PERFORMANCE AND BODY-COMPOSITION OF FINISHING GILTS (45 TO 85 KILOGRAMS) AS AFFECTED BY ENERGY-INTAKE AND NUTRITION IN EARLIER LIFE .1. GROWTH OF THE BODY AND BODY COMPONENTS

Forty-eight commercial hybrid gilts were used to determine the effects of energy intake from 20 to 45 kg on the relationship between energy intake and weight gain of the body and body components from 45 to 85 k g. Two groups of 24 gilts received a single diet either at 2.2 (restri cted) or 3.7 (control) times maintenance (M) from 20 to 45 kg. From 45 to 85 kg the pigs were fed the same diet at one of six intake levels (1.7, 2.2, 2.7, 3.2, or 3.7 x M, or ad libitum). At 85 kg, the gilts w ere dissected into organs, lean tissue (trimmed major joints), and oth er carcass parts (fat fraction). In the restricted gilts, body and lea n tissue gain between 45 and 85 kg increased curvilinearly with increa sing energy intake from 432 to 1,412 g/d and from 228 to 507 g/d, resp ectively. In the control gilts, body and lean tissue gain increased fr om 394 to 1,201 g/d and from 238 to 508 g/d, respectively. The percent age of lean tissue in the carcass decreased curvilinearly with increas ing energy intake from 62.9 to 56.5%, and from 62.5 to 53.9% in the re stricted and control gilts, respectively. The restricted gilts gained on average 140 g/d faster (P <.001) and their carcass lean tissue cont ent at slaughter was approximately 3% higher (P <.001), These differen ces increased with increasing energy level between 45 and 85 kg. The i ncreased gain was largely the result of an increase in organ growth an d gut contents and was only evident up to 65 kg. The higher lean conte nt at 85 kg in previously restricted gilts was not the result of compe nsation in lean gain but was already present at the end of the restric tion phase at 45 kg.