Effect of environmental enrichment at two stages of development on belly nosing in piglets weaned at fourteen days

Evaluation of miRNA as Biomarkers of Emotional Valence in Pigs

Simple Summary

It is widely recognized that the assessment of animal welfare should include measures of positive emotional (affective) state. Existing behavioral and physiological indicators of a positive affective state frequently lack sensitivity, objectivity or are unsuitable in a production environment. Therefore, there is a need to develop new approaches to accurately and objectively measure a positive emotional state in animals, including novel molecular markers such a miRNA. These biomarkers must be measurable in the peripheral circulation and provide an accurate account of the physiological and molecular activity in regions of the brain associated with emotional processing. Further, such markers require validation against established behavioral and physiological indices. Here we investigated the efficacy of circulating miRNA as biomarkers of emotional state in the pig.

Abstract

The ability to assess the welfare of animals is dependent on our ability to accurately determine their emotional (affective) state, with particular emphasis being placed on the identification of positive emotions. The challenge remains that current physiological and behavioral indices are either unable to distinguish between positive and negative emotional states, or they are simply not suitable for a production environment. Therefore, the development of novel measures of animal emotion is a necessity. Here we investigated the efficacy of microRNA (miRNA) in the brain and blood as biomarkers of emotional state in the pig. Female Large White × Landrace pigs (n = 24) were selected at weaning and trained to perform a judgment bias test (JBT), before being exposed for 5 weeks to either enriched (n = 12) or barren housing (n = 12) conditions. Pigs were tested on the JBT once prior to treatment, and immediately following treatment. MiRNA and neurotransmitters were analyzed in blood and brain tissue after euthanasia. Treatment had no effect on the outcomes of the JBT. There was also no effect of treatment on miRNA expression in blood or the brain (FDR p > 0.05). However, pigs exposed to enriched housing had elevated dopamine within the striatum compared to pigs in barren housing (p = 0.02). The results imply that either (a) miRNAs are not likely to be valid biomarkers of a positive affective state, at least under the type of conditions employed in this study, or (b) that the study design used to modify affective state was not able to create differential affective states, and therefore establish the validity of miRNA as biomarkers.

A survey-based assessment of risk factors for cross-sucking behaviors in neonatal kittens, Felis catus

Cross-sucking, or non-nutritive sucking on the bodies of littermates, is commonly observed in early-weaned animals. This behavior has been well-documented in production animals, which are often separated from their mothers before weaning. The behavior is less well-understood in other domestic species, such as cats (Felis catus), that can be orphaned due to neglect, maternal death, or accidental separation. Anecdotally, cross-sucking can cause injuries in kittens, sometimes severe enough to warrant euthanasia. To our knowledge, this is the first detailed study of this behavior in domestic cats. We conducted a survey of caretakers (N = 407) of kittens (< 60 days old) with the goal of identifying characteristics of individual kittens, litters, the environment, and husbandry that might be associated with the presence of cross-sucking. The final data set, representing 1358 kittens, was comprised of 301 litters experiencing sucking and 106 litters not experiencing sucking behaviors. Almost all of the kittens represented in the survey (91%) were orphaned. Results suggested that being orphaned (X 2(1) = 42.64, p < 0.001), bottle-fed (X 2(2) = 40.32, p < 0.001), younger (t(405) = 3.48 p < 0.001), separated earlier from the mother (t(376) = 3.10, p = 0.002), and being in an all-male litter (X 2(2) = 7.13, p = 0.03) increased the risks of cross-sucking. Male kittens also were more likely to be recipients of sucking behavior (X 2(1) = 32.30, p < 0.001). No clear associations between the environment or husbandry practices and the presence of sucking behavior were identified. Interruption and separation were the most frequently reported management strategies, but most kittens returned to sucking behavior when reunited. Cross-sucking is a frequently reported behavior problem in orphaned kittens that may indicate distress or poor welfare. Future research should focus on a better understanding of prevention and management strategies, and determination of the effects, if any, of cross-sucking as a kitten on adult cat outcomes or behavior.

Effect of environmental enrichment for piglets in the nursery phase

OBJECTIVE

The effect of environmental enrichment on the behaviour of piglets in the nursery phase was evaluated.

METHODS

A total of 450 hybrid pigs (21 day old), including both females and uncastrated males, weighing approximately 6 kg, were distributed in a completely randomised design with 3 treatments and 3 replicates of 50 animals each. The treatments were: i) pen without environmental enrichment (control), ii) treatment consisting of continuous environmental enrichment (CEE) with rubber balls throughout the experimental period, and iii) treatment consisting of environmental enrichment with washed balls (EEWB) during the whole experimental period which were removed daily for washing. For the behavioural evaluation, 10 animals were randomly selected per replicate. The behavioural assessments were performed once a week, from 8 am to 6 pm, using images captured with a video camera. The data were submitted to non-parametric analyses, the means were compared using the Bonferroni test, and Person's correlations were also calculated.

RESULTS

A statistical difference (p = 0.001) was observed in the B5 (playful) behaviour; the animals in the EEWB treatment group had a higher frequency of this behaviour than animals in the control treatment group. The animals in the control group showed a higher frequency of B7 behaviour (lying down) (p = 0.026) than those in the EEWB and CEE treatment groups. The animals in the control group had a higher frequency of the B9 (belly nosing) behaviour than those in the EEWB group (p = 0.015). There was a tendency towards a higher frequency of behaviour B3 (walking in the pen) (p = 0.067) when the animals received the control treatment than treatments EEWB or CEE.

CONCLUSION

The use of an enriching object improved the animal welfare and altered the correlation between the evaluated behaviours compared to the animals that did not have environmental enrichment.

Effects of Environmental Enrichment on Pig Welfare-A Review

Good husbandry conditions on farms is of key importance for assuring animal welfare. One of the most important legal documents regulating the rules of maintaining pigs is the Directive 2008/120/EC, which states that group-housed pigs should have access to litter or other materials that provide exploration and occupation. Released in 2016, the Commission Recommendation (EU) 2016/336 on the application of the Council Directive 2008/120/EC characterizes the various categories of materials that may be used to improve animal welfare. According to the document, straw is considered as an optimal material for pig housing, however, materials categorized as suboptimal (e.g., wood bark) and materials of marginal interest (e.g., plastic toys) are often used in practice and scientific research. As such, the aim of this paper is to review and systematize the current state of knowledge on the topic of the impact of environmental enrichment on pig welfare. This article raises mainly issues, such as the effectiveness of the use of various enrichment on the reduction of undesirable behavior-tail biting; aggression; and stereotypies at the pre-weaning, post-weaning, and fattening stage of pig production.

Effect of Different Environment Enrichments on Behaviour and Social Interactions in Growing Pigs

Simple Summary

Pigs reared under intensive conditions are subjected to environmental stresses such as being unable to express some natural behaviours, like socialisation, exploring and rooting. For this reason, EU legislation requires farmers to employ suitable environmental enrichments in the pens. This study aimed at evaluating how different environmental enrichment tools (wooden logs either hanging or laying and hanging metal chains in pens) affected the behaviour of growing pigs. The results show a reduction in the incidence of aggressive/damaging interactions between animals in the pen where hanging wooden logs were placed. No significant effect on non-aggressive behaviours was noted in any of the investigated conditions.

Abstract

(1) Background: Pigs are active animals that require a suitable environment to be able to express their exploratory behaviour. The aim of the present study was to compare the effects of different environmental enrichments on the behaviour, social interactions, salivary cortisol concentration and body weight of pigs during the growing phase. (2) Methods: The investigation involved 75 pigs divided into three groups. The environmental enrichments were arranged as follows: Hanging metal chains for the control group; hanging metal chains and hanging logs for the second group; hanging metal chains and logs laying on the floor for the third group. Each group was video recorded twice a week for six weeks. The scan sampling technique was used. Salivary cortisol and live body weight were also recorded regularly. Parametric (ANOVA) and non-parametric statistics were used to analyse the data. (3) Results: Hanging logs were found to be more effective than logs laying on the floor at reducing aggression within the group tested, resulting in a more comfortable environment. Salivary cortisol concentration and growth did not show significant differences between the three groups. (4) Conclusions: The use of hanging logs affected some interactive patterns that resulted in decreasing the aggressive episodes of pigs, thereby providing a more comfortable environment.

Behaviour of fattening pigs fed with liquid feed and dry feed

BACKGROUND

Facilities for fattening pigs offer limited possibilities for exploration and wet feeding systems, where the pigs drink the food instead of eating it, have expanded on behalf of dry feeding systems. As little has been made to evaluate liquid feeding from the point of view of the pigs, the aims of this study were to compare behaviour in general and behaviour at feeding in particular of fatteners offered dry or wet feed. The study was carried out in an integrated herd with age segregated rearing of pigs and access to both feeding systems in the fattening units. Apart from the feeding system, the pens were identical and they were managed by the same staff. Pigs were allocated to the fattening units at 20 kg body weight and their behaviour was studied through web cameras during day hours (07.00 to 19.00).

RESULTS

Pigs performed well in both systems, but differed in behaviour. Fattening pigs offered dry feed spent longer time (P < 0.001) eating at every feeding occasion. They also expressed fewer regroupings during the first week (P < 0.001) when the social rank not yet was established. Pigs fed liquid feed regrouped during the effective eating time, while pigs fed dry feed regrouped when the first pig already had left the through which rather reflected seeking for leftover feed. Restlessness was rarely recorded before feeding, but rather frequently afterwards. During week 5-9 restlessness was more frequently recorded among pigs offered wet feed. Pigs offered liquid feed expressed unwanted behaviour in terms of belly-nosing, and nibbling of ear or tail to a somewhat higher extent than pigs offered dry feed. In both systems the pigs were occupying themselves with straw when offered, but only as long as they regarded it as new, i.e., for around 45 min following each provision.

CONCLUSIONS

Pigs performed equivalent in both systems, but from an animal welfare view we recommend dry feed to growing pigs and suggest that liquid feed systems ought to be reserved for systems using alternative feed supplies like whey or other liquid leftovers from the food industry.

Effect of drinker type on water intake and waste in newly weaned piglets

During the first few days after weaning, pigs often experience BW loss as they adapt to eating solid food. During this time period, they are also known to drink excessively and develop abnormal oral behavior such as belly nosing. The excessive drinking may stem from the piglets' attempt to satiate hunger through gut fill from a familiar ingestive source. Gut fill through water intake may affect the establishment of feeding behavior. Using drinker devices other than the standard nipple drinker may ease the piglets' transition at weaning by facilitating the initiation of feeding and preventing the development of behavioral problems such as excessive drinking and belly nosing. In this experiment, we examined the effect of drinker type on water and food intake, growth rates, and belly nosing in newly weaned piglets. Eighteen pens of 15 piglets each (270 piglets total) were weaned at 18.1 +/- 0.1 d of age and housed in pens containing 1 of 3 drinker devices (standard nipple, push-lever bowl, and float bowl). Piglets' water and feed intake, water use, BW, and behavior were examined on a pen basis through 2 wk after weaning. Piglets with nipple drinkers wasted more water than the other piglets (P < 0.001; float, 295 +/- 70 mL x pig(-1) . d(-1); nipple, 1,114 +/- 63 mL x pig(-1) . d(-1); and push-lever, 186 +/- 63 mL x pig(-1) . d(-1)), whereas piglets with float bowls consumed less water than the other piglets (P < 0.001; float, 475 +/- 81 mL . pig(-1) x d(-1); nipple, 870 +/- 76 mL x pig(-1) . d(-1); push-lever, 774 +/- 76 mL x pig(-1) . d(-1)). Drinker type affected feeding behavior (P = 0.02); piglets with push-lever bowls spent less time at the feeder than the other piglets, although no difference was detected for feed intake (P = 0.64) or overall ADG (P = 0.16). Piglets with push-lever bowls also tended to perform less piglet-directed nosing behavior than piglets with the float bowl (P = 0.04). Piglets appear to use more water during the first 2 d after weaning with certain drinker devices. However, piglets do not appear to attain satiety through water consumption because most of the water used during the first few days after weaning is wasted. This excessive drinking and water wastage can be abated through the use of push-lever drinkers without negative implications for feed intake or growth rates.