Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: Effects of sex, initial body weight, and bodyweight distribution within groups

Feed intake characteristics of 192, 27-d-old weanling pigs housed in groups and given ad libitum access to feed and water were measured individually w ith the use of computerized feeding stations. The groups were either homoge neous or heterogeneous as to BW distribution; pigs of three defined initial BW classes were used (mean BW of 6.7, 7.9, or 9.3 kg). The effects of BW d istribution, BW class, and sex were studied with regard to average performa nce traits, latency time (interval between weaning and first feed intake), initial feed intake (intake during the first 24 h following first feed inta ke), and daily increase in feed intake during the interval between first fe ed intake and the day on which energy intake met or exceeded 1.5 times the maintenance requirement. Homogeneous and heterogeneous groups had similar l atency times, initial feed intakes, and daily increases in feed intake. For the period 0 to 34 d after weaning, ADFI and ADG were also similar for hom ogeneous and heterogeneous groups, but gain:feed ratio was greater (P < 0.0 5) in the homogeneous groups. Gilts had higher (P < 0.05) initial feed inta kes than barrows and also had greater (P < 0.05) ADFI and ADG during the pe riod 0 to 13 d after weaning. Pigs with average BW of 6.7 kg had higher (P < 0.05) initial feed intakes than their counterparts with average BW of 7.9 kg and 9.3 kg, but the daily increase in feed intake was similar for the t hree groups. The lighter pigs had more daily visits and a lower feed intake per visit and tended to have a shorter postweaning latency to the onset of feeding than the heavier pigs. This study indicates that the high variabil ity in early feeding behavior among group-housed weanling pigs may be relat ed to BW and sex.