Home Pen Research Articles

271 Does social buffering amongst familiar weaned beef calves mitigate castration stressors?

Abstract Co-mingling of beef feeder calves from multiple sources results in biological and behavioral stressors. This study is part of a project exploring social relationships between individual beef cattle and potential benefits of social buffering during stress events. Here, the specific objective was to explore whether feeder calves form preferential relationships which buffer them from surgical castration pain. Within the experiment, two treatment groups were established: Familiar calves were defined as calves who shared a source farm with two other calves in the pen, and Unfamiliar calves were defined as calves who did not share a source with any other pen-mates. It was hypothesized that Familiar calves would exhibit more lying, fewer pain-related behaviors, and fewer agonistic interactions following surgical castration than Unfamiliar pen-mates. Weaned beef bull calves [n = 102, body weight (BW) range ± SD = 112.95 to 370.10 ± 67.8 kg] from 23 source farms were randomly assigned to home pens, each comprised of three Familiar calves and three Unfamiliar calves. Cameras placed above the pens recorded video from which postural (standing and lying), social (agonistic and bunk displacements) and pain-related behaviors (wound checking and hind leg stamping) were quantified. Cattle were handled through a hydraulic squeeze chute once weekly over four consecutive weeks for data collection and standard processing procedures. On d 14 relative to arrival, calves were surgically castrated with multimodal pain mitigation. During all processing events, calves were marked with livestock paint for behavioral observations. Behavior was observed continuously for 15 min at five different time points (0 h, 1 h, 4 h, 24 h, 48 h) relative to when the last calf returned to the home pen after processing, and researchers were blind to treatment allocation. These time periods corresponded to expected periods when pain was absent and present based on duration of local anesthesia and systemic pain relief. Calf was the experimental unit. For the purpose of this abstract, data from the 48 h periods following d 7 and 14 were analyzed using the PROC GLIMMIX procedure of SAS; the model included treatment (Familiar, Unfamiliar) by week interaction. A P-value of ≤ 0.05 was considered significantly different. Regardless of treatment, preliminary analyses identified decreased lying (P < 0.02) and increased wound checking (P < 0.01) 48h following castration (d 14) when compared with the previous week (d 7). There were no observed differences for hindleg stamping (P = 0.2), agonistic behaviors (P > 0.06) or bunk displacement (P = 0.09). Based on preliminary analyses, we did not observe evidence of social buffering effects on castration stress during the immediate post-surgical period.

How do different amounts of straw as well as compost in the home pen affect the rooting motivation of growing-finishing pigs?

Rooting is a strongly motivated, species-specific behaviour of pigs. Most housing systems do not provide appropriate materials that enable the full expression of this behaviour, and it remains unclear whether straw is suitable to entirely fulfil the rooting motivation of pigs. We therefore investigated the suitability of small (minimal) and large (deep) amounts of straw as well as large amounts of compost to satisfy rooting motivation in pigs. Fifty-seven growing-finishing pigs were housed in three pens, each providing permanent access to one of the three treatment substrates. Eight pigs per group were tested individually in a classical preference test (PT) and another eight pigs in a conditioned place preference test (CPPT). In the tests, pigs could show their preference to consume freely available feed (“feed”) or feed hidden in sawdust (“root”). In the CPPT, feed was only present during training but not during testing. Pigs were exposed to the test situation twice, with approximately 72 kg and 115 kg BW. In both tests, the following variables were measured and used as outcome variables in linear mixed effect models: first decision to choose one of the two stimuli (“feed” or “root”), duration of time spent in proximity to “root”, number of changes between stimuli, and latency to the first decision. Overall, the pigs’ first decision (by tendency; P = 0.076) and the duration in proximity to “root” (P = 0.034) varied among treatments: Pigs housed with minimal straw tended to be more likely to choose “root” first (posthoc comparison; P = 0.090) and spent more time in proximity to “root” (P = 0.030) than pigs housed with compost, whereas pigs housed with deep straw were intermediate. Interestingly, the patterns of response to the treatment differed depending on the behavioural tests for both, first decision (interaction; P = 0.032) and duration in proximity to “root” (interaction; by tendency; P = 0.006). In addition, pigs in the PT changed more often between stimuli than pigs in the CPPT (P < 0.001). There was a tendency for an interactive effect between test and treatment for latency to first decision (interaction; P = 0.082), though pairwise comparisons did not reveal any differences. We concluded that in this study housing with permanent access to compost satisfied rooting motivation in pigs more than housing with minimal amounts of straw.

Dilution of broiler breeder diets with oat hulls prolongs feeding but does not affect central control of appetite

The parents of broiler (meat) chickens (ie, broiler breeders) are food-restricted until sexual maturity, ensuring good health and reproduction, but resulting in hunger. We investigated whether diets with added insoluble fiber promote satiety and reduce behavioral, motivational, and physiological signs of hunger. Ninety-six broiler breeders were fed 1 of 4 feed treatments (n = 24 per diet) from 6 to 12 wk of age: 1) a commercial diet fed to the recommended ration (R) or 2) ad libitum (AL), the same diet as R but mixed with oat hulls at 3) 20% (OH20%) or 4) 40% (OH40%). The R, OH20% and OH40% diets were approximately iso-energetic and resulted in mean 12 wk of age weights within 2.5% of each other (1.21 kg), while AL birds weighed 221% as much (2.67kg). At 12 wk of age, agouti-related protein (AGRP) expression, was, on average, more than 12 times lower in AL birds (P < 0.001) but did not differ between the fiber diet treatments and R. Pro-opiomelanocortin (POMC) expression, was, on average, over 1.5 times higher in AL birds, but was not statistically significantly affected by feed treatments (P = 0.33). In their home pens, AL birds stood/sat more, foraged less and fed more in total (P < 0.001) and OH40% birds spent longer feeding than R (P = 0.001). Motivation to forage tested by willingness to walk through water to access an area of wood shavings (without food) was not significantly affected by diet (P = 0.33). However, restricted birds were willing to cross in only 7.3% to 12.5% of tests. Mostly birds stayed on the start platform, where AL birds sat more than other treatments and OH40% birds reduced walking relative to R birds (P = 0.016). Across the behavioral and physiological measurements there was a dichotomy of effects in response to approximately iso-energetic diets differing in fiber. There were some potentially beneficial behavioral effects related to reduced foraging and walking. However, there was no evidence that these diets significantly improved physiological measures of satiety of broiler breeders.

Qualitative feed restriction affects frustration, fear, motivation to explore, and feather fault bars in Ross 308 broiler breeder cockerels

Broiler breeders show behaviours indicative of hunger and frustration stemming from unfulfilled behavioural needs for feeding. This is largely due to quantitative feed restriction which is common practice in the management of these birds, particularly in the rearing period. As an alternative, qualitative feed restriction allows a larger portion of feed to be provided without increasing the caloric intake. While several studies have assessed the effects of qualitative feeding on female broiler breeders, no such assessment has been done on broiler breeder cockerels. The aim of this study was to investigate the effects of feed dilution and roughage on the level of stress, fear and motivation to explore of broiler breeder cockerels. 200 Ross 308 broiler breeder cockerels (between 5 and 10 weeks of age) were housed in 12 pens (6 pens/treatment), 17 birds/pen. The treatments were standard feed (Control) and feed diluted with 20 % insoluble oat hulls and 150 g of alfalfa roughage daily/pen (D+R). The D+R birds received 20 % more feed per day. Novel object (NO) and frustration during thwarted feeding tests were performed in the home pen and the response recorded with video cameras. In addition, four birds from each pen were subjected to a tonic immobility test (TI). All behavioural tests were performed once a week at 6, 8 and 10 weeks of age. Finally, after euthanasia, two feathers from each bird were plucked and macroscopically examined for the presence of fault bars. The control birds showed a tendency to approach the NO faster than the D+R birds (P = 0.07) and were more likely to approach at 10 weeks of age (P = 0.006). In the frustration test, D+R birds spent less time pecking the feed container (P = 0.049), more time standing (P = 0.01) and tended to have fewer behavioural transitions (P = 0.09) than control birds, which indicates a reduction in frustration levels. In addition, Control birds stayed in TI longer than D+R birds (160.7 ± 15.5 s and 98.1 ± 15.4, respectively. P = 0.005). However, D+R had more fault bars compared to Control birds (P = 0.02), highlighting that care is needed to interpret these contradicting results. Nevertheless, the results show that the combination of feed dilution and daily roughage can have positive effects on the welfare of broiler breeder cockerels by reducing the sensation of hunger as indicated by fear, frustration, and motivation to explore.

The promotion of play behaviour in grow-finish pigs: The relationship between behaviours indicating positive experience and physiological measures

The provision of opportunities to express rewarding behaviours is a promising concept to support a better quality of life for intensively farmed pigs. Play behaviour has been associated with excitement and fun, suggesting that playing animals experience pleasurable states. Pigs play intensively between 2 and 6 weeks of age and this decreases with age thereafter. To determine if the provision of play opportunities could enhance the quality of life of pigs, this study investigated if play can be promoted and sustained in pigs beyond the natural period of expression in a commercial setting. Whether play is positive for pigs and the effect of play on average daily gain and stress physiology was also explored. Growing pigs (n = 288, 10 weeks of age), housed in standard partly-slatted pens, were assigned to either a Control treatment with no play interventions (CON, 1 m2/pig); or to a Novelty (NOV) or Play pen (PLP) treatments, with play promotion between 10 and 21 weeks delivered through play sessions 3x/week. Play treatments received the intermittent provision of destructible novel objects provided either in the home pen (NOV, 1 m2/pig), or in an enclosed ‘play pen' area providing extra space (PLP, 2.9 m2/pig). To understand if play is positive, the frequency and duration of anticipatory behaviour were recorded before play sessions, whilst play behaviour, along with indicators of emotional valence such as vocalization, tail, and ear postures, were recorded during play sessions on focal pigs (n = 144) at 11, 16 and 21 weeks. To explore the physiological response to play, saliva was collected pre and post play, and analysed for cortisol and alpha-amylase, and growth rate was calculated from trial entry and exit weights. Pigs in PLP and NOV played more frequently (p = 0.002) and for a longer duration of time (p < 0.001) across weeks compared to CON. NOV and PLP did not differ in play frequency and duration, except for week 21 when PLP played more frequently. Play treatments expressed more anticipatory behaviour and behavioural indicators associated with a positive experience (ears relaxed and forward, tail wagging, barks) compared to CON. Cortisol was elevated only in NOV compared to CON after the play session, but alpha-amylase and growth rate did not differ. Play was successfully promoted and sustained until the finishing period and equally expressed regardless of extra space. Pigs with play opportunities expressed indicators that play is a rewarding and motivating behaviour and could enhance the quality of life of farmed pigs when supported.

Early human contact and housing for pigs – part 2: resilience to routine husbandry practices

The ability of pigs to cope with routine farming practices can affect their welfare. This paper is part of a series on early experiences and stress, and reports on the effects of early human contact and housing on the responses of pigs to routine husbandry practices. Using a 2 × 2 factorial design, 48 litters of pigs were raised in either a conventional farrowing crate (FC) or a loose farrowing pen (LP; PigSAFE pen) which was larger, more physically complex and allowed the sow to move freely. Piglets were provided with either routine contact from stockpeople (C), or routine contact plus regular opportunities for positive human contact (+HC) involving 5 min of scratching, patting and stroking imposed to the litter 5 days/week from 0 to 4 weeks of age. At 4 weeks of age, piglets were weaned and re-housed with controlled mixing of litters within treatment. At 4 days of age, after only 3 bouts of the handling treatment, +HC pigs showed less escape behaviour than C pigs after capture by a stockperson for vaccinations and tail docking, and shorter durations of vocalisations throughout the procedures. The +HC pigs also showed less escape behaviour when captured by a stockperson at 3 weeks of age. The FC pigs showed less escape behaviour than LP pigs after capture by a stockperson at 4 days of age but not at 3 weeks of age. Serum cortisol concentrations were lower in FC pigs than LP pigs 2 h after weaning but not at 49 h after weaning, whereas serum cortisol concentrations were lower in +HC pigs than C pigs at 49 h after weaning but not at 2 h after weaning. In the period from 0 to 1 h after weaning, C pigs from LP performed the most escape attempts, although escape attempts were rare overall. When being moved out of the home pen by a stockperson at 21 weeks of age, FC pigs showed less baulking than LP pigs, but there were no detected effects of human contact treatment. In conclusion, both housing system and human contact during lactation affected the stress responses of pigs to routine husbandry practices. The +HC and FC pigs appeared to cope better than C and LP pigs, based on lower responses indicative of stress including escape behaviour, vocalisations and cortisol concentrations. These findings are consistent with corresponding reductions in fear that were reported in Part 1 of this series of papers.

Familiar versus unfamiliar: Revealing the complexity of sociability in pigs

Social behaviours are fundamental to gregarious animals and a dynamic force driving social structures, conflicts and cooperation. As a personality trait, sociability is defined as the individual reaction to the presence or absence of conspecifics and the motivation to associate with them. Research on sociability has been scarce compared to other personality traits, thus limiting our understanding of individual social behaviours which could potentially reflect it. To tackle this issue, we used a comprehensive approach, combining individual testing and Social Network Analysis. We designed a Novel Peer Test (NPT) to investigate sociability towards an unfamiliar conspecific. We conducted the NPT on 80 male domestic pigs at 6 weeks of age divided into 5 replicated groups over time. Each pig was confronted with an unfamiliar conspecific, separated by a fence in a familiar environment. To complement the NPT, we performed established personality tests, including an Open Field Test, Novel Object Test, Human Approach Test. All tests were repeated after two weeks. Pigs’ social interactions in the home pen were recorded and used for Social Network Analysis, and the associated weighted degree and betweenness centrality were calculated. Through Principal Component Analysis, we found that the NPT highlighted pigs’ motivation to interact with an unfamiliar conspecific, hence an aspect of sociability, and independently from novelty seeking. Additionally, the NPT may be a suitable personality test given that the behavioural profiles of the pigs were consistent over time. Pigs’ network positions in the home pen for non-agonistic interactions did not predict behaviours in the NPT. Specifically, there were no links between nosing and play during the NPT and nosing and play in the home pen. This may be due to the different contexts, as the social interactions occurred dyadically with an unfamiliar conspecific during the NPT while the social networks are based on unrestrained social interactions with a group of familiar pen-mates. In contrast, walking close to the fence separating the focal and novel pig during the NPT was predicted by agonistic interactions in the home pen. This behaviour is ambiguous to interpret since it additionally loaded on the extracted sociability trait, thus, it could be driven by sociability and/or aggression. Understanding pigs’ sociability will have implications for their welfare, highlighting the need for an adequate social environment to properly express different levels of sociability.

Associations between resilience to weaning stress and startle response in nursery age gilts

Resilience is the capacity of animals to return quickly to their pre-stress status following a disturbance, including social, physical, and/or disease challenges. In modern farming, where there are many stressors, resilience is crucial for pigs because it affects their welfare and production. The goal of the study was to assess whether behavioral response to an auditory stimulus during a startle test (acute stress) differed between pigs designated at weaning (27 +/- 2d of age) as stress-resilient (SR) or stress-vulnerable (SV). Blood samples were collected from female piglets (n = 170) from 26 litters surrounding weaning at multiple time points. Using serum cortisol levels from these samples, two female pigs from each litter (n = 52) were classified as either SR (n = 26) or SV (n = 26) and used for the startle test. The startle test was conducted when pigs were 7wk-of-age while they were housed in the nursery room and recordings were captured utilizing cameras positioned on the ceiling. We assessed startle magnitude score (SM) and time to resume home pen behavior as indicators of the pigs’ behavioral responses. In addition to stress resilience designation, pigs’ relaxed-tense score (RT), orientation to stimulus (OS), and pen position were also observed which may affect startle response. Our data suggest no relationship between behavioral response to an auditory startle test and resilience or vulnerability to weaning stress. The difference in the type of stressors needs to be considered as an acute, simple auditory stimulus was used for the startle test and a longer-lasting, multi-modal weaning stress was used for initial resilience designation. However, the startle test could be a relatively easy way to assess the fearfulness of pigs on farms, as it requires no training of pigs and can be conducted in the home pen, but further methodological improvement is required. Though our results did not support a clear connection between a behavioral fear response and physiological stress resilience, examining the resilience of pigs during their early developmental phases using behavioral markers is worthwhile. Early detection of non-resilient animals could offer the opportunity to implement more effective management strategies beginning earlier in life when pigs might be more vulnerable to stressors or the effects more long-lasting, thereby improving the welfare of pigs. Furthermore, it facilitates the selection of robust animals for future breeding. Further research is required to identify behavioral traits clearly indicative of stress resilience.

Environmental enrichment during yard weaning alters the performance of calves in an attention bias and a novel object recognition test

The weaning of beef calves in yards places multiple stressors on the animals, and environmental enrichment may help mitigate some of these stressors and improve animal welfare. This trial assessed the impacts of enrichment provision to beef calves during yard weaning using measures of biological functioning, behaviour, and affective state. Overall, calves utilised the brush more than the other provided enrichments, which were a hanging rope and a ball. Enrichment influenced the behaviours of calves during both an attention bias test, with enriched calves exhibiting behaviours associated with greater anxiety, and a novel object recognition test, with enriched calves spending less time interacting with objects. In their home pens, enriched calves performed more drinking and grooming behaviours. However, no significant differences were seen between treatments for body weight, faecal cortisol metabolites, and internal body temperature. Enrichment also did not influence any longer-term measurements of body weight, flight speed, or crush score. The study design was impacted by mud, requiring the regrouping of the animals. Thus, some results should be interpreted with caution. Overall, this study demonstrates that further work is required into the assessment of affective states for these animals as it could not be confirmed whether the results seen indicate that calf welfare was improved or impaired through enrichment provision.

Housed dairy cows utilise varied environmental enrichments and show diverse inter-individual variation in habituation

There is currently a focus on the importance of providing positive experiences to farm animals, which can be facilitated through the provision of environmental enrichment. Brushes are an established enrichment resource for dairy cows, however, enrichment opportunities beyond this appear to be limited. Resources which animals habituate to rapidly may be economically unviable and provide limited welfare benefits. This study aimed to assess the utility of simple point source enrichment for housed dairy cows, to evaluate how cows habituate to enrichment over time and whether cows show a preference for different enrichments. A preliminary experiment provided two groups of dairy cows (n=71) with continuous access to a novel object in the home pen for three weeks. In a further experiment, two groups of cows (n=75) were provided with the same novel object alongside continuous access to an outdoor concrete yard for nine weeks. Interaction with enrichment was quantified using sampled continuous 24-hour periods of video footage. Most cows continued to use both resources throughout the study. After two months the proportion of cows that continued to use the object and the outdoor yard was 0.88 ± 0.01 and 0.96 ± 0.02 per day. Cows spent on average 2.72 ± 0.37 minutes per day interacting with the novel object by the end of the trial, comparable to previously published data quantifying brush use in cows. We identified significant variability in the extent of habituation between cows. Although most cows declined their active utilisation of enrichment to some extent, one-quarter of cows alternatively increased the time they spent using enrichment by the end of the study. Linear models revealed a significant positive relationship between how much time individual cows used enrichment when initially provided and the extent to which they habituated to it by the end of the study (P<0.05), with the highest users of enrichment initially, showing the greatest decline in enrichment use over time. Cows spent more time outside at 72.76 ± 5.13 minutes per day (P<0.05) than using a novel object after two months. These results indicate that housed dairy cows will utilise additional and novel forms of enrichment if provided, suggesting the availability of these resources to be beneficial. Cows’ habituation responses to enrichment appears to not be a consistent group-level response. The provision of greater opportunities for environmental enrichment should be considered for dairy cows alongside the evaluation of enrichment use at the individual level.

Effects of ultraviolet light supplementation on hen behaviour and welfare during early lay

Poultry can see in the ultraviolet (UV) spectrum and supplementation of UVA has been shown to reduce laying hens’ fear and stress. The shorter wavelengths (UVB) also facilitate vitamin D3 production. However, UV spectrums are typically not included in indoor commercial poultry lighting which may result in less than optimum welfare of laying hens. This study predicted that UVA and UVA/B supplementation would increase desirable behaviours such as foraging and exploratory pecking and reduce measures of fear and stress. The effects of UV light supplementation were assessed on 252 ISA Brown hens during the period from 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UV0: standard control lighting with LED white light, (ii) UVA: control lighting plus a supplemental ‘daylight’ avian bulb providing UVA, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Behavioural time budgets were assessed in the home pens at 18 and 24 weeks. At 20, 23, and 26 weeks, assessments included: individual behavioural tests of tonic immobility and open field, pen-level novel object tests and blood heterophil/lymphocyte (H/L) ratios. At 27 weeks the UV supplemental lights were turned off for 3 days as a ‘stressor’ with bird locations in the pen measured before and during the stressor, along with H/L ratio and attention bias test assessments. Results showed limited effects of the supplemental lights. At 26 weeks both UV light treatments reduced tonic immobility duration (P = 0.006) and vocalisations across time in the open field test (P = 0.0003), while the UVA/B hens had lower H/L ratios than the UV0 hens (P = 0.01). However, removing the treatment lights did not result in greater stress and anxiety and there were few differences observed in the home pen time budgets. Overall, these results align with complementary findings in the same birds showing minimal impact of the UV treatments on measures of egg production, egg quality, bone health, and circulating plasma P and Ca but with an increase in serum vitamin D (25(OH)D3) for the UVA/B hens. The supplemental UV lights in this study were only on one side of the pens which could have minimised their impacts. Similarly, effects may vary at different points in the production cycle than included in this study.

Understanding the feeding strategies of growing-finishing pigs: Exploring links with pig characteristics and behaviour

A large variation in feeding patterns between pigs and over time hampers the use of data from electronic feeding stations in the continuous monitoring of growing-finishing pig welfare. Individual feeding strategies (i.e. differences between pigs that are consistent within a pig across time) likely explain part of this variation, both at the daily level - based on feeding components intake, frequency and rate – and at the diurnal level - based on feeding components circadian rhythms and night feeding. It is, however, not known exactly which feeding strategies pigs display, nor which types of pigs display which strategies. This study aimed 1) to test which (combinations of) feeding components contribute to independent feeding strategies; and 2) to see whether pigs with different feeding strategies also differ in other physical and behavioural characteristics. To identify feeding strategies, we calculated the intra-class correlation coefficient (ICC) for each day-level feeding component, which reflects the proportion of variation explained by an individual pig effect (n=98 pigs). Subsequently, high ICC day-level components were correlated to diurnal-level components known to contain feeding strategies, to assess possible overlap. Pigs with different strategies were then characterised based on physical (n=52) and behavioural (home pen and play tests, n=22–27) variables at different ages, using (generalised) linear mixed models. Four dimensions of individual feeding strategies emerged: nibbling/meal eating, fast/slow eating, day/day-night eating and consistent/inconsistent eating from day to day, sustaining after correction for pig sex or body weight. All dimensions except day/day-night eating partially overlapped at the beginning of the growing-finishing phase, but became more distinct over time. Pigs with different feeding strategies also differed in their general activity, diurnal activity and possibly dominance rank. Feeding strategies did not relate to behaviours possibly indicative of more positive or negative emotional states of pigs. Our results demonstrate that pigs showed individual differences in their feeding behaviour that are consistent across time, along continua in four distinct dimensions. These differences went beyond differences in body weight and sex, and were related to other behavioural characteristics of pigs. The presence of feeding strategies suggests that the use of pig feeding behaviour data should be corrected for individual differences between pigs.

Maternal contact and positive human interactions during lactation impacts piglet performance and behaviour during lactation

IntroductionEarly life interactions with the sow or humans can have lifelong consequences on welfare and performance in pigs. It was hypothesised that piglets that received increased maternal contact and positive human contact would display improved responses to stressful events and improved performance.MethodsNinety-eight litters were allocated to a 2 x 2 factorial design for maternal contact (MC+)/restricted maternal contact (MC-); and positive human contact (HC+)/no additional human contact (HC-). Modified farrowing crates were used to restrict maternal contact (MC-) and litters in the HC+ treatment received five minutes of daily positive human interaction (stroking). Behavioural and physiological responses were assessed during processing at three days of age and during a behaviour test in which piglets were introduced to an empty arena, novel object, human hand and human standing in the arena at 18 days of age. Observations of behaviour in the home pen and growth and survival of piglets to weaning were also assessed.ResultsAt processing, MC- piglets had more squeals (P = 0.015), tended to have more grunts (P = 0.063) and struggle attempts (P = 0.079), and had increased plasma cortisol concentrations (P = 0.009) after processing than MC+ piglets. During the behaviour test, HC+ piglets were more active (P = 0.014) and had more vocalisations (P &amp;lt; 0.05) in the empty arena than HC piglets. Furthermore, HC+ piglets were more likely to approach a human standing in the arena (P = 0.006) than HC- piglets. MC- piglets were less active (P = 0.008) and were less likely to approach the novel object (P = 0.049) than MC+ piglets. MC+ piglets tended to have higher weaning weights (P = 0.055) and more MC+ piglets were successfully weaned (P = 0.022) than MC- piglets. There was no significant effect of HC on piglet performance.DiscussionWhile positive handling did not affect behavioural and physiological stress response to processing, HC+ reduced fear of novelty and humans. These findings highlight the importance of early life experiences has on stress resilience early in life.

Effects of social housing on dairy calf response to novelty shortly after weaning and grouping

Dairy calf social development and responses to novelty are influenced by social contact, but longer-term implications of early life social housing for response to novelty in weaned calves are less clear. The objective of this study was to evaluate the effects of preweaning social housing on how dairy calves respond to novel feed and objects a few days following weaning and grouping. At birth, calves were alternately assigned to either individual (IH; n = 22 calves) or pair housing (PH; n = 18 pairs; 1 focal calf enrolled/pair). Following weaning (at 53.4 ± 2.0 d; mean ± standard deviation), calves were mingled between treatments and group-housed with calves born the same week (4 to 6 calves/pen; 12 total groups). Beginning at 56.4 ± 2 d of age, calves were exposed to 2 novel feed tests (sliced carrots and chopped red apples) conducted in the home pen on consecutive days. Following novel feed tests, a subset of calves (n = 11 IH and n = 9 PH calves, from separate paired pens) was exposed to a novel object test, conducted individually in a testing arena. During novel feed tests, the latency to contact the novel feed did not differ between treatments but previously IH calves spent more time at the feed trough (6.9 vs. 4.3 min/h, IH vs. PH, standard error = 0.25). In the novel object test, latency to contact the novel object and duration of contact did not differ between previous housing treatments but previously IH calves moved around the arena more. These results suggest that preweaning social housing had some carryover effects on behavioral responses during novel feed and novel object tests a few days following weaning and grouping, potentially reflecting differences in social feeding behavior and activity in a novel space, but avoidance of the novel object and feed were not affected.

Evaluation of the treatment efficacy of generic enrofloxacin compared to pioneer enrofloxacin for first treatment of naturally occurring bovine respiratory disease in a commercial feedlot

The primary objective of this study was to compare the treatment effectiveness of generic enrofloxacin (Tenotryl™ (enrofloxacin) injectable solution; TEN) to pioneer enrofloxacin (Baytril® 100; BAY) for first treatment of naturally occurring bovine respiratory disease (BRD) on subsequent health outcomes in a commercial feedlot. Five hundred cattle identified with BRD by pen riders with rectal temperature ≥ 104.0°F (40°C) were randomized to TEN or the BAY in a 1:1 ratio within each lot. Cattle treated for BRD were returned to their home pen and monitored for 60 days to observe subsequent health outcomes. Cattle were categorized by type (dairy-beef cross or traditional beef breed). General and generalized linear mixed models were used for statistical analyses. There were no differences in first treatment success (64.29% vs 58.16%; P = 0.19) or case fatality risk (10.97% vs 10.65%; P = 0.91) comparing the TEN group to the BAY group respectively. Traditional beef breed cattle had greater body weight at time of enrollment (890.3 lb vs 749.1 lb; P &lt; 0.01) and greater third treatment success (84.44% vs 41.67%; P &lt; 0.01) compared to the dairy-beef cross cattle. There were no differences in health outcomes in cattle administered Tenotryl compared to Baytril 100 for first treatment of BRD in commercial feedlot cattle. From an efficacy perspective, practitioners should be able to use these products interchangeably based upon the results of the study. Additional research on general animal health outcomes of dairy-beef crosses is needed for the industry.

334 Use of Feed Additives in Unweaned Calves with Compromised Gut Integrity After Transportation

Abstract The gastrointestinal tract of unweaned calves is compromised after the stress and feed restriction due to marketing and transportation. The use of feed additives to enhance intake and gut immunity at farm arrival could be a strategy to minimize those negative effects. A total of 70 dairy beef calves (50.9 ± 1.66 kg) coming from auction market and with a compromised gut integrity at arrival were used to evaluate the effect of various feed additives [FA; comprising palatability enhancers (PE), standardized olive pomace extract (OE), and tributyrin (TB)] on performance until 2 weeks after weaning. Calves were distributed in 5 treatments: calves fed milk replacer (MR) and concentrate without FA (CTR; n = 14); calves fed MR and concentrate with PE (PE; n = 14); calves fed MR with OE + PE and concentrate with PE (OEPE; n = 14), calves fed MR with TB + PE and concentrate with PE (TBPE; n = 14); and calves fed MR with OE + TB + PE and concentrate with PE (complete - COM; n = 14). At arrival animals received 2.5 L of MR twice daily at 12.5% and ad libitum concentrate feed. On day 35 of the study, animals were submitted to a social stress challenge, calves within one treatment were mixed for 24 h, and on day 36, calves returned to their home pens and the afternoon milk was removed. On day 42, all calves were weaned, and they were followed until day 56. Data were analyzed with a mixed-effects model. After transportation calves had an average of 1.6 ± 0.09 mg/L of serum Cr-EDTA the first week after arrival indicating that those calves had increased gastrointestinal permeability and a compromised gut barrier for a full week; consequently, concentrate intake during that week was decreased for all treatments (P = 0.56) with an average of 27 g·calf-1·d-1. An interaction between treatment and time (P &amp;lt; 0.01) was observed on concentrate intake the last two weeks of the study when calves were already weaned; on week 7, from day 42 to d 49, COM and TBPE calves had greater concentrate intake than CTR calves, and PE and OEPE did not differ among others; and on week 8, between day 42 and day 49, COM calves had the greater concentrate intake than CTR, while other treatments were in between. Although only numerical differences were observed in final BW, COM calves were heavier than the rest of the treatments at the end of the study. In calves with severe problems of gastrointestinal permeability at arrival, the mixture of palatability enhancers, standardized olive pomace extract, and tributyrin increases concentrate intake and potentially improve the recovery of the animals.

335 Use of Feed Additives Added to the Milk Replacer and Concentrate Or Only to the Concentrate in Unweaned Dairy Beef Calves After Transportation and Its Effects on Performance

Abstract Previous studies have shown that the use of additives to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation in unweaned calves. Unweaned dairy beef calves are fed low liquid feeding programs to avoid mechanical diarrheas and to enhance the consumption of solid feed to increase growth. A total of 78 dairy beef calves (57.8 ± 1.64 kg) coming from auction market were used to evaluate the effect of various feed additives [FA; comprising palatability enhancers (PE), standardized olive pomace extract (OE), and tributyrin (TB)] added to the milk replacer (MR) and concentrate or only to the concentrate on performance until 1 week after weaning. Calves were distributed in 6 treatments: calves fed MR and concentrate without FA (CTR-CTR; n = 13); calves fed MR without FA and concentrate with PE (CTR-PE; n = 13); calves fed MR without FA and concentrate with complete mixture OE + TB + PE (CTR-COM; n = 13); calves fed MR and concentrate with PE (PEPE; n = 13); calves fed MR with PE and concentrate with complete mixture OE + TB + PE (PE-COM; n = 13); calves were fed MR with complete mixture OE + TB + PE and concentrate with PE (COM-PE; n = 13). At arrival calves were only fed 2 L of MR twice daily at 12.5% and concentrate feed ad libitum. On day 35 of the study, animals were submitted to a social stress challenge, calves within one treatment were mixed for 24 h, and on day 36, calves returned to their home pens and the afternoon milk was removed. On day 42, all calves were weaned, and they were followed until day 49. Data were analyzed with a mixed-effects model. No differences were observed in concentrate intake the first week after transportation. However, an interaction between treatment and time (P &amp;lt; 0.01) was observed among treatments in concentrate intake from day 35 until day 49 when calves were already weaned. The PE-PE and PE-COM calves had a greater (P &amp;lt; 0.10) concentrate intake from day 28 to day 42 than CTR-CTR or CTR-PE calves, while from day 42 to day 49 the CTR-COM was the group of calves with the greatest concentrate intake. Although no differences were observed on final BW among treatments, the CTR-COM calves had numerically greater ADG than the rest of the treatments. In unweaned dairy beef calves with liquid feeding restriction, the mixture of palatability enhancers, standardized olive pomace extract, and tributyrin potentially increases concentrate intake and growth when added in the concentrate feed.

Effects of positive human contact on fear and physiological stress responses in Pekin ducks (Anas platyrhynchos domesticus) subjected to crating and transport

A growing body of research shows that farm animals frequently seek and enjoy human interaction. However, there is a lack of information on how positive human contact affects ducks' stress and fear responses. An experiment was conducted to compare the effects of positive human contact on tonic immobility (TI) duration, serum levels of corticosterone (CORT) and heat shock protein (HSP) 70 in male Pekin ducks (Anas platyrhynchos domesticus) subjected to crating or road transport. The growth performance of the ducks was also determined. In this experiment, 600 day-old male Pekin ducklings were equally assigned to one of the following human contact treatments; (1) ducks were picked up individually and stroked gently for 30 s once daily in their home pen from day 1 to day 42 (P1–42); (2) ducks were picked up individually and stroked gently for 30 s once daily in their home pen from day 1–21 (P1–21); (3) ducks were picked up individually and stroked gently for 30 s once daily in their home pen from day 21–42 (P21–42); or (4) the ducks did not receive human contact other than the routine husbandry (NC). On day 42, ducks from each experimental group were exposed to one of three conditions: crating for 3 hours, road transportation for 3 hours, or basal conditions in which they remained undisturbed in their home pens. The P21–42 ducks exhibited higher levels of stress and fear than the P1–42 and P1–21 ducks, as indicated by CORT and TI duration measurements following crating or transport. The P1–42 and P1–21 ducks exhibited higher levels of HSP70 expression than the NC group under both basal conditions and after being subjected to crating and transportation. In conclusion, this study demonstrates the beneficial effect of positive human contact from days 1–21 or days 1–42 in enhancing resilience to crating and transportation in ducks.

184 Genetic Parameters for Human-Directed Behavior and Intraspecific Social Aggression Traits in Growing Pigs

Abstract This study aimed to estimate heritabilities and genetic and phenotypic correlations for human-directed behavior and intraspecific social aggression traits in growing pigs, and to explore genetic and phenotypic correlations among them. Pigs (n = 2,314) were mixed into groups of 18 animals at 69 ± 5.2 d of age and skin lesions (SL) were counted 24 h (SL24h) and 5 weeks (SL5WK) post-mixing. Individual behavioral responses to isolation in a weighing crate (CRATE, 1 = pig performing exploratory behavior to 4 = pig performing serious, persistent attempts to escape) or when alone in an arena while a human directly approached them (IHAT) were assessed within 48 h post-mixing. During the IHAT, three separate scores were given for each pig based on the severity (0 = none to 3 = severe reaction) of their movement, vocalizations, and vigilance. Additionally, pigs were tested for behavioral responses to the presence of a single human observer walking in their home pen in a circular motion (WTP) within 1 and 4 weeks post-mixing recording pigs that followed, nosed or bit the observer. An animal model was used to estimate genetic parameters for all studied traits using the DMU software. Heritabilities (h2) for SL, CRATE and IHAT responses were low to moderate (0.17 to 0.29), with the greatest h2 estimated for speed of moving away from the approaching observer in the IHAT. Low but significant h2 were estimated for nosing (0.09) and biting (0.11) the observer at 4 weeks post-mixing in the WTP test. Positive high genetic correlations (rg) were observed between CRATE and IHAT responses (0.55 to 0.90), and within SL traits (0.60 to 0.94) while positive low to high rg were estimated within the WTP test (0.24 to 0.59) traits. Positive moderate rg were observed between CRATE and central and posterior SL24h. Genetic correlations between CRATE and IHAT test responses and WTP test traits were low, mostly negative (-0.21 to 0.05) and not significant. Low positive rg (0.06 to 0.24) were observed between SL and the WTP test traits except for the lack of rg between posterior SL24h and pigs biting or following the observer during both tests. Phenotypic correlations between CRATE and IHAT responses and SL or WTP test traits were mostly low and not significant. Under the conditions of this study, h2 estimates for all studied traits suggest they could be suitable as a method of phenotyping aggression and fear and/or boldness in pigs for genetic selection purposes. Additionally, there was evidence of genetic associations between aggression and fear indicators. These findings suggest applying selection pressure to reduce the accumulation of lesions is likely to make pigs more relaxed in a crate environment, but to alter the engagement with humans in other contexts that depends on the location of the lesions under selection.

65 Associations Between Resilience to Weaning Stress and Startle Response in Nursery-Age Gilts

Abstract Resilience is the capacity of animals to return quickly to their pre-stress status following a disturbance, including social, physical, and/or disease challenges. Understanding impact of individual resilience on behavior is key to improving the performance and welfare of farm animals. The goal of the study was to assess whether behavioral response to an auditory stimulus during a startle test (acute stress) differed between pigs designated as stress-resilient (SR) or stress-vulnerable (SV). Blood samples were collected from female piglets (n = 170) from 26 litters on the day before weaning, the day of weaning, and four days after weaning. Using serum cortisol concentrations from these samples, female pigs (n = 52) were classified as either SR (n = 26) or SV (n = 26) and used for the startle test. The startle test was conducted when pigs were 6 weeks-of age while they were housed in the nursery room. Video recordings were made with ceiling-mounted cameras from 1.5h before the test to 1.5h after the test. Videos were decoded to determine the relaxed-tense score of the pigs (RT; 1: relaxed, 3: tense; scored 10 min before testing began to describe the underlying mood of the pig), orientation to stimulus (OS; direction pigs were facing when air horn sounded), and startle magnitude score (SM; 0: no response, 4: remained frozen &amp;gt;1min). A mixed-effects ordinal logistic regression model was fit for SM including fixed effects of stress group (resilience designation (SR/SV), OS, RT, and pen position (distance from the air horn) and random effect of pen composition (social group). SM was affected by RT (P = 0.02), with pigs that had the greatest levels of underlying tension expressing less response to the stimulus. Pen position also impacted the SM (P &amp;lt; 0.01), with pigs in pens closer to the air horn displaying a stronger startle response than those housed further away. However, SR/SV designation and OS had no influence on SM. Pigs that are already tense may not be responsive to changes in their surroundings, in this case showing little response to a startling noise. Pigs closer to a startling stimulus are likely to perceive it as more threatening than pigs further away from the potential danger. Our data suggest no relationship between intensity of behavioral response to an auditory startle test and resilience or vulnerability to weaning stress. Behavioral and physiological responses to acute stress are influenced by a number of confounding factors inherent in individual animal variability, including the personalities and experiences of the pigs. However, the startle test could be a relatively easy way to assess fearfulness of pigs on farm, as it requires no training of pigs and can be conducted in the home pen, but further methodological improvement is required to enable instantaneous data collection.