ENERGY-METABOLISM OF GROWING PIGS AFTER TRANSPORTATION, REGROUPING, AND EXPOSURE TO NEW HOUSING CONDITIONS AS AFFECTED BY FEEDING LEVEL

An experiment was performed to evaluate alterations of energy metaboli sm with time in 10 groups of 16 barrows just after transportation. Ten -week-old pigs were fed at once (four groups; LF) or twice (three grou ps; MF) maintenance level (35 and 75 g.kg-75.d-1, respectively), or al lowed ad libitum access to feed (three groups; HF). The 13.5-d experim ental period was divided into two balance periods. Heat production (HP ) decreased with time. The changes in HP with time were different amon g feeding level groups (P < .001); the LF group had the greatest decre ase. Metabolizable energy intake remained constant with time for the L F and MF groups and decreased for the HF group. Requirements for maint enance energy and efficiency of ME for growth decreased with time. Fee ding level influence (P < .001) energy retention (ER) during the total experimental period. The LF group had a negative ER (-65 kJ.kg-.75.d- 1), whereas in the MF and HF groups positive values for ER were obtain ed (346 and 757 kJ.kg-.75.d-1, respectively). At all feeding levels, a nimals had a positive protein gain. The level differed between feeding levels (P < . 001). Differences among groups (P < .001) were observed in energy retained as fat. Data from the present experiment show that young pigs are not in a steady state of energy metabolism during the 2 wk after transportation. During this period, the relationship betwee n metabolic rate and feed intake alters with time.