FEED-INTAKE PATTERN OF GROUP-HOUSED GROWING-FINISHING PIGS MONITORED USING A COMPUTERIZED FEED-INTAKE RECORDING-SYSTEM

The feed intake pattern and growth performance of boars, barrows, and gilts fed diets differing in lysine and protein content were measured on 120 crossbred pigs from 27 (SD 3.7) to 81.5 (SD 9.2) kg live weight . The pigs were housed in eight mixed-sex groups with five pigs of eac h sex in each group. They were fed from an electronic feed station tha t recorded individual meal sizes and the time and duration of visits t o the feeder for each animal in the group. Four dietary treatments wer e compared. During the grower period (27 to 55 kg), diets ranged in ly sine content from .98 to 1.31%; for the remainder of the study, lysine content was .88 to 1.18%. Barrows had a greater (P <.01) number of me als per day than the other two sexes (7.4 vs 7.0 vs 7.0 +/- .10, respe ctively), but there were no significant differences among sexes for da ily feed intake or other feed intake traits. Daily feed intake increas ed with dietary lysine content, largely because of increased meal size s resulting from longer feeder occupation times at each visit. Visits to the feeder were greatest between 0900 and 1100 and lowest between 2 000 and 0400. Correlations between feeding pattern and growth traits w ere relatively low. Repeatabilities of feeding pattern traits were gen erally higher when measured over shorter time periods. These results s uggest a change in feeding behavior with increasing dietary lysine lev els and a relatively small effect of sex on feeding pattern for mixed- sex groups of 15 pigs fed from a single electronic feed station.