Distribution of Competition Potential Between Native Ungulates and Free-Roaming Equids on Western Rangelands

Free-roaming equids (i.e., feral horses [Equus caballus] and burros [Equus asinus]) are widely distributed and locally abundant across the rangelands of the western United States. The 1971 Wild Free Roaming Horse and Burro Act (WFRHBA) gave the Bureau of Land Management (BLM) and United States Forest Service (USFS) the legal authority to manage these animals on designated public lands. To fulfill this responsibility, federal agencies established an Appropriate Management Level (AML), defined as the number of horses or burros that can be sustained on a given management unit under prevailing environmental conditions and land uses. Although the WFRHBA specifies that feral equids must be managed in ecological balance with other land uses, including conservation of native wildlife, population control measures such as gathers, contraception, and adoptions have failed to keep pace with intrinsic growth rates. Over 80% of federally managed herds currently exceed prescribed population levels, making the potential for competition between native ungulates and feral equids a growing concern among state wildlife agencies. Mule deer (Odocoileus hemionus), pronghorn (Antilocapra americana), elk (Cervus canadensis), and bighorn sheep (Ovis canadensis) are of ecological and economic value to the states where they occur, and all exhibit some degree of distributional, habitat, or dietary overlap with horses or burros. Notwithstanding the scale of the problem, to date there have been no range-wide assessments of competition potential among native and feral ungulates for space, forage, or water. To address this need, we compiled demographic, jurisdictional, and species occurrence data collected from 2010–2019 by federal and state agencies. We used these data to map the distributions of 4 native ungulate species across federal equid management units (FEMUS) in 10 western states (n = 174). We then made within-state rankings of the 50 units that were ≥2 times over AML and encompassed ≥3 native ungulates. Collectively, FEMUs covered approximately 225,000 km², representing 18% of all BLM and USFS lands in affected states. Each FEMU supported ≥1 native ungulate and 14% contained all 4. The degree of overlap between native and feral species varied by state, ranging from <1% for mule deer in Montana, to 40% for bighorn sheep in Nevada. Oregon had the largest proportion of units that supported all 4 native ungulates (58%), whereas Montana and New Mexico had the fewest equids, but all populations were over target densities. Despite the perception that the problem of equid abundance is limited to the Great Basin states, high intrinsic growth rates and social constraints on management practices suggest all affected states should monitor range conditions and native ungulate demography in areas where forage and water resources are limited and expanding equid populations are a concern. © 2021 The Wildlife Society.     

Human‐horse sensory engagement through horse archery

The Mongol horse stems from ancient stock, similar to the first horses ridden on the Central Asian grassland steppe. Mongol horses subsequently migrated with their human counterparts throughout Eurasia, as far to the east as Japan. During archery festivals in Japan, horses gallop along a narrow runway within a temple complex in the heavily populated city of Kyoto. In Mongolia, with the recent re‐emergence of the ancient practice, horse and rider still gallop across the expansive grassland steppe. The euphoria one feels in riding fast on horseback with the wind against one's face can be symbolised by the concept of khii mor’ in Mongolia, which is connected with the vitality between human and horse in the practice of horse archery. Through sensory ethnography, in combination with multi‐species ethnography, this article explores embodiment between horse and rider in two quite different socio‐ecological contexts.     

Dual character of Toll-like receptor signaling: Pro-tumorigenic effects and anti-tumor functions

As a major class of pattern-recognition receptors, Toll-like receptors (TLRs) play a critical role in defense against invading pathogens. Increasing evidence demonstrates that, in addition to infection, TLRs are involved in other important pathological processes, such as tumorigenesis. Activation of TLRs results in opposing outcomes, pro-tumorigenic effects and anti-tumor functions. TLR signaling can inhibit apoptosis and promote chronic inflammation-induced tumorigenesis. TLR activation in tumor cells and immune cells can induce production of cytokines, increase tumor cell proliferation and apoptosis resistance, promote invasion and metastasis, and inhibit immune cell activity resulting in tumor immune escape. In contrast, the engagement of other TLRs directly induces growth inhibition and apoptosis of tumor cells and triggers activation of immune cells enhancing anti-tumor immune responses. Thus, the interpretation of the precise function of each TLR in tumors is very important for targeting TLRs and using TLR agonists in tumor therapy. We review the role of TLR signaling in tumors and discuss the factors that affect outcomes of TLR activation.     

Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions

The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome‐citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t‐test showed a statistically significant decrease (P < 0.01) of rate constants in equine erythrocytes at 25 °C versus 37 °C using both experimental buffer solutions. Comparing the buffer A with buffer B unpaired Student's t‐test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO₄⁼ influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3. Copyright © 2012 John Wiley & Sons, Ltd.     

Variations in the timing of reinforcement as a training technique for foals (Equus caballus)

Abstract

Horses are used worldwide for a range of activities. Their usefulness and welfare in these pursuits are strongly influenced by their trainability, which may in turn be influenced by learning ability. Handling and riding horses can expose both handler and horse to a considerable risk of injury. This risk can be reduced by employing correct handling procedures that can facilitate learning in horses. As with all training, efficacy is influenced by consistency and timing. To determine the optimum timing of reinforcement, 16 unweaned naïve foals, that had previously undergone minimal human–animal interaction (i.e., not had a headcollar previously applied), of warmblood (WB; n = 6), thoroughbred (TB; n = 5) or warmblood x thoroughbred (WB x TB; n = 6) breeding were randomly assigned to three treatment groups for testing on ten training days at approximately 14-day intervals. Pressure applied to a headcollar via a lead rope was used as the stimulus for each foal to walk forward, and this was repeated until the foal had walked a distance of 8 m. The effects of three different latencies of negative reinforcement were evaluated by releasing the pressure either immediately: as the first foreleg step commenced (Treatment 1); when the second step of the forelegs was completed (Treatment 2) or when the fourth step of the forelegs was completed (Treatment 3). Each foal's rate of learning was measured by the proportion of correct responses relative to the total number of responses performed. Behavioral responses exhibited (rears, strikes, head shakes, falls, sideways movement and hops) and the steps taken over the distance were also recorded.

Initially, the foals undergoing Treatment 1 appeared to learn more quickly than those foals undergoing Treatments 2 and 3, suggesting that Treatment 1 was associated with the greatest compliance and the quickest learning. However, the foals undergoing Treatment 3 ultimately achieved significantly (p < 0.001) more correct responses, suggesting that the longer delay of reinforcement (i.e., the longer duration of aversive stimulus) may enhance learning via the negative reinforcement inherent in lead training in foals. While some conflict behaviors were shown in all treatment groups, most were exhibited on training day 2. This was reflected in the analysis of composite behaviors performed, with training days 1 and 2 being different (p < 0.001) from training day 3, and training days 1–3 being different (p < 0.001) from training days 4–10. These changes indicate that learning occurred in all treatment groups.

The foals used in this study were sired by five different stallions. While the foals sired by stallion 2 (WB) performed significantly (p < 0.001) more correct responses, those foals sired by WB stallions were significantly (p < 0.001) less likely to perform correct responses when compared with those foals of TB or WB x TB breeding. Colts were significantly (p < 0.001) more likely to perform correct responses than were fillies.     

The factor structure of horse personality

Abstract

Two hundred and ten owners or carers completed a specially modified version of the NEO-Personality Inventory-Five Factor Inventory (NEO-PI-FFI, a well established personality questionnaire for humans) for their chosen horse. Three and five-factor Principal Components Analysis (PCA) solutions are reported and compared with published studies on the factor structure of human personality. Participants were asked how confident they were in using each of the different Big Five scales in describing their horse: neuroticism and extraversion were rated with most confidence and openness to experience with least confidence. Taking both our own factors above and the NEO scales, some comparisons between the working roles of the horse were significant; for example, horses used for teaching were less extraverted than show jumpers. Sophistication of working role also related to personality; for example, international horses were less extraverted than novices. We conclude that the study provides some evidence for cross-species similarity in the structure of personality.     

Diversity and abundance of wild host plants of lepidopteran stem borers in two different agroecological zones of Kenya

A survey was carried out between 2004 and 2005 in two ecologically different locations, Kakamega and Muhaka to assess diversity and abundance of wild host plants of lepidopteran stem borers as compared to maize plots during the cropping and non-cropping seasons. Kakamega in Western Kenya is characterized by a Guineo-Congolian rain forest mosaic and Muhaka at the Kenyan coast by a Zanzibar Inhambane mosaic with secondary grassy and woody vegetation. In Kakamega, wild host plants and maize covered 2 and 43% of the surveyed area. No variation in diversity and relative abundance of wild host plants was observed between both the cropping and non-cropping seasons. In Muhaka, the diversity and relative abundance of wild host plant species differed between seasons, with the Shannon Weaver Index (H) of 1.67 and 0.95 for cropping and non-cropping seasons, respectively. Similarly in this location, wild host plant cover varied between cropping (23%) and noncropping (17.9%). During both seasons, this was higher than the maize cover, with 10.7% and 0% for the cropping and non-cropping seasons, respectively. For both localities, the implication of the differences found in the abundance and diversity between the cropping and non-cropping seasons is discussed.     

Unwanted Horse Population in Illinois: Perceptions of Horse Owners,Non-Horse Owners,and Equine Industry Stakeholders

This paper presents the results of an investigation to determine perceptions, awareness, and knowledge of the unwanted horse population in Illinois from the viewpoint of horse owners, non-horse owners, and equine industry stakeholders. A questionnaire included items that pertained to knowledge of current legislation, equine background, current methods of controlling the unwanted horse population, and methods that respondents believe would reduce the unwanted horse population in Illinois. Results indicated that 58% of horse owners viewed horses as companion animals. Respondents perceived financial hardship to be the major reason why horses become unwanted. Current methods of managing unwanted horse populations were found to be ineffective. Reducing the costs of euthanasia and carcass disposal, allowing processing facilities to reopen in Illinois, and increasing the availability of gelding programs emerged as the most effective ways to manage the unwanted horse population. Results of this survey may lead to greater awareness of the unwanted horse population in Illinois. Furthermore, these results may lead to discussions about future legislation in the State designed to support and manage unwanted horses.     

An assessment of feral horse impacts on treeless drainage lines in the Australian Alps

The feral Horse (Equus caballus) is widespread across the Australian Alps. Feral horses degrade alpine and sub‐alpine ecosystems and damage habitat of a range of threatened species. Despite this, there is little published work to document the extent and severity of these impacts. This study investigated impacts of feral horses on treeless drainage lines at 186 sites across the Australian Alps. The study included sites in the Australian Capital Territory, New South Wales and Victoria. We assessed nine variables related to soil and stream stability and vegetation cover, which in turn influence ecosystem function and habitat quality. We found significant differences among horse‐occupied and horse‐free sites for all soil and stream stability variables assessed. For all variables assessed, the average score (and hence, condition) was worse in horse‐occupied areas. The sites in poorest condition were occupied by horses. Impacts from other mammalian herbivores species appeared to be minor. Management intervention is necessary if these impacts of feral horses are to be addressed.     

PMab-219: A monoclonal antibody for the immunohistochemical analysis of horse podoplanin

Monoclonal antibodies (mAbs) against human, mouse, rat, rabbit, dog, cat, and bovine podoplanin (PDPN), a lymphatic endothelial cell marker, have been established in our previous studies. However, mAbs against horse PDPN (horPDPN), which are useful for immunohistochemical analysis, remain to be developed. In the present study, mice were immunized with horPDPN-overexpressing Chinese hamster ovary (CHO)-K1 cells (CHO/horPDPN), and hybridomas producing mAbs against horPDPN were screened using flow cytometry. One of the mAbs, PMab-219 (IgG_2a, kappa), specifically detected CHO/horPDPN cells via flow cytometry and recognized horPDPN protein using Western blotting. Furthermore, PMab-219 strongly stained CHO/horPDPN via immunohistochemistry. These findings suggest that PMab-219 is useful for investigating the function of horPDPN.