Yusuke Eguchi

Multi-factorial investigation of various housing systems for laying hens

1. The advantages and disadvantages of various housing systems for laying hens were compared as a pilot study for work in commercial conditions. 2. At 16 weeks of age, 284 hens were introduced into one of 6 housing systems: two types of conventional cages (small: SC; large: LC), furnished cages (small: SF; large: LF), and non-cage systems (single-tiered aviary: SA; free-range: FR). 3. We evaluated the welfare, egg production, and immune response of the birds in these housing systems, built in the same location, for 18 months. For welfare evaluation, we examined their ethology, physiology, anatomy, production, and physical condition. 4. The non-cage systems, especially FR, had a low score for freedom from pain, injury, and disease, together with other disadvantages, such as pale eggs and increased feed intake for production. However, the score for freedom to express normal behaviour was high and immune response was good in the non-cage systems. 5. In the furnished cages, behaviour was more diverse in SF than in LF, and in SF immune response was comparable with the non-cage systems. 6. For freedom from fear and distress, the non-cage systems had high scores for some indicators such as TI duration, H/L ratio and claw length, while aggressive pecking and feather pecking was worse in the housing systems with large group sizes.

Studies on the visual acuity of dogs using shape discrimination learning.

Two experiments were conducted to determine the visual acuity of sheep. Three ewes were trained to discriminate between a Landolt ring and an ordinary ring of equal size associated with feed. The left and right positions of the 2 targets were shifted according to the Gellermann series. After the ewes were fully trained, their visual acuity was determined by changing the size of the rings or the distance from the target. The ewes were subjected daily to 1 or 2 sessions which consisted of 30 trials each. The criterion of successful discrimination was 2 (Exp. I) or 3 (Exp. II) consecutive sessions with more than 21 correct choices (P<0.05, Chi-square test). The best scores of visual acuity in the 3 ewes were 0.085, 0.095 and 0.19, respectively.

Relation between social order and use of resources in small and large furnished cages for laying hens

1. The objective was to determine the relation between social rank and use of resources in a small furnished cage with sufficient resources per hen (SF) and a commercial large one with less adequate allowance of facilities per hen (LF). 2. Ninety-two cross layers were used. At the age of 16 weeks, the hens were divided at random into two groups. There were 4 furnished cages with 5 birds per cage and 4 large furnished cages with 18 birds per cage. The dominance hierarchy was determined, in which highest, medium and lowest ranking hens in each cage were identified. Behaviour, use of facilities and physical conditions of these hens were measured (one in each rank category in SF, two in each in LF). 3. Dustbathing and litter scratching were more frequent in the high ranking hens than the medium and low ranked hens in LF, while no significant difference was found between them in SF. 4. No significant difference between SF and LF was found in use of nest boxes. However, pre-laying sitting tended to be less frequent in low ranking than medium and high ranking hens in LF (Social order × Cage design). In the nest box most of time was spent in pre-laying sitting by SF hens, LF high and medium ranked hens (average 94·9%). However, LF low ranking hens spent their time escaping (33·1%), pre-laying sitting (27·7%) standing (25·7%) and moving (13·5%) in the nest. 5. In the large furnished cages with less facilities per hen, high ranking hens may be expected to have priority using the dust bath. In contrast, low ranking hens rarely performed nesting behaviour fully, and spend more time using the nest box as a refuge than for laying.

Pecking behaviour of laying hens in single-tiered aviaries with and without outdoor area

1. The objective of the present study was to examine the behaviour of laying hens in single-tiered aviaries with and without outdoor areas with particular reference to the proportion of each behaviour and the ways it changed. 2. In all, 144 interbred cross layers (WL/RIR cross-breed) were used. At the age of 16 weeks, the hens were divided at random into two groups and moved to single-tiered aviary (SA) and free-range systems (FR, SA with in addition an outdoor range area covered with clover) with 18 hens per pen. Behavioural observations were conducted before, during and after access to the range. 3. All behaviours using the beak (eating, grazing, drinking, preening, aggressive pecking, feather pecking, litter pecking, object pecking and mate pecking) were recorded as pecking behaviour. 4. While most of the FR hens spent their time outside foraging, the proportion of hens eating, preening, litter pecking, object pecking, aggressive pecking and feather pecking was higher in SA than in FR hens. 5. The proportion of hens performing pecking behaviour of all types was very similar in SA (61·7 ± 2·0%) and in FR (64·0 ± 0·8%). The proportion of hens performing overall pecking behaviour increased as pre-laying sitting decreased. 6. The proportion of hens feather pecking decreased in FR during access to range and a similar tendency was found for aggressive pecking. 7. In conclusion, the total proportion of hens pecking was almost the same regardless of whether an outdoor area was provided or not, but the incidence of different types of pecking behaviour differed between SA and FR. The risk of feather pecking in FR may be lower when an outdoor grazing area is provided, although further testing on a larger scale would be essential.

Color discrimination in wild boars

Two experiments were carried out in order to clarify the color perception of Japanese wild boarsSus scrofa leucomystax. Two females were trained using an operant conditioning technique to press a switch under a positive stimulus color card in order to receive food as a reward. In Exp. 1, they were tested for discrimination between 3 colors (red, green and blue) and gray. The luminosity of all colors was the same. The wild boars succeeded in discrimination tests between blue and gray, but failed to discriminate red from gray. They also did not discriminate green from gray so clearly as blue from gray. In Exp. 2, the same wild boars were tested to discriminate between 8 kinds of color, which were created by gradating green yellow into red purple except for the 3 colors used in Exp. 1, and gray. They could clearly discriminate blue, purple blue and a part of purple from gray. In these experiments, wild boars were capable of recognizing bluish colors. However, for colors approaching green or yellow, they failed the test by degrees.

Effects of separation of resources on behaviour, physical condition and production of laying hens in furnished cages

1. Based on our previous studies, we designed a medium-sized furnished cage with a dust bath and nest box on both sides of the cage (MFS) and evaluated its usefulness. 2. We used 180 White Leghorn layers. At the age of 17 weeks, the birds were distributed at random into one of the 4 cage designs: conventional cages (CC; 6 cages and 5 hens per cage), small (SF; 6 cages and 5 hens per cage) and medium furnished cages (MFL; 6 cages and 10 hens per cage) with a ‘localised’ dust bath and nest box on one side of the cage, and MFS (6 cages and 10 hens per cage). The total allocation of resources per bird was similar for all furnished cage designs. Behaviour, physical condition and production were measured in each cage. 3. Moving was more frequent in MFS and MFL than in CC and SF. The proportion of hens performing aggressive pecking and severe feather pecking was higher in MFL than CC and SF. These aggressive interactions occurred frequently in the dust bath area in MFL; however, these tendencies were not found in MFS. Egg production and egg mass were lower in MFL than in SF, while the production in MFS was similar to those in CC and SF. MFS hens laid eggs on the cage floor more often than in MFL. 4. In conclusion, these results demonstrate the possible usefulness of MFS. However, some inconsistent results and ways of improving MFS design were also identified.

Oral behaviors of beef steers in pen and pasture environments.

This study observed the behavioral characteristics of 122 steers in eight pens and 1,136 steers at six pastures. Nonhuman animals kept in pens performed less nutritive oral behaviors and more nonnutritive oral behaviors than animals kept at pasture. Although these could not be described as stereotypies, they did represent a replacement of nutritive oral behaviors by nonnutritive oral behaviors, rather than simply an increase in resting time. This could be indicative of a level of oral frustration. At pasture, there was a greater proportion of oral behaviors in animals with low pasture availability as compared to high availability, but this was an increase in nutritive oral behaviors rather than nonnutritive oral behaviors. Factors other than oral frustration—for example, rumen fill—probably drove this increase.

Effects of daily management changes on behavioral patterns of a solitary female African elephant (Loxodonta africana) in a zoo

This study investigated the effects of changes in daily management on behavior of a solitary female elephant in a zoo. The activity budget and space utilization of the subject and the management changes were recorded for 1 year after the conspecific male died. The observation days could be categorized into five clusters (C1-C5) by the characteristic behavioral pattern of each day. C1 had the highest percentage of resting of all clusters, and was observed after the loss of the conspecific and the beginning of use of the indoor exhibition room at night. C2, which had the highest percentage of stereotypy of any cluster, was observed after the beginning of habituation to the indoor exhibition room. Also, when the time schedule of management was changed irregularly, the subject frequently exhibited stereotypic pacing (C2, C4). The subject tended to rest when exhibiting lameness in the left hind limb (C3). In C5, activity reached a high level when she could utilize a familiar place under a stable management schedule. These results indicate that management changes affected the mental stability of an elephant in the early stage of social isolation.

The Effect of Body Size on Shapes and Sizes of Gaps Entered by the Masked Palm Civet (Paguma larvata)

Abstract. To prevent damage to houses, we investigated the particular size and shape of gap that 12 masked palm civets (six subadults and six adults weighing 2.2–3.4 kg) could enter. After the animals were humanely killed, we measured the body parts of civets and compared those of animals that could and could not enter the gaps. The minimum sizes for different shapes of gaps that masked palm civets could enter were the H6 × W20 cm horizontally long rectangle, H20 × W6 cm vertically long rectangle, 8 cm square, and 9 cm diameter circle. There were no significant differences in most body parts sizes between individuals that went through the minimum-size rectangular gaps and individuals that did not. In contrast, differences in the sizes of body parts affected the minimum sizes of square and circular gaps that they entered. The minimum sizes of square and circular gaps that they entered could be predicted by the regression line of their body weight (square: y = 0.98x + 5.75, r2 = 0.76, P < 0.01, circle: y = 0.93x + 6.84, r2 = 0.72, P < 0.01).

Function of Tongue-Playing of Cattle in Association With Other Behavioral and Physiological Characteristics

To study the function of tongue-playing of cattle, this study observed 71 Japanese Black × Holstein steers after feeding in 2 repetitive experiments. The number of steers who performed tongue-playing did not differ among the 3 levels of environmentally enriched pens. Most (90.6%) performances of tongue-playing terminated within 20 min. Frequency of tongue-playing positively correlated with the frequency of resting (r = 0.25, p < .05). Frequency of eating was lower in tongue-playing steers (n = 40) than in non-tongue-playing steers (n = 31; p < .05). Frequencies of self-grooming (p < .05), ruminating (p < .05), and lying ruminating (p < .01) were higher in tongue-playing steers. Plasma dopamine concentration was lower in tongue-playing steers (p < .05). In conclusion, tongue-playing that lasts only for a short time after feeding was induced by behavioral features of steers who rest more and eat hay less at the same time as they perform grooming and ruminating.