Effects of flavoring additives on feed intake, growth performance, temperament and markers of immune function for newly received feedlot cattle.

Ninety Angus × Hereford steers (259.9 ± 36.18 kg body weight (BW)), were used in a 56-d experiment to assess the effects of flavoring additives on feed intake, and stress and immune response of newly received feedlot cattle. Steers were homogenously distributed by BW into six pens equipped with an individual feed intake monitoring system, and pen was randomly assigned to one of three treatments (15 head/pen; 30 head/treatment): a standard feedlot receiving diet (CT), or the same diet with a flavoring additive comprised of either sweeteners (Luctarom Feedlot, SW) or a mix of basic tastes (Luctarom Feedlot Mix, MX) at 1 kg/mT. Pens were equipped with a feed intake monitoring system, while BW, chute behavior, flight speed, blood and saliva samples were collected bi-weekly, and hair samples collected at 4-week intervals during the study. Data were analyzed using a mixed-effects model for a pen study using individual animal records with repeated measures. There was a treatment × week interaction (P < 0.01) where meal duration was greater in SW steers than MX and CT on wk 3, and than CT on wk 7 and 8. A trend for treatment × week interaction (P = 0.06) showed that the number of visits per day tended to be greater in SW than MX steers on wk 4 and 5, and it tended to be greater in SW than MX and CT on wk 5. The concentration of IL-6 was greater (P <0.01) on d 1 and 28 than on d 14. The IgM concentration was greater (P < 0.01) on d 1 compared to d 14, 28 and 56. The concentration of haptoglobin was greater (P < 0.01) on 14 than d 28, 42 and 56, and it was greater (P < 0.01) on d 1 than d 42 and 56. The concentration of serum amyloid A was greater (P < 0.01) on d 1 compared to the rest of sampling days. Fibrinogen concentration was greater (P < 0.01) on d 1 compared to d 14 and 42. The neutrophil-to-lymphocyte ratio was greater (P < 0.01) on d 42 and 56 compared to d 1 and 28, and greater (P < 0.01) on d 14 compared to d 28. Hair and saliva cortisol concentration were lower (P < 0.01) on d 56 compared to d 1 and 28, respectively. The use of flavoring additives, particularly when based on sweeteners (SW), caused some changes in the feeding pattern of newly received steers. These changes, however, were not consistent over the 56-d feeding period and were not accompanied by a change in growth performance, temperament, biomarkers of stress, inflammation, or immune function.

Serum concentrations of brain-derived neurotrophic factor as a potential biomarker of swine welfare.

Objective: Describe concentrations of brain-derived neurotrophic factor (BDNF) detectable in piglet sera before and after road transport, and evaluate the correlation of serum BDNF with other physiological parameters used to assess swine welfare. Animals: Commercial crosses of piglets that underwent weaning and transport at approximately 3 wk of age. Procedure: Sixteen piglets were randomly selected from a larger study for complete blood counts, serum biochemistry testing, cortisol assays, and BDNF assays. Samples were collected 1 d before transport and immediately after transport (> 30 h) under commercial conditions. We assessed the change in serum BDNF concentration; and the correlations between serum BDNF and serum cortisol, neutrophil to lymphocyte ratios (N:L), glucose, and hematological indicators of muscle fatigue. Results: Serum BDNF concentrations increased after transport (P < 0.05) and changed inversely compared to cortisol and N:L. Consistent correlations between BDNF and other physiological parameters were not observed. High inter-pig variation in serum BDNF was present at both sample times. Conclusions: Serum BDNF may be used as an additional indicator of swine welfare. Further research characterizing piglet BDNF concentrations in response to conditions promoting positive or negative affective states would be valuable. Clinical relevance: This communication discusses common hematological parameters used to quantify changes in pig welfare and introduces BDNF, which is a parameter of interest in human cognitive functioning research that may be useful for evaluating the effect of exposure to beneficial or aversive stimuli in animals. The implications of variation in sample collection, handling, and storage procedures for BDNF detection are highlighted.

Concentrations sériques du facteur neurotrophique dérivé du cerveau en tant que biomarqueur potentiel du bien-être des porcs. Objectif: Décrire les concentrations de facteur neurotrophique dérivé du cerveau (BDNF) détectables dans les sérums de porcelets avant et après le transport routier, et évaluer la corrélation du BDNF sérique avec d'autres paramètres physiologiques utilisés pour évaluer le bien-être des porcs. Animaux: Croisements commerciaux de porcelets qui ont été sevrés et transportés à l'âge d'environ 3 semaines. Procédure: Seize porcelets ont été sélectionnés au hasard dans une étude plus vaste pour une numération globulaire complète, des tests de biochimie sérique, des dosages de cortisol et des dosages de BDNF. Les échantillons ont été prélevés 1 jour avant le transport et immédiatement après le transport (> 30 h) dans des conditions commerciales. Nous avons évalué la variation de la concentration sérique de BDNF; et les corrélations entre le BDNF sérique et le cortisol sérique, les rapports neutrophiles/lymphocytes (N:L), le glucose et les indicateurs hématologiques de la fatigue musculaire. Résultats: Les concentrations sériques de BDNF ont augmenté après le transport (P < 0,05) et ont changé inversement par rapport au cortisol et à N:L. Des corrélations cohérentes entre le BDNF et d'autres paramètres physiologiques n'ont pas été observées. Une forte variation inter-porcs du BDNF sérique était présente aux deux moments d'échantillonnage. Conclusions: Le BDNF sérique peut être utilisé comme indicateur supplémentaire du bien-être des porcs. Des recherches supplémentaires caractérisant les concentrations de BDNF chez les porcelets en réponse à des conditions favorisant des états affectifs positifs ou négatifs seraient utiles. Pertinence clinique: Cette communication traite des paramètres hématologiques courants utilisés pour quantifier les changements dans le bien-être des porcs et présente le BDNF, qui est un paramètre d'intérêt dans la recherche sur le fonctionnement cognitif humain qui peut être utile pour évaluer l'effet de l'exposition à des stimuli bénéfiques ou aversifs chez les animaux. Les implications pour la détection par le BDNF des variations dans les procédures de collecte, de manipulation et de stockage des échantillons sont mises en évidence.(Traduit par Dr Serge Messier).

Exploration of plasma metabolite levels in healthy nursery pigs in response to environmental enrichment and disease resilience.

The purpose of this study was to explore plasma metabolite levels in young healthy pigs and their potential association with disease resilience and estimate genetic and phenotypic correlation with the change in lymphocyte concentration following disease challenge. Plasma samples were collected from 968 healthy nursery pigs over 15 batches at an average of 28 ± 3.23 d of age. Forty-four metabolites were identified and quantified by nuclear magnetic resonance. Pigs were then introduced into a natural disease challenge barn, and were classified into four groups based on the growth rate of each animal in the grow-to-finish phase (GFGR) and treatment rate (TR): resilient (RES), average (MID), susceptible (SUS), and dead (pigs that died before harvest). Blood samples were collected from all pigs before and 2 wk after disease challenge and complete blood count was determined. Environmental enrichment (inedible point source objects) was provided for half of the pigs in seven batches (N = 205) to evaluate its impact on resilience and metabolite concentrations. Concentration of all metabolites was affected by batch, while entry age affected the concentration of 16 metabolites. The concentration of creatinine was significantly lower for pigs classified as "dead" and "susceptible" when compared to "average" (P < 0.05). Pigs that received enrichment had significantly lower concentrations of six metabolites compared with pigs that did not receive enrichment (P ≤ 0.05). Both, group classification and enrichment affected metabolites that are involved in the same pathways of valine, leucine, and isoleucine biosynthesis and degradation. Resilient pigs had higher increase in lymphocyte concentration after disease challenge. The concentration of plasma l-α-aminobutyric acid was significantly negatively genetically correlated with the change in lymphocyte concentration following challenge. In conclusion, creatinine concentration in healthy nursery pigs was lower in pigs classified as susceptible or dead after disease challenge, whilst l-α-aminobutyric may be a genetic biomarker of lymphocyte response after pathogen exposure, and both deserve further investigation. Batch, entry age, and environmental enrichment were important factors affecting the concentration of metabolites and should be taken into consideration in future studies.

The focus of this study was to explore plasma metabolite levels in young healthy pigs and their potential association with health outcome classification following the exposure to a polymicrobial disease challenge. In addition, we explored the effect of the environmental enrichment on metabolite concentrations. Finally, we estimated genetic and phenotypic correlations between metabolites and the magnitude of change in lymphocytes levels following exposure to a polymicrobial disease challenge. We found that concentration of creatinine was lower in pigs that died before marketing, classified as "dead" and susceptible when compared to average group. This indicates that creatinine can be used as an early indicator of death and/or susceptibility of disease in pigs. Providing environmental enrichment affected the concentration of six metabolites and branched chain amino acids index. Such results would be very useful to design environmental enrichment strategies when pigs are challenged by disease in commercial farms. The magnitude of change in lymphocytes level was negatively genetically correlated with l-α-aminobutyric acid. This result indicates that l-αs-aminobutyric acid can be an early indicator of the magnitude of change in lymphocytes level. Such indicator can be collected from nucleus breeding herds in healthy animals and could provide an early biomarker of resilience.

Effects of Enrichment Type, Presentation and Social Status on Enrichment Use and Behavior of Sows-Part 2: Free Access Stall Feeding.

Continuing with previous research by our group in an ESF system, four types of enrichment treatments were assessed in gestating sows housed in Free Access Stalls: (1) Constant: constant provision of wood on chain; (2) Rotate: rotation of rope, straw and wood; (3) Stimulus: rotation of enrichments with an acoustic cue; and (4) Control: no enrichment. Treatments had a 12 day-duration. Four groups (28 ± 2 sows) were studied from weeks 6 to 14 of gestation. Groups received all treatments in random order. Three dominant and 3 subordinates per pen were selected using a feed competition test. Digital photos were collected at 10 min intervals for 8 h on days 1, 8, 10 and 12 to record interactions with enrichment. Skin lesions were assessed on days 1 and 12, and salivary cortisol was assessed in weeks 6, 10 and 14 of gestation. More enrichment use was observed in Rotate and Stimulus treatments compared to Constant, and more sows contacted enrichment when straw was provided in the Rotate and Stimulus treatments. There was no difference in the amount of enrichment use by dominants and subordinates, no cortisol concentration elevation in subordinate sows nor any difference in lesion scores. In conclusion, social status had little impact and feeding system is important to reduce stress and aggression.

Effects of Wash Protocol and Contamination Level on Concentrations of Cortisol and Dehydroepiandrosterone (DHEA) in Swine Hair.

The effect of washing procedure and contamination level on the concentrations of cortisol and dehydroepiandrosterone (DHEA) in swine hair was explored over two studies. Hair shaved from finisher pigs (n = 8) and sows (n = 8, cortisol study 1 only) was split into two treatments (two hair samples/pig) to receive either three isopropanol or methanol washes, and two paired subsamples of hair were contaminated with feces and urine, mildly or severely. Samples were further subdivided and received one, three, or five methanol washes. Hormone concentrations were quantified from the hair and wash solvent, and the ratio of hormones in the solvent to that in the hair calculated. When grouping sow and grower hair together for analysis, hair cortisol concentrations were 13% greater after three isopropanol washes compared to methanol (22.84 ± 3.12 vs. 19.77 ± 2.64 pg/mg, respectively). When analyzing sow and grower hair separately, sow hair cortisol concentrations were 20% higher following three isopropanol washes compared to methanol washes (22.06 ± 5.21 vs. 27.72 ± 5.65 pg/mg), with no differences in grower pig hair concentrations. The solvent cortisol concentrations did not differ with wash solvent. No differences were seen for DHEA. Contamination level did not influence hormone concentrations. Hair cortisol concentrations were 24% higher after one wash compared to five washes (11.98 ± 1.47 vs. 9.05 ± 0.92 pg/mg), whereas the solvent cortisol concentrations were 80% and 84% higher after one wash compared to three and five washes, respectively (21.09 ± 4.04 vs. 4.21 ± 1.62 vs. 3.36 ± 1.32 pg/mg). The solvent-hair cortisol ratio was 65% and 73% higher following one wash compared to three and five washes (1.36 ± 0.80 vs. 0.47 ± 0.12 vs. 0.37 ± 0.14). Hair DHEA concentrations were 39% higher after one wash compared to five washes (42.39 ± 6.87 vs. 26.02 ± 5.69 pg/mg). The solvent DHEA concentrations, and the solvent-hair ratio for DHEA were 94% and 98% and 92% and 98% higher going from one wash to three and five washes, respectively (solvent: 5.07 ± 0.26 vs. 0.28 ± 0.12 vs. 0.12 ± 0.09 pg/mg and solvent-hair ratio: 0.13 ± 0.006 vs. 0.010 ± 0.004 vs. 0.003 ± 0.002). Following three methanol washes, the non-contaminated hair had 46% and 48% higher hair (17.47 ± 1.12 vs. 9.35 ± 0.80 vs. 9.05 ± 1.06 pg/mg) and a 76% and 72% higher solvent (16.31 ± 8.07 vs. 3.92 ± 0.50 vs. 4.50 ± 2.31 pg/mg) cortisol concentration compared to mild and severely contaminated hair, respectively. Wash solvent influences cortisol concentrations in swine hair, but not DHEA. Contaminated swine hair should be avoided in analyses when possible.

Physiological response of weaned piglets to two transport durations observed in a Canadian commercial setting.

Observational studies describing the impact of transport duration on weaned piglet welfare are limited. Current Canadian transport regulations are heavily informed by studies involving market hogs. Due to physiological differences between weaned piglets and market hogs, additional data on their response to transport are needed for age-specific evidence-based recommendations. A cohort study was conducted to describe and compare mortality, injury, weight change, hematological or biochemical changes in hydration, muscle injury and stress response observed in weaned piglets undergoing short duration (SD, <3 h), or long duration (LD, >30 h) commercial summertime transport events. Data collection on 440 of 11,434 transported piglets occurred the morning of the day before transport (T0), at arrival (T1) and approximately 3 to 4 d (78 to 93 h) after arrival at the nursery barn (T2). Low mortality occurred over all transport events (0.06%) with no association observed between transport duration and odds of death during transport (P = 0.62). The incidence of lameness between T0 and T1 was low (1.84% of the 435 focal piglets scored) with all lameness cases identified as mild in severity. Lesions on ears and skin were more prevalent than other injury types after transport (T1) and may have been related to mixing aggression associated with weaning rather than transport alone. LD piglets weighed 0.39 kg less than SD piglets at T1 (P < 0.01), but no difference in group weight was observed at T2 (P = 0.17). Hematological and biochemical differences were present between groups at T1. LD piglets had increased hematocrit levels compared with SD piglets (P = 0.01), suggesting increased body water losses. SD piglets showed greater levels of muscle injury compared with LD piglets including elevated aspartate aminotransferase (P < 0.01) and creatine kinase (P < 0.01). However, these parameters were within normal reference ranges for piglets of this age group. Indicators of physiological stress response including cortisol and neutrophil to lymphocyte ratios were elevated in SD piglets compared with LD piglets (P = 0.02 and P < 0.01, respectively). The results of this study demonstrate that both short and long transport durations can result in detectable physiological changes in weaned piglets. The overall impact of these durations on piglet welfare should be further explored by analyzing behavioral time budgets during and after transport.

Effects of Enrichment Type, Presentation and Social Status on Enrichment Use and Behaviour of Sows with Electronic Sow Feeding.

The goal of this study was to identify practical enrichments for sows in partially or fully slatted pen systems. Four treatments were applied: (1) Constant: constant provision of wood on chain; (2) Rotate: rotation of rope, straw and wood enrichments; (3) Stimulus: rotation of enrichments (as in Rotate) with an associative stimulus (bell or whistle); and (4) Control: no enrichment, with each treatment lasting 12 days. Six groups of 20 ± 2 sows were studied from weeks 6 to 14 of gestation in pens with one electronic sow feeder. Each group received all treatments in random order. Six focal animals (3 dominant and 3 subordinate) were selected per pen using a feed competition test. Digital photos were collected at 10 min intervals for 8 h (between 8 a.m. and 4 p.m.) on 4 days/treatment (d 1, 8, 10 and 12) to record interactions with enrichment. Skin lesions were assessed on days 1 and 12, and saliva cortisol samples collected in weeks 6, 10 and 14 of gestation on focal pigs. Sows spent more time in contact with enrichments in Rotate and Stimulus treatments than Constant. Enrichment treatments did not influence lesion scores. Subordinate sows spent more time standing and near enrichments than dominants. Subordinate sows also received more skin lesions and had higher salivary cortisol concentrations than dominants. These results indicate that access to enrichment is valued by sows but can result in greater aggression directed towards subordinates.