Fiber quality and fertility in male alpacas in the Cusco region of Peru.

Introduction: High testosterone levels might be associated with coarser fiber in alpacas, affecting fiber quality. In the husbandry systems employed in the Andes, males with higher libido might have an increased frequency of successful matings than males with lower libido. This study aimed to determine some of the factors affecting fiber quality in Peruvian alpacas and to evaluate the association between fiber quality and male mating behavior. Methods: The study population consisted of 189 adult male alpacas at La Raya, Cusco, Peru, at 4,400 m above sea level, belonging to the National University of San Marcos, Lima, and the National University of San Antonio Abad of Cusco. Fiber samples were collected from male alpacas in September 2015; body condition score (BCS) was evaluated. After washing and drying, the fiber samples were analyzed using an Optical Fiber Diameter Analyser 2000; linear regression analysis between predictor variables (location of alpacas, age, BCS, and fiber color) and fiber quality outcomes was conducted. Fertility data were available only for some males belonging to San Marcos University, consisting of hand-written records from the breeding season January to April 2015; individual fertility quotients were calculated for each male. Results: Age was associated with fiber quality, young alpacas having the finest fibers (p < 0.05). An increased BCS was associated with increased fiber length, fiber diameter and spinning fineness, but decreased comfort factor (p < 0.05). White fibers were thinner (p = 0.05) than colored fibers, with lower comfort factor and spinning fineness. A significant association between the fertility quotient and fiber curvature was observed (p = 0.018). Discussion: These results suggest that careful selection of breeding individuals and attention to husbandry could result in improved fiber quality among alpaca herds in Peru. However, it would be advisable to increase the number of males studied, using more reliable methods for evaluating male fertility and pregnancy diagnosis than were available for this study.

Health assessment of nesting loggerhead sea turtles (Caretta caretta) in one of their largest rookeries (central eastern Florida coast, USA).

Reproduction is a physiologically demanding process for sea turtles. Health indicators, including morphometric indices and blood analytes, provide insight into overall health, physiology and organ function for breeding sea turtles as a way to assess population-level effects. The Archie Carr National Wildlife Refuge (ACNWR) on Florida's central eastern coast is critical nesting habitat for loggerhead sea turtles (Caretta caretta), but health variables from this location have not been documented. Objectives of the study were to (1) assess morphometrics and blood analyte data (including haematology, plasma biochemistry, protein electrophoresis, ß-hydroxybutyrate, trace nutrients, vitamins and fatty acid profiles) from loggerheads nesting on or near the beaches of the ACNWR, (2) investigate correlations of body condition index (BCI) with blood analytes and (3) analyse temporal trends in morphometric and blood analyte data throughout the nesting season. Morphometric and/or blood analyte data are reported for 57 nesting loggerheads encountered between 2016 and 2019. Plasma copper and iron positively correlated with BCI. Mass tended to decline across nesting season, whereas BCI did not. Many blood analytes significantly increased or decreased across nesting season, reflecting the catabolic state and haemodynamic variations of nesting turtles. Twenty-three of 34 fatty acids declined across nesting season, which demonstrates the physiological demands of nesting turtles for vitellogenesis and reproductive activities, thus suggesting potential utility of fatty acids for the assessment of foraging status and phases of reproduction. The findings herein are relevant for future spatiotemporal and interspecies comparisons, investigating stressor effects and understanding the physiological demands in nesting sea turtles. This information provides comparative data for individual animals in rescue or managed care settings and for assessment of conservation strategies.

Exploring the body condition of gray whales (Eschrichtius robustus) through adipocyte analysis during unusual mortality events.

The blubber is the characteristic fatty tissue of most marine mammals; it comprises adipocytes, blood vessels, lymphatics, and abundant collagen and elastic fibers. Containing the reserve of excess and accumulated energy from feeding. Previous studies found that the adipocyte area may change according to the amount of accumulated and expended energy during migration, reproduction, lactation and breeding. This cellular characteristic reflects the energetic status of an individual (i.e., the balance between intake and total energy investment), which can be interpreted as reproductive success and general health. In the present study, we measured the adipocyte area of the gray whales wintering in Laguna San Ignacio, Baja California Sur, Mexico, to evaluate body condition. Adipose tissue was sampled from 116 individuals (31 calves, 22 mothers, and 63 solitary individuals) over a study period of 62 days. Each whale was assigned a priori body condition (good, fair, poor). Histological preparations stained with hematoxylin-eosin were microphotographs used to measure the adipocyte area with the software Adiposoft as a plugin to ImageJ. The adipocyte area of the calves was significantly lower than that of the adults and showed an increase during the study period. The three body condition categories found no differences in the adipocyte area. The adipocyte area analysis applied in the present study appears to be a useful tool in assessing body condition in calves, although it appears to be limited to adults. According to the OneHealth paradigm, environmental health is closely related to the health of the gray whale, which in turn is related to public health and the socioeconomic well-being of local communities that use this species as a resource.

The gut microbiota-immune-brain axis in a wild vertebrate: dynamic interactions and health impacts.

The gut microbiota-immune-brain axis is a feedback network which influences diverse physiological processes and plays a pivotal role in overall health and wellbeing. Although research in humans and laboratory mice has shed light into the associations and mechanisms governing this communication network, evidence of such interactions in wild, especially in young animals, is lacking. We therefore investigated these interactions during early development in a population of common buzzards (Buteo buteo) and their effects on individual condition. In a longitudinal study, we used a multi-marker approach to establish potential links between the bacterial and eukaryotic gut microbiota, a panel of immune assays and feather corticosterone measurements as a proxy for long-term stress. Using Bayesian structural equation modeling, we found no support for feedback between gut microbial diversity and immune or stress parameters. However, we did find strong relationships in the feedback network. Immunity was negatively correlated with corticosterone levels, and microbial diversity was positively associated with nestling body condition. Furthermore, corticosterone levels and eukaryotic microbiota diversity decreased with age while immune activity increased. The absence of conclusive support for the microbiota-immune-brain axis in common buzzard nestlings, coupled with the evidence for stress mediated immunosuppression, suggests a dominating role of stress-dominated maturation of the immune system during early development. Confounding factors inherent to wild systems and developing animals might override associations known from adult laboratory model subjects. The positive association between microbial diversity and body condition indicates the potential health benefits of possessing a diverse and stable microbiota.

Damming of streams due to the construction of a highway in the Amazon rainforest favors individual trophic specialization in the fish (Bryconops giacopinii).

In Amazonian streams, damming caused by road construction changes the system's hydrological dynamics and biological communities. We tested whether the degree of specialization in fish (Bryconops giacopinii) individuals is higher in pristine stream environments with intact ecological conditions than in streams dammed due to the construction of a highway in the Amazon rainforest. To achieve this, stomach content data and stable isotopes (δ13C and δ15N) in tissues with varying isotopic incorporation rates (liver, muscle, and caudal fin) were used to assess the variation in consumption of different prey over time. The indices within-individual component (WIC)/total niche width (TNW) and individual specialization were employed to compare the degree of individual specialization between pristine and dammed streams. The condition factor and stomach repletion of sampled individuals were used to infer the intensity of intraspecific competition in the investigated streams. The species B. giacopinii, typically considered a trophic generalist, has been shown to be, in fact, a heterogeneous collection of specialist and generalist individuals. Contrary to our expectations, a higher degree of individual specialization was detected in streams dammed by the highway. In dammed streams, where intraspecific competition was more intense, individuals with narrower niches exhibited poorer body conditions than those with broader niches. This suggests that individuals adopting more restricted diets may have lower fitness, indicating that individual specialization may not necessarily be beneficial for individuals. Our results support the notion that intraspecific competition is an important mechanism underlying individual specialization in natural populations. Our results suggest that environmental characteristics (e.g., resource breadth and predictability) and competition for food resources interact in complex ways to determine the degree of individual specialization in natural populations.

Body condition of stranded Razorbills and Atlantic Puffins in the Western Mediterranean.

Annual mass migrations of seabirds between their breeding and wintering grounds are critical for ensuring their survival and reproductive success. It is essential to comprehend their physical condition in order to identify the causes of death and to facilitate conservation efforts. This study focuses on evaluating the age, body condition index, and metabolites in liver and muscle (triglycerides, glycerol, glycogen, cholesterol, lactate, and glucose) of stranded Razorbills (n = 84) and Atlantic puffins (n = 11). The study was conducted along the Andalusian coast of Spain during the winter season of 2022-2023. The study examined the body condition of stranded individuals and their metabolic state to determine potential factors that may have caused their deaths. The study found that the majority of stranded individuals were juveniles. Both species exhibited low levels of carbohydrate (glucose and glycogen) in their tissues and high levels of lactate in their muscles. These findings could suggest that the individuals had undergone prolonged, strenuous exercise, demanding energy on anaerobic pathways, which may have been associated with migration. The study highlights the significance of adhering to standardized protocols when assessing the body condition of stranded seabirds. Doing so can help to identify causes of death and facilitate conservation efforts. A proposed index for body condition, which incorporates biometric measurements and individual physical condition, provides a comprehensive means of understanding the health of these unique species. This study underscores the importance of further research into the conservation measures and recommendations for protecting seabird populations. It is critical to comprehend the contributing factors of mass mortality incidents to work towards safeguarding these species and preserving their vital migration patterns.

Effects of Supplementing Different Quantities of Moringa stenopetala Leaves on Plasma Metabolite and Acylcarnitine Profile, Body Condition Score and Milk Yield Performance in Zebu (Bos indicus) Cattle.

The formulation of multi-nutrient blocks based on low-cost and locally available browse feed resources can be a valid feeding strategy in Sub-Saharan Africa, where inadequate feed supply, both in quality and quantity, is a major constraint. We evaluated the four different inclusion percentages (M-0%, M-25%, M-35% and M-45%) of Moringa stenopetala leaf powder to multi-nutrient blocks on their change on blood metabolite of dairy cows under practical, ranging conditions. Multi-nutrient blocks with four inclusion rates of M. stenopetala leaves were applied as complementary feed for free ranging dairy cows. The study was performed on 24 free ranging dairy cows reared around Arba Minch town in the Southern Ethiopian Rift Valley. Blood samples were collected from the jugular vein of dairy cows both before and after supplementation. Plasma glucose, beta hydroxy butyrate (BHB), urea, creatinine, triglycerides and nonesterified fatty acids (NEFA) concentration was quantified spectrophotometrically. Dried serum spots were subject to quantitative electrospray tandem mass spectrometry to estimate changes in nutrient metabolism based on selected carnitines. Based on these measurements, the milk yield and body condition score were increased during the period of multi-nutrient block supplementation. During the supplementation period, the cows got higher plasma glucose, triglyceride and urea concentrations and lower concentrations of BHB, NEFA and creatinine. From the metabolite profiles, a more efficient nutrient use could be concluded. Although no clear dose-response relationship was observed, the highest inclusion of the M. stenopetala leaves in the multi-nutrient blocks gave the best performance. This outcome supports the idea of implementing M. stenopetala based multi-nutrient blocks on tropical smallholder farms that are not easily accessible to conventional extension services.

Lessons learned during a 12-year monitoring project with the endangered Magdalena River turtle (Podocnemis lewyana): hunting pressure, habitat degradation, and methodological considerations.

Turtle species in the Family Podocnemididae, including the Colombian endemic and critically endangered Magdalena River Turtle Podocnemis lewyana, characteristically present low recapture rates that preclude estimation of population parameters using maximum likelihood modeling. In our 12-year monitoring project with this species, we evaluated changes in relative abundances, proportions of sex/size classes, and individual body sizes and body conditions in a population in four channels in the middle Magdalena River drainage. We also inspected for associations between trends in changes in these variables and differences in hunting pressure and habitat degradation. To inspect for temporal and spatial demographic dynamics, we estimated variation in relative abundances using the Catch Per Unit Effort index, the total number of turtles captured over an entire 5-day sampling period using ten baited funnel traps. Relative abundances and the proportions of sex/size classes were different between sites and years. We found a significant decline in the proportion of females and juveniles over time, along with evidence that the females still present were smaller in body size. Our results support the hypothesis that hunting eliminates adult females from these sites, perhaps also translating into a reduction in recruitment. The lack of evidence of generalized declines in body condition of all size classes suggests that habitat degradation might contribute less to the population declines in this region. Our results also illustrate that even when recapture rates are low, monitoring turtles via standardized trapping may yield insights into the population's conservation status that other relative abundance indices cannot.

Comparison of manual and automated body condition scoring of commercial dairy cattle.

BACKGROUND: Body condition scoring of dairy cows estimates their body reserves. Automation allows increased data availability and reduced labour costs. The aim of this study was to compare an automated (AUT) body condition score (BCS) system to manual observers on a single commercial dairy farm in south-west England. METHODS: Three practising veterinary surgeons performed body condition scoring of 315 dairy cows using the agriculture and horticulture development board (AHDB) Body Condition Scorecard. AUT BCSs were obtained from two 3D cameras and compared to the BCSs recorded by the three operators. RESULTS: The AUT system only agreed with manual scorers at a BCS of 3. The system failed to detect cows classified as underconditioned (BCS ≤ 2.25) by any of the operators (sensitivity 0%). It also systematically underestimated the BCS of cows classified as overconditioned (BCS ≥ 3.5) by the operators. For overconditioned cows, the sensitivity of the AUT system ranged from 30.7% to 48.8% when compared with the manual operators. The AUT system also had weaker agreement with operators for Jersey cows, with Cohen's weighted kappa values of 0.28 for Jersey animals and 0.40 for Holsteins. LIMITATIONS: This study used a convenience sample of animals on a single farm at a single time point, so the extent to which the findings can be more widely generalised is unclear. CONCLUSIONS: The AUT system failed to detect animals classified as underconditioned by the operators and underestimated the condition of cows classified as overconditioned by the operators. Currently, without improvements to the algorithm, the clinical usefulness of such an AUT system for body condition scoring is limited.

Extreme Body Condition Index Values in Small Mammals.

The body condition index (BCI) values in small mammals are important in understanding their survival and reproduction. The upper values could be related to the Chitty effect (presence of very heavy individuals), while the minimum ones are little known. In this study, we analyzed extremes of BCI in 12 small mammal species, snap-trapped in Lithuania between 1980 and 2023, with respect to species, animal age, sex, and participation in reproduction. The proportion of small mammals with extreme body condition indices was negligible (1.33% with a BCI < 2 and 0.52% with a BCI > 5) when considering the total number of individuals processed (n = 27,073). When compared to the expected proportions, insectivores and herbivores were overrepresented, while granivores and omnivores were underrepresented among underfit animals. The proportions of granivores and insectivores were higher, while those of omnivores and herbivores were lower than expected in overfit animals. In several species, the proportions of age groups in underfit and overfit individuals differed from that expected. The male-female ratio was not expressed, with the exception of Sorex araneus. The highest proportion of overfit and absence of underfit individuals was found in Micromys minutus. The observation that individuals with the highest body mass are not among those with the highest BCI contributes to the interpretation of the Chitty effect. For the first time in mid-latitudes, we report individuals of very high body mass in three shrew species.

Relationship between skin and body condition in three species of baleen whales.

The assessment of free-ranging cetacean health through the study of skin conditions using photographs has gained prominence in recent years. However, little attention has been given to the relationships between cetacean skin conditions, species, and body condition. To explore this relationship among baleen whale species along the northwestern coast of Spain, we employed a non-invasive method involving photograph analysis. In this study, we examined skin conditions (including injuries, epizoites and ectoparasites, pigmentation disorders, skin lesions, and anatomical malformations) and body condition (overall physical contours and form, as an indicator of nutritional status and health) in 3 species of whales (blue, fin, and minke whales). This methodology facilitated the identification of 29 subcategories of distinct skin conditions and an assessment of body condition over a 5 yr period (2017 to 2021). In our study, we present evidence linking hypopigmentation, protruding pieces of tissue, and tattoo-like lesions to 'Poor' body condition in the 3 baleen whale species. Fin whales exhibited a higher susceptibility to mottling (prevalence = 17.7%), while blue whales were more prone to starbursts (prevalence = 90.5%). Additionally, we found a significant relationship between skin condition diversity and individual body condition. Our findings contribute valuable information to the broader understanding of the health status of baleen whales. Further investigations are necessary to delve into the etiology of the documented skin conditions and their potential implications for individual survival. This study serves as a foundation for ongoing research aimed at advancing our comprehension of these findings.

Association between body condition score and abdominal fat assessed by ultrasound in Jersey cows.

BACKGROUND: Body condition score (BCS) is a subjective tool and the deposition of subcutaneous fat differs from the deposition of abdominal fat. OBJECTIVE: The aim of this study was to evaluate by multivariate regression models and ultrasonography the amount of fat accumulated in different areas of the abdominal cavity in Jersey non-pregnant non-lactating cows and its association with their BCS. METHODS: From a commercial farm, 21 non-pregnant non-lactating Jersey cows were selected at random. Cows were placed in a headlock line, and BCS was evaluated (scale 1-5 with a 0.25 unit increment) by the same assessor. Ultrasonographic evaluation was performed using a Sonosite machine in duplicate, considering key anatomical points of the body to predict total abdominal fat (AT), retroperitoneal fat (RT), omental fat (OT) and mesenteric fat (MT). A regression analysis for each abdominal fat depot and the BCS was run using SAS. RESULTS: Models from the lowest to the largest r2 are reported. The r2 for the models were MT r2 = 0.023; RT r2 = 0.1047; OT r2 = 0.323 and AT r2 = 0.369. Correlation between BCS and abdominal fat depots was positive, lower for mesenteric and retroperitoneal fat, but higher for omental and total abdominal fat. Cows were divided on the basis of the median of BCS distribution to high (≥3.5) and low (≤3.25). Those with high BCS had significantly larger amounts of fat in different anatomical areas of abdominal cavity than cows with low BCS. CONCLUSION: BCS has a low-to-moderate association with abdominal fat depots, but a high variability exists within each BCS punctuation, which supports the notion that fat accumulation patterns and metabolic turnover between abdominal and subcutaneous fat differ from each other.

Observed declines in body size have differential effects on survival and recruitment, but no effect on population growth in tropical birds.

Declines in body size can be an advantageous physiological response to warming temperatures, or a result of physiological and nutritional stress. Either way, studies often assume that these climate-induced trait changes have important implications for fitness and demography. We leveraged almost three decades of capture-mark-recapture data of 51 bird species in Panama to examine if body size has changed through time, how sensitive body size is to changes in weather, and if body size impacts population demography. We evaluated two metrics of body size, structural size (wing length), and body condition (residual body mass). Over the study, wing length changed in varying directions for 88% of species (23 decrease, 22 increase), but the effects were weak, and change was only significant for two species. Conversely, body condition declined for 88% of species (45), effects were stronger, and that change was significant for 22% of species (11). This suggests that nutritional stress is likely the cause of changes in body size, not an adaptive response to warming. Precipitation metrics impacted body condition across three of our four feeding guilds, while wing length was only impacted by weather metrics for two guilds. This suggests that body condition is more sensitive to change in weather metrics compared to wing length. Lastly, we found that the impact of changes in body size on survival and recruitment was variable across species, but these relationships were in the opposite direction, ultimately resulting in no change in population growth for all but one species. Thus, while different stages (adult survival and recruitment) of populations may be impacted by body size, populations appear to be buffered from changes. The lack of an effect on population growth rate suggests that populations may be more resilient to changes in body size, with implications for population persistence under expected climate change.

Corticosterone treatment results in fat deposition and body mass maintenance without effects on feeding behaviour or immunity in female lizards (Tropidurus catalanensis).

Throughout life, animals must maintain homeostasis while coping with challenging events. The period after reproduction can be challenging for oviparous females to maintain homeostasis since they direct most of their energy stores to vitellogenesis, possibly increasing the vulnerability to stressors. Changes in glucocorticoids' (GC) secretion promote various behavioural and physiological adjustments daily and to restore balance after facing stressors. However, when GC are elevated for extended periods, which usually occurs in response to chronic exposure to stressors, they can affect feeding behaviour and suppress the immune function. We aim to elucidate the effects of chronic corticosterone (CORT) exposure on feeding behaviour, body condition and immune function in female lizards, Tropidurus catalanensis, in the post-reproductive period. Thirty animals were divided into three groups: 1. Control (no experimental procedure performed); 2. Empty Implant (animals implanted with empty silastic tube); and 3. CORT Implant (animals implanted with silastic tube filled with CORT, with a chronic continuous release for at least a week). CORT plasma levels feeding behaviour, body condition (body index [BI] and fat index [FI]), leukocyte count, and several immune function variables (bacterial killing ability [BKA], hemagglutination titer, phytohemagglutinin [PHA] immune challenge and leukocyte count) were evaluated. After implantation, CORT treated animals maintained stable body mass through the experiment, while Control and Empty Implant groups displayed weight loss. In the CORT treated animals, there was also a positive relation between BI and FI, and higher FI when compared to groups 1 and 2. No effects of CORT were observed on feeding behaviour nor on the immune function.

Performance and metabolic evaluation in primiparous beef cows under grazing at different breeding ages.

We aimed to evaluate the metabolic and performance differences in primiparous Nellore cows, which became pregnant at 14 or 24-mo old. Thirty-eight cows with 202 ± 5 days of gestation were divided into two treatments according to breeding age: 14 or 24-mo. Cows were evaluated for body weight (BW), body condition score (BCS), carcass characteristics, milk yield, calves's performance, and blood characteristics. The animals were managed in eight paddocks under continuous grazing and evaluated from 90 d before parturition until 240 d after calving. We observed an interaction between breeding age and time (P < 0.01) for cow BW. Both breeding age categories experienced BW loss during parturition, with a concurrent decrease in BCS. However, following their first calving, the BW of 24-mo cows remained stable (P > 0.05), whereas 14-mo cows exhibited a gradual recovery in BW after parturition (P < 0.05). Milk yield was greater in 24-mo animals (P < 0.01), but decreased with increasing milking days (p < 0.05) for both groups. The weight gain calves from the heifers bred at 24-mo was greater (P < 0.01), which reflected in greater BW at weaning. The beta-hydroxybutyrate (ß-OHB) concentration was greater before calving and a marked decrease after parturition (P < 0.05). The 24-mo cows had greater blood ß-OHB (P < 0.01) at prepartum and 30 days after calving. Blood progesterone was greater in 24-mo cows (P > 0.05). Primiparous beef cows that conceive at either 14 or 24-months of age exhibit distinct nutritional requirements and metabolic profiles. Notably, cows that conceive at 24-months of age have the advantage of weaning heavier calves and displaying a more consistent reproductive cycle following their first calving than cows that conceive at 14-months.

Effects of a physical exercise programme on bodyweight, body condition score and chest, abdominal and thigh circumferences in dogs.

BACKGROUND: Research on the effects of physical exercise on canine body composition is limited. The aim of this study was to investigate the effects of a physical exercise programme on bodyweight, body condition score (BCS) and chest, abdominal and thigh circumferences in dogs. Twenty-one healthy dogs of different breeds exercised together with their owners during an eight-week programme consisting of jogging and strength exercises. Standardised measurements were performed in triplicates with a measuring tape on standing dogs. Chest circumference was measured at three anatomical locations, abdomen at two and thigh at one. Data on bodyweight, BCS (9-point scale) and circumferences were analysed with mixed model repeated measures analyses to evaluate changes after the programme and effects of target distance. RESULTS: Seven dog owners choose a target distance of 2 km and 14 owners choose 5-10 km. Mean BCS decreased (P = 0.007) after the programme (5.1 ± 0.9 vs. 4.7 ± 0.6) but there was no effect of target distance. Almost all chest and abdominal circumference measurements decreased (P ≤ 0.007) with the 2 km group driving the reduction in chest circumference and the 5-10 km group driving the reduction in abdominal circumference. In contrast, thigh circumference (28.8 ± 0.4 vs. 30.2 ± 0.4) increased (P = 0.007) while bodyweight was maintained. There were positive correlations between BCS and abdominal/chest ratios before and after the programme (Pearson correlation; R square ≤ 0.43, P ≤ 0.0012) but the mean ratio remained constant. CONCLUSIONS: Results indicated a redistribution between total body fat and muscle mass in body composition of normal weight to slightly overweight dogs after the physical exercise programme. The use of bodyweight alone was not a reliable evaluation method to complement the BCS assessment. However, repeated measurements of chest, abdominal and thigh circumference might aid in the assessment of body composition in dogs performing physical exercise. Further research should include a control group and objective evaluations of total body fat and lean mass, in order to investigate the effectiveness of physical exercise as a freestanding method for decreasing BCS and increasing muscle mass in overweight dogs.

Do sexual differences in life strategies make male lizards more susceptible to parasite infection?

Female and male hosts may maximise their fitness by evolving different strategies to compensate for the costs of parasite infections. The resulting sexual dimorphism might be apparent in differential relationships between parasite load and body condition, potentially reflecting differences in energy allocation to anti-parasitic defences. For example, male lacertids with high body condition may produce many offspring while being intensely parasitised. In contrast, female lacertids may show a different outcome of the trade-offs between body condition and immunity, aiming to better protect themselves from the harm of parasites. We predicted that females would have fewer parasites than males and a lower body condition across parasitaemia levels because they would invest resources in parasite defence to mitigate the costs of infection. In contrast, the male strategy to maximise access to females would imply some level of parasite tolerance and, thus, higher parasitaemia. We analysed the relationship between the body condition of lizards and the parasitemias of Karyolysus and Schellackia, two genera of blood parasites with different phylogenetic origins, in 565 females and 899 males belonging to 10 species of the Lacertidae (Squamata). These lizards were sampled over a period of 12 years across 34 sampling sites in southwestern Europe. The results concerning the Karyolysus infections were consistent with the predictions, with males having similar body condition across parasitaemia levels even though they had higher infection intensities than females. On the other hand, females with higher levels of Karyolysus parasitaemia had lower body condition. This is consistent with the prediction that different life strategies of male and female lacertids can explain the infection patterns of Karyolysus. In contrast, the parasitaemia of Schellackia was consistently low in both male and female hosts, with no significant effect on the body condition of lizards. This suggests that lizards of both sexes maintain this parasite below a pathogenic threshold.

Los machos y hembras pueden maximizar su eficacia biológica mediante la evolución diferencial de estrategias que compensen los costes asociados con las infecciones parasitarias. Por ejemplo, los machos con una alta condición corporal pueden producir muchas crías aun estando altamente parasitados. Mientras que es común que las hembras inviertan más energía en protegerse frente a los parásitos, lo que podría comprometer el mantenimiento de su condición corporal. Nuestra hipótesis es que las diferencias sexuales en la asignación de energía pueden quedar de manifiesto al analizar la relación entre la intensidad de infección con la condición corporal. También esperamos que las hembras tengan menos parásitos que los machos y que su condición corporal esté correlacionada negativamente con su carga parasitaria. Por el contrario, esperamos que los machos tengan más parásitos en parte porque su estrategia implicaría cierto nivel de tolerancia si con ello pueden incrementar su inversión reproductiva. Hemos analizado la relación entre la condición corporal y las parasitemias de Schellackia y Karyolysus, dos parásitos sanguíneos, en 565 hembras y 899 machos de 10 especies de la familia Lacertidae (Squamata) durante 12 años en 34 localidades en el suroeste de Europa. El patrón para Karyolysus fue coherente con las predicciones, ya que la condición corporal de los machos no se correlacionó con su parasitemia, a pesar de que estas fueron mayores que en las hembras. Mientras que la relación fue negativa en las hembras. Por lo que el patrón de infección de Karyolysus concuerda con las diferentes estrategias de inversión energética en machos y hembras. Sin embargo, en el caso de Schellackia las parasitemias fueron más bajas en hospedadores de ambos sexos y su parasitemia no se correlacionó con la condición corporal. Este resultado sugiere que Schellackia es mantenido en umbrales subpatogénicos.

Haemosporidian intensity and nestlings' life-history along an urban-to-rural gradient.

Urban areas, i.e. dense housing and reduced green spaces, can significantly impact avian health, through altering land use and increasing biotic and abiotic stress. This study assessed the association of urbanization on haemosporidian infections, vectors, immune response, and body condition in Parus major nestlings, across four classes of urbanization along an urban-to-rural gradient in Vienna, Austria. Contrary to our expectations, vector abundance remained consistent across the gradient, while an increase in leukocyte count is positively associated with total parasite intensity. We found that nestlings in more urbanized areas exhibited higher parasite intensity and altered immune response, as evidenced by variations in the heterophil to lymphocyte ratio and leukocyte counts. Culicidae female vectors were associated with nestlings' total parasites, scaled mass index, and industrial units. Nestlings in highly developed areas had higher infection rates than those in forests, suggesting increased exposure to infections. However, there was no clear relationship between total female vectors and total parasites. The level of urbanization negatively affected nestling body condition, with a decrease in fat deposits from forested to highly urbanized areas. Our findings highlight the complex interplay between urbanization, vector-borne parasite transmission, and host immune response, emphasizing the need for comprehensive urban planning to improve wildlife health and guarantee ecosystem functioning. Understanding how urbanization affects bird immunity and parasite infections is critical for adapting urban landscapes for wildlife health and ecosystem integrity.

Direct and indirect costs of parasitism preceding a population decline of an Arctic ungulate.

Parasites negatively affect the fitness of ungulate hosts directly, and in wild ungulates, these effects may be synzootic with other stressors, such as limited nutritional resources. In the Arctic, muskoxen (Ovibos moschatus) occur in a highly seasonal environment and must rely on finite energetic resources for survival and productivity. We investigated the costs of gastrointestinal nematodes on the body condition and reproductive status of 141 muskoxen, on Banks Island, Canada, when the population was at a peak in numbers and density. Using a Partial Least Squares Path Modelling approach, we found that high adult nematode abundance was associated with lower body condition, and high parasite abundance was associated with female reproduction including the indirect effect through on body condition (n = 87). These findings suggest that individuals prioritize energetic reserves for reproduction over parasite defence. In fall 2003, a severe icing event that restricted access to forage was associated with high overwinter mortality of muskoxen and a population crash. Through direct and indirect costs of parasite infection on body condition and reproduction, the high abundance of parasites may have contributed to the effects of this extreme weather event. Understanding the mechanisms in which parasites impact fitness can help explain the ecological drivers of ungulate populations and predict the interactions between the environment and populations.

A demographic and performance assessment of horses used in draw-based Intercollegiate Horse Shows Association competitions.

Intercollegiate Horse Show Association (IHSA) competitions evaluate riders on equitation and skills when riding randomly drawn horses. This study considered demographic and competition-related variables of horses involved in IHSA competitions, and their correlation to performance through points accumulated. Demographics were recorded for fifty-nine horses in two-day Hunter Seat and Western IHSA shows along with use of artificial riding aids, day of competition, number of rides, and points, to evaluate performance. Data were analyzed using a mixed effect model and correlation coefficients with significance set at P < 0.05 (SAS 9.4). Hunter Seat horses averaged more rides per day than Western (P < 0.0001), but points per ride were not different between disciplines (P = 0.57) or days of shows (P = 0.47). Use of artificial aids did not impact points per ride a horse accumulated (P = 0.63 Hunter Seat, P = 0.41 Western). Age, (r = -0.10, P = 0.60; r = 0.02, P = 0.90), BCS (r = 0.15, P = 0.42; r = 0.17, P = 0.34), height (r = 0.20, P = 0.28; r = 0.15, P = 0.39), and weight (r = 0.23, P = 0.23; r = 0.20, P = 0.25) were weakly correlated with points earned for Hunter Seat and Western horses, respectively. Random draw in IHSA is suggested to be effective for equitation competitions, allowing a fair opportunity for riders, regardless of the horse-related factors evaluated in this study.