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ANIMAL PRODUCTION |
Department of Agriculture, Meiji University, Kanagawa, Japan 214-8571
Abstract
The behavior of stalled females pigs was observed to investigate the relations between behavior and reproductive performance. A commercial farrow-to-finish farm equipped with a computerized recording system with approximately 300 female pig inventories was visited three times to observe three postural behaviors (lying, standing, and sitting) and three stereotypies (vacuum chewing, drinker playing, and bar biting) of stalled females at 15-min intervals for 6 h (25 times including 0 min of one zero-time sampling) after feeding. Relative frequencies (%) of the postural behaviors and the stereotypies for 6 h were expressed as a percentage of a total of 25 time observations. Statistical models for reproductive performance included each behavior, parity, and day of visit. Among 609 pregnant females observed at our three visits, the means in relative frequencies (%) of lying, standing, sitting, vacuum chewing, drinker playing, and bar biting for 6 h were 60.1 ± 0.91, 32.3 ± 0.87, 7.60 ± 0.44, 12.7 ± 0.65, 0.4 ± 0.06, and 0.2 ± 0.50%, respectively. Among 514 farrowed females of the 609 pregnant females, the means of total pigs born, pigs born alive, pigs born dead, birth litter weights, pigs weaned, and adjusted 21-d litter weights were 12.3 ± 0.13, 11.2 ± 0.12, 1.1 ± 0.06, 17.1 ± 0.18 kg, 10.3 ± 0.08, and 68.1 ± 0.40 kg, respectively. Females showing a high relative frequency (
36%) of vacuum chewing during gestation produced fewer (P < 0.05) total pigs born (11.7 ± 0.38 vs. 12.6 ± 0.22) than those showing no vacuum chewing. No relationships were found between vacuum chewing and other performance measurements such as pigs born alive, pigs weaned, and adjusted 21-d litter weights. Neither postural behavior nor the other stereotypies were related to reproductive performance. The farrowing rate was not related to any postural behavior and stereotypy in logistic regression mixed models. This study suggests that a subpopulation of females exists on commercial farms that frequently exhibit vacuum chewing and give birth to fewer total pigs. High frequency of vacuum chewing in those females may be indicative of their suboptimal reproductive performance.
Key Words: Pigs • Stereotypies • Vacuum Chewing
Introduction
Breeding females are housed singly or in groups in current swine production. Stall housing systems for pregnant females have been widely used in Japan. Housed females often show stereotypies, which are defined as behaviors that are relatively invariant, regularly repeated, and without an obvious function (Fraser and Broom, 1990
). Feed restriction causes the development of oral stereotypies in females residing in various housing types (Lawrence and Terlouw, 1993). Among oral stereotypies, vacuum chewing, bar biting, and drinker play are widely recognized (Fraser and Broom, 1990; Vieuille-Thomas et al., 1995).
Stalled females produce greater numbers of pigs born alive than tethered sows (den Hartog, 1993; McGlone et al., 1994), but stalled females show more stereotypic behavior than tethered females (McGlone et al., 1994). Few studies have reported the factors related to female-to-female variation in the behavior of stalled females and the relation between behavior and reproductive performance on commercial farms, but several studies have reported on the welfare of pigs in stall housing systems (Friend et al., 1988; Curtis et al., 1989; Robert et al., 1993). In this study, we describe the behavior of stalled pregnant females on a commercial farm to investigate the relationships of their behavior with parity and gestation periods, and potential associations between their behavior and reproductive performance.
Materials and Methods
Farm
This study was conducted on a commercial farrow-to-finish farm in Eastern Japan that had approximately 300 female pigs and used a computerized recording system (PigCHAMP Inc.; Ames, IA). Approximately 90 % of breeding females on this farm were F1 crossbreds of Large White and Landrace. The Large White and Landrace breeding stocks were originally imported from the United States.
In this study, sows were mated at first estrus after weaning, delayed mating after weaning was not practiced, and AI followed by natural mating were used. Pregnancy was confirmed on d 21 by ultrasonography. Females, including both gilts and sows, were housed in stalls on a partially slatted floor from first mating throughout gestation. Horizontal bars separated the individual stalls sides, but no horizontal bars were in the front of the females. The dimensions of the gestation crates were 213 cm long, 57 cm wide, and 106 cm high. Pregnant females were daily fed 2 kg of a gestation diet of corn and soybean meal in the morning. The calculated composition of the gestation diet was 13.2% CP, 0.9% Ca, 0.8% P, and 3,180 kcal/kg of ME (as-fed basis).
Time Sampling of Behavior and Videotaped Records
The farm was visited in March, August, and November during 2001 to observe the behavior of gestation females. Three trained observers walked quietly along the rows of stalled females and observed three postural behaviors (standing, not standing, and sitting) and three stereotypies (drinker play, vacuum chewing, and bar biting) at 15-min intervals for 6 h by time sampling (Martin and Bateson, 1993) starting from the end of the morning feed distribution between 0730 and 0800. Relative frequencies of the postural behaviors and the stereotypies for 6 h were expressed as a percentage of a total of 25 time observations.
To validate our time sampling, 21 females were videotaped for 24 h to observe only postural behavior at the three visits. The female behavior was recorded at 0.2 frames per second and videotapes were viewed at 2.4 frames per second. For each female, the percentages of postural behavior (%) for 6 h were calculated. The percentages of each behavior recorded by our observers were compared with the videotaped records. The difference between 6-h and 24-h behavior in the 21 females was also analyzed.
Definitions of Behavior and Reproductive Performance Measures
Standing was defined as a posture in which a female was upright with all four feet on the ground, and sitting was a posture in which a female had her rear end on the floor with two front feet on the ground. Lying was a posture in which a female was neither standing nor sitting. Vacuum chewing was defined as oral activities with saliva, but no food in her mouth. Bar biting was a behavior in which a female bit the bars of the stall. Drinker play included drinking water behavior.
An electronic recording file for the computerized production data was collected 5 mo after the last farm visit. The investigated variables were total pigs born, pigs born alive, pigs born dead, birth litter weights, pigs weaned, adjusted 21-d weights, and lactation lengths.
Statistical Analysis
Summary statistics were calculated by using the Univariate procedure in SAS (SAS Inst., Inc., Cary, NC). Parity was categorized into three groups: 0, 1 to 2, or 3. Gestation days (GD) were categorized into three groups: early (1 to 34 d), mid (35 to 80 d), and late (81 d) gestation. A square root transformation was performed on the relative frequencies of sitting, vacuum chewing, bar biting, and drinker play to use as a dependent variable in statistical models because many females did not show these behaviors. The relative frequencies of each behavior were also categorized by no frequency, 10, or 25 percentiles of observed females into two or three groups. Three groups of vacuum-chewing-frequency records (Figure 1) were formed: no vacuum chewing, a medium frequency (4 to 32%), and a high frequency (36%) of vacuum chewing. Three groups of sitting-frequency records were formed: no sitting, a medium frequency (4 to 20%), and a high (24%) frequency of sitting. Two groups of bar biting and drinker play were formed: did or did not. These categorized behavior groups were formed to use as independent variables. All model analyses were performed in the Mixed procedure of SAS. Two-way interactions were evaluated in each model (P < 0.05). The statistical models for each behavior frequency (%) included parity groups and visited days in a 1,000-d calendar. The models for reproductive performance included percentages of each behavior or categorized behavior groups, parity group, and visited day. All statistical models included visited day as a random variable in the Mixed procedure of SAS. Logistic regression analysis was used because farrowing occurrence at the individual female level is a binomial trait (yes or no). Multiple logistic regression analyses in mixed models using the GLIMMIX macro of SAS were used to find an association between each behavior and subsequent farrowing occurrences. The model included each behavior, parity group, and visited day. A paired t-test was used to compare time sampling records with videotaped records.
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Table 1 summarizes the statistics of relative frequency (%) of observed behavior by stalled pregnant females and subsequent reproductive performance. Of 609 observed females, only 20 females (3.3%) showed 5.4 ± 1.02% of 6 h in bar biting, 51 females (8.4%) showed 4.9 ± 0.34% of the 6 h in drinker play, and 395 females (64.9%) showed 19.6 ± 0.82% of the 6 h in vacuum chewing. Figure 1
shows the frequency distribution of vacuum chewing (%) in the 609 females. Subsequent performance measures were extracted from a recording system. The overall farrowing rate was 84.4% with 514 farrowed females of 609 mated females (Table 1). Annual culling and replacement rates on this farm were 46.4 and 56.3%, respectively.
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Gilts had higher percentages of lying than sows, whereas sows had higher percentages of standing, vacuum chewing, and drinker play than gilts (Table 2; P < 0.05). Parity and sitting showed no relationship (Table 2).
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81-d group showed higher percentages of lying than those in the GD 35-to-80-d group and had lower frequencies for standing than those in other GD groups (P < 0.05). Females in the GD 35-to-80-d and 81-d groups showed higher percentages of sitting than those in the GD 1-to-34-d group (P < 0.05; Table 3). Females in the GD 35-to-80-d group had higher percentages of vacuum chewing than those in the GD 1-to-34-d group and had higher percentages of bar biting than those in the GD 81-d group (P < 0.05; Table 3).
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36%) of vacuum chewing produced fewer total pigs born (11.5 ± 0.36 vs. 12.5 ± 0.25) than those with no vacuum chewing (Table 4). However, no association was found between the vacuum chewing groups and pigs born alive (P = 0.097) and dead pigs (P = 0.131). No other performance measures, such as previous lactation lengths, birth litter weights, and adjusted 21-d weights were associated with the vacuum chewing groups. No other stereotypies and postural behaviors were associated with any measures in reproductive performance. Finally, the farrowing rate was not related to any postural behavior and stereotypies in logistic regression analyses. The parity group was associated with all reproductive performance measurements (P < 0.05). No two-way interactions between each behavior and parity on any reproductive performance were found.
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). Females showed higher percentages of lying and shorter standing in the 24-h videotaped records than those in the 6-h time-sampling records (P < 0.05).
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Based on their practices, breeding stocks, and reproductive performance measures, such as farrowing rate, pigs born alive, and lactation length, the farm of this study is an average commercial farm in Japan. Using this typical commercial farm, our results indicate that females showing frequent vacuum chewing may produce fewer numbers of total pigs born than those with no vacuum chewing. Females in stall housing systems produce more piglets and show more active behaviors than tethered females (McGlone et al., 1994). The results of this study suggest that a subpopulation of females frequently showing vacuum chewing with fewer total pigs born exists on commercial farms. Our data suggest that approximately 10% of stalled females frequently (>36% of the time) show vacuum chewing.
Fewer total pigs born suggest reduced embryo survival in early pregnancy (Dial et al., 1992) or lower ovulation/fertilization rates. Our results showing few total pigs born may indicate increased embryo mortality or decreased ovulation/fertilization rates in females susceptible to stressors. For example, high ambient temperature adversely affects embryonic survival after breeding (Edwards et al., 1968). Like high temperature, exposure to the stressors of feed restriction and confinement during early gestation may affect low embryo survival (Friend et al., 1988) in some females, although we did not measure physiological stress indicators, such as glucocorticoids (Zanella et al., 1998), in stalled females.
Our study suggests that stalled pregnant females on commercial farms spend approximately 60% of the time for lying, approximately 30% of the time for standing, and the remaining time for sitting during the 6 h after a mealtime.
The oral stereotypies of vacuum chewing (12.7%), bar biting (0.2%), and drinker play (0.4%) were recognized in our study. Our observations may be consistent with previous studies that showed 9.58% vacuum chewing observed at 10-min intervals for 24 h (den Hartog, 1993), and 17.5% oral and nasal behavior using videotaped records (McGlone et al., 1994). Our results for bar biting agree with the study by den Hartog (1993) that showed 0.2% bar biting by stalled sows, but the stalls on our commercial farm had no horizontal bars in the front of females.
Our study confirmed that sows spend less time lying than gilts, and they had more time standing, vacuum chewing, and drinker play than gilts. Our results are consistent with previous studies that showed a higher frequency of standing and stereotypies is related to increased parity in tethered sows (Cariolet and Dantzer, 1984; Rushen, 1985; McGlone et al., 1994), and probably increased time in confinement. Results of this and previous studies suggest that experienced sows altered their behavior in confinement housing.
Our results show that females in mid-gestation had more time for sitting and vacuum chewing than those in early gestation, but females in late gestation spent more time lying than those in mid-gestation. Late-pregnancy females logically tend to lie for a longer time than early-gestation females because of the increased weights of their fetuses. Our results were consistent with a study that showed sows sit longer at 63 d of gestation than those at 14 d of gestation (Jensen et al., 1995).
The time to change from a standing to a lying posture is negatively correlated with stall length relative to female length (Anil et al., 2002). Although we did not measure the intervals from one posture to another posture, females in late gestation and old-parity sows may be more reluctant to move than females in early gestation and young gilts because of their body size. The physical space requirement of the females may also have to be reconsidered (Curtis et al., 1989).
No differences in the three postural behaviors between time sampling and videotaped records indicate that our time sampling was accurate and can be a rather inexpensive way to conduct some audits for welfare assurance programs on commercial farms. However, our 24-h videotaped records indicated that our observations on postural behavior for 6 h after feeding may be underestimated or overestimated to judge female behavior for a day because females spend more time for lying and less time for standing at night than during the day (Ruckebusch, 1972).
Implications
Results of this study suggest that a subpopulation of females frequently showing vacuum chewing with fewer total pigs born exists on commercial farms. A high frequency of vacuum chewing in those females may be indicative of their suboptimal reproductive performance, although no other performance measurements were associated with vacuum chewing. We recommend that swine producers keep records and pay close attention to the reproductive performance of pregnant females that frequently show vacuum chewing.
1 Correspondence: Higashi-mita 1-1-1, Tamaku, Kawasaki (phone: 81-42-795-6088; fax: 81-42-795-6088; e-mail: cf30209{at}isc.meiji.ac.jp).
Received for publication September 11, 2003. Accepted for publication January 21, 2004.
Literature Cited
Anil, L., S. S. Anil, and J. Deen. 2002. Relationship between postural behavior and gestation stall dimensions in relation to sow size. Appl. Anim. Behav. Sci. 77:173–181.
Cariolet, R., and R. Dantzer. 1984. Motor activity of pregnant tethered sows. Ann. Rech. Vet. 15:257–261.[Medline]
Curtis, S. E., R. J. Hurst, H. W. Gonyou, A. H. Jensen, and A. J. Muehling. 1989. The physical space requirement of the sow. J. Anim. Sci. 67:1242–1248.
Dial, G. D., W. E. Marsh, D. D. Polson, and J. P. Vaillancourt. 1992. Reproductive failure: Differential diagnosis. Pages 88–137 in Diseases of Swine. 7th ed. A. L. Leman, B. E. Straw, W. L. Mengeling, S. D’Allaire, and D. J. Taylor, ed. Iowa State Univ. Press, Ames.
Edwards, R. L., I. T. Omtvedt, E. J. Turman, D. F. Stephens, and G. W. A. Mahoney. 1968. Reproductive performance of gilts following heat stress prior to breeding and in early gestation. J. Anim. Sci. 27:1634–1637.
Fraser, A. F., and D. M. Broom. 1990. Farm Animal Behaviour and Welfare. 3rd ed. CABI, Oxon, U.K.
Friend, T. H., L. Taylor, G. R. Dellmeier, D. A. Knabe, and L. A. Smith. 1988. Effect of confinement method on physiology and production of gestating gilts. J. Anim. Sci. 66:2906–2915.
den Hartog, L. A., G. B. C. Backus, and H. M. Vermeer. 1993. Evaluation of housing systems for sows. J. Anim. Sci. 71:1399–1344.
Lawrence, A. B., and E. M. C. Terlouw. 1993. A review of behavioral factors involved in the development and continued performance of stereotypic behaviors in pigs. J. Anim. Sci. 71:2815–2825.[Abstract]
Martin, P., and P. Bateson. 1993. Measuring Behaviour. 2nd ed. Cambridge Univ., Cambridge, U.K.
McGlone, J. J., J. L. Salak-Johnson, R. I. Nicholson, and T. Hicks. 1994. Evaluation of crates and girth tethers for sows: reproductive performance, immunity, behavior and ergonomic measures. Appl. Anim. Behav. Sci. 39:297–311.
Robert, S., J. J. Matte, C. Farmer, C. L. Girard, and G. P. Martineau. 1993. High-fiber diets for sows: effects on stereotypies and adjunctive drinking. Appl. Anim. Behav. Sci. 37:297–309.
Ruckebusch, Y. 1972. The relevance of drowsiness in farm animals. Anim. Behav. 20:637–643.[Medline]
Rushen, J. P. 1985. Streotypies, aggression and the feeding schedules of tethered sows. Appl. Anim. Behav. Sci. 14:137–147.
Vieuille-Thomas, C., G. Le Pape, and J. P. Signoret. 1995. Stereotypies in pregnant sows: indications of influence of the housing system on the patterns expressed by the animals. Appl. Anim. Behav. Sci. 44:19–27.
Zanella, A. J., P. Brunner, J. Unshelm, M. T. Mendl., and D. M. Broom. 1998. The relationship between housing and social rank on cortisol, ß-endorphin and dynorphin (1–13) secretion in sows. Appl. Anim. Behav. Sci. 59:1–10.
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