Newborn Ungulates Research Articles

A seasonal pulse of ungulate neonates influences space use by carnivores in a multi-predator, multi-prey system.

The behavioral mechanisms by which predators encounter prey are poorly resolved. In particular, the extent to which predators engage in active search for prey versus incidentally encountering them has not been well studied in many systems and particularly not for neonate prey during the birth pulse. Parturition of many large herbivores occurs during a short and predictable temporal window in which young are highly vulnerable to predation. Our study aims to determine how a suite of carnivores responds to the seasonal pulse of newborn ungulates using contemporaneous global positioning system (GPS) locations of four species of predators and two species of prey. We used step‐selection functions to assess whether coyotes, cougars, black bears, and bobcats encountered parturient adult female ungulates more often than expected by chance in a low‐density population of mule deer and a high‐density population of elk. We then assessed whether the carnivore species that encountered parturient prey more often than expected by chance did so by shifting their habitat use toward areas with a high probability of encountering neonates. None of the four carnivore species encountered GPS‐collared parturient mule deer more often than expected by chance. By contrast, we determined that cougar and male bear movements positioned them in the proximity of GPS‐collared parturient elk more often than expected by chance which may provide evidence of searching behavior. Although both male bears and cougars exhibited behavior consistent with active search for neonates, only male bears used elk parturition habitat in a way that dynamically tracked the phenology of the elk birth pulse suggesting that maximizing encounters with juvenile elk was a motivation when selecting resources. Our results suggest that there is high interspecific and intersexual variability in foraging strategies among large mammalian predators and their prey.

Parasitized or non-parasitized, why? A study of factors influencing tick burden in roe deer neonates.

Ixodes ricinus, the most common species of tick in Europe, is known to transmit major pathogens to animals and humans such as Babesia spp. or Borrelia spp. Its abundance and distribution have been steadily increasing in Europe during recent decades, due to global environmental changes. Indeed, as ticks spend most of their life in the environment, their activity and life cycle are highly dependent on environmental conditions and therefore, on climate or habitat changes. Simultaneously, wild ungulates have expanded their range and increased dramatically in abundance worldwide, in particular roe deer (Capreolus capreolus), allowing tick populations to grow and spread. Currently, tick infestation on newborn wild ungulates is poorly documented. However, newborn ungulates are considered more sensitive to tick bites and pathogen transmission because of their immature immune systems. Thus, improving knowledge about the factors influencing tick infestation on newborns is essential to better understand their health risks. This study was conducted at Trois-Fontaines Forest, Champagne-Ardenne, France (1992–2018). Based on a long-term monitoring of roe deer fawns, we used a novel Bayesian model of the infestation of fawns to identify which biotic or abiotic factors were likely to modify the level of infestation by ticks of 965 fawns over time. We show that tick burden increased faster during the first days of life of the fawns and became constant when fawns were five days old and more, which could be explained by the depletion of questing ticks or the turnover of ticks feeding on fawns. Moreover, despite the known positive influence of humidity on tick activity, the tick burdens were weakly related to this parameter. Our results demonstrate that tick infestation was highly variable among years, particularly between 2000–2009. We hypothesize that this results from a modification of habitat caused by Hurricane Lothar.

Short communication: Comparative estimation of colostrum quality by Brix refractometry in bovine, caprine, and ovine colostrum

Newborn ungulates depend on the timely supply of colostrum containing sufficient immunoglobulins to obtain passive immunity against disease. Brix refractometry enables a rapid on-farm estimation of colostrum quality and has been intensively studied in bovines. However, the suitability of Brix refractometers for assessing colostrum quality in goats and ewes has been scarcely evaluated. The present study compared bovine, caprine, and ovine colostrum quality estimation using an optical Brix refractometer. In addition, between-species variations in the relationships between Brix values and colostrum constituents (IgG, fat, protein, and lactose) and the accuracy of Brix refractometry at different cutoff values were evaluated by a receiver operating characteristic curve analysis. We measured the Brix value and contents of IgG, fat, protein, and lactose in 324 colostrum samples (108 cows, 116 does, and 100 ewes). Thresholds for classification of good colostrum quality (as determined by ELISA) were set at 50 mg IgG/mL in cows and 20 mg/mL in does and ewes. Bovine colostrum showed the greatest IgG concentrations compared with caprine and ovine colostrum. Fat and protein content was higher in sheep colostrum compared with the other species, whereas the highest lactose concentrations were detected in goat colostrum. Brix values ranged from 11.4 to 34.6% (22.1 ± 4.2%; mean ± standard deviation), 15.4 to 40.0% (28.5 ± 6.8%), and 8.8 to 39.8% (21.6 ± 5.3%) in bovine, ovine, and caprine colostrum, respectively. In all 3 species, Brix was highly correlated with IgG and protein concentrations (cows, r = 0.83 and 0.98; goats, r = 0.83 and 0.89; sheep, r = 0.75 and 0.87). Optimal cutoff points for greatest accuracy of Brix measurements were 19.3% Brix in cows [with 87.1% sensitivity (Se) and 100% specificity (Sp)], 20.7% Brix in does (with 53.5% Se and 100% Sp), and 26.5% Brix in ewes (with 75% Se and 91.3% Sp). In conclusion, Brix refractometry is an acceptable tool for on-farm estimations of colostrum quality in does and ewes despite distinct between-species variations in colostrum composition.

The Immature Gut Barrier and Its Importance in Establishing Immunity in Newborn Mammals.

The gut is an efficient barrier which protects against the passage of pathogenic microorganisms and potential harmful macromolecules into the body, in addition to its primary function of nutrient digestion and absorption. Contrary to the restricted macromolecular passage in adulthood, enhanced transfer takes place across the intestines during early life, due to the high endocytic capacity of the immature intestinal epithelial cells during the fetal and/or neonatal periods. The timing and extent of this enhanced endocytic capacity is dependent on animal species, with a prominent non-selective intestinal macromolecular transfer in newborn ungulates, e.g., pigs, during the first few days of life, and a selective transfer of mainly immunoglobulin G (IgG), mediated by the FcRn receptor, in suckling rodents, e.g., rats and mice. In primates, maternal IgG is transferred during fetal life via the placenta, and intestinal macromolecular transfer is largely restricted in human neonates. The period of intestinal macromolecular transmission provides passive immune protection through the transfer of IgG antibodies from an immune competent mother; and may even have extra-immune beneficial effects on organ maturation in the offspring. Moreover, intestinal transfer during the fetal/neonatal periods results in increased exposure to microbial and food antigens which are then presented to the underlying immune system, which is both naïve and immature. This likely stimulates the maturation of the immune system and shifts the response toward tolerance induction instead of activation or inflammation, as usually seen in adulthood. Ingestion of mother's milk and the dietary transition to complex food at weaning, as well as the transient changes in the gut microbiota during the neonatal period, are also involved in the resulting immune response. Any disturbances in timing and/or balance of these parallel processes, i.e., intestinal epithelial maturation, luminal microbial colonization and mucosal immune maturation due to, e.g., preterm birth, infection, antibiotic use or nutrient changes during the neonatal period, might affect the establishment of the immune system in the infant. This review will focus on how differing developmental processes in the intestinal epithelium affect the macromolecular passage in different species and the possible impact of such passage on the establishment of immunity during the critical perinatal period in young mammals.

Diagnostics of the manifestation of biological laws in animals

Rearing young farm animals in the early stages of postnatal ontogeny is a critical point. There are many aspects of theoretical and practical research on improving the safety and prevention of diseases of calves, but one of the main ones is a comprehensive knowledge of the morphofunctional and adaptive features of calves during the newborn period. To continue to exist in a modified environment is to maintain vital activity and some aspects of homeostasis that are characteristic of organisms of this species, this level of development of its nervous and hormonal mechanisms. When analyzing the incidence and death of calves, it was found that the transfer of calves from individual cells to General ones and the change of milk feeding to hay and mixed feed provokes the growth of diseases at the age of 10 days and older than one month (70%), and also dies at this age (58%). Morpho-physiological features of newborns are the impenetrability of the placenta of hoofed productive animals to the immunoglobulins of the mothers ’ blood. Nature has created a unique mechanism for receiving immunoglobulins in the body of newborn ungulates. After direct maternal immune protection during pregnancy ceases, nature replaces it with colostrum immune protection. To confirm and derive biological laws, the dynamics of immunoglobulins in the blood and colostrum of cows and pigs before and after childbirth were studied.

Suitability of GPS telemetry for studying the predation of Eurasian lynx on small- and medium-sized prey animals in the Northwestern Swiss Alps

Predator diet composition and kill rates have to be known in order to quantify predation pressure on prey populations. While ground-truthing of GPS location clusters (GLCs) is a reliable method for finding large- and medium-sized prey items, finding the remains of small prey is still considered a major difficulty. In this study, we searched GLCs of Eurasian lynx Lynx lynx in the Northwestern Swiss Alps in order to determine if GLC analysis is a suitable method for detecting kill sites of new-born ungulates and other small prey animals. Juvenile ungulates made up 26% of the prey spectrum and 17% total consumed biomass (TCB), while hares, marmots, and red foxes accounted for 25% of all found prey items (8% TCB). Lynx spent significantly more time in GLCs containing large prey, but no clear transition in GLC duration for distinguishing between large (≥ 10 kg; mean duration = 46.9 h, SD = 30.1 h) and small prey (< 10 kg; mean duration = 26.7 h, SD = 21.1 h) could be defined. We explored the influence of different cut-off values for GLC duration on lynx diet composition. GLCs with a duration of < 9 h had less than 25% detection success, but still contained 13% of all small prey items. We conclude that GLC analysis is a promising tool for exploring predation on new-born ungulates, mesopredators, and other smaller prey animals weighing between 2 and 10 kg. However, substantial field effort is mandatory to sufficiently detect prey remains in short-lasting GLCs.

Re-evaluating neonatal-age models for ungulates: does model choice affect survival estimates?

New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001–2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by >15 days for white-tailed deer, >20 days for mule deer, and >10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly versus daily) for estimating survival.

Dead before detection: addressing the effects of left truncation on survival estimation and ecological inference for neonates

SummaryNeonate survival is a key life history trait, yet remains challenging to measure in wild populations because neonates can be difficult to capture at birth. Estimates of survival from neonates that are opportunistically captured might be inaccurate because some individuals die before sampling, resulting in data that are left truncated. The resulting overestimation of survival rates can further affect ecological inference through biased estimates of covariate effects in survival models, yet is not addressed in most studies of animal survival. Here, we quantify the effects of left truncation on survival estimates and subsequent ecological inference.Vaginal implant transmitters (VITs) enable capture of ungulates at birth, yielding data without left truncation. The effects of left truncation on survival estimation were quantified using age‐dependent survival models for VIT and opportunistically captured neonatal deer. Differences in daily survival rates (DSRs) and cumulative survival probability were calculated for the first 70 days of life. In addition, left truncation was simulated by removing fawns that died during the first 1 or 2 days of life from the VIT‐caught sample, isolating the effect of left truncation.Cumulative probability of survival during the first 70 days of life was overestimated by 7–23% for fawns caught opportunistically compared with those caught by VIT, depending on model design. Differences in DSRs were large at age 1 day, but had converged by age 30 days. Simulated left truncation resulted in overestimates of survival of up to 31%. Model selection and covariate coefficients were strongly affected by left truncation, producing spurious ecological inference, including changes to sign and/or magnitude of inferred effects of all covariates.We recommend (i) every effort be made to capture neonates; (ii) consistent capture methods, using at least in part non‐truncating techniques, be implemented across years and study areas; and (iii) exclusion of left‐truncated data from survival estimates until DSRs converge with those calculated from non‐truncated data. This work emphasizes the importance of accounting for left truncation in survival estimation for any species with strong age‐dependent survival in order to prevent biased conclusions produced by sampling method rather than true ecological effects.

Low risk of marking-induced abandonment in free-ranging white-tailed deer neonates

Abstract Marking-induced abandonment has been suggested as the most common cause of marking-induced mortality of free-ranging, newborn ungulates in North America. However, there has been no direct study of marking-induced abandonment in free-ranging ungulates, and its relevance to neonate survival is inconclusive. We describe our capture, marking, and monitoring of white-tailed deer (Odocoileus virginianus) neonates born to radiocollared dams in north-central Minnesota over 5 springs (1997, 1999–2002), as it relates to marking-induced or natural abandonment. We assumed that all neonates dying within 4 days post-marking were possible occurrences of abandonment. We captured 89 neonates; 6 (7%) died within 4 days (4 to predation, 2 to unknown causes). We found no conclusive evidence of marking-induced abandonment. Handling had no impact on neonate survival, even though nearly 40% of neonates were handled >15 minutes. Time of marking (post-parturition) was similar among survivors and nonsurvivors; 48% of surv...

Relationships between Mother and Infant Red‐necked Wallabies (Macropus rufogriseus banksianus)

AbstractYoung red‐necked wallabies first look out of the pouch at 6 months of age, and may begin to leave it for short periods a month later. Their mothers do not exclude them from the pouch until they are 9 or 10 months old, and in the intervening time they may spend quite long periods abroad, but return to the pouch when alarmed.During their first month after permanently emerging from the pouch, infant wallabies spend much of their time alone in dense vegetation, while their mothers feed and rest elsewhere. Over the subsequent four months to weaning the young spend most, but not all of their time with their mothers; infants use small home ranges and rarely accompany their mothers into open areas. Sons follow their mothers more closely, and spend more time with them, than daughters do. While together, mothers and offspring interact with a low frequency; suckling bouts are rare but quite long. Mothers and young usually flee in different directions if alarmed, and find one another again later.Other species of macropods as small as, or smaller than red‐necked wallabies also display behaviour comparable to the hiding of the newborn young of many species of ungulates, while the larger kangaroos of more open habitats have following young. This trend in the occurrence of hiding and following parallels the distribution of the same traits in ungulates, except that hiding is less strongly and less widely expressed in the macropods. This difference between the two groups is probably due to the marsupial mode of reproduction: young macropods of a developmental stage comparable to newborn ungulates can evade predation by entering the pouch, while the infant ungulates must either hide alone or follow their mothers.

The ultrastructure of neonatal calf intestine and absorption of heterologous proteins.

AbstractThe ultrastructural morphology of the jejunal and ileal cells of newborn calves was similar to the intestinal absorptive cells of other newborn ungulates. Microvilli were well developed, tubules or invaginations in the apical cytoplasm were extensive. Large supranuclear vacuoles were limited to the ileal cells. After injection of ferritin‐IgG or ferritin into ligated intestinal loops, the ferritin particles were found around the microvilli and within the tubular system. After 2‐6 hours ileal vacuoles containing ferritin were found near the basal membrane. In the jejunal cell ferritin was found only in the tubules. No ferritin could be detected in calf sera after injection into the intestinal loops. To establish that heterologous proteins were absorbed, calves were given human serum via stomach tube and their sera subsequently was found to contain circulating levels of human albumin and gamma globulin. Also newborn pigs and suckling rats also were given ferritin; but it could not be detected in their sera. The results of these experiments suggest that while the neonatal intestine is permeable to some het‐erologous proteins, ferritin is not transported across the absorptive cell into the circulation.