John J. McGlone

Absence of lithium-induced taste aversion after area postrema lesion

Anatomical and physiological evidence indicates that the area postrema (AP) lacks a blood-brain barrier6, la and is thus permeable to blood-born substances which do not penetrate most other areas of the brain. The classical experiments of Borison (refs. 5, 7) demonstrated that the AP region contains chemoreceptors which stimulate vomiting in some species in response to certain drugs. This finding suggests that one function of the AP is to detect ingested toxins and trigger their expulsion from the gastrointestinal tract. In addition to producing vomiting, some toxic substances, which are encountered by animals in association with novel foods, may result in formation of learned responses known as conditioned taste aversions (CTAs)3A 1. These learned responses decrease the probability that animals will subsequently ingest particular foods which were previously associated with toxic effects. Berger et al. 4 were the first to demonstrate that the AP plays a critical role in the formation of CTA by some chemical substances. Taste aversions formed by scopolamine methyl nitrate (SMN), a neuroactive substance which does not cross the blood-brain barrier, were shown to be mediated by the AP. On the other hand, the CTA formed by D-amphetamine, a drug which readily penetrates the blood-brain barrier, does not require an intact AP. On the basis of these data, it appears that more than one mechanism may exist for the formation of CTAs. Moreover, these results provide evidence of an important role for the AP region in behavioral, as well as in gastrointestinal, functions. Lithium chloride (LiCI) is a compound which is widely used in CTA studles2,~2, t3. However, the mechanism by which LiCI induces CTAs ts not known. The

Farm animal welfare in the context of other society issues: toward sustainable systems

The measurement of farm animal well-being has evolved through several stages to return to the most agreed-upon system of evaluation that uses a multidisciplinary approach. The multidisciplinary approach includes measures of animal behavior, physiology, anatomy and health and immunity. However, the multidisciplinary approach must be used in the context of other important society issues including: food safety, environmental protection, worker health and safety, economics, international trade, domestic protection, public perception and consumer economics. Only by taking into account all society issues, can the multidisciplinary approach yield useful information to the modern consumer in a manner that can develop sustainable animal production systems.

EVIEW: Compilation of the Scientific Literature Comparing Housing Systems for Gestating Sows and Gilts Using Measures of Physiology, Behavior, Performance, and Health 1

The objective of this review was two-fold. First, a series of meta-analyses (analyses of treatment effects across studies) were performed on available data from scientific literature to determine whether sow behavior, performance, or physiology differed for sows in group pens or individual stalls. Second, research publications in areas of performance and health, physiology, and behavior of pregnant gilts and sows in studies that directly compared gestation sow housing systems were summarized. Common systems were stalls, tethers, and various types of group housing systems. Results of meta-analyses showed that the average levels of productivity, oral-nasal-facial behaviors (ONF), and blood cortisol were statistically similar for sows in group pens and stalls. For the review, in some studies, circulating cortisol concentrations were greater among gestating females kept in tethers compared with other systems; however, overall cortisol was not altered by housing system. Immune parameters were largely not influenced by housing system. Housing system did not alter heart rate. Gestation housing system may influence sow behavior including stereotypic ONF, postural locomotory, feeding behaviors, or social behaviors. Overall, total ONF behaviors were comparable between gestation sow housing systems. However, tethered and stalled sows exhibited more stereotypic ONF compared with sows in group or outdoor systems. Compared with group housing, individually confining sows during gestation resulted in postural and movement restrictions. Stall size and design can impact postural adjustments and inter-stall aggression of individually housed sows. Inconsistent performance and health results were found among sow housing studies. Sows in stalls consistently had equal or greater reproductive performance compared with sows in other systems. Farrowing rate for sows in individual stalls was equal to or superior to sows in other systems. Farrowing rate was clearly superior among sows in stalls compared with group systems, where dynamic social groups were employed. However, tethered sows may have reduced litter size and increased piglet birth weight. Sows in group housing systems, particularly electronic sow feeder (ESF) systems, had injury scores greater than sows in either stalls or tethers. Gestation housing system (individual vs group) may impact sow welfare in the farrowing area (using stalls or pens). In conclusion, although individual studies found significant housing system effects, subjected to the overall evidence from adequately designed studies meta-analyses revealed that gestation stalls (non-tethered) or well-managed pens generally (but not in all cases) produced similar states of welfare for pregnant gilts or sows in terms of physiology, behavior, performance, and health.

Airborne Microbial Flora in a Cattle Feedlot

ABSTRACT A total of 1,408 cattle held in eight commercial feedlot pens were used to examine the quantity and diversity of microorganisms in cattle feedlot air. The effect of two feeding patterns on the generation of airborne dust and the total numbers of microorganisms was also examined (four feedlot pens/treatment). Microbial samples were collected, and dust particles that were 2.5 μm or less in diameter were measured with a Dustrak monitor during the evening dust peak for 4 days at sites both upwind and downwind of the feedlot pens. An Andersen biological cascade sampler was employed with different medium and incubation combinations for the capture and identification of bacteria and fungi. The results showed that when bacteria were considered, only nonpathogenic gram-positive organisms were recovered. However, gram-negative bacteria may have been present in a viable but nonculturable state. Fungi were recovered in smaller numbers than bacteria, and none of the fungi were pathogenic. The Dustrak results showed that one feeding pattern resulted in cattle behavior that generated levels of downwind dust lower (P = 0.04) than the levels generated by the behavior resulting from the other feeding pattern. However, the Andersen sampler results showed that there were no differences between feeding patterns with regard to the total number or diversity of microorganisms. The disparity may have been due to the different operating principles of the two systems. The overall numbers of microorganisms recovered were lower than those reported in studies of intensively housed farm animals in which similar recovery techniques were used.

Space requirements for finishing pigs in confinement: behavior and performance while group size and space vary

Abstract A total of 450 pigs were used in two studies to examine the effects of group size and floor space on use of space and pig performance for pigs held in confinement on total concrete slats. In the first study, pigs showed similar weight gain, feed intake and feed efficiency when held in pens providing 0.74 m2 per pig and in group sizes of 10, 20 or 40 pigs per pen. Pig injury/morbidity rates were greatest for pigs held at 40 pigs per pen. Examination of pig postures every 30 min for a 24-h period allowed us to use published allometric equations to determine amount of floor space occupied by pigs and amount of floor space free or unoccupied. Free space perpig increased as group size increased. In the second performance trial, removal of 50% of the free or unused space resulted in no performance problem; however, removal of all the free space (or exactly meeting pig body space needs) resulted in reduced pig weight gain. These data support the idea, firstly, that space needs per pig decrease slightly as group size increases. Secondly, to avoid performance set-backs, pigs require some free space beyond their static space requirements (beyond their need for resting places for their bodies).

Tail docking in pigs: acute physiological and behavioural responses

Tail docking of piglets is a routine procedure on farms to control tail-biting behaviour; however, docking can cause an acute stress response. The objectives of this research were to determine the stress responses to tail docking in piglets and to compare two methods of tail docking; cautery iron (CAUT) and the more commonly used blunt trauma cutters (BT). At approximately 6 days of age, piglets were tail docked using CAUT (n = 20), BT (n = 20) or sham tail docked with their tails remaining intact (CON; n = 40). Blood samples were taken prior to tail docking and at 30, 60 and 90 min after tail docking to evaluate the effect of tail docking on white blood cell (WBC) measures and cortisol concentrations. The above experiment was repeated to observe behaviour without the periodic blood sampling, so as not to confound the effects of blood sampling on piglet behaviour. Piglet behaviour was recorded in the farrowing crate using 1 min scan-samples via live observations for 60 min prior to and 90 min after tail docking. Total WBC counts were reduced (P > 0.05) among BT and CAUT compared with CON piglets 30 min after tail docking. Cortisol concentrations were higher (P < 0.01) among BT compared with CON and CAUT piglets 60 min after tail docking. Cautery and BT-docked piglets spent more (P < 0.05) time posterior scooting compared with CON piglets between 0 and 15 min, and 31 and 45 min after tail docking. Piglets tail docked using CAUT and BT tended to spend more (P < 0.07) time sitting than CON piglets between 0 and 15 min post tail docking. Elevated blood cortisol can be reduced by the use of the CAUT rather than the BT method of tail docking. Although the tail docking-induced rise in cortisol was prevented by using CAUT, the behavioural response to BT and CAUT docking methods was similar.

Consequences of restraint stress on natural killer cell activity, behavior, and hormone levels in rhesus macaques (Macaca mulatta)

Three experiments were performed to determine the effect of stress on the neuroendocrine-immune system in nonhuman primates. In Experiment 1 the diurnal variation in cell and hormone levels was determined. The percentages of neutrophils, monocytes, and eosinophils fluctuated throughout the 24-hr period, while white blood cell (WBC), neutrophil-to-lymphocyte ratio (N:L), hemoglobin (Hgb), natural killer cell cytotoxicity (NK activity) and beta-endorphin levels did not. Experiment 2 investigated the effects of ketamine and restraint on behavior. Scratching was increased in control monkeys and animals receiving ketamine, whereas passivity was increased in chair-restrained animals. In Experiment 3, eight adult male rhesus monkeys were restrained in primate chairs at 0600h. Behavior was filmed for 3 hr and blood samples were collected at 0700, 0800, and 0900. Whole blood was analyzed for total WBC and percentage of each leukocyte type. NK activity was also measured. Plasma levels of cortisol and beta-endorphin were determined and behavior was quantitated from video-records. WBC and the percentage of neutrophils increased during the restraint period, while the percent lymphocytes and monocytes decreased. NK activity also decreased over time after restraint whereas plasma cortisol and beta-endorphin levels increased significantly. Although after the 3 hr of restraint stress, changes were found in hormone levels, behavior, and NK activity, there were no significant correlations between the parameters measured. Thus, our results indicate that there is not a common neuroendocrine response or single neuroendocrine mediator that results in predictable behavioral changes and immune suppression following stress.

Influence of resources on pig aggression and dominance

Relationships between presence of feed and water and aggressive behaviour and correlations between dominance and use of these resources were investigated in 64 five to eight week old pigs (Sus scrofa ). Pens of four randomly-selected pigs were established. Social dominance order was obtained largely within the first four hours but aggressive behaviour reached zero 19.4 hours after regrouping four pigs. Whether feed or water were present, pigs fought at similar levels. Pigs who were more aggressive did spend more time drinking water when resources were limited. Pigs that headed the aggressive dominance order did not gain preferred access to resources when they were in limited supply nor when they were abundant.

Environmental enrichment influences on pig behavior, performance and meat quality

Abstract The influence of environmental enrichment and genotype were evaluated for effects on performance, behavior and carcass characteristics in 320 pigs from weaning to slaughter at over 110 kg. Ten treatments were evaluated including two genotypes and five levels of enrichment, arranged factorially. Genotypes were PIC C-15×405 cross (C-15) which is a commonly employed commercial hybrid in the US swine industry and PIC EXP-94×405 cross (EXP-94; one-eighth Meishan). The herd was positive for Porcine Respiratory and Reproductive Syndrome virus which contributed to a high rate of mortality (6–40% death rate within treatments). The five environmental treatments were isolation (NEG), weekly normal handling (NOR), daily normal handling plus the addition of environmental enrichment devices (TOYS), daily normal handling plus 2-min pleasant handling bouts with humans 5 days/week (HUM), and the same as HUM plus TOYS ( T + H ). Averaged over genotypes, growth and efficiency measures were not effected by the range of environmental treatments performed. Enrichment treatments and genotypes tended to interact ( P =0.07) for average daily gain and Feed:Gain ratio. C-15 pigs showed similar ADG and F:G ratio in the five enrichment treatments. However, EXP-94 pigs exposed to the TOYS had improved ADG and F:G ratio ( P T + H and NEG treatments. Pigs in the NEG had less backfat opposite the last rib and last lumbar vertebrae ( P P

Impact of spontaneous exercise on performance, meat quality, and muscle fiber characteristics of growing/finishing pigs.

The objective of this experiment was to determine if increased space and exercise for finisher pigs (0.90 vs 9.45 m2/pig) affects performance, meat quality, or muscle fiber characteristics. Newsham barrows (n = 32, 4 pens/treatment) were placed in one of two space allocations: control space allowance (CONT) or in a long pen with increased space allowance (10x). Pigs were weighed every 28 d and feed intake/pen was calculated. Pigs were filmed for behavioral analysis on d 70 and 100 using video recorders to determine walking distances over a 24-h period. After a 5-h transport and 2-h rest period, pigs (approximately 115 kg) were slaughtered on the same day at a commercial facility. Muscle samples were obtained from the longissimus lumborum (LL) and semimembranosus (SM) muscles within 1 h postmortem for muscle fiber typing. Backfat thickness and pH decline were measured on the left side of each carcass. After 24-h chilling, a boneless loin was collected from each pig and stored at 2 degrees C until analyzed. On d 14 postmortem, loins were cut at the 10th rib for color evaluations, and chops were cut for Warner-Bratzler shear (WBS) force and sensory analysis. Histochemical staining methods were used for the detection of type I, IIA, and IIB/X muscle fiber types. There were no significant differences (P > 0.10) in live weight, ADG, ADFI, or G:F ratio of the two experimental groups evaluated. Pigs finished in 10x pens walked a greater (P < 0.01) distance over a 24-h period than pigs finished in the CONT pens. Pigs finished in the lOx pens were fatter (P < 0.05) at the last lumbar vertebra than pigs finished in the CONT pens, but no significant differences were found in loineye area, loin color, marbling scores, WBS, sensory panel scores, retail display measures, or muscle fiber type percentages. Expanded space allowance to increase exercise resulted in no improvements in pig performance, pork loin measures, or muscle characteristics.