IndexMotivation and redirected oral behaviorsGastrointestinal diseasesDental diseasesConclusion“Dry” commercial sows in today's intensified production system are fed a quantitatively limited diet during most of the pregnancy. This restriction is carried out not only with the aim of reducing feed costs, but also to avoid excessive body weight gain and fat deposits which could compromise the welfare of the animals and consequently reduce their reproductive performance. The behavior of these breeding sows is often characterized by increased activity during feeding times and the performance of redirected oral behaviors, such as excessive drinking and chewing, especially after feeding. The latter has been widely accepted as stereotypical behavior. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Research dating back more than 30 years, when gestating sows were tied and kept in individual stalls, suggests that food restriction, particularly persistence of feeding motivation and confined environment are the reasons main for the execution of these behaviors. Rushen, 1984 in his detailed observational study on 55 sows concluded that the chewing of the bar and the general excitement before the meal were related to anticipation, while the additional drinking after the consumption of the food was the result of the persistence of the motivation of the meal which she had not been satisfied by the ration. Similar results were reported by Appleby and A. Lawrence, 1987 in their study where gilts were provided double the amount of their limited ration and showed a low incidence of repetitive behaviours. The authors concluded that the housing system combining confinement and food restriction is not suitable for pregnant pigs. Motivation and redirected oral behaviors One approach to better understanding oral repetitive behaviors in sows is to examine the mechanisms underlying their performance using motivational concepts. For example, Hughes and Duncan, in 1988, examining a series of behavioral models, proposed that the increase in motivation that results from the additive effect of environmental and dietary factors triggers appetitive behavior which in itself has a positive feedback on motivation . In the case of food restriction and confinement, the environment does not allow sufficient expression of consumptive behavior (negative feedback) to defuse this motivation, and the animal enters a closed cycle of performing repetitive elements of appetitive behaviors. In support of the argument that motivation persists after feeding, research measuring operant response rates of boars maintained at similar levels of food restriction to sows showed sustained levels of feeding motivation even immediately after the end of feeding. meal. Subsequently, Terlouw et al., 1991a studied the separate and interactive effects of restraint and food restriction and concluded that the main factor influencing the performance of repetitive behaviors is food deprivation and, to a much lesser extent, confinement. . Their research also indicated that appetitive behaviors such as sniffing and rooting after eating did not decrease with increased performance of stereotypes such as drinking and chewing – activities that appear more related to consumption behavior. It should be noted that a portion of the animals in the latter study were not observed over the periodpreceding feeding, which may have hidden the impact of pre-feeding appetitive behavior. Additionally, the research was conducted on gilts, so stereotyped behaviors may not have been fully developed. As discussed by A. Lawrence and Terlouw, 1993 in their review, non-specific factors such as behavioral arousal and learning may have a more significant impact on gilts. longer-term persistence of repetitive behaviors than previously suggested, although empirical evidence for this role may be somewhat controversial. For example, Terlouw et al., 1993 tested whether the excitement of a new sound or an unexpected meal in the afternoon provoked the performance of stereotyped behaviors among sows. Ingestion of the meal was followed by increased levels of activity, chain handling, and alcohol consumption, whereas the loud sound of the novel was not. However, when Haskell et al., 2000 manipulated sows' pre-prandial arousal by delaying feed administration, performance of repetitive behaviors after feeding increased. This suggests that, although food delivery may have the most direct impact on the expression of postprandial repetitive behaviors, the arousal that arises from pre-meal appetitive anticipatory behavior also facilitates the enactment of stereotypies. Furthermore, the highly predictable feeding schedule that sows are imposed on probably further contributes to pre-feeding arousal and persistence of oral behaviors. Some research suggests that enacting stereotyped behaviors post-eating may be a coping strategy to reduce stress resulting from evoked arousal. Terlouw et al., 1991b studied the latter by comparing plasma cortisol levels (a hormone that increases with stress) between sows classified as stereotypically high or low. Chain manipulation was not related to cortisol levels, but there was a trend for lower levels of the hormone with increasing alcohol consumption. However, the authors concluded that this may have been a physiological consequence of drinking a large amount of water. It should also be noted that pigs are very reactive to signals indicative of food and its absence, so with the experience of being fed on a fixed schedule sows probably learn that food will not be present outside of feeding times. According to A. Lawrence and Terlouw, the 1993 stereotypies could be seen as an extreme form of learning. In a physically and behaviorally restrictive environment over which animals have no control, the behavioral repertoire may be reduced to a few behaviors focused toward limited incentives that enable the performance of foraging behavior (such as fences). The long repetition of these few behaviors gradually becomes a habit that is difficult to reverse. In support of this view, some studies report increased levels of standing and performing repetitive behaviors among older sows in later farrowing. Rushen, 1985 also indicated that pigs with higher parity exhibited appetitive and additive behaviors more stereotypically than younger sows. On the other hand, Terlouw and Lawrence, 1993 reported relatively constant activity levels between parities and a reduced amount of trough- and floor-directed behavior among low-feeding sows in successive parities, but an increase in drinking-related activities . Furthermore, when the low-feeding sows in the latest study were provided with an increased feed ration in parity four,the performance of repetitive behaviors did not decrease even after two months. Each of the above-mentioned studies goes some way to explaining the complex picture behind the motivational processes underlying the performance of oral repetitive behaviors in breeding pigs. In recent years, much research has focused on a qualitative restriction of sow nutrition or in other words on alternative diets with fibers with lower energy density and supplied in greater quantities. Therefore, most updated studies investigate the effect of fiber-containing diets on sows' feeding motivation. Less work focuses on the primary motivational processes underlying the implementation of actual oral behaviors, especially since such research often requires considerable funding and is time consuming. However, the demand for meat has led to significant changes in the pig industry, mainly related to improved productivity: animals are bred for increased appetite and large litter sizes. The latter may have had an impact on the behavioral needs of the animals especially in terms of satiety and hunger. Therefore, detailed and up-to-date research is needed to examine how industry pressure may have altered sow behavior itself. Health Issues as Factors Underlying the Performance of Repetitive Oral Behaviors It would be difficult to gain a better understanding of the development and persistence of repetitive oral behaviors in gestating sows just by observing behavioral patterns. Some physiological (health) problems such as intestinal disease and tooth decay might also influence the performance of these behaviors. Gastrointestinal Diseases Studies in horses and calves show that oral stereotypies such as tongue playing, cradle biting and wind sucking, also commonly performed by sows could be associated with underlying gastrointestinal dysfunction. For example, (Wiepkema et al. (1987) indicated that abomasal ulcers were rare in calves that performed more and more tongue play; in contrast, animals that did not engage in this behavior developed the condition. In experimental research K. Johnson et al. (1998) manipulating the diet of horses by adding Founderguard (a supplement that reduces acidosis in the hindgut) to their concentrated feed resulted in decreased performance of abnormal oral behaviors. association with acidity-influenced gastrointestinal dysfunction as ulcers. Nicol et al., 2002 studied this latter aspect by examining whether providing horses with an antacid diet would influence the development of ulcers and significantly reduce biting behavior ulceration scores and the authors reported a decrease in However, the results of the latter study were almost significant, probably due to the small sample size, and should be interpreted with caution. Although none of the research mentioned above identifies a direct causality, some authors hypothesize that by performing these behaviors the animals secrete excess saliva which can counteract the acidity in the stomach). On the other hand, further research in horses suggests that other health problems related to the gastrointestinal tract could also be associated with performing oral stereotypies. For example, an epidemiological study conducted in 21 clinics showed a high positive correlation between cradle biting/wind sucking and epiploic foramen entrapment colic. Malamed et al., 2010 reported similar findings from their research and concluded that these behaviors do notare associated with a particular category or severity of colic. Not much research has been conducted to investigate possible gastric or ulcerative conditions that may be related to the development and persistence of oral stereotypies in pregnant pigs, but there is evidence that a relationship may indeed be present. In a study examining the effect of an antacid diet on ulcers and stereotypies in gestating sows, the treatment did not influence ulceration or behavior, but the authors indicated a relationship between an increase in the number of bar bites between animals with high ulcer scores. More recently, Rutherford et al., 2018 reported that finishing pigs with gastric ulcers spent significantly more time standing than animals without ulcerations. Although the research was conducted among finishing sows, these findings may explain the increased standing time and performance of oral behaviors among sows in later parity reported in some studies. There are also findings suggesting a prevalence of ulcers among gestating sows, further supporting the hypothesis that some of the oral behaviors performed during feeding may be the result of deteriorating gut health. Research investigating risk factors for gastric ulcers in pigs at slaughter, examining the stomachs of 15,741 animals, reported the highest incidence of ulcerations in slaughtered sows. Such results are to be expected since in today's intensive production sows are often fed pelleted feed made up of small particles. The latter, combined with feeding rations, have been identified as main reasons for the development of ulcerations in pigs and other animals (. Further detailed research combining dietary manipulation, detailed behavioral observation and post-examination is needed. mortality to gain a better understanding of the possible relationship between oral behaviors and gastrointestinal health in breeding pigs. Dental Diseases When addressing health issues that could result in abnormal oral behaviors, it would be worth discussing possible dental caries which is likely to be accompanied by pain and discomfort. general for the animal can lead to repetitive oral behaviors. Few articles have addressed the dental health of sows focusing mainly on post-mortem examination. E. Johnson et al., 2003 examined sow heads from two slaughterhouses and reported that approximately 85% of the animals had one or more significant dental lesions. Other studies indicated a lower incidence of tooth wear and injury, but the rate was still remarkably high, between 30% and 42%. Some authors suggest that significant lesions of the molars or incisors are the result of bar biting, while others argue that these conditions are time-related. However, other factors can also contribute to the development of dental disease in sows. Routine husbandry practices, such as cutting and grinding piglets' teeth, have been reported to cause necrosis, gingivitis, and severe pulp inflammation in the weeks following the procedures. It can be argued that these deciduous teeth will be replaced later in life, but it is known from human dentistry that untreated infection of a deciduous tooth can lead to an alternation in the development of the permanent successor and bacterial invasion of the surrounding tissue (Cordeiro and Rocha, 2005). Therefore, sows whose teeth have been cut or ground are very likely to suffer from tooth decay and severe gingivitis. Another point to consider is that breeding pigs are fed.