1、 外文翻译 原文 Exploratory Behavior and the Welfare of Intensively Kept Animals Material Source: Journal of Agricultural Ethics, Volume 2, pp. 161-169 Author: D. G. M. Wood-Gush, K. Vestergaard ABSTRACT Exploratory behavior is considered underthe following categories:(1)extrinsic exploration in which the
2、animal seeks information about convention reinforcers such as food, (2) intrinsic exploration which is directed toward stimuli which may have no biological significance, further divided into inspective and inquisitive exploration. In the former the animal inspects a particular object; in the latter,
3、 the animal performs behavior to make a change in its environment, rather than merely responding to a change. Extrinsic exploration is synonymous with the ethological term,appetitive behavior.It is shown that much of the behavior indicative of frustration reported in intensively housed animals occur
4、s when the appetitive component of a drive rather than the consummatory component, is prevented.Consideration of inspective exploration is necessary for good husbandry practice, for fear is an important competing response. Inquisitive exploration has not been widely investigated in infraprimate spec
5、ies, but the authors present several possible examples in thespecies of common agricultural animals.However, they suggest that the propensity to show this type of exploration may vary between closely related species. In environments barren to the extent of stifling exploration, animals may develop a
6、pathy, and its relevance to animal welfare is discussed. Keywords Exploratory behavior, animal welfare, farm animals, zoo animals. Exploratory behavior is a largely neglected area of animal behavior but we feel that it is a major factor to be considered in the welfare of animals. Berlyne (1960) divi
7、ded it into a number of categories:Extrinsic exploratory behavior consists of those responses directed at obtaining information about conventional reinforcers such as food or a nesting site. It is thus synonymous with appetitive behavior and in this article we interchange the terms. Intrinsic explor
8、ation,on the other hand, is defined as exploration directed at stimuli that may have no biological significance; the investigation of a novel object in the animals habitual environment would fall into this category. Berlyne further istin-guished between inspection of a particular object, inspective
9、exploration, and inquisitive in which the animal performs behavior to make a change rather than re-exploration, spond to a change (Birke and Archer 1983). In general it is agreed that exploratory behavior will have a vital function in the life of animals in the wild, allowing them to gain informatio
10、n about their home range or territory that will be vital for survival. The wild boar, for example, does not live in large populations; most animals leave their natal group eventually to form small new groups, very likely inhabiting completely new areas. The male is entirely solitary. Within its home
11、 range a group will have sites for special purposes such as feeding, resting, sleeping, and wallowing (Fr/idrich 1974). To gain such a comprehensive knowledge of their environment the animals will have explored the home range and will each carry a cognitive map of the home range. Interestingly, it w
12、as shown in a study cited by Blasettietal. (1988), in which wild boars were followed using radio telemetry, that the animals on average spent 16% of their time traveling. This ability does not appear to have been lost in domesticated species. A brief study on a small group of domestic pigs released
13、into an area of woodland in southern Sweden showed that during the first few days the pigs ranged widely over sections of the area but later restricted their movements to sections of the enclosure with the required resources, behavior indicative of the formation of a cognitive map and well-developed
14、 exploratory behavior (Wood-Gush et al. 1989). In another study, Grazfeld (1986) has reported on the behavior of the Nez noir sheep or Schwarznasenschaf of Switzerland which also have well separated sites for grazing and resting, also indicating the possession of cognitive maps. Although this breed
15、is very old, dating from at least the fifteenth century and thought to be virtually unchanged, it is unlikely that it is unique among domesticated animals; cattle and sheep living under extensive agricultural conditions would also have to exercise their exploratory capabilities in order to survive.
16、Russell (1983) argued that the division of exploratory behavior will be artificial in most cases, for an animal patrolling its territory will indulge in both extrinsic and intrinsic exploration. However, in the case of animals kept in monotonous farm or laboratory conditions, the division seems impo
17、rtant. Extrinsic exploration is under the control of different causal mechanisms from intrinsic exploration and under mechanisms that may vary temporally; at one time, for example, being controlled by hunger mechanisms and by nesting behavior at another. Nevertheless, despite different causal mechan
18、isms, it is possible that while performing the appetitive component of one drive, the animal through latent learning may be acquiring information useful in relation to other motivational systems. Therefore with respect to animal welfare, we deal with the differ- ent types of extrinsic exploration or
19、 appetitive behavior together, regardless of their controlling mechanisms. On the other hand, it has been suggested (Baxter 1983) that the sow, if provided with a nest comfortable to her udder, will forgo much of her nesting behavior. However, proof of this has not yet come to hand. It has been show
20、n that the sow approaching parturition performs much appetitive behavior (Jensen 1986), seeking a place that is safe and that has a number of other criteria, as would her relative, the wild boar sow. Domestication may have blurred some of the responses, but as Stolba and Wood-Gush (1989) reported, t
21、he behavior of the two subspecies is very similar, if the domesticated sow is given the opportunity to express her behavioral repertoire. The question in rela- tion to the welfare of the intensively kept animal is whether conditions that prohibit the fulfillment or performance of extrinsic explorato
22、ry behavior are detrimental. Before proceeding to discuss this question, it is necessary to define two terms. We often use the term abnormal behavior. Most of these behavior patterns belong to the categories listed as abnormal by Wiepkema et al. (1983). In addition, a behavior pattern which may appe
23、ar normal in execution but which is performed at a significantly high rate or performed out of context is referred to as abnormal. When we say that the animal is frustrated, we mean that it is motivated to perform a particular behavioral sequence but is thwarted because of interference or lack of su
24、itable stimuli to guide its behavior or is in conflict, due to the simultaneous arousal of conflicting motivational systems. The apathy, by which it is meant that the animal ceases to respond to stimuli second term is that would normally elicit a response. The excessive and often stereotyped pacing
25、by hens of some strains in battery cages before oviposition signifies the absence of the stimuli that would normally guide the hens behavior through the stages of seeking a nest site, building a nest, and then sitting until oviposition; the hen is blocked at the early stage of the appetitive compone
26、nt of oviposition (Wood-Gush 1972). In addition, Wood- Gush found that the birds in battery cages which showed high frequencies of pacing in the prelaying period also respond to experimental frustration by pacing.Furthermore, escape responses are frequently performed by these birds while pacing (Woo
27、d-Gush and Gilbert 1969; Sodeikat 1983). There can therefore be little doubt that when hens are unable to fulfill this type of appetitive behavior by finding relevant stimuli for the next phase, the), find their position aversive. In addition, Sodeikat (1983) showed that this appetitive phase of the
28、 prelaying behavior is prolonged in ca ged birds compared to birds on deep litter. Sows also show abnormal behavior when the appetitive component of nest-building is prevented (Baxter 1982). Control sows in Baxters study, given ample straw in a spacious pen, carried straw and built nests. Sows in th
29、e farrowing crates at a corresponding physiological state showed extremely high rates of shifting from lying to standing and vice versa, while the control sows were active, choosing a nest site and constructing a nest. Like the hens of another strain in battery cages described by Wood- Gush (1972),
30、the sow in a farrowing crate then goes into some element of nest-building behavior which is abnormal in some respect, even to the extent of damaging herself (Baxter 1982). Red deer hinds (Arman et al. 1978) and white-tailed deer hinds (Town- send and Bailey 1975) penned in small enclosures also pace
31、 at the perimeter fences in the hours before calving, suggesting that they too are frustrated in the appetitive phase of parturition when kept in such enclosures. In cattle the sucking behavior of the calf may be considered part of the appetitive component of milk ingestion. In a clear-cut study B6e
32、 (1988) showed that calves not allowed to proceed to milk ingestion by sucking performed significantly more abnormal behavior than calves that were able to suck before milk ingestion.Yet another example concerns horses: Behavioral abnormalities are often found in stallions used for semen collection
33、in which they perform the consummatory component without the appetitive component (Sch/ifer 1978). In barren environments, animals may redirect the appetitive components of feeding behavior toward penmates, causing damage and injury, as suggested by Hoffmeyer (1969) with respect to feather pecking a
34、nd cannibalism in pheasants. Like-wise, nibbling of the body parts of penmates by piglets has been ascribed to redirected exploratory behavior (van Putten and Dammers 1976). In many other motivational systems, apart from feeding, the appetitive component is likely to be redirected in this way in bar
35、ren environments. In such cases the link between extrinsic exploration and welfare is obvious. Summarizing these results, it appears that either denying the animal the chance to perform appetitive behavior or denying it the opportunity to carry out meaningful appetitive behavior forces it into a sta
36、te indicative of frustration or aversion. Often deprivation may increase appetitive behavior disproportionally compared with consummatory behavior, because there are often several links in that component, each with its own controlling external stimuli, most of which may be absent. Indeed, we suggest
37、 that frustration is more frequently due to blocking of the appetitive behavior than the blocking of the consummatory component. In a recent and very cogent paper Hughes and Duncan (1988) have produced a motivational model which shows theoretically how the frustration of appetitive behavior can lead
38、 the animal into a cycle of repetitive, stereotyped behavior. However, further study is necessary to discover the relative importance of the two components in any particular case. Inspective exploration is important for consideration in good husbandry; when introducing animals to a new location or a
39、 new feeding system, for example, the operator must realize that fear is an important part or a competing response in inspective exploration (Murphy and Wood-Gush 1978). Inquisitive exploration, on the other hand, presents a different concept. First we must ask what proof there is of its existence i
40、n animals such as the common farm species. Russell (1983) discussed how patrolling of the animals home range will result in novelty seeking and how it will provide the animal with the opportunity for developing mastery of its environment. We may therefore expect to find inquisitive exploration in in
41、fra-primate species. Indeed it has been demonstrated in rodents. (See Russell 1983 for review of pertinent literature.) Evidence from experiments with farm animals is somewhat indirect in that certain findings may be interpreted as evidence of inquisitive exploration, although the experiments were p
42、erformed to test entirely different hypotheses. Duncan and Hughes (1972), for example, trained hens which lived alone in a modified Skinner box with a minimum of external stimulation to peck a disk for food. After the birds had learned this task, food was made freely available without the hens havin
43、g to peck at the disk. However, the hens did not abandon disk-pecking entirely; when both freely available food and food from the operant response were simultaneously available, the birds resorted to pecking at the disk for a part of their food. One interpretation of these findings is that the hens
44、were performing inquisitive exploration. In another case Baldwin and Start (1985) trained young pigs to obtain light by placing their snouts in a slit and thereby break a beam which led to a brief period of light. The animals were found to respond significantly above the control response rate that w
45、as measured when the beam was inactive. It is possible that some of the responses were due to inquisitive exploration. Further evidence of inquisitive exploration comes from a study by Wood-Gush et al. (in prep.) in which it was found that piglets would leave their home pen to explore a new area. In
46、 addition there was evidence that piglets reared in an environment enriched by a floor covering of wood shavings and that contained branches and stones showed less inquisitive exploratory behavior of a novel area accessible from the home pen than those from a barer environment. A similar finding in
47、relation to inspective exploration in growing pigs had been reported by Stolba and Wood-Gush (1980) with regard to inspective exploration. Taken together these experiments suggest that the young pigs in the barer environment were suffering from a deprivation of exploratory behavior. Berlyne (1960) l
48、inked inquisitive exploration with boredom, and the citations above of some possible examples of inquisitive exploration raise the question as to whether boredom can be considered in the case of farm animals. In the wild, when an animals drives have been satisfied, it is unlikely that natural select
49、ion would have led to animals, liable to predation, passing into a neutral state. (We do not count sleep or resting as neutral states, because they have their own appetitive phases and are essential for survival.) It would be more adaptive for the animal to use the extra time positively, and in many cases one might expect that the animal would resort to the appetitive component of the behavior that is the least satisfied. Higher up the phylogenetic scale, animals in such a state may begin to
