FEEDING LACTATING PRIMIPAROUS SOWS TO ESTABLISH 3 DIVERGENT METABOLICSTATES - III - MILK-PRODUCTION AND PIG GROWTH

First-litter sows fitted with stomach cannulas were used to test the h ypothesis that making gilts anabolic during lactation by providing the m with extra nutrition would increase milk production and pig growth. Gilts were allocated to one of three dietary treatments after farrowin g: I) restricted, sows were fed 50% of their estimated ad libitum inta ke; 2) ad libitum, sows were encouraged to eat as much feed as possibl e; and 3) superalimented, sows were infused seven times daily through their cannula to achieve a 25 to 30% increase in energy intake in exce ss of that achieved by sows fed on an ad libitum basis. Milk productio n was estimated in mid- (d 10 to 15) and late (d 21 to 25) lactation b y a modification of the isotope dilution technique. Milk production wa s similar between treatments in mid-and late lactation (P > .05), and this was reflected in a similarity in weaning litter weight (P =.238). Milk composition was similar also (P >.05) between dietary treatments . Superalimentation provided gilts with 38% more energy (P <.001) than gilts fed on an ad libitum basis, and they accrued live weight (5.1 k g) and backfat (1.8 mm) during lactation (P <.001). These data provide evidence that, unlike multiparous sows that show an increase in milk yield when made anabolic during lactation, primiparous sows seem to pa rtition extra energy into body growth rather than into milk production .