Diagnosis of pregnancy in wood bison using a bovine assay for pregnancy-specific protein B

Blood samples were collected from 51 wood bison (Bison bison athabascae ) and evaluated for the presence of an antigen that cross-reacted with antisera to pregnancy-specific protein B(PSPB). The objective of this study was to determine if the PSPB radioimmunoassay (RIA) was a reliable indicator of pregnancy in these animals. Pregnancy of mature females was determined either at autopsy (20 animals) or by palpation per rectum after chemical immobilization (18 animals). The antigen was not detected in either males or juvenile females. There was minor cross-reaction in sera of one of nine nonpregnant females that had been exposed to males. The antigen was found in the sera of 25 of 27 females that were confirmed pregnant. It was concluded that the PSPB RIA was a useful tool in the determination of pregnancy in wood bison.     

Effects of maternal age and condition on parturition and the perinatal period of Antarctic fur seals

The effect of maternal age and condition on the date of parturition and the duration of the perinatal period of Antarctic fur seals at Bird Island, South Georgia, were investigated over three consecutive breeding seasons. Females rear young during a four-month lactation period in a highly seasonal but predictable environment. Although females may first pup at three years of age, they did not attain full adult size until six years of age; older females (≥ 6 years) tended to be heavier, longer, and in better condition than younger females (3–5 years). Older females returned to breeding beaches earlier and could occupy the most suitable pupping sites, and gave birth when densities of animals on the beaches were low (i.e. more favourable for pup survival). Females that arrived earlier were able to remain ashore longer with their pups prior to departing on their first foraging trips but this was unrelated to either maternal age or condition. Younger females returned later in the pupping season, possibly as a result of late implantation due to smaller energy reserves than older and larger females. In 1990 all females arrived late, were in poorer condition, gave birth to lighter pups, and had shorter perinatal periods. This suggests that not only was implantation late but that females returned to an area of low food availability prior to parturition.     

THE EFFECT OF BIRTH DATE ON FITNESS OF FEMALE DWARF PERCH,MICROMETRUS MINIMUS (PERCIFORMES: EMBIOTOCIDAE)

Lifetime reproductive success may vary considerably with birth date. I measured phenotypic selection on female birth date in a viviparous teleost fish (Embiotocidae: Micrometrus minimus) by sampling birth-date cohorts over time in Tomales Bay, California. Four episodes of selection were measured: survival from birth to first reproduction, reproductive success in the first breeding season, survival to second reproduction, and reproductive success in the second season. Birth date had a significant impact on fitness in the first two episodes. Early born females were more successful in their first breeding season than late born females (directional selection on birth date), but early born females were less likely to survive the period between birth and first reproduction, relative to females born in the middle of the season (stabilizing selection on birth date). The final two episodes of selection had no detectable effect on birth date. Because of the relationship between birth date and survival in the first year, overall selection on female birth date was stabilizing.     

R51163 as a sedative for handling and transporting plains bison and wapiti.

Forty captive wapiti (Cervus elaphus) and thirty-two bison (Bison bison bison) were tested in April and October 1988, respectively, for their response to the sedative R51163. Treatment animals were injected with either 0.1, 0.2, or 0.3 mg of R51163/kg and then observed for 72 hr. Behavior was significantly altered by the drug. Hyperactive, aggressive, and milling behavior was characteristic of treated wapiti and they were extremely dangerous and reared when hind quarters were touched. Although treated plains bison displayed some milling behavior, they were generally more calm than wapiti. There was a marked difference between sexes in plains bison for all behavioral categories. Male bison were more ataxic, often observed in sternal or lateral recumbency, less conscious, and were slower to respond than females or controls. Respiratory rate increased in treated wapiti and plains bison, and heart rates of treated wapiti increased. Because of the powerful sedative effect on large, male bison, R51163 may be useful for handling unmanageable or dangerous animals and warrants further studies.     

The annual cycle of shedding Eimeria oocysts by European bison (Bison bonasus) in the Bialowieza Primeval Forest, Poland

Between April 2008 and March 2009, we analyzed the pattern of coccidian oocysts present in the feces of the European bison (Bison bonasus L., 1758) and found 4 species (Eimeria bovis , E. canadensis, E. ellipsoidalis, E. zuernii) previously reported from this host and 3 species (Eimeria alabamensis, E. cylindrica, E. pellita) that are new host and locality records. All the species occurred in bison females, and only 4 occurred in males; E. bovis was the most prevalent in both sexes. The overall prevalence of Eimeria spp. invasion reached 34.7% in cows and 13.9% in bulls. The highest prevalence was noted in early spring, with a peak in April, and the lowest in late autumn and winter. The oocyst count per gram of feces (OPG) varied from 50 to 1,350; no symptoms of clinical coccidiosis were observed. We found a significant influence of winter aggregations of bison on shedding of coccidian oocysts. The prevalence and OPG values were higher in bison congregating in large numbers around winter-feeding sites in comparison to other sites. We suggest that the coming together of cows during the growing season impacts the gender-related differences in prevalence and the number of coccidian species involved. This observation probably results from an increased production of oocysts by sub-clinically infected individuals in high-density bison populations.     

Lack of compensatory body growth in a high performance moose Alces alces population

Considerable work has been done on disentangling important factors determining early development in body size, yet our knowledge of the extent to which animals living under varying conditions can achieve catch-up growth for a bad start in life is limited. Here, we investigated how body mass at the age of 8 months influenced adult body mass in a moose Alces alces population living under excellent environmental conditions on the island of Vega in northern Norway. We also investigated if mother age and birth date effects on calf body mass persisted until adulthood. We show that neither males nor females were able to show compensatory growth before they reached adulthood, and that part of the variation in adult body mass may have been due to variation in mother age and date of birth. The pattern observed in males can be related to their growth strategy in relation to reproduction, while such results were not expected in females where size-dependent start of reproduction is likely to interact with body growth. We suggest that the good environmental conditions experienced on Vega led to females having small somatic costs of an early start of reproduction or that larger females were able to acquire more resources for growth than their smaller conspecifics. In both cases, females that postpone their first reproduction may not be able to achieve catch-up growth for their lower early body mass compared to females that start reproduction at an early age. Our results concur with previous studies indicating that compensatory growth is weak in moose, increasing the likelihood that variation in life history characters are also transferred between generations.     

Body mass and measurements of the European bison during postnatal development

Body mass of the European bisonBison bonasus (Linnaeus, 1758) was determined for 152 animals (86 males, 66 females) from captive breeding centre in Białowieża and for 492 (248, 244) animals from the free-ranging herd in the Białowieża Forest. Body measurements were taken for a total of 472 bison (204, 268). Age-related changes in body mass and measurements of 375 bison (165, 210) were analysed. Bison body mass was significantly correlated with age. Captive bison were heavier than those from a free-ranging herd. Measurements showed the changes in bison body structure in the postnatal development. All measurements were highly correlated with age and mass of the animals and increased most intensively during the first year of life. Sex-related differences in body mass and measurements were most pronounced in bison ≥ 3 years old. Physical development of females ends at the age of 5 years, and that of males at the age of 7 years.     

Genetic Analysis of the Henry Mountains Bison Herd

Wild American plains bison (Bison bison) populations virtually disappeared in the late 1800s, with some remnant animals retained in what would become Yellowstone National Park and on private ranches. Some of these private bison were intentionally crossbred with cattle for commercial purposes. This forced hybridization resulted in both mitochondrial and nuclear introgression of cattle genes into some of the extant bison genome. As the private populations grew, excess animals, along with their history of cattle genetics, provided founders for newly established public bison populations. Of the US public bison herds, only those in Yellowstone and Wind Cave National Parks (YNP and WCNP) appear to be free of detectable levels of cattle introgression. However, a small free-ranging population (~350 animals) exists on public land, along with domestic cattle, in the Henry Mountains (HM) of southern Utah. This isolated bison herd originated from a founder group translocated from YNP in the 1940s. Using genetic samples from 129 individuals, we examined the genetic status of the HM population and found no evidence of mitochondrial or nuclear introgression of cattle genes. This new information confirms it is highly unlikely for free-living bison to crossbreed with cattle, and this disease-free HM bison herd is valuable for the long-term conservation of the species. This bison herd is a subpopulation of the YNP/WCNP/HM metapopulation, within which it can contribute significantly to national efforts to restore the American plains bison to more of its native range.     

ANNUAL REPRODUCTIVE CYCLE OF THE FEMALE HAWAIIAN MONK SEAL (MONACHUS SCHAUINSLANDI)

Abstract: The annual reproductive cycle is described for the adult female Hawaiian monk seal ( Monachus schauinslandi ) from data collected at Laysan Island (1982–1991) and Lisianski Island (1982–1983) in the Northwestern Hawaiian Islands. Pupping, lactation, weaning, and molting were directly observed, while mating was rarely observed and was, therefore, inferred from the occurrence of mounting injuries and from adult male and female association patterns. Pooled birth rates during the study period were 0.544 for all adult-sized females and 0.675 for females parous in earlier years. For parturient females, pupping peaked in late March and early April, weaning in May, mounting injuries in May and June, and molting in July. For non-parturient females, the median mounting injury and molting dates occurred 17 and 28 days earlier, respectively. Pupping date set the timing of subsequent events in the annual cycle, but the timing of those events was adjusted by loss of the pup or poor physical condition of the female. Individual pupping patterns varied widely. The mean interval for births in consecutive years was 381 days; females that pupped in consecutive years gave birth later each season. Conversely, females who skipped a year or more gave birth earlier their next pupping season.     

Reproduction and Survival of Yellowstone Bison

ABSTRACT The conservation of bison (Bison bison) from near extinction to >4,000 animals in Yellowstone National Park has led to conflict regarding overabundance and potential transmission of brucellosis (Brucella abortus) to cattle. We estimated survival and birth rates from 53 radiocollared adult female bison during 1995–2001, and we used calf:adult (C:A) ratios to estimate reproduction with the combined effects of pregnancy, fetal loss, and neonatal mortality during 1970–1997. Annual survival of adult females was high (0.92; 95% CI = 0.87-0.95) and constant. Birth rates differed by brucellosis status and age. Birth rates were 0.40 calves per female (95% CI = 0.15-0.65) for brucellosis-positive 3 year olds, 0.63 (95% CI = 0.39-0.87) for individuals testing negative, and 0.10 (95% CI = 0.00-0.24) for individuals contracting brucellosis that birth year (sero-converters). Birth rates were 0.64 (95% CI = 0.52-0.76) for brucellosis-positive individuals ≥4 years old, 0.81 (95% CI = 0.73-0.89) for brucellosis-negative individuals, and 0.22 (95% CI = 0.00-0.46) for sero-converters. Spring C:A ratios were negatively correlated with snow pack (β = −0.01 to −0.03, R² = 0.26-0.60, P < 0.05). Growth rate was highly elastic to adult survival (0.51), and juvenile survival (0.36) was 3 times more elastic than fecundity (0.12). Simulations suggested brucellosis eradication via vaccination would result in increased birth rates and a 29% increase in population growth (γ = 1.09), possibly leading to more bison movements outside the park. Our results will help park managers evaluate bison population dynamics and explore consequences of management actions and disease control programs.     

Group Composition Affects Seasonal Birth Timing in Captive Japanese Macaques

We analyzed birth dates recorded during an 18-year period in a group of Japanese macaques housed in the Rome zoo to assess the influence of environmental, physiological, and social factors on birth seasonality. Birth timing differed significantly among years. Birth timing was affected by reproductive condition of females—ones that had given birth in the previous year delivered significantly later than those that had not—but not by their age or dominance rank. We conducted further analyses separately on females that had or had not given birth in the previous year. In both subgroups of females mean birth date was not influenced either by environmental temperature and rainfall during the previous mating season or by group size. On the contrary, among females that had not given birth in the previous year, socionomic sex ratio—ratio of sexually mature males to sexually mature females—is positively correlated with both mean birth date and date of the first birth, but not with date of the last birth. Contrarily, among females that had given birth in the previous year, there is no significant relationship between these variables. We hypothesize that the effects of socionomic sex ratio on birth timing might depend on competition among males for access to fertile females. When the number of males per female was higher, mutual disruption of consort pairs may have led to a delay in the onset of mating.     

Variable variation: annual and seasonal changes in offspring sex ratio in a bat

Many organisms produce offspring with sex-ratios that deviate from equal numbers of males and females, and numerous adaptive explanations have been proposed. In some species, offspring sex-ratio varies across the reproductive season, again with several explanations as to why this might be adaptive. However, patterns for birds and mammals are inconsistent, and multiple factors are likely involved. Long-term studies on a variety of species may help untangle the complexity. I analyzed a long-term data set on the variation in offspring sex-ratio of the big brown bat, Eptesicus fuscus, a temperate-zone, insectivorous species. Sex ratio varied seasonally, but only in some years. Births early in the season were significantly female biased in years in which parturition occurred relatively early, but not in years with late parturition. Survival of female pups increased with earlier median birth date for the colony, and early-born females were more likely to survive and reproduce as one-year olds, compared to later-born pups. I argue that, due to the unusual timing of reproductive activities in male and female bats that hibernate, producing female offspring early in the year increases their probability of reproducing as one year olds, but this is not the case for male offspring. Thus, mothers that can give birth early in the year, benefit most by producing a female pup. The relative benefit of producing female or male offspring varies depending on the length of the growing season and thus the time available for female pups to reach sexual maturity. This suggests that not only does sex-ratio vary seasonally and among years, depending on the condition of the mother and the environment, but also likely varies geographically due to differences in season length.     

Contraception of bison by GnRH vaccine: a possible means of decreasing transmission of brucellosis in bison

Preventing pregnancy in brucellosis-infected bison (Bison bison) provides a potential means of preventing transmission of disease. To determine whether a gonadotropin-releasing hormone (GnRH) vaccine was effective in reducing pregnancy in bison and to study the safety of injecting GnRH in pregnant bison, a study was conducted at the Idaho Fish and Game Wildlife Health Laboratory in Caldwell, Idaho (USA). Four pregnant and two nonpregnant female bison were given a single injection of GnRH vaccine, and five pregnant adult females were given a sham injection that contained only adjuvant. Three of the GnRH-vaccinated bison that were pregnant at the time of vaccination delivered healthy calves. One treated bison had dystocia that resulted in a dead calf. All control bison delivered healthy calves. After calving, females of both groups were exposed to two bulls. Treated bison were palpated 6 wk after exposure to the bulls, and blood was drawn for pregnancy-specific protein B analysis. The six treated bison were not pregnant. The sham-treated bison became pregnant and delivered viable calves. This study demonstrates that a single dose of GnRH vaccine is effective in preventing pregnancy in female bison for at least 1 yr.     

Growth and survival of New Zealand sea lions, <Emphasis Type="Italic">Phocarctos hookeri:</Emphasis> birth to 3 months

Offspring birth mass and growth rate represent important life history traits, which influence many vital population and individual characteristics, while offspring survival is a key factor in variation in female reproductive success. For a threatened population of pinnipeds, such as New Zealand sea lions, Phocarctos hookeri, (Grey, 1844, NZ sea lions), understanding individual life history parameters and population dynamics is vital for their management and conservation. This is the first study of the behaviour of females during parturition, pup birth mass and growth, and pre-weaning survival of NZ sea lions, Enderby Island, Auckland Islands during austral summer breeding seasons, 2001/2002 to 2003/2004. Pregnant females arrived ashore 2.1 ± 0.16 days prior to giving birth. After parturition, mothers suckled their pups for 8.6 ± 0.16 days before leaving on their first foraging trip. Male pups were born significantly heavier than female (males 10.6 ± 1.4 kg, females 9.7 ± 0.9 kg). Pups lost on average 48 ± 0.14 g per day mass during the early postpartum period (between birth and mothers first foraging trip). Pup mortality did not vary by pup sex, birth mass, date of birth or any maternal characteristics however it varied significantly between years due to a bacterial infection epidemic (Pup mortality at 60 days: 2001 32%; 2002 21%; 2003 12%). The absolute growth rate per day for pups was 151 g/day over all years. Pup growth rate measured as the slope of linear line fitted to pup mass by age was consistently higher for pups with heavier birth mass, male pups and during the 2002 season. High offspring mortality and slow growth rates coupled with maternal foraging behaviour at their physiological limits may reflect a threatened species which has limited ability for population growth in an environment which is at the extreme of their historical range and impacted upon by fisheries.     

Post-bottleneck mtDNA diversity in a free-living population of European bison: implications for conservation

A free-living population of European bison Bison bonasus in the Białowieża Primeval Forest originated from only seven founder animals after a severe bottleneck that occurred at the beginning of the 20th century. Consequently, the contemporary population of the species is characterized by low genetic diversity. We studied a total of 195 individuals (127 males and 68 females). A 1429 bp fragment of mitochondrial DNA (mtDNA) including the D-loop region was analyzed in 87 individuals and revealed only three distinct haplotypes. Nucleotide ( π ) and haplotype ( H _d) diversity values were estimated for the European bison and were compared with π and H _d estimated from three individuals of American bison Bison bison . Very low diversity values were found in the European bison in comparison with the diversity values found in the American bison. The low mtDNA variability in the European bison is in concordance with theoretical expectations for a species that has undergone a severe and recent bottleneck. A management strategy for the preservation of the rare and very rare haplotypes present in the Białowieża population of the European bison is discussed. Furthermore, all 195 individuals were investigated for heteroplasmy involving these three haplotypes, in order to detect a possible association between heteroplasmy and the incidence of males affected by posthitis , a disease that affects the male reproductive organs, leading to necrotic lesions. Heteroplasmy was found in 15 females, in 17 males affected by posthitis and in 11 non-affected males, and no significant association was found.     

Never too late? Consequences of late birthdate for mass and survival of bighorn lambs

In strongly seasonal environments, the timing of birth can have important fitness consequences. We investigated which factors affect parturition date and how birthdate interacts with sex, maternal characteristics and environmental variables to affect the growth and survival of bighorn sheep (Ovis canadensis) lambs in a marked population in Alberta. Over 14 years, the estimated birthdate of 216 lambs ranged from 21 May to 18 July. Parturition date was heritable and genetically correlated with maternal mass the previous fall. Weaning a lamb delayed parturition the following year by about 7 days. Birthdate did not affect summer growth rate, but late-born lambs were lighter in mid September (the approximate time of weaning) than early-born ones. Birthdate did not affect survival to weaning, but late birth decreased survival to 1 year for male lambs. Forage quality, measured by fecal crude protein, did not affect survival to 1 year. Once we accounted for lamb mass in mid September, birthdate no longer affected the probability of survival, suggesting that late birth decreased survival by shortening a lamb's growing season. Because there was no compensatory summer growth, late-born lambs were smaller than early-born ones at the onset of winter. Our data highlight the importance of birthdate on life history traits and suggest that resource scarcity had more severe consequences for juvenile males than for females.     

Factors associated with birth rate and live birth rate in multi-male breeding groups of rhesus monkeys

Reproductive records of 284 female rhesus monkeys housed in six multimale corrals at the California Primate Research Center were examined for the birth seasons 1977–1982 to determine possible associations between the probability of birth or live birth and female age, parity, origin, parturition in the previous season, infant birth date, and infant birth date in previous season. Multiple logistic regression analysis was used to identify and quantitate the effects of factors on the probability of birth or live birth, while controlling for the possibly confounding effects of other factors in the model. Females who had infants early in the previous season were 2.5 times as likely to give birth as those who had infants late in the previous season. Females with two or three previous births were 2.1 times as likely to give birth, and those with four or five previous births were 6.7 times as likely to give birth as were females with no or one previous birth. Controlling for other factors (age, parity, and timing of birth in the previous season), corralborn females were 3.3 times as likely to give birth as either wild-caught or domestic-born monkeys not native to the corrals. Domestic-born females who were not corral natives were 0.3 times as likely to have live births as wild-caught females. Births late in the season were 1.8 times as likely to result in live infants as births early in the season.     

Trypanosoma lewisi: termination of pregnancy in the infected rat

Trypanosoma lewisi has previously been described as a nonpathogenic parasite of the rat, but these experiments demonstrate that both embryonal and maternal death may occur in the pregnant rat after infection with this parasite.Rats infected early in the first week of pregnancy resorbed their young with little apparent difficulty, and exhibited parasitemia curves typical of nonpregnant infected females of similar age.Rats infected late in the first week of pregnancy experienced greater difficulty resorbing the young, with half of the females dying shortly before parturition. The parasitemia counts were also similar to those of nonpregnant infected rats.The majority of rats infected during the midterm of pregnancy died at the time of parturition, without giving birth to their young. The number of parasites in these animals was abnormally high compared to nonpregnant infected females. Unusually large numbers of dividing trypanosomes were present in the placentae of these animals, many of them containing 8–16 nuclei and kinetoplasts.Animals infected during the last week of pregnancy gave birth to litters of normal size with little apparent difficulty, and had extremely low parasite counts.The hematocrits of all groups of infected animals showed a decrease at the time of peak parasitemia, and the hematocrits of all groups of pregnant rats showed a decrease at the time of birth, except for those infected when day 2 pregnant. These animals completely resorbed their young. The weight losses of rats infected on day 2 and day 6 of pregnancy reflected a termination of pregnancy.     

Morphometric variation of the skull during postnatal development in the Lowland European bisonBison bonasus bonasus

We studied the variation of linear measurements and skull capacity in Lowland European bisonBison bonasus bonasus (Linnaeus, 1758) during postnatal development, and the dependencies of the parameters in relation to sex, age, and body mass of the animals. Material consisted of 599 bison skulls (310 males and 289 females), within the age range of 1 month to 21 years (males) and to 27 years (females). In the group of calves to 1 year old, no sex connected differences in skull measurements were observed, whereas the skull capacity in older calves was significantly larger (0.01>p>0.001) in males than in females. From the third year of life, most skull measurements display characteristics of sexual dimorphism. Skull development in both sexes is most intensive during the first three years of life, and slows from the age of 5. In older individuals of both sexes (≥ 6 years), orbital breadth continues growing and, in females, breadth of splanchnocranium continues increasing. Growth in a bison’s skull capacity is most intensive up to the third year of life and slows from the age of 5. During postnatal development, a bison skull grows proportionally except the neurocranium, which grows slightly slower in comparison with basal length and its development finishes earlier than that of splanchnocranium. In ontogenesis, a bison skull grows much slower compared to body mass. In relation to body mass, skull capacity and the height of neurocranium grow most slowly while orbital breadth grows most intensively. The results obtained were compared with data on skull sizes of bison born in 1930–1950 and bred in captivity and with skulls of the American bisonBison bison. Inbreeding is probably responsible for some types of phenotypic abnormalities in the skull which appear in modern European bison.     

Annual variation in the timing of reproduction in Antarctic fur seals, Arctocephalus gazella, at Bird Island, South Georgia

The arrival of Antarctic fur seals at a breeding beach on Bird Island, South Georgia, was studied over five consecutive breeding seasons, 1983 to 1987. Experienced bulls arrived first and established breeding territories on the beaches in anticipation of the arrival of the cows. Male arrival, which is less synchronous within years than female arrival, was significantly later in 1987 than in any other year. Female arrival, estimated by pup birth date where necessary, was highly synchronous; it usually started when 80% or more of potential territory sites were occupied by males. Cows arrived significantly later in 1984 and 1987 than in 1983, 1985 or 1986. The late arrival of both males and females in 1987 is attributed to unusually severe climatic conditions during the preceding winter. The late arrival and reduced fecundity of females in 1984 is attributed to markedly reduced food availability during the austral winter and summer of 1983. Males were not affected in 1984 because they could move away from the area of reduced food availability earlier than females and because they have a more varied diet. Factors influencing the winter distribution, the timing and pattern of arrival and the breeding of male and female Antarctic fur seals are discussed.