EATING BEHAVIOR OF LACTATING SOWS RECEIVING GROWTH HORMONE-RELEASING FACTOR - EFFECT OF MEAL FREQUENCY AND HIGH-FIBER GESTATION DIETS

Forty-eight Yorkshire x Landrace gilts were used in an experiment with a factorial design (2 x 2 x 2). The treatments were control or bulky diet during gestation (4.1 vs. 15.3% crude fiber), the number of meals served daily in lactation (2 or 4) and three daily s.c. injections of saline or of 1 mg of a human growth hormone-releasing factor analog ( GRF) from day 3 to day 29 of lactation. The animals were video-recorde d for 30 s every 5 min over a 24-h period and observed continuously at feeding time at weeks 2 and 4 of lactation. Injections of GRF to lact ating sows decreased the time spent eating after feed distribution (P = 0.007) but not eating frequency over 24 h. GRF-treated sows performe d more oral non-feeding activities after feed distribution and over 24 h (P < 0.05). Sows fed four times a day spent less time eating and mo re time lying per feeding period than sows fed twice (P < 0.05) but th e total eating time over the day was similar. Lying frequency did not decrease in GRF-treated sows fed at 23:15 h, contrary to saline-inject ed sows (P = 0.02). Feeding high-fiber diets during gestation had no e ffect on eating behavior during lactation. In conclusion, GRF injectio ns during lactation modified the eating behavior of sows. However, usi ng a bulky diet during gestation or increasing meal frequency during l actation did not counteract the decrease in eating time due to GRF.