Age estimation in young dogs by radiographic assessment of the canine pulp cavity/tooth width ratio.

Age estimation in adult dogs can be performed by the radiographic measurement of the tooth pulp cavity, but the technique has hardly been described. In this study, the application of measuring pulp/tooth width ratios (P/T ratios) of the maxillary canine teeth was investigated. Pulp and tooth widths were measured at two locations on 166 maxillary canine teeth of the heads of 84 dog cadavers, using digital extraoral lateral oblique open mouth radiographs. The dogs belonged to different breeds and sexes and had a known age between 194 and 1907 days (approximately 6 months - 5 years). Both at the cemento-enamel junction (CE) and the half-height of the tooth, a comparable non-linear regression with age was demonstrated. Measuring at the CE location was less hindered by wear or superimposition. No statistically significant difference according to sex and breed size and no clinically significant difference according to skull type was found. The highest predictable capacity was found in the youngest dogs until the age of 448 days, of which 84.4% of the canine teeth had a P/T ratio above 0.39. Our results demonstrate that measuring P/T ratios of canine teeth can be used in practice to assign dogs to age categories, with the highest accuracy in young adult dogs.

Age determination of common bottlenose dolphins (Tursiops truncatus) using dental radiography pulp:tooth area ratio measurements.

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.

Age determination in dog puppies by teeth examination: legal, health and welfare implications, review of the literature and practical considerations.

Age determination of puppies represents a significant issue of animal welfare and forensic medicine, particularly for what concerns trade and imports of dogs. Despite the movement of puppy dogs before the age of 15 weeks is forbidden by Regulation (EU) No 576/2013, the occurrence of illegal transport of younger puppies is not uncommon. The illegal trade of puppies increases instances of falsified documentation, the counterfeit of vaccine certificates and discrepancies between the declared age and the real age of the puppies. Consequently, determining the exact age of animals and evaluating their welfare become legally crucial. Dental examination currently represents the most common approach to estimate the age of a puppy in clinical practice and in forensic investigations. In this work we addressed the legal, health and welfare issues associated with dogs' trade and import and we reviewed the existing literature referring to the assessment of age in dogs by dental examination. The imprecision and inaccuracy of this method make it poorly convincing in legal proceedings. The reasons for such vagueness are to be ascribed both to the lack of standardization and to many variability factors (size, breed, sex, diet, etc.) which influence dental eruption and development.

Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda.

OBJECTIVES: Ecological factors, but also tooth-to-tooth contact over time, have a dramatic effect on tooth wear in primates. The aim of this study is to test whether incisor tooth wear changes predictably with age and can thus be used as an age estimation method in a wild population of mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIALS AND METHODS: In mountain gorillas of confidently known chronological age (N = 24), we measured the crown height of all permanent maxillary and mandibular incisors (I1 , I1 , I2 , I2 ) as a proxy for incisal macrowear. Linear and quadratic regressions for each incisor were used to test whether age can be predicted by crown height. Using these models, we then predicted age at death of two individual mountain gorillas of probable identifications, based on their incisor crown height. RESULTS: Age decreased significantly with incisor height for all teeth, but the upper first incisors (I1 ) provided the best results, with the lowest Akaike's Information Criterion corrected for small sample size (AICc) and lowest Standard Error of the Estimate (SEE). When the best age equations for each sex were applied to gorillas with probable identifications, the predicted ages differed 1.58 and 3.33 years from the probable ages of these individuals. CONCLUSIONS: Our findings corroborate that incisor crown height, a proxy for incisal wear, varies predictably with age. This relationship can be used to estimate age at death of unknown gorillas in the skeletal collection, and in some cases, to corroborate the identity of individual gorillas recovered from the forest postmortem at an advanced state of decomposition. Such identifications help fill gaps in the demographic database and support research that requires individual-level data.

Anatomy of equine incisors: Pulp horns and subocclusal dentine thickness.

BACKGROUND: Equine incisors are often reduced in height during corrective dental procedures. Increased knowledge of subocclusal dentine thickness and pulp morphology may help prevent iatrogenic pulpar exposure. Although such data exist for equine cheek teeth, there are currently no reliable data for incisors. OBJECTIVES: To measure the distances between pulp cavities and the occlusal as well as the labial surfaces of equine incisors and to test if these distances change with age. Furthermore, pulp morphology with regard to number and orientation of pulp horns was investigated. STUDY DESIGN: Observational study using cadaver material and high-resolution computed tomography. METHODS: Upper and lower incisor arcades were removed from heads of 13 horses and scanned with high-resolution computed tomography. 3D Models were reconstructed and configuration as well as number of the pulp horns was evaluated. Anatomical marker points were set to measure distances between the pulp horn tips and the labial and occlusal surfaces. RESULTS: Subocclusal dentine thickness ranged between 1.5 and 11.7 mm in upper and 0.7 and 6.7 mm in lower incisors. It decreased with tooth age. Distance to labial aspect ranged between 3.5 and 9.0 mm in upper and 3.8 and 8.1 mm in lower incisors and increased with tooth age. MAIN LIMITATIONS: Details of horse management, feeding and previous dental care were not available. Therefore, it remains unknown how these factors influenced the results. CONCLUSIONS: Although mean subocclusal dentine thickness of greater than 4.1 mm was found, equine incisors occasionally have less than 1 mm of thickness with potential for iatrogenic pulpar exposure during incisor reduction. Therefore, great care should be exercised by any practitioner during incisor reduction.

Comparison of Micro-Computed Tomography and Digital Intraoral Radiography to Determine the Accuracy of Digital Radiographic Measurements of Mandibular Molar Teeth in Dogs.

INTRODUCTION: The purpose of this study was to compare root and root canal width measurements between digital intraoral radiography (IOR) and micro-computed tomography (µCT). The accuracy of IOR measurements of canine mandibular molars was scrutinized to assess feasibility of developing a model to estimate animal age based on dentinal thickness. MATERIALS AND METHODS: Thirty-nine canine mandibular first molars were imaged using µCT and IOR. For each tooth, the root and root canal width of the mesial and distal roots were measured by a single observer at 3 marked sites on µCT and IOR. Two different software programs were used to measure the radiographs. The radiograph measurements were compared to each other and to the µCT measurements. The µCT images were considered the anatomic reference standard for structural representation. RESULTS: The data collected demonstrated IOR bias and variability throughout all measurement sites, with some sites being more affected than others. Neither IOR system produced unbiased measurements that closely reflected the µCT measurements consistently. The overall lack of agreement between measurements demonstrated the difficulties in developing a standardized protocol for measuring root and root canal width for the first molar teeth in dogs. CONCLUSION: Developing a protocol to accurately measure and compare µCT and IOR measurements is challenging. Designing a measurement system that would allow for universal application to age dogs would require continued research utilizing a standardized approach to overcome the limitations identified in this article.

SCREENING FOR BOVINE TUBERCULOSIS IN AFRICAN BUFFALO (SYNCERUS CAFFER) IN NGORONGORO CONSERVATION AREA, NORTHERN TANZANIA: IMPLICATIONS FOR PUBLIC HEALTH.

In the Ngorongoro Conservation Area (NCA), Tanzania, where wildlife and livestock interaction is intense, greater potential for intra- and interspecies disease transmission is expected. We assessed the prevalence of bovine tuberculosis in African buffalo (Syncerus caffer) residing on the valley floor of the crater in the NCA. Apparently healthy animals were randomly selected from herds in nine sites of the Ngorongoro Crater. Syncerus caffer buffalo herds were located using very high-frequency radio-aided rangers positioned in various observation points around the crater in the NCA. A total of 102 African buffalo from 16 herds were immobilized from the ground using a cocktail of 4-10 mg etorphine hydrochloride (M99) and 60-150 mg azaperone tartrate. The M99 was reversed using 10-25 mg diprenorphine hydrochloride depending on age of animals. An interferon gamma assay was performed on harvested plasma samples using sandwich enzyme linked immunosorbent assay. Of the 102 animals sampled, two (2%) African buffalo tested positive for bovine tuberculosis. These results corroborate those of the skin test done recently in cattle in the NCA. The presence of bovine tuberculosis in livestock and wildlife suggested the possibility of cross-species transmission of the disease, indicating the need for appropriate intervention measures.

Lambdapapillomavirus 2 in a Gray Wolf ( Canis lupus ) from Minnesota, USA with Oral Papillomatosis and Sarcoptic Mange.

Oral papillomatosis was diagnosed in a gray wolf ( Canis lupus ) with sarcoptic mange from Minnesota, US found dead in February 2015. Intranuclear inclusion bodies were evident histologically, and papillomaviral antigens were confirmed using immunohistochemistry. Sequencing of the L1 papillomavirus gene showed closest similarity to Lambdapapillomavirus 2.

Baylisascaris procyonis Demography and Egg Production in a California Raccoon Population.

California has more reported human raccoon roundworm cases than any other state due to large and overlapping human and raccoon populations. Infection by this parasite, Baylisascaris procyonis , is relatively benign in raccoons but can cause severe pathology in other species. Disease risk is driven by environmental egg contamination which increases with raccoon density, worm intensity, and worm prevalence. To improve knowledge about risk to humans and other species, 189 raccoons from southern California were examined to investigate how host age and season affect worm abundance, demography, and fecundity. Adult worms were present in animals as young as 10 wk and 100% of 4-mo-old raccoons were infected. Although 80% of sampled raccoons hosted adult B. procyonis , prevalence and abundance were lower in older animals. There were more worms in juvenile than in adult raccoons, resulting in a convex age-intensity profile. Coupled with raccoon demography, this drove fall peaks in parasite abundance and egg production. Eggs per-gram feces averaged 4,606 ± 661 (SE), and this output increased with worm intensity, with no evidence that crowding reduced parasite size or fecundity. High parasite egg outputs from hosts in this California raccoon population increase human exposure risk, and this risk could be reduced by management strategies that target heavily infected juvenile raccoons.

Conjoined Fetal Twins in a Harbor Seal (Phoca vitulina).

In July 2013, a stranded harbor seal (Phoca vitulina) died giving birth to conjoined fetuses. The twins were joined at the abdomen and thoracolumbar spine with the vertebral axis at 180°. The cause of this unique anomaly--a first for this species--was not identified.

PREVALENCE OF ANTIBODY TO ALEUTIAN MINK DISEASE VIRUS IN EUROPEAN MINK (MUSTELA LUTREOLA) AND AMERICAN MINK (NEOVISON VISON) IN SPAIN.

The European mink (Mustela lutreola) has undergone a dramatic decline and is one of the most endangered mammals in the world. The invasive American mink (Neovison vison) is considered the main factor for this decline. However, the American mink's introduction and the subsequent ecological concurrence of the two species cannot solely explain the decline or disappearance of the European mink. Aleutian mink disease virus (AMDV) is the main health problem in fur farming worldwide, causing varied clinical syndromes that depend on the viral strain and host factors. Infection with AMDV has been speculated to contribute to the decline of the European mink, but a detailed study has not been performed. To assess the potential effects of AMDV infection on the conservation of the European mink, we surveyed AMDV antibody in samples from 492 native European mink and 1,735 feral American mink collected over 16 yr. The antibody prevalence in European mink was 32%. There were no statistically significant differences in antibody prevalence between sexes, among years, or among weight classes. For recaptured European mink, incidence of seroconversion (negative to positive) was 0.46 cases per animal-year at risk. For positive animals, the incidence of conversion from positive to negative was 0.18 cases per animal-year at risk. In 1,735 feral American minks, the overall prevalence was 32.4% and varied among the six wild populations studied. Infection with AMDV appears to be endemic, distributed across the entire ranges of both species, and no effects on the population dynamics of either species were observed.

Age determination in dogs using ocular light reflection, dental abrasion and tartar.

OBJECTIVE: The knowledge of an animal's age is important for disease probability, prognoses, or epidemiological questions, but unfortunately, it is often unknown for dogs in animal shelters. A simple estimating procedure is preferable being quick and easy to perform, even for non-veterinarians. MATERIAL AND METHODS: In 295 dogs the dimension of light reflection (diameter in millimetres), visible on the posterior lens capsule using a penlight, the grade of dental abrasion and dental tartar were documented photographically and the exact weight and age in days were obtained. These photographs were evaluated blinded. The dogs were divided randomly into two groups. The first group was used to establish a model for age determination using linear and logistic regression models considering the documented parameters, which was then validated with the data of the second group. RESULTS: The size of ocular light reflection and age correlated significantly (r = 0.781; p < 0.001; sy,x = 2.45 years [SD of y for given x]). The linear regression model gave the final equation: Estimated age [months] = 13.954 + 33.400 × lens reflection [mm] + 8.406 × dental abrasion [grade] + 8.871 × tartar [grade] with a standard error of estimation of 2.26 years. CONCLUSION AND CLINICAL RELEVANCE: Age determination, even based on three parameters results in a large standard deviation making age estimation in dogs very crude.

Determining the age of cats by pulp cavity/tooth width ratio using dental radiography.

The purpose of this study was to evaluate the effect of age on the ratio of pulp cavity/tooth width (P/T ratio) in healthy cats. The dental radiographs of 32 cats (16 males and 16 females) were generated with a digital dental X-ray unit with the animals under general anesthesia. Standardized measurement of the canine teeth was performed by drawing a line on the radiograph perpendicular to the cemento- enamel junction (CEJ) of the tooth. There was an inversely proportional correlation between chronological age and the P/T ratio. Moreover, a strong Pearson squared correlation (γ(2) = 0.92) was identified by the curved regression model. No significant differences in the P/T ratio based on gender or breed were found. These results suggest that determination of age by P/T ratio could be clinically useful for estimating the chronological age of cats.

Evaluation of the maximum length of deciduous teeth for estimation of the age of infants and young children: proposal of new regression formulas.

The methodology used to identify individuals in forensic anthropology requires a minimum degree of precision and accuracy and should be based on identified and representative samples. Achievement of these objectives in infant skeletons is hampered by the scarcity of appropriate samples. The dental age estimation methods of Liversidge et al. (Am J Phys Anthropol 90: 307-313, 1993) and Deutsch et al. (Growth 49: 207-17, 1985) were applied to the Granada osteological collection of identified infants (Granada, Spain) in order to evaluate its applicability in a Mediterranean population. Significant differences were found between the estimated and real ages in both cases. Based on the measurements obtained in 140 fetuses and infants, new regression formulas were developed to estimate age from the metric study on deciduous teeth. Independent functions are provided for each deciduous maxillary and mandibular tooth in each sex, along with the margin of error (95% confidence interval). These formulas appear to offer one of the best methods available for estimating the age of Mediterranean infants in forensic anthropology settings.

Determining the age of cats by pulp cavity/tooth width ratio using dental radiography

The purpose of this study was to evaluate the effect of age on the ratio of pulp cavity/tooth width (P/T ratio) in healthy cats. The dental radiographs of 32 cats (16 males and 16 females) were generated with a digital dental X-ray unit with the animals under general anesthesia. Standardized measurement of the canine teeth was performed by drawing a line on the radiograph perpendicular to the cementoenamel junction (CEJ) of the tooth. There was an inversely proportional correlation between chronological age and the P/T ratio. Moreover, a strong Pearson squared correlation (gamma2 = 0.92) was identified by the curved regression model. No significant differences in the P/T ratio based on gender or breed were found. These results suggest that determination of age by P/T ratio could be clinically useful for estimating the chronological age of cats.

First European interlaboratory comparison of tetracycline and age determination with red fox teeth following oral rabies vaccination programs.

The first European interlaboratory comparison of tetracycline and age determination with red fox (Vulpes vulpes) tooth samples was organized by the European Union Reference Laboratory for rabies. Performance and procedures implemented by member states were compared. These techniques are widely used to monitor bait uptake in European oral rabies vaccination campaigns. A panel of five red fox half-mandibles comprising one weak positive juvenile sample, two positive adult samples, one negative juvenile sample, and one negative adult sample were sent, along with a technical questionnaire, to 12 laboratories participating on a voluntary basis. The results of only three laboratories (25%) were 100% correct. False-negative results were more frequently seen in weak positive juvenile samples (58%) but were infrequent in positive adult samples (4%), probably due to differences in the ease of reading the two groups of teeth. Four laboratories (44%) had correct results for age determination on all samples. Ages were incorrectly identified in both adult and juvenile samples, with 11 and 17% of discordant results, respectively. Analysis of the technical questionnaires in parallel with test results suggested that all laboratories cutting mandible sections between the canine and first premolar obtained false results. All the laboratories using longitudinal rather than transverse sections and those not using a mounting medium also produced false results. Section thickness appeared to affect the results; no mistakes were found in laboratories using sections <150 µm thick. Factors having a potential impact on the success of laboratories were discussed, and recommendations proposed. Such interlaboratory trials underline the importance of using standardized procedures for biomarker detection in oral rabies vaccination campaigns. Several changes can be made to improve analysis quality and increase the comparability of bait uptake frequencies among member states.

Detection of antibodies in wild ruminants to evaluate exposure to liver trematodes.

Wild ruminants sharing pastures with domestic livestock are at risk of infection by liver trematodes. Detection of antibodies provides a very useful tool to gain more knowledge about the distribution of these parasites. Non-lethal methods are strongly encouraged for the analysis of the risk of infection among wild ruminants. A seroepidemiological survey was conducted to analyze exposure to hepatic trematodes ( Fasciola hepatica and Dicrocoelium dendriticum ) in wild ruminants from southern Spain. Blood samples were collected from 69 bovids (Mouflon + Spanish ibex) and 143 cervids (red deer + fallow deer) from Sierra de Cazorla, Segura and Las Villas Natural Park. The samples were analyzed using the excretory/secretory antigens of each trematode to determine the IgG response. All the animals were examined at necropsy for the presence of flukes, and the species, age, and gender of the animals were recorded. Fasciola hepatica were only observed in cervids (3%; 95% confidence interval [CI]  =  2-8), while D. dendriticum specimens were recorded in 1% (0-8) of bovids and 4% (CI  =  2-9) of the cervids. The IgG-seroprevalence against F. hepatica was significantly higher in the cervids. Statistical differences according to gender were observed. The bovids exhibited the greatest percentages of positive cases to D. dendriticum antigens, and the DdES-seroprevalence was related to age of the animals. When considering all the factors, the FhES-seroprevalence was initially distributed according to the type of ruminant (cervids), gender (male), and age (>2 yr).

Stable isotope series from elephant ivory reveal lifetime histories of a true dietary generalist.

Longitudinal studies have revealed how variation in resource use within consumer populations can impact their dynamics and functional significance in communities. Here, we investigate multi-decadal diet variations within individuals of a keystone megaherbivore species, the African elephant (Loxodonta africana), using serial stable isotope analysis of tusks from the Kruger National Park, South Africa. These records, representing the longest continuous diet histories documented for any extant species, reveal extensive seasonal and annual variations in isotopic--and hence dietary--niches of individuals, but little variation between them. Lack of niche distinction across individuals contrasts several recent studies, which found relatively high levels of individual niche specialization in various taxa. Our result is consistent with theory that individual mammal herbivores are nutritionally constrained to maintain broad diet niches. Individual diet specialization would also be a costly strategy for large-bodied taxa foraging over wide areas in spatio-temporally heterogeneous environments. High levels of within-individual diet variability occurred within and across seasons, and persisted despite an overall increase in inferred C(4) grass consumption through the twentieth century. We suggest that switching between C(3) browsing and C(4) grazing over extended time scales facilitates elephant survival through environmental change, and could even allow recovery of overused resources.

A complete skull of an early cretaceous sauropod and the evolution of advanced titanosaurians.

Advanced titanosaurian sauropods, such as nemegtosaurids and saltasaurids, were diverse and one of the most important groups of herbivores in the terrestrial biotas of the Late Cretaceous. However, little is known about their rise and diversification prior to the Late Cretaceous. Furthermore, the evolution of their highly-modified skull anatomy has been largely hindered by the scarcity of well-preserved cranial remains. A new sauropod dinosaur from the Early Cretaceous of Brazil represents the earliest advanced titanosaurian known to date, demonstrating that the initial diversification of advanced titanosaurians was well under way at least 30 million years before their known radiation in the latest Cretaceous. The new taxon also preserves the most complete skull among titanosaurians, further revealing that their low and elongated diplodocid-like skull morphology appeared much earlier than previously thought.