Broiler chicken thigh and breast muscle responses to cold stress during simulated transport before slaughter.

The effect of acute cold exposure was assessed on broiler physiology, breast and thigh muscle metabolites, and meat quality. In total, 160 male birds at ages of 5 and 6 wk were exposed to temperatures of -9 to -15°C (cold stressed) and +20°C (control) in a simulated transport chamber for 3 h before slaughter followed by 0 or 2 h of lairage. Bird physiology parameters, including core body temperature, live shrink, blood glucose, and muscle temperature, were assessed. Core body temperature was monitored every minute using i-Button data loggers, and live shrink and blood glucose were assessed. Total glucose and lactate concentrations at 30 h postmortem, as well as ultimate pH (pH(u)), color, and water-holding attributes were evaluated on pectoralis major muscle of breast and iliotibialis muscle of thigh. Birds were grouped based on their microclimate temperature to control and cold-stressed groups (0 to -8, -8 to -11, and -11 to -14°C). Significant (P < 0.05) decreases in core body temperature and breast and thigh muscle temperatures were observed at simulated transport temperatures below 0°C. In addition, higher (P < 0.05) live shrink and lower blood glucose values were observed as a result of 3-h exposure to temperatures below 0°C, exacerbated as temperature decreased further below -8°C. Thigh muscle was almost depleted of glycogen reserve compared with a significant but small reduction in breast muscle glycogen when exposure temperature was below -8°C. Similarly, much greater effects were observed on thigh pH(u) and quality attributes compared with breast. In addition, 84% incidence of the dark, firm, dry quality defect was observed in thigh meat (pH(u) > 6.4, L* < 44) compared with 42% incidence of dark, firm, dry in breast meat (pH(u) > 6.1, L* < 46) when transportation temperature was below 0°C. Results of this study showed that thigh muscle was affected more severely than breast muscle by exposure to cold temperatures before slaughter.

The effect of simulated cold weather transport on core body temperature and behavior of broilers.

During the winter in Western Canada, broilers are routinely transported in ambient temperatures ranging from 0°C to -40°C, yet there is little research in this area. This study examined the physiology and behavior of broilers undergoing simulated transport at typical Western Canadian winter temperatures. Groups of 15 broilers aged 32 to 33 d were exposed to an air stream regulated to -5, -10, or -15°C. Birds were placed into a typical transport drawer. Following baseline observations, the drawer was placed into a test chamber where cold air was drawn past the birds for 3 h. Three replications were conducted at each temperature. The birds adjusted their position within the drawer based upon the temperature distribution within the drawer. In comparison to the baseline period, exposing the birds to a cold air stream caused them to avoid the front plane (P = 0.003) which was the coldest area within the drawer. The birds did not adjust their usage of the middle (P = 0.308) and rear (P = 0.640) planes, because these were the warmer areas within the drawer. The total amount of space the birds occupied within the drawer did not decrease when exposed to the test chamber (P = 0.669). The core body temperature (CBT) did not vary and was within the known normal range during the normal (P = 0.528), pre-chamber (P = 0.060), and post-chamber (P = 0.285) periods. The CBT of the birds significantly decreased during the in-chamber period (P < 0.001) and then increased during the lairage period (P < 0.001). The shrink loss (P = 0.981) and amount of time to resume feed consumption (P = 0.357) were not affected by exposing the birds to temperatures of -5°C and colder. Exposing birds to temperatures of -5°C and colder had a negative effect on the CBT of the birds. However, the birds demonstrated behaviors which mitigated the negative effect that cold exposure could have on their CBT.

Heat and moisture production by broilers during simulated cold weather transport.

To ensure broiler welfare during winter transport, it is necessary to manage heat and moisture accumulation within the transport vehicles. Hence, it is necessary to determine heat production (HP) and moisture production (MP) rates under representative conditions. An environmental chamber containing a standard transport drawer was used. Cold air was drawn from outside the building, warmed to the desired temperature, and passed through the drawer at 0.35 m(3)/s. Broilers were fasted for 7 h, placed into the drawer, and exposed to test conditions within the chamber for 3 h. Air temperature and RH were measured upstream and downstream of the insulated bird compartment at 1-min intervals. Differences in the paired temperature and RH values were used to calculate sensible HP and MP for each 1 min of confinement. Effects of temperatures between -8 and -18°C and a control (+20°C) were measured for birds in 2 conditions. In condition A, there were 15 birds/drawer. Birds were 32 to 33 d old and weighed 1.8 kg. Packing density was approximately 27 kg/drawer (31 kg/m(2)). In condition B, there were 19 or 22 birds/drawer. The drawers with 19 birds contained birds that were 39 to 40 d old that weighed 2.68 kg. In the drawers with 22 birds, the birds were 35 to 36 d old and weighed 2.29 kg. In either case, the packing density was approximately 50 kg/drawer (59 kg/m(2)). Thus, the birds in condition B were bigger, more numerous, and more tightly packed than the birds in condition A. Drawers were balanced for sex. At +20°C, HP and MP rates were similar to other published values. However, for both conditions, HP and MP rates increased with decreasing exposure temperatures. In condition A, HP was 6.08 ± 0.43 W/kg and MP was 4.46 g/h per kg at 20°C compared with 87.5 ± 10.3 W/kg and 22.08 ± 5.05 g/h per kg at -15°C. In condition B, HP was 8.12 ± 1.24 W/kg and MP was 5.53 ± 1.68 g/h per kg at 20°C compared with 45.92 ± 1.95 W/kg and 12.33 ± 0.22 g/h per kg at -18°C.

Variability in vocal and behavioural responses to visual isolation between full-sibling families of beef calves.

In order to assess the value of vocal response as an indicator of welfare in cattle, it is necessary to investigate factors which influence vocal behaviour of individuals, that are independent of the specific environmental conditions to which they are exposed. The effect of parental differences, sex, age and weight on vocal responses of calves to visual isolation were examined. The relationship between vocal response and the amount of body movement during isolation were also evaluated.Seventeen full-sibling families of beef calves (N=130) were created by breeding five sires with 13 superovulated dams. Embryos were transferred into unrelated cows, which reared the calves to weaning age. Vocal response of calves and body movement were measured on four occasions, while they were visually isolated for 1min on a single animal scale platform. The first two observations were made on the day of weaning (mean age 166 days) and the following day. At the third and fourth observations their average ages were 278 and 350 days, respectively. On the four occasions 33.3, 34.8, 27.8 and 38.6% of calves, respectively, vocalized. Both sire and family had a significant influence on the number of vocalizations and acoustic properties of the sounds. Electronically-measured movement while on the scale was also influenced by sire and family, but there was no relationship between vocal responses and body movement. There was a tendency (P=0.08) for older and therefore heavier calves to produce longer vocalizations. In the final observing session, age and weight were positively correlated with fundamental frequency and the sound pressure level at the frequency of greatest intensity, and negatively correlated with the loudest harmonic. At the last two observations, significantly more heifer calves than bull calves vocalized. There was little difference between the acoustic properties of heifers' and bulls' vocalizations.The considerable individual variability in vocal response within a group of identically-treated calves is partly due to parental genetic influences that are independent of rearing and early experience. Other endogenous characteristics such as sex, age and weight also influence vocal response. But there is no clear relationship between individual temperament (as assessed by the amount of body movement during isolation) and characteristics of vocal response.

Animats: computer-simulated animals in behavioral research.

The term animat refers to a class of simulated animals. This article is intended as a nontechnical introduction to animat research. Animats can be robots interacting with the real world or computer simulations. In this article, the use of computer-generated animats is emphasized. The scientific use of animats has been pioneered by artificial intelligence and artificial life researchers. Behavior-based artificial intelligence uses animats capable of autonomous and adaptive activity as conceptual tools in the design of usefully intelligent systems. Artificial life proponents view some human artifacts, including informational structures that show adaptive behavior and self-replication, as animats may do, as analogous to biological organisms. Animat simulations may be used for rapid and inexpensive evaluation of new livestock environments or management techniques. The animat approach is a powerful heuristic for understanding the mechanisms that underlie behavior. The simple rules and capabilities of animat models generate emergent and sometimes unpredictable behavior. Adaptive variability in animat behavior may be exploited using artificial neural networks. These have computational properties similar to natural neurons and are capable of learning. Artificial neural networks can control behavior at all levels of an animat's functional organization. Improving the performance of animats often requires genetic programming. Genetic algorithms are computer programs that are capable of self-replication, simulating biological reproduction. Animats may thus evolve over generations. Selective forces may be provided by a human overseer or be part of the simulated environment. Animat techniques allow researchers to culture behavior outside the organism that usually produces it. This approach could contribute new insights in theoretical ethology on questions including the origins of social behavior and cooperation, adaptation, and the emergent nature of complex behavior. Animat studies applied to domestic animals have been few so far, and have involved simulations of space use by swine. I suggest other applications, including modeling animal movement during human handling and the effects of environmental enrichment on the satisfaction of behavioral needs. Appropriate use of animat models in a research program could result in savings of time and numbers of animals required. This approach may therefore come to be viewed as both ethically and economically advantageous.

Eating behavior and the experience of hunger following gastric bypass surgery for morbid obesity.

BACKGROUND: Numerous different factors may contribute to the varying degrees of success observed following gastric bypass surgery. It is likely that alterations in the subjective experiences of hunger and satiety, as well as behavioral factors, are important. Our aim was to investigate the association of several factors, including qualitative aspects of hunger and satiety, eating patterns, and the emotional valence of different foods, to the weight loss that occurred following obesity surgery. METHODS: A questionnaire covering aspects of hunger, eating and satiety was administered to three groups: (1) a group of people who had undergone gastric bypass surgery with an acceptable weight loss; (2) a morbidly obese group of patients prior to their surgical intervention; (3) a group of people of normal weight. RESULTS: There were significant differences amongst the three groups in scoring on standardized eating disorder scales, in the amount they could eat, and in the experience of hunger. The presurgery, waiting-list group was more receptive to food-related than interoceptive cues when deciding to stop eating. 'Eating styles' also differed across the groups. CONCLUSIONS: It is concluded that changes in specific food-related behaviors and other psychological variables interact with the physical restriction to eating. The relative weighting of other variables needs further exploration.

The value of serum carcinoembryonic antigen in predicting recurrent disease following curative resection of colorectal cancer.

UNLABELLED: Carcinoembryonic antigen (CEA) estimations are used to facilitate early diagnosis of recurrent disease after treatment for colorectal cancer. PURPOSE: This study was designed to determine the natural history of patients with normal and abnormal levels of CEA. METHODS: Patients undergoing potential curative resection of colorectal tumors (Dukes Stage A-C) entered a prospective, randomized trial comparing two follow-up regimens (to be reported separately) had CEA levels measured every 3 months for two years; then every 6 months for the next three years. In the study protocol, a rise in CEA was not an indication for investigation to determine recurrence unless there was also other evidence of recurrent disease. RESULTS: Three hundred eleven patients were followed for a median of 4.5 (range, 2-5) years. Recurrent disease developed in 98 (32 percent) patients, 57 of whom had an elevated CEA (sensitivity 58 percent), with a median lead time of six (range, 1-30) months from first abnormal CEA to diagnosis of recurrent disease by other means. The specificity, positive predictive value, and negative predictive value of CEA as an indicator of subsequent recurrent disease was 93 percent, 79 percent, and 83 percent, respectively. The sensitivity of CEA for predicting hepatic metastases was 80 percent, with a median lead time of eight (range, 1-30) months, compared with only 46 percent for sites of recurrent disease other than the liver. CONCLUSIONS: CEA was the first indicator of recurrent disease in 58 percent of all patients and in 80 percent of patients with liver metastases. The diagnosis of recurrent disease may be made several months earlier by investigating the first abnormal CEA level, although any benefit in terms of survival remains to be proven.

Quality of life after gastric bypass for morbid obesity.

One year after gastric restriction surgery, 70 per cent of 118 women completed a questionnaire about lifestyle and eating behaviour changes. Mean weight loss was 35.4 kg. Patients reported a moderate reduction in appetite, and most avoided specific foods which they previously enjoyed, usually because of epigastric discomfort and/or nausea and vomiting. Patients had initiated or resumed a mean of 1.8 activities, most of which involved physical exercise. Sexual interest, enjoyment and frequency were all increased. Raised sexual satisfaction correlated strongly with overall outcome satisfaction. Seventy-two per cent of respondents rated themselves as very pleased, and 18 per cent as fairly pleased, with the overall results of the operation, and responses to the open-ended questions were often strikingly enthusiastic. However, most patients emphasized the difficulty of adjusting to radically new eating habits in the first 2-3 months after surgery, during which they experienced their greatest need for social support and encouragement.

Psychosocial and physical activity changes after gastric restrictive procedures for morbid obesity.

Gastric restrictive procedures for morbid obesity are frequently performed to reduce problems arising from the physical limitations and social isolation of massive obesity. Numerous reports have described changes in weight after gastric restrictive operations, yet few studies have documented changes in the secondary effects of obesity. This report deals with changes in psychosocial status and physical activity occurring in 240 patients who remained in the study 3 years after surgery. These patients were members of a group of 310 patients who were entered into a prospective randomized trial to assess the relative benefits of three forms of gastric restrictive procedure. Prior to operation, and at yearly intervals after operation, the physical activities and psychosocial status of each patient was assessed by a standardized semi-structured interview. At the time of the three-year interview the median weight loss for these patients was 29.5 kg which represents 53% of excess weight lost. This weight loss was associated with a marked reduction in the amount of food eaten. There was a significant increase in the number of patients smoking more than 20 cigarettes a day and a mild increase in alcohol intake. There were significant improvements in the level of self-image and state of happiness. The social lives and sex lives of the majority of patients were improved and a significantly greater number of patients reported being in a stable emotional relationship at 3 years after operation than did so pre-operatively. There was a marked increase in the number of patients in full-time or part-time employment from 38% prior to surgery to 60% at 3 years after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric surgery for morbid obesity. The Adelaide Study.

The efficacy of three gastric restriction operations were compared in a prospective randomized study of 310 morbidly obese subjects. The median patient age was 34 years (range, 18 to 62 years). They were predominantly female (13:1) and had a median pre-operative weight that was 198% of their ideal weight (range, 160% to 318%). There was an equitable dispersion of perceived risk factors between the groups under study and there were no deaths during the perioperative period. Compliance with follow-up at 3 years was 91%. When success was defined as a loss of more than 50% of excess weight or a current pregnancy, the success rates at 3 years were 17% for gastrogastrostomy, 48% for vertical gastroplasty, and 67% for Roux-en-Y gastric bypass (p less than 0.001). Although the gastric bypass operation took longer to perform, there were similar outcome patterns for the three groups during the postoperative period. We conclude that the Roux-en-Y gastric bypass is the preferred procedure for the surgical treatment of morbid obesity.

Psychological status before and after gastric restriction as predictors of weight loss in the morbidly obese.

Before gastric restriction, 118 morbidly obese women were psychiatrically assessed by clinical interview and self-report questionnaire. One year after surgery, 71 repeated the questionnaires. Weight was assessed at yearly intervals until the four year follow-up (n = 91). The maximum mean weight loss of 35 kg occurred at one year follow-up, when questionnaire respondents reported a slight overall improvement in personal and marital adjustment, and 72% rated themselves as very pleased with the results of surgery. Subsequently, 70% of patients regained weight, although the mean annual increase was only 1.9 kg. Marital dissatisfaction was a significant positive predictor of weight at one year, and generalized anxiety was a significant negative predictor of weight at four years. An increase in phobia scores at one year predicted subsequent maintenance of weight loss, whereas an increase in extrapunitiveness (mainly irritability and criticism of others) predicted subsequent weight gain.

Common duct exploration or endoscopic sphincterotomy for choledocholithiasis?

The relative indications for operative common duct exploration (CDE) and endoscopic sphincterotomy (ES) in treating common duct stones are often unclear. This prospective study compared CDE and ES in treating choledocholithiasis after excluding patients with acute cholecystitis, idiopathic pancreatitis, sphincter of Oddi dysfunction and malignant disease. One hundred and two patients had 105 CDE and a further 50 patients had 57 ES. Of the patients having CDE, 76 also had cholecystectomy for gall-bladder (GB) disease while 26 had prior cholecystectomy. With ES, in 16 the GB was present and not removed while 34 patients had had prior cholecystectomy. Hospitalization was significantly less following ES. There was one peri-operative death after CDE and none after ES. There were two late biliary-related deaths, 3 and 27 months after ES, in patients who developed acute cholecystitis. In post-cholecystectomy patients having ES, complications were fewer and less severe after ES (15%) than CDE (41%). In patients with an intact GB, peri-operative complications occurred in 30% after cholecystectomy and CDE. Following ES alone, complications occurred in 33% with the majority of these complications arising from the diseased GB. It is concluded that the optimal treatment for post-cholecystectomy patients with bile-duct stones is ES. In elderly patients with an intact GB, the bile-duct stones can be treated by ES; whether subsequent cholecystectomy is necessary should be assessed on the likelihood of future GB complications.

Single-dose antibiotic prophylaxis in contaminated abdominal surgery.

Although perioperative antibiotic cover reduces the incidence of septic complications associated with abdominal surgery, the optimum duration of antibiotic exposure is open to question. This clinical trial compared the efficacy of a single dose of moxalactam (1 g intravenously) with an extended course of moxalactam (1 g intravenously for eight doses) in 1027 patients undergoing contaminated abdominal surgery. The wound infection rate was 5.4% (28/519) for the single-dose schedule and 6.1% (31/508) for the extended-cover regimen (the respective 95% confidence intervals being 3.6% to 7.7% and 4.2% to 8.6%). Over 80% of all patients undergoing abdominal surgery during the period of study were entered into the trial. There was no significant difference in the incidence of other complications between the two groups under study. It is concluded that a single dose of moxalactam is as effective as a 48-hour course when attempting to prevent infection after contaminated abdominal surgery.

Psychological status of morbidly obese women before gastric restriction surgery.

One hundred and eighteen of 142 morbidly obese women had gastric restriction surgery after completing self-report questionnaire measures of psychosocial adjustment as part of their preoperative psychiatric assessment. Compared with an age-matched normal population, they scored significantly higher on measures of phobic anxiety, somatization, depression, hostility, and marital dissatisfaction, the last being associated mainly with later onset obesity. Factor analysis of questionnaire and weight data showed that weight was largely independent of psychological adjustment, although associations occurred when analysis was restricted to the data on married women, in which marital and self-assertion abnormalities loaded significantly on the same factor.

Is operative cholangiography always necessary?

To determine whether operative cholangiography could be performed on a selective basis, 272 consecutive patients undergoing cholecystectomy and routine operative cholangiography were studied prospectively. Appropriate clinical, biochemical and operative data were recorded and the surgeon was asked to estimate the likelihood of common bile duct stones. These factors were correlated with the subsequent cholangiographic and operative findings. From this information, four criteria were selected as indications for performing an operative cholangiogram: an abnormal common bile duct, a wide cystic duct, or elevated levels of alkaline phosphatase or bilirubin documented in the previous six months. Operative cholangiograms would have been indicated by the presence of one or more of these criteria in only 139 of the 272 patients in the study (51 per cent). Only one unsuspected stone would have been missed. It is concluded that a policy of selective cholangiography could have been safely adopted in this series of patients.