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1. At thermoneutrality (28 degrees C), CSF Na+:Ca2+ in hens was 61.66; under thermal stress (39 degrees C), it changed to 59.38 (30 min), 62.58 (3 hr), and 52.44 (10 hr); no change in ratio occurred at 15 degrees C. 2. ICV Ouabain and/or EGTA increased body temperature (TR) but not respiration rate (RR) at 39 degrees C. 3. At 28 degrees C, Ouabain decreased, and EGTA increased, TR and RR. 4. Ca2+ may be more critical than Na+ in thermoregulation. 5. Heat stress appears to stimulate Na+-transport mechanisms other than Na+-ATPase. 6. RR appears to be a function of TR, not of ion balance.

Performance data of two modified-open-front non-mechanically ventilated swine nurseries have shown that solar energy can be effectively utilized to maintain a productive environment within the animal space during cold weather (temperatures as low as —26°C ( — 15 °F). The nurseries feature a monoslope roof design and passive collector panels that also function as warm weather ventilation panels. An active solar-heating system uses a ground-level collector operated in conjunction with an in-floor solar heat distribution and storage system. The nurseries were designed to handle pigs weighing from 7 to 23 kg (15 to 50 lb). An average of 19% of the solar energy incident on the collector was transferred to the floor surface during the heating seasons from October 1980 to January 1982. Season "heating" costs were approximately 1.0% of the estimated cost to heat the nursery by conventional means.

Adrenal and behavioral responses in swine restricted to varying degrees of mobility were examined to determine what component may impose chronic stress. The components of restriction considered were the inability to turn around and/or move freely. For 5 to 6 weeks 32 pigs were restrained such that pigs A) could move freely; B) could not turn around or move freely; C) could not turn around but could move back and forth the same distance as pigs in A; or D) could turn around but not move freely. After 4 weeks no significant differences due to degree of restraint were found in the profile of serum cortisol concentrations, neutrophil:lymphocyte ratio and ambulatory abilities; however overall cortisol concentrations were higher in pigs that could turn around but not move freely. Increases in serum cortisol due to ACTH injection were higher in pigs that could turn around but not move freely. No alterations in the manner in which gilts stood up and layed down could be observed. Collectively these data suggest that swine adapt when mobility is restricted to not turning around and not moving freely but cannot when animals can turn around but not move freely.

Feeding behaviour and feed consumption of growing pigs (36 kg) were observed over a 6-day period while they were in two chambers, each housing four pigs. The temperature in one chamber was held constant at 33°C while the other cycled between a minimum of 26°C at 0530 h and a maximum of 40°C at 1400 h. The light schedule was 16 h light (0500–2100 h) and 8 h dark. Water and feed were provided ad libitum. Each chamber had one feeder capable of accommodating three pigs. Feeding behaviour was monitored continuously on a video recorder while feed consumption was determined every 4 min from an electronic output from a feeder scale. Feed consumption and feeder usage in both treatments were primarily a response to the light: dark pattern with two peaks in food intake; one at about the time the lights were turned on and the other shortly before the lights were turned off. Cyclic temperatures resulted in similar daily feed intakes and feeder usage, but shifted the diurnal feeding pattern. Feed consumption shifted to the coolest part of the thermal cycle, and the period of highest feed intake occurred earlier in the morning and later at night than those in the constant temperature treatment. The feeder was occupied for only 22 and 23% of the time in the constant and cyclic temperature treatment, respectively. During peak feeding activity, feeders were utilized by only one pig ∼50% of the time. Social facilitation did not appear to influence feeder usage. Only 25% of total feeding time occurred with two or three pigs at the feeder. During the remaining time, feeder usage was on an individual animal basis. During periods of peak feeder usage, 30% of the feeder usage was by two or three pigs at one time in the constant temperature treatment, while 40% of the feeder usage was by two or three pigs in the cyclic temperature treatment. Rate of ingestion (defined as feed consumed in g min −1 a pig was at the feeder) indicated that for 74% of the time the pigs in both temperature treatments consumed feed at a rate −1 per pig. Mean ingestion rates for both thermal treatments were similar (15 g min −1 per pig).

1. Hens received ICV injections of Ca2+ (1.98 g/100 ml) or Na+ (7.25 g/100 ml) at 28 degrees C and, following acclimation, at 37 or 20 degrees C, respectively. 2. At 28 degrees C (thermoneutrality), rectal temperature rose (P less than 0.05) following Na+ and fell (P less than 0.05) following Ca2+, similar to mammals and broiler chickens. 3. At 37 degrees C, Ca2+-induced hypothermia did not occur; nor did the Na+-associated hyperthermia at 20 degrees C. 4. Acclimation to a high or low temperature may produce an endogenous shift in CSF ion levels that make additional ion administration ineffective in affecting body temperature.