Effect of a Seven Day Stair-Step Feeding Regimen Versus Ad Libitum Feeding Throughout Lactation on Sow and Litter Performance

Purdue University 1998 Swine Research Report. Stair-step feeding regimens, commonly implemented in Europe, are intended to reduce the incidence of periparturient hypogalactia syndrome (PHS; formerly known as mastitis metritis and agalactia, MMA) and transient drops in mid-late lactation feed intake. Swedish stair-step feeding regimens usually start the sow on a feed intake close to maintenance the day of or the day after farrowing and step up feed intake in small increments over the entire lactation length. Some American producers have adopted a modified version of this strategy and step up sow feed intake gradually during the first 3 to 4 days postpartum. Again, the intent is to step up the sows feed intake slowly and avoid drops in feed intake later in lactation. Avoiding symptoms sometimes associated with PHS, such as feed refusal and constipation, are other reasons American producers sometimes restrict sow feed intake early in lactation. Feed restriction during early lactation reduces total lactation feed intake (Moser et al., 1987; Stahly et al., 1979), increases mobilization of sow body fat reserves (Neil, 1996), and extends the wean to estrus interval (King and Dunkin, 1986). Restriction of feed intake during lactation reduces levels of insulin, glucose and IGF-1 in sows; decreased levels of these compounds are hypothesized to be directly involved in the reduction in ovarian activity and LH pulse frequency (Tokach et al., 1992). The objectives of this study were to 1) assess the impact of two lactation feeding regimens on sow feed intake, body weight loss, backfat loss, litter weight gain and preweaning mortality. We also wanted to 2) relate the effects of these feeding strategies to sow energy balance through the measurement of circulating metabolite levels.