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Hoop Housing for Feeder Pigs Offers aWelfare-Friendly Environment

Compared to a NonbeddedConfinement System

Donald C. Lay Jr. and Mark F. HaussmannDepartment of Animal Science

Iowa State University

Mike J. DanielsDepartment of Statistics

Iowa State University

Total confinement systems of swine production offer several benefits and costs interms of animal welfare. Swine raised in total confinement are protected from envi-ronmental extremes and predators; however, welfare concerns stem from observa-tions of stereotypic behavior and lameness of pigs, common in some of these systems.Because total confinement systems are expensive to build and maintain compared toless intensive systems, producers have become interested in an inexpensive alterna-tive: hoop structures (Hoop). Open-ended Quonsets shaped like a half cylinder lyingon its flat side, the Hoop use bedding to keep the pigs dry and allow this bedding tocompost beneath the pigs to keep them warm in winter. This project compared the be-havior and physiology of pigs in a nonbedded confinement system (NBCS) with thosein the Hoop. Two experiments, 1 in the winter and 1 in the summer, assessed the wel-fare of pigs based on the incidence of aberrant behavior, physiologic response to han-dling, incidence of lameness, and the performance of play behavior. Pigs raised in theNBCS performed more aberrant behaviors and less play behavior, had greater plasmacortisol in response to handling (but fewer vocalizations), and a greater incidence ofinjuries than did the pigs raised in the Hoop. Based on these data, pigs in the Hoopwere adjudged to have enhanced welfare as compared to pigs raised in the NBCS. Be-cause the welfare of pigs in the Hoop appears to be greater than the welfare of pigs

JOURNAL OF APPLIED ANIMAL WELFARE SCIENCE, 3(1), 3348Copyright 2000, Lawrence Erlbaum Associates, Inc.

Requests for reprints should be sent to Donald C. Lay Jr., Department of Animal Science, Iowa StateUniversity, 2356 Kildee Hall, Ames, IA 500113150. E-mail: [email protected]

raised in the NBCS, future research should determine which factors are most impor-tant to pigs and then try to incorporate these into production systems.

The trend in swine production during the last 50 years, in North America, has been tomove away from outdoor, open, dirt-lot systems to a totally confined system. Theeconomy of scale offers farmers a significant income on a commodity that provideslittle revenue on an individual pig basis. There are several important differences inthe two production methods in terms of swine welfare. The outdoor system typicallyprovides a greater amount of space per pig and thus allows swine the freedom tomove and choose an environment. Because these pigs have more space, they aremore easily able to escape aggressive encounters with penmates.

The outdoor system, however, offers several disadvantages as well. Pigs maybe exposed to environmental temperature extremes that could negatively affecttheir welfare. In addition, they are more likely to be challenged with disease thatcannot be eradicated from the soil on which they live and that can be carried in bywildlife. The move to a total confinement system has helped to eliminate the wel-fare concerns of thermal stress and disease that challenge outdoor swine; however,it has created concerns of its own. Swine in total confinement are provided withless floor space per pig, and denied access to bedding or a suitable substrate inwhich to root. The challenge of a social stress and thwarting of highly motivatedbehaviors can decrease the welfare of swine.

Hoop structures (Hoop) recently have been introduced as an inexpensive alter-native to todays total confinement system. The Hoop is made of 1.8-m sidewallswith a tarp pulled over tresses to form a Quonset-shaped structure (Figure 1). In

34 LAY, HAUSSMANN, DANIELS

FIGURE 1 A typical hoop structure. This facility has 1.8-m sidewalls with a tarp pulled overmetal tresses to form a Quonset-shaped structure. The flooring is dirt covered with bedding, ex-cept for a concrete slab on which the waterers and feeders rest.

addition to being open aired, with just one large area to house finishing pigs, thissystem uses bedding to manage manure and provide warmth for the swine.

To investigate this new method of swine housing, we compared the behaviorand the response to handling of pigs housed in hoop structures to pigs housed in asystem that used floor spacing typical of that found in todays systems and inwhich no bedding was provided.

PROCEDURES

The following experiments were conducted with the approval of the Iowa StateUniversity Committee on Animal Care (Log number 1940921S).

Experiment 1

The first experiment was conducted during January, February, and March of1998. Pigs weighing 45 kg were assigned to one of two treatments: nonbeddedconfinement system (NBCS) or Hoop. The NBCS was designed as a total con-finement, slatted floor building with 3.96 m 4.11 m pens over a shallow ma-nure pit for liquid manure management. Each of the six pens housed 22 pigsfrom the start of the study until they reached slaughter weight (approximately114 kg), providing approximately 0.74 m2 per pig. Pens were separated fromeach other and an access alley by vertical metal gating. The pens were equippedwith two double-headed nipple waterers and one feeder providing eight feederspaces. Room temperature was maintained at approximately 15.6C.

The 450 pigs in the Hoop treatment were housed in one of three hoops (n =150 per hoop) measuring 9.1 m 18.3 m each, providing approximately 1.1 m2per pig. The hoop structures were bedded with bales of cornstalks such that theentire floor was covered except for a 5.5 m 9.1 m concrete slab on which twofeeders (12 feeder spaces each; Pride of the Farm, Hawkeye Steel Products, Inc.,Houghten, IA) and two waterers (2 water spaces each; Richie, Ritchie Industries,Conrad, IA) were placed. When the bedding started to become wet, new beddingwas added on top of the existing bedding.

Both the confinement unit and the hoops were located on the same farm, sepa-rated by approximately 45 m. Both treatments received the same feed and were man-agedbythesamepersonnel todecrease treatmentdifferencesdue tomanagement.

Observations were conducted on pigs in both treatments at 1, 2, and 3 monthsafter entry into housing treatments. No observations were conducted once pigs be-gan to be pulled from treatments for slaughter. The temperature on the days of ob-servation averaged 4.4C outdoors and 15.6C indoors. Pigs in both treatmentswere observed simultaneously by trained observers. To conduct these observa-

HOOP HOUSING FOR FEEDER PIGS 35

tions, three trained observers worked together to observe one of the hoop pens for15 min. At the same time, two trained observers recorded data on two separatepens for the NBCS pigs (each observer recorded behavior in both treatments, twotimes daily).

When this set of observations was complete, the observers switched to observethe next pen (Hoop treatment) or the next two pens (NBCS treatment). This proce-dure was repeated once more until all pigs in both treatments had been observed.For the next 30 min, no data were recorded, after which the procedure was repeatedonce again. These observations continued for two additional sets such that eachpen of pigs was observed during four 15-min periods at approximately 9:00 a.m.,10:30 a.m., 12:00 p.m., and 1:30 p.m. All occurrences of aberrant behavior such asurine drinking, anal massage, belly nosing, repetitive biting or chewing on aconspecific, and bar biting were recorded. In addition, manipulation was re-corded when a pig bit, chewed, or rooted on another pigs body anywhere besidesthe belly, tail, and ear, as these behaviors were considered separately.

Experiment 2

This experiment was conducted the same as Experiment 1, with only the follow-ing alterations. This experiment was conducted during the 4 months from July toOctober of 1998. Four days of observations were conducted beginning 1 monthafter the pigs were introduced to their treatments. The pigs were weaned directlyinto their treatments and weighed 16.8 kg on entry. All agonistic encounters dur-ing the 15-min observations were recorded. An agonistic encounter was definedas an aggressive interaction with a penmate that had the potential to cause harm,such as biting and pushing. Agonistic encounters were defined as long if theywere more than 5 sec in duration or short if they were 5 sec or less in duration.All occurrences of play behavior were also recorded. Play behavior consisted ofspontaneous scampering, spontaneous running (for Hoop pigs this would occuroften with cornstalk in mouth), and chasing (when partners switched roles). Asin Experiment 1, pigs remained in their treatment until slaughter at approxi-mately 114 kg. The temperature on the days of observation averaged 22.4C out-doors and 25.6C indoors.

At approximately 3 months of age, 10 pigs from each treatment (randomly se-lected from alternate pens) were subjected to a stress test consisting of handling.During this test, one male pig was randomly selected and herded into an alley di-rectly outside of the pen or hoop. The alley, for both treatments, was 0.61 m wide 21.3 m long. On entry into the alley, the pig was herded to one end, designated asthe starting point. The pigs respiration rate was recorded by counting movementof the animals sides. Then the pig was immediately snared around the nose whilea blood sample was collected from the vena cava via the external jugular vein. Assoon as the sample was collected (approximately 20 sec), the pig was herded down


the alley and back until 3 min had elapsed since entry into the alley. Again, respira-tion rate was calculated, a blood sample collected, and the herding procedure re-peated until 5 min had elapsed, at which time the last respiration rate and bloodsample was collected.

To evaluate the extent of leg injury to the pigs at 4.5 months of age, each pigwas visually inspected to record the number and severity of leg abrasions andswollen joints. The location of each injury was recorded in relation to the front orback legs.

Cortisol concentrations were determined on duplicate samples using commer-cially available coated-tube radioimmunoassay kits (Pantex, Santa Monica, CA).Samples were reassayed if the duplicates differed by more than 5.00%. Theintra-assay coefficient of variation was 9.82% and the inter-assay coefficient ofvariation was 11.20%. The recovery rate for cortisol added to porcine plasma was96%. Cross reactivity of the antiserum was as follows: cortisol, 100.0%;prednisolone, 40.0%; 11desoxycortisol, 13.3%; corticosterone, 10.5%; and corti-sone, prednisone, and dexamethosone were less than 3.1% (analysis by Pantex).

Data for all behavioral observations were corrected for the number of animalsper pen by dividing the rate of the behavior by the number of animals in the pen.Bar biting was not included in the analysis because pigs in the NBCS had a greateropportunity to perform this behavior compared to Hoop pigs. However, the meansare still included in the figure for reference by the reader. The general linear modelprocedure of Statistical Analyis System Institute, Inc. (SAS; 1988) was used on thedata that were log-transformed to homogenize the variance. The pen was consid-ered the experimental unit and the main effects in the model were treatment, day,session (observation during the day), and appropriate interactions. Data for plasmacortisol concentrations were also analyzed using the general linear model proce-dure of SAS. The repeated measures model included terms for treatment and time.Day was not a factor as all handling procedures occurred on the same day. The rateof injuries was totaled for each experimental pen and analyzed usingWilcoxonMannWhitney statistics (SAS, 1988).

RESULTS

Experiment 1

Figure 2 illustrates the frequency of bar biting, belly nosing, and manipulationduring all three observation periods. In every instance, NBCS pigs performedmore of these behaviors (p < .01). Ear and tail biting were also performed morefrequently by NBCS pigs (Figure 3; p < .01), although mounting behavior wasperformed more frequently by Hoop pigs (p < .01) and no difference was foundin the frequency of urine drinking (p > .10).


38

FIGURE 2 Behavioral data from Experiment 1. NBCS stands for nonbedded confinementsystem; Hoop stands for hoop structures. Means are expressed as the rate of performance for 10pigs during a 15-min observation. Bar bite was counted every time a pig bit the metal partitionsin the pen. Belly nose was counted for each push that a pig made on the stomach of a penmate.Belly nose was less than one for Hoop pigs. Manipulate was counted as every time a pig rooted,chewed, or bit a conspecific other than on the ear, belly, or tail (as these were counted as separatebehaviors; see Figure 3). Bars in a histogram for a particular behavior with different superscriptsdiffer (p < .01).

FIGURE 3 Behavioral data from Experiment 1. NBCS stands for nonbedded confinement sys-tem; Hoop stands for hoop structures. Means are expressed as the rate of performance for 10 pigsduringa15-minobservation.Earand tailbitewerecountedasevery timeapigbit theearor tailofapenmate. Urine drinking was counted as an event when the pig drank the urine of a penmate.Mounting was counted as an event when a pig would mount a penmate. Both ear bite and tail bitewere less than .1 for the Hoop pigs. Bars in a histogram for a particular behavior with different su-perscripts differ (p < .01).

Production data for these pigs were analyzed by separate researchers(Honeyman et al., 1998). Their data indicate that pigs in both treatments per-formed similarly. Although pigs in confinement were found to have a slightlygreater weight gain (p < .08), average daily gain (p < .03), and feed efficiency (p .10). In addition, no differences were found for percent mortality (p > .10).

Experiment 2

Behavioral observations during Experiment 2 indicate more fighting (p < .001)among pigs housed in the NBCS treatment than among pigs housed in the Hoop(Figure 4). In addition, NBCS pigs mounted penmates and tail bit more fre-quently than did Hoop pigs (Figure 4; p < .001). However, the incidence of playbehavior in NBCS pigs was lower than in Hoop pigs (Figure 4; p < .001). Wealso found that pigs raised in the NBCS belly nosed and manipulated theirpenmates much more frequently than did Hoop-raised pigs (Figure 5; p < .001).


FIGURE 4 Behavioral data from Experiment 2. NBCS stands for nonbedded confinementsystem; Hoop stands for hoop structures. Means are expressed as the rate of performance for 10pigs during a 15-min observation. All behavioral categories are as described for Experiment 1. Inaddition, short and long indicate agonistic encounters. A short encounter was defined as 5 sec orless, and a long encounter was greater than 5 sec. These encounters were characterized by bitingand pushing by an aggressor in which the roles were not exchanged. Play was characterized byspontaneous scampering, spontaneous running, and chasing (when partners switched roles).Bars in a histogram for a particular behavior with different superscripts differ (p < .001).

During the stress test, consisting of handling for 5 min, we found that pigsraised in the Hoop emitted more grunts and squeals than did NBCS pigs (Table 1; p< .02). We found no differences in the frequency of defecations or urinations be-tween treatment animals (p > .10); however, we did find that the NBCS pigs com-pleted more laps (Table 1; p < .02) during the handling than the Hoop pigs. Thus,the NBCS pigs moved 255.6 m during the handling procedure, whereas Hoop pigscovered only 191.7 m during the 5-min handling stress test.

Plasma cortisol concentrations increased in pigs from both treatments duringthe handling stress (Figure 6; p < .001), starting at approximately 50 ng/mL and el-evating to 70 ng/mL. The NBCS pigs had consistently greater plasma cortisol con-centrations than did the Hoop pigs (p < .04). Although the pigs showed differencesin plasma cortisol concentrations, respiration rates averaged 72 breaths per minuteand did not differ between pigs in either treatment (Figure 6; p > .10).

Leg injuries were seen predominantly on pigs housed in NBCS (p < .02), withNBCS pigs having 2.3 .17 injuries per pig versus only .78 .40 for the Hoop pigs.This is dramatic when we consider that the percentage of pigs in each treatment withat least one injury was 71% in NBCS pigs compared to only 34% in the Hoop pigs.Lameness was considered separately from injury and found to be a relatively minorproblem, with only two Hoop pigs and five NBCS pigs being judged lame.


FIGURE 5 Behavioral data from Experiment 2. NBCS stands for nonbedded confinementsystem; Hoop stands for hoop structures. Means are expressed as the rate of performance for 10pigs during a 15-min observation. Behavioral categories are as described for Experiment 1, Fig-ure 2. Bars in a histogram for a particular behavior with different superscripts differ (p < .001).

The production data from these pigs (Larson, Honeyman, & Penner, 1999)again indicated that Hoop pigs performed similarly to NBCS pigs. No differencewas found for weight gain (p > .10), but average daily gain was found to be greaterfor Hoop pigs (p < .001), whereas feed efficiency was found to be greater forNBCS pigs (p < .01). NBCS pigs, however, were found to be more lean (p < .001).No differences were found in percent mortality (p > .10).


TABLE 1Behavior of Pigs During a 5-Minute Stress Test

NBCS Hoop

Behavior (Rate) M SE M SE

Grunt 7.5 1.8a 44.3 8.0bSqueal 3.8 0.9a 10.8 1.9bUrinate 0.1 0.1a 0.4 0.2aDefecate 0.6 0.2a 1.3 0.3aLaps 6.0 0.5a 4.5 0.3b

Note. NBCS = nonbedded confinement system; Hoop = hoop structures; SE =standard error. The test consisted of herding the pigs in a 0.61 m 21.3 m alley. Lapsrefer to the number of times a pig moved from the beginning of the alley to its end andback again. Numbers in rows with different superscripts differ, p < .02.

FIGURE 6 Plasma cortisol concentrations and respiration rate during the 5-min handlingstressor. NBCS stands for nonbedded confinement system; Hoop stands for hoop structures. AtTime 0, respiration rate was recorded, and a blood sample was collected from a pig who had justentered the test alley. The pig was then herded in the alley until 3 min had elapsed, respirationand a blood sample was again collected, and the procedure was repeated again after 5 min hadelapsed. Plasma cortisol concentrations were greater for the NBCS pigs compared to the Hooppigs (p < .04).

DISCUSSION

This study was designed to compare two completely different systems for housingswine: Hoop versus NBCS. Because of the inherent differences in these two sys-tems, it is impossible to attribute the differences in behavior and physiology thatwere found to exist between these two populations of pigs to any one factor. Obviousdifferences between the systems that could have contributed to biological differ-ences between pigs are (a) provision of bedding, temperature, space, group size,complexity of the environment; and (b) the ability of the animal to both choose amicroenvironment and perform natural behaviors.

The criteria used to measure welfare in this study are a combination of thoseproposed by Broom (1986), Fraser (1993), and Moberg (1996). We judge an ani-mal to have good welfare if it is free of pathological conditions, does not performbehaviors excessively in what appears to be an attempt to cope with the environ-ment, and performs what appears to be positively rewarding experiences such asplay and exploration. In addition, we subscribe to the idea of Broom, Mendl, andZanella (1995) that indicating poor welfare does not require a multitude of mea-sures. The absence of even one measure of good welfare can indicate that the ani-mal is experiencing poor welfare.

In Experiment 1, we considered behaviors to be aberrant if they were excessivein performance or inappropriately directed. Excessive performance was character-ized by a pig performing the behavior so frequently that it was abnormal when com-pared to the behavior of the majority of its penmates. For instance, belly nosing wasusually performed by several of the pigs in the pen, at a rate measured in the hun-dreds, whereas the majority of the pigs in the pen did not perform belly nosing. Aber-rant behaviors included manipulating others, ear biting, tail biting, urine drinking,and mounting. Those that we classified as stereotypic were bar biting and belly nos-ing. In every case except twourine drinking and mountingwe found that pigsraised in the NBCS system performed these behaviors at much greater frequencythan did pigs raised in the Hoop. In Experiment 2, similar measures of aberrant be-havior were measured, as well as agonistic and play behaviors. Again, in every case,NBCS pigs performed more aberrant behavior than did Hoop pigs. In addition,NBCS pigs had a greater frequency of agonistic encounters but performed less playbehavior. These findings clearly indicate that the welfare of pigs raised in the Hoopis better than that of pigs raised in the NBCS.

Aberrant or abnormal behaviors have been widely discussed in the literature inrelation to animal welfare. Wood-Gush and Vestergaard (1989) classified behav-iors that appear normal but are performed at a high rate or in an inappropriate con-text as abnormal. These abnormal behaviors are thought to be expressed due to aconflict created by the need to perform a behavior but the inability to do so(Wood-Gush & Vestergaard, 1989). They suggested that it is the inability to per-form appetitive behaviors that causes redirected behaviors to be performed on


penmates. For instance, in many of our production systems animals are providedwith ample food. However, a behavioral pattern consists of appetitive,consummatory, and refractory stages. Provision of food allows the animal to per-form the consumatory and refractory stages but not the appetitive stage, the behav-ior pattern in swine of grazing or rooting.

Thus, if a pig has a need to perform this appetitive stage of behavior but cannot,the need is often expressed as an abnormal behavior, such as excessive rooting on ahard surface floor, biting metal bars, or rooting on its neighbors stomach. Simi-larly, Hughes and Duncan (1988) noted that rooting by pigs is directed at penmatesor inanimate objectsas a vacuum activityin barren environments. They alsonoted that this abnormal behavior ceases when straw is provided, suggesting theappetitive behavior of rooting through forage has not been satisfied in these barrenenvironments and remains as a need to be satisfied.

The performance of stereotypic behavior has typically been associated with en-vironments that are inadequate. Rushen (1984, 1985), however, suggested that ste-reotypic behavior performed by sows housed in stalls or tethers is due to feedingfrustration and the persistence of feeding motivation. Likewise, Dailey andMcGlone (1997) found that sows on pasture, dirt lot, or indoor gestation stall per-formed an equal amount of stereotypic behavior and suggested that these behav-iors may be natural for animals that are provided a limited amount of feed. This islikely to be the important factor in these studies, as sows typically are limit fed andmaintain a high degree of motivation to eat. This situation is different from the pigsin this study, which had unlimited access to feed. Thus, the environment in whichthe NBCS pigs were housed is likely the agent responsible for the elevated expres-sion of stereotypic behavior.

Hughes and Duncan (1988) contended that the expression of stereotypic behav-ior indicates that an ethological need has been frustrated. Further, they argued thata concern for animal welfare is created when an animal is motivated to perform abehavior but is prevented from doing so. Broom and Johnson (1993) concludedthat it is widely accepted that the performance of stereotypic behavior is indicativeof poor welfare. Assessments by Cronin, Wiepkema, and Hofstede (1984) and Ma-son (1991) indicated that stereotypic behaviors are performed by animals pre-vented, due to social isolation and housing in barren environments, fromperforming certain behaviors that may be designated as needs.

The greater rate of abnormal behaviors expressed in NBCS pigs found in thisstudy is similar to results found by others for animals in barren environments(Broom, Mendl, & Zanella, 1995; Van Putten & Dammers, 1976). Beattie,Walker, and Sneddon (1992) compared pigs raised in a barren environmentde-fined as intensive housingwith pigs raised in an enriched environment that pro-vided extra space, peat, and straw. Their study was designed to give the pigscontrol. If they chose, the pigs could root in the peat or straw; otherwise, they couldmove to a different area of the pen. Mirroring the results found in our study, these


authors showed that pigs in the barren environment performed more nosingthesame as our manipulating otherand tail biting and had more agonistic encoun-ters. The greater incidence of agonistic encounters is likely due to the barren envi-ronments. As Mench and van Tienhoven (1986) suggested, some productionsystems may provide a significant challenge to an animals adaptive capabilities,and the barrenness of some may create tension due to the lack of key environmen-tal stimuli that are needed to elicit specific behavioral patterns. This increased ten-sion would likely lower the threshold at which agonistic encounters are initiated.

Many studies on enrichment for swine are confounded, because floor space dif-fers between the enriched environment and the control environment, making it dif-ficult to determine if differences in behavior are more likely due to space or toenrichment. Research, as cited by Beattie, Walker, and Sneddon (1992), found thatenrichment played a much larger role than did additional space. Furthermore, Fra-ser (1975) found that tethered sows performing oral stereotypes reduced the ex-pression of these stereotypes when provided with loose straw.

Play behavior is important to the welfare and adaptability of animals. Fagen(1981) provided an extensive review of play and its characteristics. Among the hy-pothetical benefits cited are increase in strength, increase in physical skill, and nor-mal development of cognitive skills that are necessary for behavioral adaptabilityand versatility. In Experiment 2, we found that Hoop pigs performed more play be-havior than did NBCS pigs. Lawrence (1987) suggested that play is a luxury to beperformed only when other behavioral needs have been met. Therefore, he con-tended that the expression of play behavior is indicative of good welfare.

The high degree of injury seen in the NBCS pigs is a clear indication that theirwelfare is poorer than the Hoop pigs. As Signoret (1983) stated, the decrease inwelfare indicated by the presence of wounds is not ambiguous. Swine in confine-ment systems often are noted to have injuries or lameness (Bckstrm, 1973;Vieuille et al., 1996). The injuries noted in our study typically were enlargedspherical areas around the hock, shoulders, and knees. Often these injuries wereobvious contact points between the confinement flooring and the injured site. Asignificant portion, however, were sites that did not appear to be contact points,such as the lateral aspect of the antebrachium directly above the carpal joint, wherea lump was present that did not appear abraded. These injuries may result from thestrain put on the growing limbs of swine due to the hard surface of the floor.

During the handling stressor, we found that Hoop pigs vocalized more and per-formed fewer laps during handling. This is in contrast to the work of Fraser (1974)who found that, during an open field test, more active pigs were also more vocal.Fraser, however, did not actively herd the animals; he merely allowed them to re-main in a novel environment for 10 min. Possibly, our procedure of keeping the pigmoving during the 5-min handling procedure caused different results from that ofFraser. We hypothesized that pigs that perceived the handling as more stressfulwould grunt and squeal more. We had not considered that the squeals would be


given in response to direct contact with the pig and that this would happen only ifthe pig refused to move away from the handler. Unfortunately, we were not look-ing for this during the trial and thus do not have data on the conditions under whichthe vocalizations were given.

The greater frequency of squeals performed by the Hoop pigs may have oc-curred as the handler had to move these animals more forcefully. The fact thatHoop pigs performed fewer laps and had lower plasma cortisol may indicate thatthey were less stressed by the handler and, therefore, more willing to walk moreslowly in front of the handler and more likely to stop. In contrast, the NBCSpigs would run to the end of the alley to escape the handler. Because the alleywas in front of the pigs home pen for both treatments, pigs frequently wouldstop by their pen in what appeared to be an attempt to escape the handler and re-turn to safety.

Plasma cortisol concentrations are often used as the pillar by which stress ismeasured, as evidenced by the many studies that depend on it for their assessmentof stress (Cronin, Barnett, Hodge, Smith, & McCallum, 1991; Fell & Shutt, 1986;Janssens, Helmond, & Wiegant, 1994). They should not be used, however, as thesole measure of stress or animal welfare (Rushen, 1991). Sustained increases inglucocorticoid concentrations greater than 40%, however, have been suggested toindicate a risk to animal welfare on the basis of detrimental consequences to me-tabolism, immune function, and reproduction (Barnett & Hutson, 1987). Hooppigs had a lower stress response during the handling procedure, as shown by theirplasma cortisol concentrations. Because handling occurred only for a short period,it is likely that the plasma cortisol concentrations decreased after the pigs were re-turned to their home pen. This potential to increase plasma cortisol to concentra-tions greater than 40% baseline, however, provides concern for the welfare ofthese pigs if they are to be exposed to chronic stress.

The handling procedure was designed to be stressful and included snaring thepig and performing a jugular puncture to collect blood. The stressfulness of theprocedure is reflected by cortisol concentrations that are similar to those found byothers in which pigs were stressed (Klemcke, Nienaber, & Hahn, 1989; McGlone,et al., 1993) compared to concentrations found for unstressed pigs (Dantzer,Gonyou, Curtis, & Kelley, 1987; Klemcke et al., 1989).

Resting respiration rates for swine are approximately 40 breaths per min whenlying (Reece, 1993). Respiration rate was not different in our study, even thoughthe NBCS pigs completed more laps. Possibly, respiration rate is not a sensitivemeasure that is able to detect differences brought on by a stressor. Or, perhaps therespiration rate was close to maximumrespiration rates when lying down aregreater than those when standingand a further increase was not possible. Thus,based on plasma cortisol, it appears that the Hoop pigs were less stressed by thehandling procedure than were the NBCS pigs, although the data on vocalizationsmerit more research.


McBride (1984) challenged ethologists to formulate management systems inwhich all of the natural behaviors and activities of livestock are facilitated, into aproductive life, more appropriate for their behavioral repertoires than most mod-ern systems (p. 481). He suggested this approach will help to decrease the chronicwelfare problems associated with animals not adapting to intensive production. Itappears the hoop structures are a move in this direction.

Our study found that Hoop pigs performed fewer abnormal behaviors, hadlower plasma cortical concentrations in response to stress, had a greater rate ofplay behavior, and fewer leg injuries than NBCS pigs. Based on these findings, wejudge the welfare of Hoop pigs to be better than that of NBCS pigs. Because thewelfare of Hoop pigs appears to be better than the welfare of pigs raised in theNBCS, future research should attempt to determine which factors are most impor-tant to pigs and then try to incorporate these into production systems.

ACKNOWLEDGMENTS

This article was supported by the Hatch Act and State of Iowa funds.We thank the Leopold Center for Sustainable Agriculture for financial support

of this project. In addition, we thank Dave Burke, Heather Buchanan, KerryGillooly, Sara Kaiser, Brian Lucas, Rich Olsen, Macenzie Pollitt, and Sara Strandfor assistance in data collection and management.

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