INFLUENCE OF DIETARY NUTRIENT DENSITY, LEVEL OF FEED INTAKE AND WEANING AGE ON YOUNG PIGS. II. APPARENT NUTRIENT DIGESTIBILITY AND INCIDENCE AND SEVERITY OF DIARRHEA

Abstract

One hundred and twenty-eight pigs were allotted to a factorial design involving two weaning ages (3 and 4 wk), two diets (normal density, ND, and high density, HD) and two levels of feed intake (ad libitum and restricted) and fed for 28 d postweaning. Feed restriction increased the digestibility of energy (P < 0.05). Apparent digestibility of energy and protein increased with time postweaning (P < 0.05). Pigs weaned at 4 wk of age had higher nutrient digestibilities than those weaned at 3 wk only in the second week postweaning (P < 0.05), showing that the digestive system of older pigs adapts faster. The apparent digestibility of the HD diet was not different from that of the ND diet. Diarrhea was more severe when pigs were weaned at 4 wk (P < 0.10), or when receiving the HD diet (P < 0.10), or when offered feed ad libitum (P < 0.10), showing that both volume of feed consumed and nutrient intake influence occurrence of diarrhea. Postweaning diarrhea was most severe (P < 0.05) and most frequent (P < 0.05) during the first week and declined thereafter. The rate of decline was fastest in older pigs (P < 0.05) with restricted feed intake (P < 0.05) and pigs receiving the ND diet (P < 0.05). There was a significant negative correlation (P < 0.05) between apparent energy and protein digestibility and incidence and severity of diarrhea during the first week postweaning. The results suggest that nutrient intake is more important in predisposing piglets to diarrhea than the volume of feed consumed. Key words: Pigs, weaning, digestibility, diarrhea