Effects of increasing energy intake and foraging behaviours on the development of stereotypies in pregnant sows

Management factors affecting gestating sows’ welfare in group housing systems — A review

Public concern on the methods of raising food-producing animals has increased, especially in the last two decades, leading to voluntary and mandated changes in the animal production methods. The primary objective of these changes is to improve the welfare of farm animals. The use of gestational stalls is currently a major welfare issue in swine production. Several studies assessed the welfare of alternative housing systems for gestating sows. A comparative study was performed with gestating sows housed in either individual stalls or in groups in a pen with an electronic sow feeder. This review assessed the welfare of each housing system using physiological, behavioral, and reproductive performance criteria. The current review identified clear advantages and disadvantages of each housing system. Individual stall housing allowed each sow to be given an individually tailored diet without competition, but the sows had behavioral restrictions and showed stereotypical behaviors (e.g., bar biting, nosing, palate grinding, etc.). Group-housed sows had increased opportunities to display such behavior (e.g., ability to move around and social interactions); however, a higher prevalence of aggressive behavior, especially first mixing in static group type, caused a negative impact on longevity (more body lesions, scratch and bite injuries, and lameness, especially in subordinate sows). Conclusively, a more segmented and diversified welfare assessment could be beneficial for a precise evaluation of each housing system for sows. Further efforts should be made to reduce aggression-driven injuries and design housing systems (feeding regimen, floor, bedding, etc.) to improve the welfare of group-housed sows.

Blood profile, hormones, and telomere responses: potential biomarkers in horses exhibiting abnormal oral behaviour

The high prevalence of abnormal oral behaviour (AOB) in working horses has been linked to management issues and the pathophysiology of this behaviour remains unclear. Therefore, this study aims to elucidate the blood profile, hormones, and telomere length responses between low and high levels of AOB among different horse working groups. A total of 207 healthy horses from various breeds were initially selected from four working groups (leisure riding, equestrian, endurance, and patrolling) and observed for the time spent on AOB. Then, six horses each with higher and lower AOB than the population means were randomly selected from each of the working groups and categorized as high and low AOB horses, respectively. Blood samples were collected for haematology, biochemistry, cortisol, ghrelin, leptin, and relative telomere length analyses. High AOB horses notably had higher values of glucose, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and creatine kinase (CK) compared to low AOB horses. High AOB horses also recorded higher plasma cortisol and ghrelin, but lower leptin concentrations. Among working groups, both endurance and patrolling horses presented the highest values in sodium, potassium, chloride, phosphate, ALT, and CK. While patrolling horses had the lowest levels of urea, ALP, and albumin levels, equestrian and leisure horses recorded the highest and lowest plasma cortisol and leptin concentrations, respectively. Finally, the telomere length of endurance and patrolling horses were significantly greater than leisure and equestrian horses. The present findings suggest that AOB horses had distinctive physiological characteristics that could be linked to improper diet and a demanding workload, while ghrelin and leptin hormones could be potential biomarkers for this behaviour.

Floor Feeding Sows Their Daily Allocation over Multiple Drops per Day Does Not Result in More Equitable Feeding Opportunities in Later Drops

This research studied whether floor feeding group-housed sows their daily allocation over multiple feed drops per day provides more equitable feeding opportunities in later drops. Over four time replicates, 275 sows were mixed into groups of 10 for both their first and second gestations (200 sows/gestation, 126 sows observed in both gestations). The feeding behavior of individual sows was recorded for 10 min following each of four feed drops per day (0730, 0900, 1100, 1500 h) on days 2, 9 and 51 post-mixing. The location of feeding sows (i.e., feeding in areas associated with high, reduced or little/no food availability) was also recorded. Sow aggressive behavior on day 2 was used to classify sows as dominant (D), subdominant (SD), or submissive (SM). Dominant sows spent the most time feeding in areas of high-food availability (gestation 1, p < 0.001; gestation 2, p = 0.023); SD sows fed more frequently than D sows from areas of reduced food availability (gestation 1, p = 0.001; gestation 2, p = 0.025); and SM sows performed more feeding behavior in areas of little/no food availability (gestation 1, p < 0.001; gestation 2, p < 0.001). These relationships did not change over feed drops or days in either gestation (p > 0.05). Further research on the management and design of floor feeding systems is required, with a particular emphasis on increasing accessibility to sows that avoid the feeding area.

Key determinants of pig welfare: implications of animal management and housing design on livestock welfare

The present review using the pig as a model has highlighted the importance of the design of the housing system on the welfare of farm animals. It has emphasised the need for research on animal welfare in new and modified housing systems, as well as current but contentious systems, to be attentive to the design contributions of these systems to animal welfare. The review has highlighted areas for future research to safeguard sow and piglet welfare, including the following: effective environmental enrichment for gestating sows in intensive, indoor and non-bedded systems; opportunities to increase foraging and feeding times in feed-restricted gestating sows; design features that allow both access to important resources, such as feed, water and a comfortable lying area, and escape opportunities to reduce aggression and minimise risks to the welfare of group-housed sows; and less confined farrowing and lactation systems. The review also shows that animal welfare problems may be less a function of the type of housing system than of how well it operates. The skills, knowledge and motivation of stockpeople to effectively care for and manage their animals are integral to the standard of welfare experienced by their animals. Attitudes influence not only the manner in which stockpeople handle animals, but also their motivation to care for their animals. Thus, training targeting technical skills and knowledge as well as the attitudes and behaviours of stockpeople should be a primary component of the human resource management practices at a farm. While public concerns and policy debates often focus on intensive housing systems, research indicates that the design and management of both indoor and outdoor housing systems is probably more important for animal welfare than is generally recognised.

Effects of group housing on sow welfare: a review

Factors that have been shown to impact the welfare of group-housed sows are discussed in this review. Floor space allowance markedly affects sow welfare. In addition to quantity of floor space, the quality of space is important: spatial separation between sows can be provided with visual or physical barriers and stalls. Whereas 1.4 m/sow is insufficient, further research is required to examine space effects in the range of 1.8 to 2.4 m/sow in more detail. The period immediately after mixing has the most pronounced effects on aggression and stress, and therefore, well-designed mixing pens offer the opportunity to reduce aggression, injury, and stress while allowing the social hierarchy to quickly form. Because hunger is likely to lead to competition for feed or access to feeding areas, strategies to reduce hunger between meals through higher feeding levels, dietary fiber, or foraging substrate should be examined. However, feeding systems, such as full-body feeding stalls, can also affect aggression and stress by providing protection at feeding, but deriving conclusions on this topic is difficult because research directly comparing floor feeding, feeding stalls, and electronic sow feeder systems has not been conducted. Familiar sows engage in less aggression, so mixing sows that have been housed together in the previous gestation may reduce aggression. Although there is evidence in other species that early experience may affect social skills later in life, there are few studies on the effects of early "socialization" on aggressive behavior of adult sows. Genetic selection has the potential to reduce aggression, and therefore, continued research on the opportunity to genetically select against aggressiveness and its broader implications is required. Most research to date has examined mixing sows after insemination and knowledge on grouping after weaning is limited.

Effects of distillers‘ dried grains with solubles on behavior of sows kept in a group-housed system with electronic sow feeders or individual stalls

Li, Y. Z., Phillips, C. E., Wang, L. H., Xie, X. L., Baidoo, S. K., Shurson, G. C. and Johnston, L. J. 2013. Effects of distillers’ dried grains with solubles on behavior of sows kept in a group-housed system with electronic sow feeders or individual stalls. Can. J. Anim. Sci. 93: 57–66. A study was conducted to investigate the effects of diets that contained distillers’ dried grains with solubles (DDGS) on stereotypic behaviors of gestating sows housed in stalls and aggression in a group-housed system. Sows were fed corn–soybean-based control (CON) or treatment (DDGS) diets starting from their previous breeding cycle (40% and 20% DDGS as-fed basis during gestation and lactation, respectively). Group-housed sows were mixed in pens with an electronic sow feeder within 1 wk after mating. Behaviors of focal sows (n=27 in stalls, n=40 in pens) were video-recorded for a period of 24 h between 4 and 8 d after mating. Salivary cortisol levels were measured on 32 focal sows (n=16 in stalls, n=16 in pens) during the week before mating (week 0), 1 wk and 12 wk after mating. In pens, DDGS sows fought for longer periods (P=0.05), tended to fight more frequently (P=0.06), and had greater cortisol concentrations (P<0.001) at mixing compared with CON sows. In stalls, DDGS sows spent more time resting (P=0.02), less time performing stereotypies (P=0.05), and had lower cortisol concentrations (P=0.03) in week 12 compared with CON sows. These results indicate that DDGS diets may compromise the welfare of sows in pens, but improve the welfare of sows in stalls.

Effects of water supplementation with tryptophan and vitamin B6 or feeding hydrogenated fat on reducing hunger-induced drinking pre-slaughter in pigs

Faucitano, L., Torrey, S., Matte, J. J., del Castillo, J. R. E. and Bergeron, R. 2012. Effects of water supplementation with tryptophan and vitamin B6 or feeding hydrogenated fat on reducing hunger-induced drinking pre-slaughter in pigs. Can. J. Anim. Sci. 92: 319–326. A current food safety challenge at pig slaughter plants comes with the presence of stomachs filled with liquid induced by hunger-related drinking in lairage. With the objective to reduce hunger-related excess drinking, 30 barrows were assigned to three treatments (10 pigs per treatment): (1) unsupplemented water or feed regimen (CONT), (2) L-Tryptophan (3 g L−1) and vitamin B6 (10 mg L−1) in the drinking water for 5d (TRP-B6), (3) hydrogenated fat (HF) supplemented at 10% in the diet for the last day of feeding before pre-slaughter fasting. As compared with CONT, neither TRP-B6 nor HF supplementation influenced behaviour in lairage and water intake at anytime over the pre-slaughter fasting period as reflected on stomach weight and its liquid content at slaughter (P>0.10). However, in HF-fed pigs plasma non-esterified fatty acids concentrations tended to be lower (P=0.09) while carcass yield was higher (P=0.04) than CONT pigs. It appears, therefore, that neither drinking water supplementation with TRP-B6 for 5 d nor feeding HF the last day before slaughter can be recommended strategies to limit excess water drinking prior to slaughter and liquid stomach content at slaughter. However, dietary HF supplementation the last day before slaughter may attenuate the effects of fasting on body energy reserves and improve carcass yield.

Effects of a high-fiber diet and frequent feeding on behavior, reproductive performance, and nutrient digestibility in gestating sows1,2

A study was conducted to determine the effects of feeding a corn-soybean meal (control) diet vs. a corn-soybean meal-40% soybean hulls (high fiber) diet, as well as the frequency of feeding (once vs. twice daily), on the welfare and performance of gestating sows. Two hundred thirty-nine mixed-parity sows were assigned to a 2 x 2 factorial arrangement of treatments. Sows fed once daily received their entire meal at 0730, whereas sows fed twice daily received one-half of their feed allotment at 0730 and the other half at 1430. The behavior of 68 focal sows (> or = 16 sows per treatment combination) was observed on d 1 postweaning, and on d 40 and d 80 of gestation. The percentage of time standing, lying, sitting, feeding, inactive, and performing stereotypic behaviors was determined. Saliva samples were collected to determine cortisol concentrations. Sow BW and backfat depth were determined on d 0, 40, and 80 of gestation, within 24 h of farrowing, and at weaning. An energy and nitrogen digestibility study was conducted using 36 sows assigned to each of the 4 treatment combinations. Over a 24-h period, the sows fed the high-fiber diet spent less time lying (P < 0.05) than the sows fed the control diet. The frequency of feeding did not affect sow behavior measured over a 24-h period. During mealtimes, sows fed the high-fiber diet spent more time feeding (P < 0.05) than sows fed the control diet. Feeding the high-fiber diet did not affect stereotypic behavior measured over 24 h or during mealtimes. Neither diet nor feeding frequency affected salivary cortisol concentration. Sows fed the high-fiber diet gained less BW and lost backfat (P < 0.05) during gestation compared with sows fed the control diet, whereas sows fed once daily gained less BW and lost backfat (P < 0.05) compared with sows fed twice daily. Sows fed the high-fiber diet had fewer pigs born (P < 0.05) compared with sows fed the control diet. Feeding frequency had no effect on size or weight gain of litters. Sows fed the high-fiber diet exhibited lower digestibility of DM, energy, and N (P < 0.05) compared with sows fed the control diet. Feeding a high-fiber diet utilizing soybean hulls or increasing feeding frequency did not enhance the welfare of sows by reducing stereotypic behaviors nor did it improve reproductive performance.

Effect of sow parity and weight at service on target maternal weight and energy for gain in gestation1

The objective of this study was to evaluate targeted maternal weight gains in sows by parity group during gestation. Weight and backfat gains during gestation by parity, weight, and backfat groups also were analyzed. The data evaluated were a subset (374 sows) of a larger experiment that compared three methods of feeding sows during gestation on weight and backfat gains and subsequent reproductive performance. Feed allowances were based on modeled calculations of energy and nutrient requirements to achieve target sow maternal weight and backfat gains. Actual backfat gain for gilts and sows was regressed on maternal weight gain and estimated energy available for gain. The regression equations were then used to predict maternal weight gains for target backfat gains for three parity groups (gilts, Parity 1 and 2 sows, and Parity 3 and older sows). For gilts and Parity 1 and 2 sows, much greater target maternal weight gains are required to achieve 6 and 9 mm of backfat gain, whereas Parity 3 and older sows require maternal weight gains similar to those targeted to achieve the desired backfat gain. Given similar energy intake levels above maintenance, gilts gained more weight than multiparous sows, as gain was based more on protein and less on fat and thus was more efficient. Gilts required more maternal weight gain than sows to achieve similar backfat gains due to the higher protein and low fat contents of gain in younger, lighter sows compared with older parity sows. Low-backfat sows that needed to gain large amounts of backfat failed to achieve these large gains. We speculate this failure may be due to lower tissue insulation levels with the low backfat levels and higher activity levels of these sows compared with high-backfat sows. It seems that both parity and weight are individually important factors that influence energy and nutrient requirements for gestation in the modern sow.

Pregnancy-related changes in behavior and cardiac activity in primiparous pigs

Pregnancy in mammals is a time of considerable physical, physiological and behavioral change necessary for the continuance of the gestation. Gestating pigs are often used in behavior and welfare studies; yet, there are little published data describing how pregnancy affects normal behavior and cardiac activity patterns. The objective of this work was to describe the longitudinal dynamics of cardiac activity and behavior during pregnancy in primiparous pigs (gilts). The behavior and cardiac activity of nine gilts were recorded on eight occasions at certain fixed time points during their pregnancy: 1-2 weeks before oestrus and mating (week -1), 14 days postmating (week 2), and days 30 (week 4), 44 (week 6), 65 (week 9), 79 (week 11), 93 (week 13) and 107 (week 15) of pregnancy. Temporal changes in behavior patterns were present in all gilts over the course of gestation. Pretest levels of general activity progressively declined between weeks -1 and 15, as indicated by a decrease in the proportion of observations spent rooting (p<0.001), walking (p<0.001) and standing (p<0.001). There was a corresponding increase in inactivity (p<0.001), and the proportion of time spent sleeping, as opposed to lying alert, increased also (p<0.001). Apart from RR-min and its corresponding HR-max indices, all time-domain parameters were influenced by the stage of gestation. Specifically, mean HR increased (p<0.001), whereas the root-mean-square of successive differences (RMSSD) and standard deviation (S.D.) decreased (p<0.001). Pregnancy further impacted the frequency domain measures of heart rate variability. From week -1 to 15, the absolute magnitude of Total power (p<0.001) decreased, HF power decreased (p<0.001) and LF power increased (p=0.004). In conclusion, pregnancy induced widespread changes in behavior and in sympathovagal regulation of cardiac activity in pigs that were reflected in both the time and frequency domain indices of heart rate variability analysis.

Comparison of three methods of feeding sows in gestation and the subsequent effects on lactation performance1

A total of 684 sows from breeding groups over 6 wk was used to compare three methods of feeding during gestation on gestation and lactation performance. Control gilts and sows were fed according to body condition based on a scale of 1 to 5 (1 = thin, 5 = fat). Sows were visually assessed for body condition at breeding and were assigned a daily feed allowance to achieve a BCS of 3 at farrowing. Treatment 2 used feeding levels based on backfat thickness (measured between d 0 and 5 after breeding) and weight at weaning for sows or service for gilts. Feed allowance was calculated to achieve a target backfat of 19 mm at farrowing, and remained constant from d 0 to 101 of gestation. Feed allowances were based on modeled calculations of energy and nutrient requirements to achieve target sow maternal weight and backfat gains. Treatment 3 was identical to Treatment 2, except that feeding pattern was altered for thin sows and gilts (<15 mm at service) in an attempt to reach 19 mm by d 36 of gestation. Sows were weighed at the previous weaning, and gilts were weighed at service, with both weighed again between d 112 and 114 of gestation. Backfat was measured between d 0 and 5, and again between d 108 and 113 of gestation. At farrowing, sows on Treatments 2 and 3 had 19 and 19.1 mm of backfat, respectively, whereas control sows tended to have greater (P < 0.07) backfat (20 mm). On average, sows targeted to gain 6 to 9 mm of backfat failed to reach target gains regardless of feeding method. Feeding sows in gestation based on backfat (Treatments 2 and 3) resulted in a numerically higher proportion of sows in the target backfat range of 17 to 21 mm (40.2, 53.3, and 52.6% for control and Treatments 2 and 3, respectively) at farrowing and a numerically lower percentage of fat sows (>21 mm), but no difference in the percentage of thin sows (<17 mm) compared with feeding based on body condition. In conjunction with this observation, sows fed based on BCS were fed higher (P < 0.05) feeding levels in gestation than were sows fed based on backfat depth. Gestation feeding method had no effect on performance during lactation. Feed intake in lactation was lower (P < 0.05) for high backfat sows (>21 mm) at farrowing compared with sows with <21 mm. The high proportion of sows in the optimal backfat category demonstrates that feeding based on backfat and BW has potential for facilitating more precise feeding during gestation.

Feeding motivation and stereotypies in pregnant sows fed increasing levels of fibre and/or food

Twenty-one multiparous sows were used in a Latin square design, from days 7 to 90 of gestation, to test the effect of fibre and food levels on feeding motivation and feeding-related stereotypies. Treatments were: VHF (very high-fibre, 29% ADF, 50% NDF, 4.5kg/day); HF (high-fibre, 23% ADF, 43% NDF, 3.5kg/day); C (control, 8% ADF, 20% NDF, 2.5kg/day); and control fed ad libitum (CAL). All diets except CAL provided a similar amount of major nutrients on a daily basis and were served in two meals. Each sow was subjected to each treatment for a 21-day period, at the end of which, behavioural observations were made. Two-hour observation periods starting at the afternoon food delivery revealed that sows spent more time eating on VHF and CAL (mean=21.2min) than on HF (13.2min) and C (7.6min) and more time on HF compared to C (p<0.01). When time spent eating was removed from total observation time, the percentage of remaining time spent in stereotypies was lower for VHF (median=17.9%) compared to C (median=49.8%), and lower for CAL (median=6.3%) compared to all other diets (p<0.01). During the period when lights were on (6.00-18.00h), 5min interval scans showed that VHF sows spent more time lying down and less time standing than C sows (p<0.05). Also, CAL sows spent more time lying down than sows on other treatments (p<0.01). During operant conditioning tests (OCT) performed before the afternoon meal and after the morning meal, less rewards were obtained by CAL sows (p<0.01), with no difference between other treatments. In conclusion, no reduction in feeding motivation of sows fed high-fibre diets could be measured by OCT, but very high levels of fibre were effective at reducing stereotypies and activity during the 2h post-feeding. However, these effects were not as marked as those observed with ad libitum feeding.

Diversity of behaviour during novel object tests is reduced in pigs housed in substrate-impoverished conditions

Modern intensive farming conditions lack the diversity of substrates present in more natural environments and offer young animals fewer opportunities for interaction. Evidence exists that this may affect the organization of interactive patterns of behaviour, but shifts in behavioural diversity have not been measured directly. We investigated the effect of the substrate in the home pen on the diversity of behaviour in young growing pigs, Sus scrofa. Over 5 months, 26 pigs were housed singly in either substrate-impoverished (SI) or substrate-enriched (SE) conditions. Once every month we recorded the behaviour of these pigs in detail both in the home pens and in two novel object tests. In addition, we calculated the diversity of behaviour shown by SI and SE pigs in the home pen and in the novel object tests, using a relative behavioural diversity index. In the two novel object tests, SI pigs were less mobile than SE pigs and focused their behaviour on particular substrates. In addition, SI pigs showed less diverse behaviour than SE pigs. Our results show that the less diverse behaviour of SI pigs previously recorded in their home pens persists under novel conditions, supporting the hypothesis that substrate-impoverished housing conditions structurally affect the organization of behaviour in young growing pigs. Copyright 2000 The Association for the Study of Animal Behaviour.