The effects of environmental temperature on the growth and metabolism of pigs given different amounts of food

Abstract

I . Twelve castrated male pigs were kept at each of three temperatures and given food at one of three levels of intake. The temperatures and daily food intakes (expressed as g/kg0.7a) were 23O (80, 100, IZO), 13" (100, 120, 140), 3-5" (120, 140, 160). Growth and nitrogen metabolismwere measured duringgrowth from 20 kglive weight until slaughter at gokg live weight, when the body contents of N and fat were estimated.2. Growth rate increased with each unit of daily food intake ( I g/kgO.'* live weight) by 7.73This value did not vary significantly with temperature. Daily growth rate was depressed by 17.8 5 2.3 g for each I' fall of temperature.3. Daily N retention estimated by the balance method exceeded by 2.59 g/d that estimated by the comparative slaughter technique. Both results led to the same conclusion, which echoed that found with growth rate, that there was no significant effect of temperature on the response of N retention to increasing food intake. Taking the mean of the two estimates, N retention at a constant food intake fell by 0.38fo.055 g/d for each I' fall of temperature. These regressions did not vary significantly with temperature. When considered at a constant food intake, body composition did not alter significantly with temperature.

Models of heat production and critical temperature for growing pigs

“…This value was used in equation (15) to calculate a critical temperature. The positive mean errors for the wooden slatted floors Source Close et al (1971), Verstegen et al (1973), Close and Mount (1978) Single pigs Close (1971), Fuller and Boyne (1972), Close and Mount (1978) Grouped pigs Close et al (1971), Verstegen et al (1973), Verstegen and Van der Hel (1974) All data may be due in part to the assumed value of R fA5 = 0-23°Cm 2 /W being too low. If the experimental air temperature was less than the calculated critical temperature then equation (13) was used to give the predicted heat loss.…”

“…If the experimental air temperature was less than the calculated critical temperature then equation (13) was used to give the predicted heat loss. All the data above 13 MJ/day came from Fuller and Boyne (1972) and the two points clearly apart from the rest are their only data at 13°C placed in the thermoneutral zone by the model. The percentage error was calculated as absolute error x 100/the experimental heat loss.…”

Liveweight, Protein Deposition and Digestibility Responses in Growing Pigs Exposed to Low Temperature

“…Graham et al (1959) found that increasing feeding level from maintenance to 1.5 times maintenance reduced energy digestibility in sheep. Fuller andBoyne (1971,1972) (. For personal use only.…”

Influence of low ambient temperatures on heat production and energy balance of single-housed growing pigs fed ad libitum: a comparison with group-housed pigs

“…When temperature decreases below the lower critical temperature, HP increases to meet the additional requirement for thermoregulation. One of the main adaptations of ad libitum fed pigs to low ambient temperature is increasing the energy intake so that the energy balance and growth performance can be maintained [1,4,7,8,10,14,15]. Additionally, an increased contribution of physical activity to total HP at low temperatures has been reported [16], as well as an improvement of energy efficiency [2,5,11,14,16,21].…”