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The modern hyper-prolific sows result in a high number of piglets per litter even higher than the number of available functional teats. These larger litters are characterized by high within-litter birth weight variation and consequently greater mortality and lower growth rates of undersized piglets. Sow milk yield is insufficient to achieve the maximum growth potential of these larger litters. The effects of artificial rearing on the growth, small intestinal morphology and digestion capacity of these piglets remain unclear. Therefore, the objective of this study was to investigate growth performance and structural and functional characteristics of the small intestine, in artificially reared versus suckling piglets of different weight categories (LBW versus NBW) and at various points in time (d 10 and d 28). A total of 20 crossbred pairs of normal birth weight (NBW) piglets (1.48±0.11 kg at birth) and low birth weight (LBW) piglets (0.87±0.04 kg at birth) were selected from 10 litters at a local farm. All piglets (n=40), were allotted to 4 treatment groups. Groups 1 and 2 contained piglets that suckled until either d 10 (n=10) or 28 of age (n=10), respectively. Groups 3 and 4 contained animals that were separated from the sow at d 3 of age and were subsequently artificially reared using a commercial milk formula until d 10 (n=10) or d 28 (n=10). The formula-feeding was started at d 3 after birth to allow piglets to ingest sufficient amounts of colostrum.
NBW piglets had higher average daily gain (ADG) compared to LBW piglets (P<0.01). During d 3–10, formula-fed piglets showed reduced ADG and lactase activities compared to suckling piglets (P<0.01). In contrast, animals that were formula-fed until d 28 had a comparable ADG compared to sow-fed pigs. In addition, formula-fed piglets had a greater absorptive area (P<0.01), maltase and sucrase activities (P<0.05) and deeper crypts (P<0.03) compared to suckling piglets. In general, the differences between LBW and NBW piglets were scarce.
In conclusion, artificial rearing of 3d-old piglets resulted in minor symptoms of gastrointestinal disorders during the first week of formula-feeding. Long-term formula feeding resulted in similar growth performances and improved gut growth and functional maturation. Artificially reared piglets benefit from the ad libitum availability of formulated milk by an increased absorptive intestinal capacity due to the latter and their elevated sucrase and maltase activities, formula-fed piglets will probably better adapt to the shift towards solid feed.
De Vos, M., Huygelena, V., Willemena, S., Fransen, E., Casteleyn, C., Van Cruchten, S., Michiels, J., Van Ginneken, C. (2014) Artificial rearing of piglets: Effects on small intestinal morphology and digestion capacity. Livestock Science 159; 165–173.