (Pecari tajacu), and estimated intra-class correlations among herds sampled from three Texas populations. Analyses on data partitioned by breeding group showed a clear signal of male-biased dispersal; sex-specific fixation indices associated with genetic variation among social groups within populations yielded values for females (F(GP)=0.91), which were significantly larger than values for males (F(GP)=0.24; P=0.0015). The same general pattern emerged when the analyses were conducted on age classes (albeit nonsignificantly), as well as categories of individuals that were predicted a posteriori to be dispersers (adult males) and philopatric (adult females and all immatures). By extending a previously published methodology based on biparentally inherited markers to matrilineally inherited haploid data, we calculated sex-specific rates of contemporary dispersal among social groups within populations (m(male symbol)=0.37). These results support the idea that mitochondrial DNA haplotype frequency data can be used to estimate sex-specific instantaneous dispersal rates in a social species.

Cholinesterase activity in white-winged doves exposed to methyl parathion.

Captive white-winged doves (Zenaida asiatica) were exposed to various levels of methyl parathion (MP) in drinking water to determine effects on brain and blood cholinesterase (ChE) activity. We conducted two experiments to test the influence of MP dose (the amount of MP actually ingested), MP concentration (the amount of MP per unit water), and exposure duration (number of days exposed to a constant MP concentration) on ChE activity. Plasma ChE activity was not useful in predicting brain ChE activity. Methyl parathion concentration had a greater influence on plasma and brain ChE activity levels than dose or time of exposure. These results contribute to the evaluation of irrigation water as a route of exposure of wildlife to pesticides.

Thyroid hormone concentrations in black bears (Ursus americanus): hibernation and pregnancy effects.

Previous studies on thyroid hormones in hibernating bears have used very few sampling periods, so that the time course of any change is poorly understood. In this study, plasma sampled from pregnant and nonpregnant black bears before and during hibernation (16 samples each at 10-day intervals) was assayed by radioimmunoassay for concentrations of thyroxine (T4) and triiodothyronine (T3). Only free T4 showed a difference (P = 0.019) between females that produced cubs and those that did not, but this appeared to be due to higher preimplantation values. Free T3, total T3, and free T4 varied (P = 0.001, 0.038, 0.002, respectively) among sampling periods: during December, bears had depressed concentrations. These lowered concentrations were maintained during hibernation for the free hormones. Our data confirm previous work showing that food restriction and/or physiological preparation for hibernation is coincident with depressed plasma concentrations of thyroid hormones. Hormonal changes associated with pregnancy were minor.

Sodium economy in white-tailed deer (Odocoileus virginianus).

Sodium is considered the mineral most limiting to growth and reproduction of mammalian herbivores worldwide. Notwithstanding the large database on physiological adaptations to low sodium intake, information on maintenance sodium requirements and sodium dynamics of mammals is depauperate. We measured sodium intake and output in adult, nonreproductive white-tailed deer (n = 15) over four seasons to estimate daily requirements for sodium on a seasonal and an annual basis. Dietary sodium content was based on best available predictions of sodium requirements. With regression techniques, we estimated metabolic fecal excretion and endogenous urinary losses of sodium. Average daily sodium requirement, defined as the minimum sodium intake at which intake equaled excretion, was estimated to be 3.27 mg kg-1 body mass d-1. Seasonal estimates did not vary. We propose that sodium requirements for maintenance in mammalian herbivores scale to body mass at an exponent that is similar to that for metabolic rate and forage intake (0.71-0.75). Development of an allometric relationship between sodium need and body mass would permit stronger inference regarding the role of sodium in population regulation, foraging decisions, or distribution and movements of mammalian herbivores.

Immobilization of collared peccaries (Tayassu tajacu) and feral hogs (Sus scrofa) with Telazol and xylazine.

A 1:1 mg mixture of Telazol and xylazine hydrochloride (100 mg of Telazol and 100 mg of xylazine per ml) was used to immobilize wild collared peccaries (Tayassu tajacu) and feral hogs (Sus scrofa); mean (+/-SD) intramuscular dosage rate was 4.73 +/- 0.86 mg/kg and 4.35 +/- 0.68 mg/kg for peccaries (n = 107) and hogs (n = 49), respectively. Mean (+/-SD) induction time (time from injection until complete immobilization) was 4.6 +/- 2.5 minutes for collared peccaries and 4.4 +/- 1.9 for hogs. Peccaries became conscious at 64 +/- 29 minutes and first stood at 92 +/- 33 minutes after initial injection. Hogs became conscious at 54 +/- 26 minutes and first stood at 78 +/- 38 minutes after initial injection. A 1:1 mg mixture of Telazol and xylazine provided an effective and safe method to immobilize both species and provided adequate analgesia and anesthesia for short surgical procedures.

Coccidia of the collared peccary (Tayassu tajacu) in southern Texas with descriptions of three new species of Eimeria (Apicomplexa: Eimeriidae).

In February 1993, fresh fecal samples were collected from 47 collared peccaries (Tayassu tajacu) killed by hunters at the Chaparral Wildlife Management Area, southern Texas, USA. Five species of coccidia (Eimeria chaparralensis n. sp. [9/47, 19%], Eimeria dicotylensis n. sp. [21/47, 21%], Eimeria pecari n. sp. [2/47, 4%], Eimeria sp. [1/47, 2%], and Klossia sp. [1/47, 2%]) were observed. Measurements are in micron. Sporulated oocysts of E. chaparralensis are rough-walled, elongate ovoidal, 43.3 x 28.5 (37-52 x 26-35); sporocysts are elongate ellipsoidal 21.8 x 9.0 (16-27 x 7-12); micropyle (approximately 4.9), Stieda, and substieda body are present; sporocyst residuum is present in newly sporulated oocysts; polar granule and oocyst residuum are absent. Sporulated oocysts of E. dicotylensis are smooth-walled, ovoidal, 25.7 x 20.1 (23-29 x 17-23); sporocysts are ellipsoidal 13.0 x 6.9 (11-17 x 6-9); micropyle and oocyst residuum are absent; polar body sometimes present; Stieda body and sporocyst residuum always present. Sporulated oocysts of E. pecari are smooth-walled, elongate ellipsoidal, 26.8 x 18.1 (22-31 x 15-21); sporocysts are elongate ellipsoidal 16.4 x 5.9 (13-22 x 4-7); micropyle (approximately 5.8) with collar, Stieda body, substieda body, and sporocyst residuum are present; polar granule and small oocyst residuum sometimes present. There were no sex or age differences in prevalences of infection, and there were no positive or negative associations between any species of eimerian. The majority of hosts were infected with a single species of Eimeria. Overall prevalence of infection with eimerians was 23/47 (49%).

Circannual variations in bear plasma albumin and its opioid-like effects on guinea pig ileum.

Previous studies suggest that hibernation is controlled by an opioid system. In this study we examined the effect of plasma albumin fractions drawn from black bears at timed intervals while in hibernation or during the awake state in fall and winter, on induced contractility of the guinea pig ileum. Four hundred nM morphine produced typical suppression of contractility and 400 or 1000 nM naloxone (an opiate antagonist) restored it. Twenty mg of lyophilized albumin fraction from the winter hibernating bear caused similar suppression, the effect being greater than that of either summer bear or winter-active bear plasma albumin. Naloxone reversed the suppression in all cases. Strong suppression of contractility was also demonstrated with 2.5 nM [D-Pen2.5]-enkephalin (DPDPE), a delta agonist, but only minor suppression with 2.5 nM dynorphin A, a kappa agonist. Results support the opioid nature of the albumin-bound hibernation-induction trigger substance, that it binds to the delta opiate receptor, and that delta agonist opioid production may increase during the hibernation season.

Glycosylated hemoglobin as a stable alternative to serum glucose in white-tailed deer.

We compared serum glucose concentration and percent glycosylated hemoglobin (GH) in captive and wild white-tailed deer (Odocoileus virginianus) to determine stability of glucose relative to GH. Temporal changes in levels of serum glucose and GH were ascertained from serial blood samples collected from three captive deer over a 2-week period. State of glycemia also was determined for 17 wild deer that were collected from three populations in southeastern Oklahoma and southwestern Arkansas (USA). Concentration of serum glucose of captive deer decreased (P = 0.04) from 190.4 to 155.8 mg/dl over the 2 weeks; percent GH did not differ temporally (P = 0.30). Percent GH of wild deer did not differ (P = 0.23) when deer were separated into 2 groups (high and low state of glycemia) based on the median serum glucose concentration. We found a significant difference (P = 0.04) in percent GH among wild deer populations; serum glucose concentration did not differ (P = 0.72) among populations. Our results indicate that percent GH is more stable than serum glucose concentration and may be useful in population comparisons of nutritional condition.

Rectal temperatures of immobilized, snare-trapped black bears in Great Dismal Swamp.

Rectal temperature was determined for 84 black bears (Ursus americanus) during 99 handlings in Great Dismal Swamp, Virginia and North Carolina (USA). All bears had been trapped with cable snares and immobilized with a 2:1 ketamine hydrochloridexylazine hydrochloride mixture. Temperatures were significantly greater in males and varied significantly by season. Immobilized bears began panting at rectal temperatures greater than 42.0 C. One death occurred at 43.0 C. We recommended cooling measures on black bears at rectal temperatures of greater than or equal to 40.0 C.

Seasonal variation in serum testosterone, testicular measurements and semen characteristics in the collared peccary (Tayassu tajacu).

Blood samples and testicular measurements were obtained from 4-8 captive adult collared peccaries monthly for 18 months and from wild adult males during summer (N = 16) and winter (N = 22) seasons. Serum concentrations of testosterone were determined by radioimmunoassay. Semen samples were collected monthly by electroejaculation from captive males for 1 year. Serum testosterone concentrations and testicular measurements varied in a low-amplitude circannual pattern, with maximum mean testosterone concentrations in fall and winter (1150-1400 pg/ml) and minimum values in summer (500-700 pg/ml). Circannual rhythms appeared to be related to dominance. Serum testosterone levels in wild males generally were lower than in captive males, although this difference was not significant (P greater than 0.05). Semen characteristics did not exhibit a circannual rhythm. These results suggest that the male peccary remains reproductively fertile throughout the year, yet may undergo a facultative summer quiescence influenced by ambient temperature and social factors.

Indices for physiological assessment of nutritional condition in pregnant collared peccaries (Tayassu tajacu).

Hematological and serum biochemical responses to two levels of dietary energy (high energy [HE], 3300 kcal digestible energy [DE]/kg; moderate energy [ME], 2300 kcal DE/kg) and protein (high protein [HP], 16.0% crude protein; moderate protein [MP], 8.4% crude protein) during gestation in 15 collared peccaries (Tayassu tajacu) were examined. Dietary energy and protein levels influenced body weight gain during gestation. Red blood cell counts and lymphocyte concentrations were higher and neutrophil concentrations were lower among females fed an HP diet compared to those fed an MP diet. Alkaline phosphatase and alpha-2 globulin concentrations were higher among females fed an MP diet. Aspartate aminotransferase and cholesterol concentrations were higher and calcium and thyroxine concentrations were lower among females fed ME diets compared to those fed HE diets. These results suggest that physiological indices used in combination with morphological measurements can be useful in assessing collared peccary nutritional health during gestation.

Urea concentration in collared peccary milk as an indicator of protein nutritional status.

Milk urea nitrogen (UN) concentration was examined as a possible index to protein-energy intake in female collared peccaries (Tayassu tajacu). Captive adults were bred and assigned to one of four experimental diets through gestation and lactation. Females fed a high protein diet produced milk with UN concentrations exceeding those of low-protein-fed females. A low energy intake tended to elevate UN concentrations in milk.

Vitamin A levels of blood in collared peccaries (Tayassu tajacu) from south Texas.

Serum vitamin A concentrations were determined for 24 adult female collared peccaries from 1 captive and 2 wild populations during the period 30 January-15 March, 1983. Normal serum vitamin A concentrations of well-fed captive peccaries (mean = 39.0 micrograms/dl) were slightly higher than the reported range of values for domestic swine. Mean vitamin A concentrations of blood serum did not differ among the captive and 2 wild populations. However, a few individuals from the wild populations had low serum levels of vitamin A which suggested a possible vitamin A deficiency for these females.

Absolute and allometric relationships between internal morphology and body mass in the adult collared peccary, Tayassu tajacu (Tayassuidae).

Selected morphological features of 8 adult male and 8 adult female collared peccaries (Tayassu tajacu) shot from southern Texas during March 1983 are described. A total of 16 adult peccaries with an average body mass of 18.68 +/- 0.61 (SE) Kg was examined. Significant differences between males and females were observed for absolute and relative mass of liver and lungs, and relative heart mass. These visceral organs were heavier among females than males. Significant sex effects were also found for absolute and relative mass of the dorsal scent gland. The dorsal scent gland contributed twice as much to total body mass in males as in females. No sexual dimorphisms of the gastrointestinal tract were noted. Females had a significantly greater portion of total visceral fat deposited around the kidneys than did males. Relative mass of the mandible was significantly greater in males than in females. Adult males had extremely large accessory sex glands. The bulbourethral and seminal vesicle glands comprised 0.27 per cent of the total body mass. Allometric growth coefficients (b) varied among the various organs and glands examined, ranging from below (eyes, b = 0.34) to well above (seminal vesicles, b = 1.87) unity. Growth coefficients of lungs, kidneys, pituitary gland, and thyroid gland during adulthood greatly exceeded respective values in developing nurslings.

Endocrine and metabolic responses of the collared peccary (Tayassu tajacu) to immobilization with ketamine hydrochloride.

Serial physiological responses were examined for 150 min from captive collared peccaries during immobilization with ketamine hydrochloride. Rectal temperatures decreased significantly (P less than 0.01) during anesthesia. Serum concentrations of total proteins, albumin, cholesterol, alanine aminotransferase, and calcium declined significantly (P less than 0.05) during the first 45 min post-immobilization before stabilizing. Concentrations of lactate dehydrogenase and alkaline phosphatase in sera showed similar but nonsignificant (P greater than 0.05) trends. Inorganic phosphorus and aspartate aminotransferase concentrations increased significantly (P less than 0.05) throughout the trial. Concentrations of serum glucose and glucocorticoid during the immobilization period were highly variable between individuals. Serum electrolytes, urea nitrogen, creatinine, gammaglutamyl transferase and progesterone were not significantly (P greater than 0.05) affected by immobilization. Elevations in serum testosterone were noted. Results indicated appropriate sampling times relative to immobilization for assay of particular serum biochemicals and steroid hormones during investigations of the physiology of the collared peccary.

Serum progesterone, estradiol-17 beta, and glucocorticoids in the collared peccary during gestation and lactation as influenced by dietary protein and energy.

Sixteen pregnant collared peccaries were assigned to four experimental diets representing two levels of crude protein and two levels of digestible energy. Serum levels of progesterone, estradiol-17 beta (E2), and glucocorticoids were measured by radioimmunoassay. There was no significant dietary effect (P greater than 0.05) associated with any hormone during gestation. Progesterone did not differ between days 11 and 140 of gestation (X +/- SE = 36.48 +/- 1.11 ng/ml, N = 72), began to decline during the last week prepartum, and continued to decline within 24 hr of birth. Glucocorticoid concentrations remained level throughout gestation (X +/- SE = 6.57 +/- 0.45 microgram/dl, N = 74). E2 levels were low during the first 90 days of gestation, rose significantly (P less than 0.001) from 10.11 +/- 1.73 pg/ml (X +/- SE, N = 8) at Days 81-90 gestation to 49.07 +/- 12.87 pg/ml (N = 3) at 2-4 days prepartum (Days 141-147 of gestation), and declined rapidly to baseline levels within 24 hr of farrowing. Litter size had no effect on progesterone or E2 concentrations. There was no significant dietary effect on litter size or gestation length. During lactation, glucocorticoids and E2 remained stable and did not differ by diet, while progesterone concentrations appeared to be affected by diet. Individuals on the high energy-high protein diet returned to normal ovarian function before animals on the other three diets. Results indicated that the pregnant collared peccary can maintain a reproductive steroid environment that allows for fetal development in the face of moderate caloric or protein restriction and that the lactating peccary can undergo a postpartum ovulation in the presence of good nutrition.

Relationships between internal morphology and body mass in the developing, nursling collared peccary, Tayassu tajacu (Tayassuidae).

Morphological characteristics that reflect size differences due to dietary conditions are in wide use to assess nutritional status of many wild ungulates. This study was designed to provide baseline information on the development of internal visceral and endocrine structures of nursling collared peccaries (Tayassu tajacu) from birth to six weeks of age (weaning). A high energy-high protein ration was fed ad libitum to lactating females, and absolute and relative mass of selected visceral organ, endocrine, and fat depots were measured in various aged nurslings. Linear measurements were also obtained on components of the gastrointestinal tract. Allometric growth coefficients (b) varied considerably among the various organs and glands examined, ranging from below (brain, b = 0.26) to well above (thymus, b = 1.61) unity.

Physiological responses of the adult male collared peccary, Tayassu tajacu (Tayassuidae), to severe dietary restriction.

Metabolic and hormonal responses of eight adult male collared peccaries (Tayassu tajacu) to an ad libitum diet intake, or 25% of an ad libitum intake, were examined. Blood samples for hematological, serum-biochemical and hormonal profiles were collected at three week intervals during the nine week experiment starting 4 August 1983. Males fed on the restricted diet lost an average of 26% of their body weight during the trial, compared to a slight weight gain for those fed ad libitum. Characteristics of the red and white blood cell populations were not influenced by diet intake, with the exception of mean corpuscular volume, which was consistently lower amongst males fed on the restricted diet. Restricted food intake resulted in significantly elevated serum values for urea nitrogen, urea nitrogen:creatinine, urea index, alpha globulin:beta globulin, gamma globulin:albumin, nonesterified fatty acids, alkaline phosphatase and lactate dehydrogenase isozymes (LD1 and LD2). Restricted food intake resulted in significantly lowered serum values for total alpha globulin, alpha-1 globulin, total beta globulin, beta-1 globulin, beta-2 globulin, glucose, triglycerides, calcium, magnesium, sodium, chloride, copper and triiodothyronine. Serum levels of creatinine, total protein, albumin, alpha-2 globulin, uric acid, total bilirubin, cholesterol, aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase, lactate dehydrogenase, phosphorus, calcium:phosphorus, potassium, iron, zinc and thyroxine were unaffected by diet intake level. Semen evaluation indicated spermatogenesis was not affected by dietary restriction despite reductions in scrotal circumference and ejaculate gel volume. Serum testosterone levels were significantly lower among males fed on the restricted diet after nine weeks. These data suggest male libido might be depressed during poor range conditions, while maintenance of spermatogenesis might permit them to take immediate advantage of improved range conditions. Blood analysis of metabolic and hormonal function can provide useful information for predicting the adult male's nutritional and reproductive condition.