The fertility of sows has increased dramatically over the past two decades, and currently, the number of total born piglets in Denmark is 16.8 piglets per farrowing (Vinther, 2013). Piglet mortality is high, and 10 to 12 percent of the total born piglets die before or during the birth process and another 10 to 12 percent die shortly after birth (Pedersen et al., 2010).
It is indeed a great challenge to keep the piglets alive around parturition (Rutherford et al., 2013), and improved knowledge on feeding sows during the transition period from late gestation to early lactation seems to be a central key for improving productivity of hyperprolific sows.
Colostrum intake is a limiting factor for piglet survival (Quesnel et al., 2012). If the colostrum intake exceeds 200 grams, the piglet survival is higher than 90 percent; but if the colostrum intake becomes less than 100 grams, the survival drops to less than 40 percent (Quesnel et al., 2012). Insufficient intake of colostrum is typically experienced by one or more piglets in any litters because of the high competition in litters born by hyperprolific sows. In addition, insufficient intake may be experienced by many piglets if the colostrum production of the sow is inadequate. Selection for high prolificacy among sows has indirectly reduced the birth weight of piglets due to uterine crowding (Foxcroft et al., 2009). Unfortunately, the capability of ingesting colostrum is reduced in small-born piglets (Amdi et al., 2013), but inclusion of fiber in the sow diets may ameliorate the colostrum intake of these piglets (Loisel et al., 2013; see below).
The colostrum production is highly variable among sows (Le Dividich et al., 2005), and up to one third of all sows do not produce sufficient amounts of colostrum to cover the need for all littermates (Quesnel et al., 2012). At present it is not known to which extent genetics, health and management factors affect colostrum production of sows, but recently the importance of sow nutrition in late gestation was demonstrated. Feeding sows with 2.5 g/d of hydroxy-methyl butyrate (HMB) from day 108 of gestation increased the colostrum intake from 434 to 512 g/piglet (P = 0.05; Flummer and Theil, 2012) and no mortality from birth to 24 hours of age was observed in HMB litters.
In another study, sows were fed with +/- 1.3 percent conjugated linoleic acid (CLA; an equal mixture of cis-9/trans-11 and trans-10/cis-12 isomers) from day 108 of gestation, and CLA fed sows tended to produce less colostrum (409 vs 463 g; P = 0.07). In addition, more piglets died or were moved during the first week of lactation to other sows to ensure their survival when fed CLA (17.6 percent) as compared to 7.8 percent in the control group (P = 0.04; Krogh et al., 2012). These studies emphasize that nutrition is important but is of less importance from a practical point of view because HMB is too expensive to use as supplement and because CLA impaired the colostrum production.
Dietary inclusion of fiber seems to be a more promising way of improving the colostrum production of sows, although not all fiber sources are beneficial for the colostrum production. In a study by Theil et al. (2013), sows fed high fiber diets originating from either pectin residue or sugar beet pulp had a higher production of colostrum (520 and 504 g/piglet, respectively) compared to sows fed a high fiber diet based on potato pulp or a low fiber standard diet (393 and 414 g/piglet, respectively; P = 0.02). In that study, the diets were allotted to the sows from mating until d 107 of gestation, whereas sows were supplied with low fiber diets from day 108 of gestation until weaning 28 day after parturition.
In another recent study, Loisel et al. (2013) showed that inclusion of fiber from day 92 of gestation increased the colostrum intake of piglets with birth weights below 900 grams. The overall colostrum production was numerically highest for sows fed the high fiber diet but not statistically different. As a consequence, the piglet mortality from day 1 to 21 of lactation was reduced from 14.7 to 6.2 percent (P = 0.01), which emphasize that colostrum production of the sow and nutrition during the transition period is important for sow productivity.
*Extracted with permission from a presentation at the 2013 meeting of the Society of Feed Technologies in the UK. References are available from the author upon request.