Equine welfare encompasses the physical and psychological well-being of horses, focusing on their health, comfort, and overall quality of life. This area of study addresses various aspects, including nutrition, housing, behavior, and management practices, aiming to ensure that horses are kept in environments that meet their physiological and behavioral needs. Research in equine welfare examines factors such as stress indicators, pain assessment, and the impact of human interactions on horse behavior and health. This page compiles peer-reviewed research studies and scholarly articles that explore the assessment, improvement, and implications of welfare practices in equine management.
Schüle E.Because of the growing interest in animal health and welfare in breeding and sport--specially in the horse--the regulation of the German Riding Association (FN) was updated. The result--the LPO 2000--refer more functions to the veterinarian. At first the permanent presence of the vet is necessary, at second he controls the correct, new installed vaccination against influenza-virus. The functions of vet-check, general horse-control and doping are wide up in number and consultation. For this the veterinarian must decree about much experience and good preparation. The organisations of the veterin...
Ahlswede L.Future competition horses may suffer from health impairments due to complex or partial genetic components as well as to management faults in respects to keeping, feeding and health prophylaxis against infectious diseases. This health risks exist during the whole rearing period: from late pregnancy till far beyond weaning. Health impairments reduce trade value and practical use, and interfere with aspects of animal protection. In the field of breeding permission, first in stallions, applied research ist needed. For horse farms a praxis-oriented comprehensive advisory service should be establish...
Collins MN, Friend TH, Jousan FD, Chen SC.Three groups of slaughter-type horses, totaling 30 mares and 29 geldings, were used to determine density effects on displacement (distance moved during a stop), falls, injuries, and orientation using a single-deck, open-topped commercial semi-trailer. Each horse was assigned to one of two treatments: high density (1.28 m(2)/horse with 14 horses) or low density (2.23 m(2)/horse with eight horses). Both treatments occurred sequentially on the same day (treatment order was alternated each trial), using the middle 2.44x7.32 m compartment of a large semi-tractor trailer. The horses were transported...
Whiting TL, Sauder RA.Horses intended for slaughter in Western Canada are frequently transported in double-deck trailers, where headroom may be restricted. Poll and withers height was estimated from type photographs of various horse breeds. The headroom required by Canadian legislation and codes of practice may not be sufficiently restrictive to protect the welfare of sport type horses when transported.
Jeffcott LB, Kohn CW.Following public concern about the weather conditions for the 1996 Olympic Games in Atlanta an international research programme was initiated. The primary objective of this effort was to identify strategies for ensuring welfare of horses competing in the heat. Field observations of horses during the endurance test of 3-day events in Europe, Canada, and the USA characterised the work effort of this form of competition; laboratory treadmill studies assessed limitations to performance of heat and humidity, explored the relationships of thermoregulatory demands to the phases of the competition and...
Linklater WL, Cameron EZ, Minot EO, Stafford KJ.Feral horse, Equus caballus, breeding groups, called bands, usually include one but sometimes up to five stallions. We found that mares were loyal to single-stallion (SS) or multistallion (MS) bands or were social dispersers (maverick mares, Mv). The spacing and social behaviour of mares and stallions in single- and multistallion bands was measured. Indices of mare well-being were also measured including activity budgets (feeding: MS>SS=Mv; resting: MSSS), maternal effort in maintaining contact with foals (MS=Mv>SS), parasite levels in faeces (MS>Mv>SS), body condition (MS=Mv<SS...
McDonnell SM, Freeman DA, Cymbaluk NF, Schott HC, Hinchcliff K, Kyle B.To compare quantitative measures and clinical assessments of behavior as an indication of psychologic well-being of stabled horses provided drinking water continuously or via 1 of 3 intermittent delivery systems. Methods: 22 Quarter Horse (QH) or QH-crossbred mares and 17 Belgian or Belgian-crossbred mares (study 1) and 24 QH or QH-crossbred mares and 18 Belgian or Belgian-crossbred mares (study 2). Methods: Stabled horses were provided water continuously or via 1 of 3 intermittent water delivery systems in 2 study periods during a 2-year period. Continuous 24-hour videotaped samples were used...
Stull CL.Nine trailer loads of horses (n = 306) transported to slaughter facilities with distances ranging 596 to 2,496 km were studied to characterize the type of horses used in commercial markets and the physiological responses and number of injuries due to transportation under summer environmental conditions. Slaughter horse candidates were middle-aged (11.4+/-.4 yr), possessed moderately fleshy body condition, weighed 432+/-3.3 kg, and were of Quarter Horse or Thoroughbred breeding. The mean weight loss during commercial transport was 4%. The percentage of injured horses was greater (P < .05) fo...
Mills DS.Horses constantly modify their behaviour as a result of experience. This involves the creation of an association between events or stimuli. The influence of people on the modification and generation of certain behaviour patterns extends beyond the intentional training of the horse. The impact of any action depends on how it is perceived by the horse, rather than the motive of the handler. Negative and positive reinforcement increase the probability of specific behaviours recurring i.e. strengthen the association between events, whereas punishment reduces the probable recurrence of a behaviour ...
McGreevy PD, Nicol CJ.Crib-biting is a common oral stereotype. Because of perceived deleterious effects on the health and appearance of subjects the prevention of crib-biting is regularly attempted. The resourcefulness of horses in satisfying their motivation to perform this behaviour often frustrates owners' efforts at prevention. This paper reviews the efficacy and observable consequences of attempting to prevent crib-biting by a variety of methods. These include attempts to prevent the grasping of objects, to interfere with air-engulfing and to introduce punishment for grasping and neck-flexion. Other approaches...
Cooper JJ, Mason GJ.Many behaviours in domestic animals, such as the 'stable vices' of horses, are treated because they are considered undesirable for economic or cultural reasons, and not because the activity affects the horse's quality of life. The impact of a behaviour on the human reporter is not a function of its impact on the animal performer, and an understanding of the causes and effects of the particular activity is necessary to assess the costs and benefits of treatment. Where the behaviour is a sign of poor welfare, such as an inadequate environment, treatment can best be achieved by removing these und...
McGreevy PD, Nicol CJ.The results of an experimental study of the motivational consequences of short-term prevention of crib-biting are reported here. Eight test horses wore a cribbing collar for 24 h. This was effective in preventing crib-biting in 6 subjects. Using analysis of co-variance that accounted for baseline differences in crib-biting rate, test horses showed significantly more crib-biting than control horses on the first day after prevention (P < 0.05). There was also a highly significant increase in the crib-biting rate of test horses on the first day after prevention in comparison with their baselin...
Mills DS.The biological diversity of a species gives rise to individual differences in behavioural tendency. Traditionally, this variation has been considered to be of little scientific importance or value, but the description and quantification of the fundamental basis of this variability is relevant to many aspects of equine science. The reliable identification of these features may allow the development of more accurate diagnostic and prognostic indicators for a range of clinical diseases. Biologically based traits also provide a more rational basis for selective management and breeding programmes i...
Tobin T, Harkins JD, Sams RA.Proper veterinary care of horses requires that horses in training have access to modern therapeutic medication. However, the sensitivity of equine drug testing now allows for detection of pharmacologically insignificant concentrations of many therapeutic medications. In 1995, the Association of Racing Commissioners International (ARCI) resolved that members 'address trace level detection so as not to lead to disciplinary action based on pharmacologically insignificant traces of these substances'. The rationale behind this approach is to prevent overly-sensitive testing from inhibiting the prop...
Pick M.After a brief introduction to the most important aspects of the current sport of horse-racing the equipment and tack will be described with respect to the horses wellbeing: bridles, tonguestrap, blinkers, saddle and girth. With reference to incorrect equipment for the rider, the wip and its misuse will be discussed. Problems with saddling and at the starting gate are often indicators of the incorrect application of aids. Then the misuse of the automatic horse trainer, treadmills and swimmingpools will be explained. Finally, the three most important requirements for improving the protection of ...
Preuschoft H, Witte H, Recknagel S, Bär H, Lesch C, Wüthrich M.The functions of the most common head-gears for horses are analysed from a biomechanical point of view. With the exception of the stable halter are all of them designed to enlarge the tensile forces transmitted through the reins or the longe, and to concentrate the enlarged forces on sensitive parts of the horse's head: the nose, or the lips, mandible and tongue. Since the direction, duration and size of these tensile forces are the essential factors to modulate signals for controlling the horse, a device has been developed to measure, or at least roughly quantify these forces. The mechanical ...
Müller C.During the last years, trotting races met with massive criticism, because some of the numerous items of equipment were not to be reconciled with animal protection. In March 1998, the Trotting Association (HVT), as well as the list of authorized equipment. The so-called "positive list" includes harnesses, bridles, bits, auxiliary reins, driving reins, whips and other aids, among other things brushing boots, ear-muffs and head-pole. Especially criticized items are submitted to an assessment according to the present animal protection law. Moreover, possibilities are shown to make positive conditi...
Grandin T, McGee K, Lanier JL.To assess the prevalence of severe welfare problems in horses that arrive at slaughter plants and to identify horses that were unfit for travel. Methods: Prevalence survey. Methods: 1,008 horses. Methods: Horses arriving at 2 slaughter plants were observed. The following were rated severe welfare problems in horses: body condition scores of 1 or 2 (emaciated) of 9; recumbency (down) or the inability to walk; fractured limbs or other foot or limb problems that extremely impaired mobility; severe wounds, such as deep cuts, extensive lacerations, abrasions on the head or back, eye injuries, negle...
Krueger K, Trager L, Farmer K, Byrne R.Tool use has not yet been confirmed in horses, mules or donkeys. As this subject is difficult to research with conventional methods, we used a crowdsourcing approach to gather data. We contacted equid owners and carers and asked them to report and video examples of "unusual" behaviour via a dedicated website. We also searched YouTube and Facebook for videos of equids showing tool use. From 635 reports, including 1014 behaviours, we found 20 cases of tool use, 13 of which were unambiguous in that it was clear that the behaviour was not trained, caused by reduced welfare, incidental or accidenta...
Sambraus HH, Radtke K.Studies were made on 27 horses which were known to weave. They were stallions, mares and geldings between the ages of 3 and 22 years. The horses were individually observed for several days in their habitual surroundings. A period, in which a horse makes pauses of not more than ten minutes, is considered a weaving phase. Shorter pauses subdivide the weaving phase into weaving series. The basic unit of weaving is the weaving displacement, i.e. the head movement between the turning points. The number of daily weaving displacements of the horses examined varied from less than 400 up to almost 18,0...
Jackson K, Kelty E, Tennant M.Equine peripheral caries can cause significant morbidity and can have considerable welfare implications. Recent research suggests that diets with high water soluble carbohydrate (WSC) content are associated with high risk of peripheral caries. Previous work has indicated that the condition may be treatable if the inciting cause is removed and the damaged tooth allowed to erupt out, being replaced by the unaffected tooth previously under the gingival margin. Objective: To see whether the peripheral caries process can be ceased if oaten hay (typically high WSC) is removed from the diet and repla...
Keener MM, Tumlin KI.Equestrian sport has various welfare issues and educational needs. To address these complex interactions, we propose an integrated approach called the Triple-E Model, which focuses on the equine, equestrian, and environmental triad. A literature review of existing models suggests that complexities of these interactions are overlooked, despite the significant impact of equine industries on economics, healthcare, and animal welfare. This paper discusses current models and theories used to evaluate equine-equestrian-environmental interactions and introduces the Triple-E Model to foster multidisci...
du Toit N.Geriatric horses have a high prevalence of dental disease, which is a culmination of age-related dental changes and dental disease throughout the life of the horse that may have long-term consequences. Wear abnormalities, diastemata with periodontal disease, pulpitis and endodontic disease, infundibular caries, and equine odontoclastic tooth resorption and hypercementosis become more prevalent with age. Recognition of age-related dental disease at an early stage can help to treat and possibly preserve teeth for longer. With a natural decrease in masticatory efficiency, it is even more importan...
MacMillan KM, Millican LJ, Burns JJ, McClure JT, Vanderstichel R.The objective of this study was to determine the proportion of horse farms on Prince Edward Island, Canada that comply with the requirements of the (Code). An investigator performed on-farm assessments while administering a questionnaire to owners of 50 horse farms. The percentage of farms in compliance with specific requirements in the Code ranged from 20% to 100% per requirement. The largest areas of non-compliance regarding facilities and housing were the lack of the ability to segregate sick or injured animals and the lack of an emergency action plan. It was determined that 72% of farms w...
Moser M, Keller R, Blaser C, Fürst AE.One of the varied tasks of the Large Animal Rescue Service Switzerland and Liechtenstein (GTRD CH/FL)® is the recovery of animals from manure and cesspools. The aim of the present retrospective study was the evaluation of the rescue protocols of the GTRD CH/FL from such operations and the documentation of a rescue procedure. In the past 25 years, a total of 176 animals have been rescued from manure and cesspools. These included 113 cattle, 51 horses and 12 pigs. All animals could be safely rescued with the animal rescue and transport net (TBTN) or the large animal vertical rescue set (GTVBS)....
Warren LK, Whelen A.The gruelling race schedules maintained by horses competing in chuckwagon racing raises concern for the horses' ability to recover quickly and continue to perform at a high level. The amount of bodyweight lost and the time required for recovery of this weight loss have been used to assess the level of stress imposed on horses competing in various multiple-day events. In this study, bodyweights were obtained from 40 Thoroughbred geldings (mean +/- s.e.; bodyweight 521.5 +/- 4.4 kg) before and after racing during a 5 day chuckwagon race meet. Body condition score (BCS) was determined on the firs...
Wegner W.In 1893 a major component of veterinary practice derived from 4 million horses and from farm animals, whereas thousands of dogs were even slaughtered every year, especially in Saxony and Silesia. Nowadays companion animals figure as an element of ever growing importance for the practitioner. Teaching and research adapted themselves to this altered situation, research funding and professional politics not yet so completely. In former days veterinarians even presided the licensing committees for breeder animals--today the animal breeding act merely mentions them in connection with institutions o...
Christie JL, Hewson CJ, Riley CB, McNiven MA, Dohoo IR, Bate LA.An equine abuse policy was developed as an adjunct to an equine management survey. If at least 3 of 5 categories caused concern, a report to the authorities was indicated. The policy was not used but, in the absence of other guidelines, it might assist veterinarians considering potential abuse cases. Dans une enquête sur la gestion équine, un volet portant sur une politique concernant les mauvais traitements infligés aux chevaux a été développée. Lorsqu’au moins 3 des 5 éléments étudiés semblaient problématiques, un rapport aux autorités compétentes était recommandé. La poli...
McIlwraith CW.The article discusses the key findings and discussions from the fifth Welfare and Safety of the Racehorse Summit. This summit presented several ways in which data collection and analysis can […]
During the last century and today, the Tennessee walking horse has been used primarily for pleasure and show competition. Unique and natural to the breed is a smooth four-beat “running walk” gait. In the 1950s the accentuated or exaggerated running walk, known as the “big lick” became popular at high-level competitions. The combination of exaggerated high-action step in front and long stride behind is still considered desirable in today's horse show competitions, and it is often achieved through soring. Soring is the practice of applying a substance or mechanical device to the lower li...
O'Brien M, Mochel JP, Kersh K, Wang C, Troy J.Pain management is critical to equine welfare with non-steroidal anti-inflammatory drugs (NSAID) commonly used in horses. However, systemic NSAID use is limited by harmful gastrointestinal and renal side effects. Intravenous regional limb perfusion (IVRLP) is a technique used in horses that produces high, local antibiotic concentrations while limiting systemic circulation. NSAID-IVRLP would be a novel method of local pain management while limiting systemic NSAID side effects. To date, NSAID-IVRLP administration has not been reported in horses. This study aimed to identify the pharmacokinetics ...
Nyberg L, Linnavalli T, Hartmann E, Kalland M.Many horse enthusiasts have insufficient knowledge about horse behavior and welfare (BW) and learning and human-horse communication (LC), which poses a risk for both horse welfare and human safety. The main objective of this study was to investigate why riding school pupils participate or do not participate in non-riding education in BW and LC, using Self-determination theory (SDT). SDT posits that the quality of motivation is related to the individual's basic psychological needs. A convenience sample of 568 riding school pupils from Finland and Sweden completed an online questionnaire. The re...
Di Genova C, Sutton G, Paillot R, Temperton N, Pronost S, Scott SD.Infection with equid herpesvirus 1 (EHV-1), a DNA virus of the Herpesviridae family represents a significant welfare issue in horses and a great impact on the equine industry. During EHV-1 infection, entry of the virus into different cell types is complex due to the presence of twelve glycoproteins (GPs) on the viral envelope. To investigate virus entry mechanisms, specific combinations of GPs were pseudotyped onto lentiviral vectors. Pseudotyped virus (PV) particles bearing gB, gD, gH and gL were able to transduce several target cell lines (HEK293T/17, RK13, CHO-K1, FHK-Tcl3, MDCK I & II), de...
Wood MK, Mason RM, Burk SV, Birmingham SSW.The goal of this study was to determine whether oral administration of α-casozepine (Zylkene) supplementation decreases the risk of disease in foals, as measured through salivary cortisol levels, temperature, clinical signs of disease, and body weight before and after weaning. Methods: 20 Thoroughbred foals were observed over 10 weeks, beginning 14 days prior to the time of weaning. Methods: Experimental foals were randomly selected and given α-casozepine daily for 10 weeks, while the controls received a placebo with the same frequency as the experimental group. The average daily height and ...
Ribikauskas V, Kreizaitė J, Morkūnaitė J, Arney DR, Kučinskienė J.Hippotherapy is considered as a beneficial field of activity for Žemaitukas, a Lithuanian native horse breed. The aim of this study is to analyze the suitability of Žemaitukas breed horses for hippotherapy by using a set of tests based on the temperament, behavioral reactions, and zoometric measurements. Results of these tests inform whether the future use of Lithuanian native horses in hippotherapy can ensure their welfare. In total, 32 horses were evaluated. Twenty-nine of the evaluated horses were horses of the Žemaitukas breed that had never been used for hippotherapy, the others were h...
Stowe CJ, White H.An overabundance of wild horses and burros on federal lands can lead to suboptimal welfare when there are insufficient forage and water resources. Placing some of these animals in private homes has been identified as a key part of the solution. A nationwide online survey completed by 2,247 current and former horse owners is used to assess the feasibility of accommodating this strategy. The survey tool addressed basic horse ownership and demographic information, previous experience with wild horses, and hypothetical wild horse adoption scenarios. Results suggest that most respondents are recept...
Vidal Moreno de Vega C, de Meeûs d'Argenteuil C, Boshuizen B, De Mare L, Gansemans Y, Van Nieuwerburgh F, Deforce D, Goethals K, De Spiegelaere W....Mapping-out baseline physiological muscle parameters with their metabolic blueprint across multiple archetype equine breeds, will contribute to better understanding their functionality, even across species. Aims: 1) to map out and compare the baseline fiber type composition, fiber type and mean fiber cross-sectional area (fCSA, mfCSA) and metabolic blueprint of three muscles in 3 different breeds 2) to study possible associations between differences in histomorphological parameters and baseline metabolism. Methods: Muscle biopsies [m. pectoralis (PM), m. vastus lateralis (VL) and m. semitendin...
Pereira-Figueiredo I, Rosa I, Sancho Sanchez C.Horses are often still exposed to stressful or inadequate conditions and difficult relationships with humans, despite growing concerns about animal welfare. In the present study, we investigated the impact of different approaches of short-term handling sessions on young Lusitanian horses raised on a high-breed farm, specifically on their later adaptability to humans and stressful environments. Thirty-one foals (3 months old ± 15 days), from both sexes, were separated into three groups, one submitted to 3 consecutive days of handling sessions (Int-H), another to one handling session each month...
Ruet A, Lemarchand J, Briant C, Arnould C, Lansade L.In stabled horses, several behaviours are considered to be important indicators of the state of welfare at the individual level: stereotypies, aggressive behaviours towards humans and the "withdrawn", alert, sternal, lateral and observation postures. Until now, these behaviours have been extensively studied in relation to different horse management practices. However, little is known about their changes or consistency over time. This study aimed to investigate differences in the expression of these behaviours assessed on 44 stabled horses during an initial 3-month period and then again on the ...
Determination of morphological and biochemical blood indices facilitates assessment of the health and welfare of horses, their nutrient demand, the effects of training already undertaken, and the horses' suitability for exercise. Identification of the season-dependent components and the effects of sex and exercise on changes in frequently referenced haematological and biochemical parameters was the main goal of the current study. Unassigned: The blood morphology of 21 healthy adult Shetland ponies (11 mares and 10 stallions) aged 6.5 ± 1.4 years from the central Pomeranian region in Poland wa...
Hedenborg S, Kronborg M, Sätre A, Radmann A, Torell Palmquist G, Andersson P.To improve horse welfare and ensure a sustainable equestrian future, we need to understand human behavior in relation to the challenges of the sector. The purpose of this paper is to map and analyze how individuals within the equine sector in Sweden and Norway define the environmental challenges they are faced with and how these are related to questions about horse welfare. A mixed-methods parallel design was used. The data consist of survey answers and semi-structured interviews. The survey, responded to by 697 Swedish and Norwegian participants, ensured statistical validity and power through...
Wolframm IA, Heric L, Allen AM.At a time of mounting ecological crises and biodiversity loss, there is an urgent need for nature-based solutions. Equestrian properties cover a considerable proportion of the European rural and peri-urban landscape and provide much potential for integrating ecosystem services, such as the inclusion of small landscape features. The aim of this study was to investigate the presence and quality of landscape features (LF) to help determine how the equine sector can contribute to the agro-ecological transition. Using a citizen science approach, 87 commercial and 420 private yard owners reported th...
Felici M, Cogger N, Nanni Costa L, Riley CB, Padalino B.Studies on equine air transport practices and consequences are scarce. This prospective study aimed to describe horse and air journey details and practices, document how horse behavior and health changed during the air transport phases, quantify the occurrence of welfare issues, and identify possible associations between horse and journey details, air transport practices, and welfare issues. Results: Data were collected from before departure to five days after arrival on 118/597 horses traveling on 32 commercial air journeys on different routes, varying in duration and conditions. Most horses ...
Phannithi T, Laikul A, Pathomsakulwong W, Rungsri P, Apichaimongkonkun T, Watchrarat K, Cherdchutham W.External hoof characteristics, balance, and conformation have been extensively studied in horses; however, mules remain understudied in these aspects. This study evaluated the size, shape, and symmetry of untrimmed and unshod forelimb hooves, compared the symmetry between forelimb hooves and stratified external forelimb hoof measurements based on the body condition score of mules raised in the foothill plains of northern Thailand. The forelimb hooves of 38 mules were photographed and 33 parameters, including angular and linear measurements, were analyzed. A multivariate analysis was used to ex...
Knych HK, Weiner D, McKemie DS, Traynham M, Blea J.Butorphanol is commonly administered, both by the intravenous and intramuscular routes, to racehorses to facilitate handling for diagnostic procedures. As the administration of butorphanol for therapeutic purposes is considered appropriate, in order to avoid inadvertent positive drug tests, a thorough understanding of the pharmacokinetics of this drug is necessary. In the current study, 12, exercised Thoroughbred horses were administered a single intramuscular dose of 0.1 mg/kg butorphanol, and serum and urine samples were collected at various times post drug administration for determination...
Esterl-Byrne LL, Huseman CJ, Haynes C, Kinman LA, Jones TN.The welfare of unwanted horses presents a significant concern for the equine industry. However, there is a lack of research on how unwanted horses are affected by major crises. The drastic changes that resulted from the COVID-19 pandemic presented ample opportunity to investigate how unwanted horses are impacted by challenging circumstances. Study objectives were to evaluate the COVID-19 pandemic's impact on the unwanted horse population and determine the current perceptions of horses in-transition. A 23-question online survey designed using Qualtrics was administered electronically to adults ...
Schoenecker KA, King SRB, Hennig JD, Cole MJ, Scasta JD, Beck JL.There are two species of free-roaming feral equids in North America: horses (Equus caballus) and donkeys or "burros" (E. asinus). Both species were introduced as domestic animals to North America in the early 1500s and currently inhabit rangelands across the western United States, Canada, and all continents except Antarctica. Despite their global distribution, little is known about their fine scale spatial ecology. Contemporary research tools to assess space use include global positioning system (GPS) tracking collars, but older models were problematic due to stiff collar belting causing poor ...
Barton CK, Hector RC, Hendrickson DA, Kawcak CE, Nelson BB, Goodrich LR.To compare 3 perioperative feeding regimens and their effect on anesthetic complications, manure output, and colic proportion in healthy horses. Methods: 45 horses presenting for elective orthopedic procedures were randomly assigned to 1 of 3 groups: not fasted (NF; continuous access to hay perioperatively), fasted muzzled (FM; 10-hour preoperative fast with slow refeeding postoperatively and muzzle placement), or fasted not muzzled (FNM; same as FM without muzzle placement). Anesthetic protocol was standardized. Outcomes compared between groups included anesthesia time, arterial oxygenation, ...
