Gas exchange in boars of different development stages during motor activity

Continuous measurements were performed on 16 untrained boars for VO2, VCO2, and rectal temperature, prior to, during, and after running exercises on an horizontal exercise belt, with speeds set to 1.3 m.s-1 corresponding to something between 23 and 43 kg of body weight b.wt. or 0.7 and 1.3 m.s-1 corresponding to 76 to 86 kg of b.wt. The highest values of VO2 and VCO2 (ml.min-1/kg-1 b.wt.) and of rectal temperature (degrees C) were 36.78 +/- 3.57, 40.23 +/- 6.17, and 41.9 +/- 0.6 in younger animals or 21.49 +/- 2.46, 22.53 +/- 3.12, 40.8 +/- 0.5, 29.3 +/- 5.15, 30.6 +/- 4.77, and 40.7 +/- 0.45 for somewhat older animals for belt speeds of 0.7 and 1.3 m.s-1. Exercise belt speeds of 0.7 to 1.3 m.s-1 were found to be suitable for testing aerobic metabolic capacity of untrained young boars.     

Gas metabolism and body temperature during submaximal, maximal and supramaximal physical activity of swine

VO2, VCO2, gas exchange ratio (R = VO2/VCO2), and rectal body temperature were continuously measured on 6 young fattening pigs and 16 boars during repeated runs (0.7, 1.3, and 2.5 m/s-1) on a horizontally moving belt. Close correlations, almost linear, were found to exist between VO2, VCO2, and rectal temperature in situations in which VO2 moved close to its individual maximum as a result of preselected challenge intensity. None of these 3 parameters was increased further and in keeping with turnover, if higher challenge intensities were chosen.     

Acid-base status in the blood of domestic pigs during exhausting locomotor stress of small and medium intensity]

Twenty-two fattening pigs were stressed until their rectal temperatures had reached 42 degrees C. The means of stress included walking on moving conveyor belt at ambient temperatures between 22 degrees C and 27 degrees C and relative humidities between 69 and 98%, belt speeds of 0.7 m/s, 1.3 m/s or 0.7 m/s, and stimulation by means of a forcing rod. Rectal temperature, respiratory frequency, lactic acid level in blood plasma, pH, as well as pCO2 and base excess in the blood were measured prior to, during, and after stressing. Gasping was strongly pronounced due to severe alkalisis, but it was somewhat mitigated on running on the belt with exposure to additional stress on account of lactic acid accumulation in the plasma.     

The oxygen uptake capacity of swine

Comprehensive studies into domestic pigs and wild boars together with literature data provided a basis for an assessment of aerobic metabolic capacity (VO2max) of swine. The values quoted, from 20 to 94 ml/min-1/kg, had been due to several factors of methodological approach, growth, training, and nutrition as well as to pathophysiological aspects. For full capacity utilisation of VO2max, untrained pigs can be challenged at belt velocities between 0.8 and 1.8 m/s-1 and trained animals at 5 m/s-1.     

Reactions of the domestic pig to exhausting motor stress of middle intensity

The VO 2max value was established from twelve pigs, followed by checks of their responses to endurance stress (walk 0.7 m/sec, ambient temperatures between 22 degress C and 24 degrees C, relative humidities between 67 and 78 per cent). Also measured were the rectal temperature, heart rate, respiratory rate, haemoglobin level of the blood, haematocrit, mean corpuscular haemoglobin concentration, plasma volume, blood volume, total haemoglobin, plasma glucose concentration and plasma lactid acid concentration. A differentiation could be made between one group weighing between 53.3 +/- 2.47 kg and enduring 97 +/- 9 minutes and another weighing 60.0 +/- 1.38 kg and enduring 36 +/- 6 minutes. The two groups differed from one another for their plasma and blood volumes, their values being 42.6 +/- 3.8 ml/kg and 67.5 +/- 7.5 ml/kg or 33.5 +/- 3.4 ml/kg and 52.2 +/- 5.9 ml/kg. The groups produced quantitatively different responses to endurance stress. The demands implied in endurance were widely met by the circulatory system, while the energy transfer was characterised primarily by aerobic energy collection.     

Effects of warm-up intensity on kinetics of oxygen consumption and carbon dioxide production during high-intensity exercise in horses

OBJECTIVE: To compare effects of low and high intensity warm-up exercise on oxygen consumption (VO2) and carbon dioxide production (VCO2) in horses. ANIMALS: 6 moderately conditioned adult Standard-breds. PROCEDURES: Horses ran for 2 minutes at 115% of maximum oxygen consumption (VO2max), 5 minutes after each of the following periods: no warm-up (NoWU); 10 minutes at 50% of VO2max (LoWU); or 7 minutes at 50% VO2max followed by 45-second intervals at 80, 90, and 100% VO2max (HiWU). Oxygen consumption and VCO2 were measured during exercise, and kinetics of VO2 and VCO2 were calculated. Accumulated O2 deficit was also calculated. RESULTS: For both warm-up trials, the time constant for the rapid exponential increase in VO2 was 30% lower than for NoWU. Similarly, the rate of increase in VCO2 was 23% faster in LoWU and HiWU than in NoWU. Peak values for VO2 achieved during the high-speed test were not significantly different among trials (LoWU, 150.2 +/- 3.2 ml/kg/min; HiWU, 151.2 +/- 4.2 ml/kg/min; NoWU, 145.1 +/- 4.1 ml/kg/min). However, accumulated O2 deficit (ml of O2 equivalents/kg) was significantly lower during LoWU (65.3 +/- 5.1) and HiWU (63.4 +/- 3.9) than during NoWU (82.1 +/- 7.3). CONCLUSIONS AND CLINICAL RELEVANCE: Both the low- and high-intensity warm-up, completed 5 minutes before the start of high-intensity exercise, accelerated the kinetics of VO2 and VCO2 and decreased accumulated O2 deficit during 2 minutes of intense exertion in horses that were moderately conditioned.     

Resting rectal temperature of Vietnamese potbellied pigs.

OBJECTIVE: To determine resting rectal temperatures of Vietnamese potbellied pigs. DESIGN: Prospective clinical trial. ANIMALS: 85 potbellied pigs on a single farm and 27 potbellied pigs examined at a veterinary teaching hospital for routine veterinary care. PROCEDURE: Rectal temperatures of the potbellied pigs on a farm were measured during the morning, afternoon, and evening. Rectal temperatures at the time of initial examination were obtained from medical records for the potbellied pigs examined at the hospital. RESULTS: Mean rectal temperatures for both groups of potbellied pigs were the same. Overall unadjusted mean +/- SD rectal temperature was 37.6 +/- 0.8 C (99.7 +/- 1.5 F; range, 35.1 to 39.6 C [95.2 to 103.3 F]). However, diurnal variation in rectal temperature was found among the farm population of potbellied pigs. After adjustment for age and repeated sampling, rectal temperatures recorded during the morning were found to be significantly lower than temperatures recorded during the afternoon and evening (mean difference, 0.5 and 0.9 C [0.9 and 1.6 F], respectively), and rectal temperatures recorded during the afternoon were found to be significantly lower than temperatures recorded during the evening (mean difference, 0.4 C [0.7 F]). There was a significant inverse linear relationship between age and rectal temperature. CONCLUSIONS AND CLINICAL RELEVANCE: Rectal temperatures of Vietnamese potbellied pigs may be lower than the lower limit of the reference range reported for domestic pigs. Because of diurnal variation in rectal temperatures, it is important to compare temperatures obtained at the same time of day when assessing patients.     

Evaluation of blood glucose concentration during exertion. 6. Effect of anemia on the glucose regulation capacity of domestic swine in standardized running exercise]

Individual mean blood glucose values and the scatter of individual values were determined in six healthy and six anaemic pigs before, during and after ten minutes of exercise on a belt moving at 78 m/min (environmental temperature 22-24 degrees C, relative humidity 55-65%). The glucose regulatory capacity of anaemic pigs was inferior to that of healthy pigs. Blood glucose regulation was related to haemoglobin content and to the increase in rectal temperature during exercise.     

Effects of handling intensity and live weight on blood acid-base status in finishing pigs

The objective of this study was to determine the effect of live weight on the plasma acid-base response of pigs subjected to various handling intensities. Eighty pigs (equal numbers of barrows and gilts) were used in a completely randomized block design with a 2 x 2 x 2 factorial arrangement of the following treatments: 1) live weight (light [104 kg] vs. heavy [128 kg]), 2) handling intensity (low vs. high), and 3) gender (barrows vs. gilts). Before the handling test, pigs were weighed, venous blood samples were taken to establish baseline levels, and rectal temperature was measured. Pigs were allowed to rest for 2 h before being subjected to the handling treatments, which consisted of moving the pigs through a course (12.2 m long x 0.91 m wide), for a total of eight laps. Animals on the high-intensity treatment were moved rapidly through the course and subjected to a total of 16 single shocks (two shocks per lap) with an electric livestock goad, whereas pigs on the low-intensity treatment were moved at their own pace using a moving panel and a paddle. Rectal temperature and a venous blood sample were taken immediately after handling and at 2 h after handling. Blood plasma was assayed for pH, partial pressure of carbon dioxide (PCO2), partial pressure of oxygen (PO2), saturated oxygen (SO2), total carbon dioxide (TCO2), bicarbonate (HCO3), base excess, and lactate. Live weight had no effect on the baseline measurements. After handling, light pigs had higher (P < 0.05) blood SO2 (65.6 vs. 57.2+/-2.80%) and showed a greater (P < 0.05) increase in PO2 from baseline to post-handling than heavy pigs (15.6 vs. 8.3+/-2.63 mmHg). Post-handling, pigs on the high- compared with the low-intensity handling treatment had greater (P < 0.001) lactate (19.1 vs. 4.9+/-0.56 mmol/L) and PO2 (51.6 vs. 36.5+/-2.44 mmHg) with lower (P < 0.001) TCO2 (18.6 vs. 34.7+/-0.64 mmol/L), pH (7.02 vs. 7.36+/-0.015), HCO3 (16.7 vs. 33.0+/-0.62 mmol/L), and base excess (-14.2 vs. 7.5+/-0.75) values. There were no effects of gender on blood measurements or rectal temperatures. Results from this study highlight a major effect of pig handling intensity, a limited effect of live weight, and no effect of gender on blood acid-base responses to handling.     

Energy balance and growth rate of outbred and inbred male guinea pigs

Water intake, food consumption, growth rate, and rectal temperature were measured daily for 14 days and oxygen uptake was determined weekly for 3 weeks in healthy outbred (Hartley stock) and inbred (strains 2 and 13) male guinea pigs. Body weights ranged from 300 to 465 g, and ages were approximately 6 to 10 weeks. Strain-13 guinea pigs had the lowest daily body weight gain (3.27 +/- 0.33 g), when compared with strain-2 (4.04 +/- 1.21 g) and Hartley guinea pigs (5.72 +/- 1.08 g). Outbred guinea pigs also had highest values of water intake and water/food intake ratio(s), and had significantly (P less than 0.05 and 0.01) lower oxygen uptake values than did inbred guinea pigs. The ratio of daily average body weight gain to the corresponding daily retained calories, with or without corrections of body surface area (0.05 m2), was higher in Hartley stock than in the strain-13 guinea pigs. Rectal temperatures and food consumption were similar in all guinea pigs. Data indicated that the outbred Hartley guinea pig had a faster growth rate and appeared stronger physiologically, compared with inbred strains.     

Effect of anemia on various reactions of the domestic swine due to physical exertion. 3. Changes in plasma glucose and lactic acid concentrations]

Six anaemic and six healthy pigs were exercised for ten minutes on a belt moving at 78 m/min. Initial blood glucose values in healthy pigs averaged 71.2 mg/100 ml, and they changed very little during and after exercise. Initial values were similar in anaemic pigs (70.7 mg/100 ml), but they increased continuously, during exercise, reaching a peak of 157.4 mg/100 ml one minute after the end of exercise. Blood lactic acid increased from 1152 to 2463 mmol/litre in healthy pigs during the first minute of exercise, and then fell gradually. In anaemic pigs it increased from 1652 to 8478 mmol/l during the ten minutes of exercise, and then fell gradually. Correlations between lactic acid and haemoglobin content, between rectal temperature and Hb, and between lactic acid and changes in rectal temperature were discussed.     

Effects of conditioning and maximal incremental exercise on oxygen consumption in sheep

To assess the suitability of sheep for exercise studies, the effect of incremental exercise and conditioning on oxygen consumption (VO2) was studied. Six sheep were adapted to a treadmill and subsequently trained 8 weeks. The sheep were then studied, in random order, using 3 incremental exercise protocols (EX-1, EX-2, and EX-3). The protocols were chosen to approximate high (EX-1), moderate (EX-2), and low (EX-3) intensity exercise by varying treadmill speed and incline. The sheep were then conditioned for an additional 12 weeks and retested on the EX-2 protocol. During exercise, VO2, gas exchange ratio (R), and rectal temperatures (Tb) were recorded. All 3 protocols resulted in significant increases in VO2, R, and Tb (P less than 0.05). Maximum VO2 for EX-1, 49.9 +/- 5.0 ml/min/kg of body weight, was significantly greater than maximum VO2 for EX-2 and EX-3, 37.8 +/- 6.5 and 42.3 +/- 6.0 ml/min/kg, respectively (P less than 0.05), whereas maximum R and maximum Tb were similar. After the additional 12-week conditioning, time on the treadmill increased 40% from 9.58 +/- 0.87 to 13.4 +/- 0.44 minutes, and maximum VO2 increased 27% to 48.1 +/- 9.1 ml/min/kg. These data indicated that maximum VO2 varied with intensity of the exercise, 12 weeks of maximal exercise conditioning was sufficient to produce a measurable training effect (ie, increase endurance and maximum oxygen consumption) and sheep are suitable for maximal exercise studies where VO2 measurements are desired.     

Effects of N,N-dimethylglycine on cardiorespiratory function and lactate production in thoroughbred horses performing incremental treadmill exercise

In a crossover study, either a placebo paste or N,N-dimethylglycine was administered orally at a dose rate of 1.2 mg/kg twice daily for five days to six thoroughbred horses, with bodyweights ranging from 424 to 492 kg. Using previously determined regression equations for oxygen uptake (VO2) against speed for each horse, a standardised exercise test was given with speeds equivalent to fixed percentages of the maximum oxygen uptake (VO2max). The test consisted of two minutes at speeds equivalent to approximately 40 per cent and 50 per cent VO2max, and one minute at speeds that produced approximately 60, 70, 80, 90 and 100 per cent VO2max. During the last five seconds of each exercise stage, the values of VO2, carbon dioxide production (VCO2), heart rate, arterial blood and plasma lactate concentrations, arterial blood gases and pH were measured. Before and immediately after the exercise test, muscle biopsies were collected from the middle gluteal muscle to determine the muscle lactate concentrations. The administration of N,N-dimethylglycine produced no significant differences in any of the measured values, and it is concluded that the compound has no beneficial effects on cardiorespiratory function or lactate production in the exercising horse.     

Comparison of yearling, two-year-old and adult Thoroughbreds using a standardised exercise test

The purpose of this study was to compare exercise measurements in yearling, two-year-old and adult Thoroughbreds using a standardised treadmill incremental exercise test. Peak oxygen consumption (VO2 peak: 128.0 +/- 2.1, 140.0 +/- 2.1, 163.7 +/- 3.4; ml/kg/min +/- se, P less than 0.05), peak packed cell volume (PCV peak: 0.50 +/- 0.01, 0.58 +/- 0.01, 0.64 +/- 0.01 litres/litre +/- se, P less than 0.05) and the maximum number of steps completed in the exercise test (STEPmax: 7.7 +/- 0.1, 8.1 +/- 0.1, 8.6 +/- 0.1; steps +/- se, P less than 0.05) increased with age and degree of physical activity. Peak venous lactate concentration (LACpeak: 21.3 +/- 1.5, 19.5 +/- 1.7, 14.4 +/- 1.7; mmol/litre +/- se, P less than 0.05) and peak respiratory exchange ratio (Rpeak) were significantly higher in both groups of younger horses compared to the adult racehorses. Peak heart rate (HRpeak: 230 +/- 2, 231 +/- 3, 229 +/- 3; beats/min +/- se) did not change with age or training. The rate of change of VO2 between steps in the exercise test (VO2trans) was significantly lower in the adult racehorses at the highest exercise intensities. The slopes of the linear approximation between R (LinR bx), the natural log transformation of venous lactate concentration (LogLAC bx), and heart rate (HR bx) with velocity were significantly lower in the trained adult racehorses. The slope of venous lactate concentration normalised to per cent VO2peak (LogLAC per cent bx) was significantly lower and R breakpoint (R brkpt) normalised to per cent VO2peak was significantly higher in the trained adult racehorses. There was a more rapid decrease in venous lactate and a more rapid return to initial R values in the adult horses relative to the younger, untrained horses. No significant age or training effects were found in the remainder of the post exercise measurements. These results indicate that aerobic power and exercise capacity increased with age and training. Anaerobic power was already well developed even at a young age.     

Effects of grouping unfamiliar cohorts, high ambient temperature and stocking density on live performance of growing pigs

Ninety-six crossbred intact male pigs (34.5 +/- 3.5 kg BW) were allocated by weight and vocalization score to a 2 x 2 x 2 dynamic experimental design including two stocking densities (1 or 2 m(2)/pig), two temperatures (22 degrees C and 30 degrees C), and two short groupings of unfamiliar cohorts (six pigs as one pig per group, and six pigs per group). The study was conducted over 8 wk, and live weight gain (WTG) and feed intake (FI; as-fed basis) were measured weekly. During the first week, pigs were housed in individual pens from four independent rooms. To group pigs, pen partitions were removed. Pigs were grouped in Rooms 2 and 3 from wk 2 to 4, and in Rooms 1 and 4 during wk 7. Temperature was increased from 22 degrees C to 30 degrees C in Rooms 1 and 2 during wk 4 and 7. Pen partitions were replaced in Rooms 2 and 3 at the end of wk 4 and in Rooms 1 and 4 at the end of wk 7 to return pigs to their individual pens. Grouping pigs decreased FI during wk 3 (15.08 +/- 0.43 vs. 14.03 +/- 0.41 kg P < 0.10), and during wk 7 (17.42 +/- 0.46 vs. 14.24 +/- 0.41 kg; P < 0.01). In addition, grouping had a negative effect (P < 0.001) on WTG at wk 3 (7.38 +/- 0.28 vs. 5.71 +/- 0.28 kg) and at wk 7 (6.70 +/- 0.26 vs. 2.99 +/- 0.26 kg). For grouped pigs, raising the temperature decreased (P < 0.01) WTG (7.49 +/- 0.29 vs. 6.41 +/- 0.29 kg during wk 4, and 3.37 +/- 0.38 vs. 2.62 +/- 0.38 kg during wk 7). Mean FI was decreased (P < 0.01) with the 30 degrees C treatment during wk 7 only (15.49 +/- 0.33 kg at 22 degrees C compared with 12.99 +/- 0.33 kg at 30 degrees C). Compensatory feed intake was evident after the treatments had ceased at wk 6, whereby previously heat-treated grouped pigs had a higher FI (17.97 +/- 0.45 kg) than the animals individually housed at 22 degrees C (12.99 +/- 0.33 kg). Stocking density effects were noted after the grouping and high temperature treatments had ceased. For instance, during wk 5, low-density-housed pigs grew faster (P < 0.001) than their high-density counterparts (9.04 +/- 0.38 vs. 7.49 +/- 0.29 kg). In conclusion, under the conditions of this study, the grouping of unfamiliar cohorts and high ambient temperature treatments had a detrimental effect on pig performance, and these effects were reversible.     

The effect of physical training on skeletal muscle enzyme composition in pigs.

Running exercise in pigs results in an elevation of lactic acid in blood. This elevation in blood lactate does not occur in physically conditioned pigs. Activities of succinic dehydrogenase, fructose-l,6-diphosphate aldolase, lactate dehydrogenase and creatine Phosphokinase as well as the myoglobin content were determined in m. gastrocnemius from 6 ergometer-trained and 4 untrained pigs. The succinic dehydrogenase and myoglobin contents were significantly higher (P<0.01) in trained animals, whereas no changes were noted in the aldolase and creatine Phosphokinase contents. The lactate dehydrogenase showed somewhat reduced levels in the trained pigs. This was accompanied by an increased H/M subunit ratio. The results provide evidence for an increase in the maximal aerobic metabolism in trained pigs and that trained pigs to a higher extent can rely on an aerobic energy metabolism during running exercise.     

Effect of anemia on various reactions of the domestic swine due to physical exertion. 2. Components of cardiovascular function and body temperature]

The following measurements were made in six anaemic and six healthy pigs during and after physical exertion on a belt moving at 70 m/min for 10 minutes at environmental temperature of 22-24 degrees C and relative humidity of 55-65%:--rectal temperature (RT), heart rate, total haemoglobin, plasma volume (PV), blood volume (BV) and plasma osmolarity (PO). The increase: in RT and PO, heart rate during exercise, respiratory rate after exercise, and the fall in PV and BV during exercise as well as changes in erythrocytes were all more pronounced in anaemic pigs than in healthy pigs.     

Comparative ergoespirometric adaptations to a treadmill exercise test in untrained show Andalusian and Arabian horses

Significant differences exist in the respiratory adaptation to exercise in different equine breeds. This research describes the ergoespirometric response to exercise of Andalusian (AN) and Arabian (A) horses, both selected according to morphological criteria. Thirteen untrained male horses (6 AN and 7 A) performed a treadmill exercise test (TET) with a slope of 6%, with workloads starting from 5 m/s and increasing 1 m/s every 3 min until the horses were not able to keep the required velocity. Tidal volume (TV), respiratory rate, minute ventilation (VE), oxygen uptake (VO2), carbon dioxide production, peak oxygen uptake (VO2peak), respiratory exchange ratio (RER), exercise time to fatigue (ETF) and respiratory aerobic threshold (RAT) were determined. AN horses presented higher TV and VE, whereas respiratory rate, VO2 and VCO2 were lower at the same velocities. RER was similar between breeds. ETF was longer in A horses (556.7 ± 66.5 in AN vs. 607.1 ± 71.1 s in A) and no significant differences were found in RAT (5.50 ± 0.50 in AN vs. 5.86 ± 1.07 m/s in A). In summary, despite the more intense ventilatory response to exercise at the same velocity, AN horses had lower VO2. The AN horse develops a more intense ventilatory response to fixed velocities than the A horse and it could be interesting to clarify the role of the locomotion characteristics in this response.     

Performance of finishing pigs in hoop structures and confinement during winter and summer

Performance of finishing pigs in hoop structures or confinement during winter and summer was evaluated in Iowa. Hoops are large, tent-like shelters with cornstalks or straw for bedding. During summer and winter seasons for 3 yr (1998 to 2001), six trials were conducted using three hoop barns (designed for 150 pigs per pen, one pen per hoop) or a mechanically ventilated confinement barn with slatted floors (designed for 22 pigs per pen, six pens in the barn). A total of 3,518 pigs started the trials. Summer trials were June through October, and winter trials were December through April. Target stocking density was 1.11 m2/pig in hoops and 0.74 m2/pig in confinement. Identical corn-based diets were fed ad libitum from 16 to 118 kg for 127 d. Pigs were scanned before harvest for backfat and loin muscle area. When seasons were merged (season x housing interaction, P > or = 0.05), hoop-fed pigs had more backfat (21.8 +/- 0.3 vs 20.8 +/- 0.2 mm; P < 0.001), smaller loin muscle area (41.3 +/- 0.3 vs 43.0 +/- 0.2 cm2; P < 0.001), less lean percentage (51.1 +/- 0.2 vs 52.1 +/- 0.1%; P < 0.001), and less yield (74.9 vs 75.8 +/- 0.1%; P < 0.001) than confinement-fed pigs. When season x housing type interactions were observed (P < 0.004), summer hoop-fed pigs had greater ADG (834 +/- 5 vs 802 +/- 3 g/d; P < 0.001), required fewer days to 113 kg (174.9 +/- 0.9 vs 178.5 +/- 0.6 d; P < 0.01), had similar ADFI (2.40 +/- 0.03 vs 2.35 +/- 0.02 kg/d, as-fed basis) and gain:feed (G:F; 348 +/- 4 vs 342 +/- 3 g/kg) compared with confinement-fed pigs. Lean gain/day and efficiency of lean gain did not differ between housing systems. During winter, hoop-fed pigs had similar ADG (794 +/- 5 vs 801 +/- 3 g/ d), required more days to 113 kg (176.7 +/- 0.9 vs 172.9 +/- 0.6 d; P < 0.01), had greater ADFI (2.54 +/- 0.03 vs 2.35 +/- 0.02; P < 0.001), less G:F (313 +/- 4 vs 341 +/- 3; P < 0.001), less lean gain/day (312 +/- 2 vs 322 +/- 1 g/d; P < 0.01), and less efficiency of lean gain (130 +/- 2 vs 144 +/- 1 g lean gain/kg feed; P < 0.01) than confinement-fed pigs. Percentage of mortalities and culls did not differ between housing systems. During summer, there was a trend for fewer light pigs at marketing (< 100 kg) from hoops (0.8 vs 1.7%; P = 0.10). During winter, there were more light pigs at marketing from hoops (3.9 vs 1.3%; P = 0.01) than from confinement. Bedding use in hoops was 92 and 122 kg/pig for summer and winter, respectively. Performance of finishing pigs in bedded hoop structures depends in part on thermal environment.     

Evaluation of four warming procedures to minimise heat loss induced by anaesthesia and surgery in dogs

OBJECTIVE: To evaluate the efficiency of four warming procedures, introduced after anaesthetic induction and continued during surgery, in minimising heat loss in anaesthetised dogs. DESIGN: Dogs were paired. One of each pair was a control; the other was subjected to one of four warming procedures. METHODS: Ninety-six dogs were involved in total. Pairs of dogs were matched for breed, hair length, and type of surgical procedure and placed adjacent to each other in a large temperature-controlled surgical theatre. One dog within each pair was assigned to one of four warming procedures that commenced immediately after anaesthetic induction. Group 1 (11 pairs) were placed on a purpose-designed prewarmed (41 degrees C) electrically heated pad. Group 2 (18 pairs) were placed on a prewarmed electric heat pad (41 degrees C), cocooned by four wrapped water bottles (initially 41 degrees C) and subjected to radiant heat (150 watt lamp placed 50 cm away from the head of the dog). Group 3 (11 pairs) were surrounded by a forced air warming mattress (set at 43 degrees C). Group 4 (8 pairs) were connected via the anaesthetic breathing circuit to a heater/humidifier (set at 41 degrees C). Rectal temperature measurements were recorded every 15 min for the first 3 h of anaesthesia. The fall in rectal temperature of the control dog was subtracted from the fall in temperature of the treatment dog and this measurement was used to assess the efficacy of the various warming procedures. RESULTS: The mean rectal temperature of unheated 'control' dogs decreased 1.9 +/- 0.6, 1.4 +/- 0.4 and 1.1 +/- 0.4 degrees C over the first, second and third hour respectively. After 3 h the temperature fall differential for all groups were 0.7 +/- 0.7 (Group 1), 3.1 +/- 1.1 (Group 2), 2.4 +/- 1.1 (Group 3) and 1.0 +/- 1.1 degrees C (Group 4). Thus the group 2 procedure was the most successful in preventing a drop of temperature followed by groups 3, 4 and 1. CONCLUSION: Large dogs undergo significant reduction in core body temperature especially during the first 2 h of anaesthesia and surgery. Supplementary warming substantially reduces this fall in body temperature, although certain warming procedures were found to be more effective than others.