Models of heat production and critical temperature for growing pigs

1. A deterministic model for thermoneutral heat production of growing pigs on barley-based diets has been developed and validated. The model variables are live weight (20 to 100 kg) and metabolizable energy intake (not less than maintenance). The root-mean-square error for 62 data is 049 MJ/day (3·2%). 2. A deterministic model for heat production of growing pigs below their critical temperature has been developed and validated. The model variables are: air temperature, air velocity, floor type, live weight (20 to 100 kg), and group size. The root-mean-square error for 78 data is 0·77 MJ/day (5·6%). 3. The two heat production models are combined to give a model for the lower critical temperature for growing pigs. 4. These models may be used to quantify and compare the effects on energy balance of different combinations of nutrition and environment. They should help to clarify the issues when practical decisions in pig production are made and should also help in the design of nutritional and physiological experiments.

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