Effects of Adding Liquid Lactose or Molasses to Pelleted Swine Diets on Pellet Quality and Pig Performance.

Two experiments evaluated the effects of liquid lactose (SweetLac63) and molasses in swine diets on pellet quality and pig performance. A total of 194 nursery pigs (DNA 241×600, initially 6.7 kg) from 2 groups were used in a 33-d experiment. Pigs were weaned at 27 d and randomly assigned to pens balanced by BW, sex, and within group with 4 to 7 pigs per pen. A total of 32 pens were used to provide 8 pens per treatment. Pens were allotted to 1 of 4 dietary treatments consisting of a control diet containing 19.1% total sugars from whey powder and permeate and experimental diets with a percentage of whey permeate replaced by either 5 (5LL) or 10% liquid lactose (10LL) or 9.4% cane molasses (9.4M). All diets were balanced for SID Lys and total sugars and fed in pelleted form. Treatments were fed from d 0 to 21, and a common pelleted diet fed from d 21 to 33. Hot pellet temperature and production rate decreased (P<0.05) from the control to 9.4M with 5LL and 10LL having intermediate effects. Pellet durability index (PDI) increased (P<0.05) from control to 5LL, 10LL and 9.4M, respectively. From d 0 to 21, there were no treatment effects on ADG or G:F. In pigs fed the control diet, ADFI decreased (P<0.05) compared to those fed 10LL with 5LL and 9.4M being intermediate. From d 0 to 33, ADFI increased (P<0.05) in pigs fed 10LL compared those fed other diets. There were no treatment effects on ADG or G:F. For Experiment 2, a total of 289 finishing pigs (initially 53.5 kg) from 3 groups were used in a 53-d experiment. Pens were randomly assigned to 1 of 4 dietary treatments within location block and group. There were 6 pens per treatment with 8 to 14 pigs per pen, with number of pigs and gender balanced across treatment. Dietary treatments were a control pelleted diet with 0, 2.5, 5, and 7.5% liquid lactose. Pellet durability index improved (linear, P<0.01) with increased levels of liquid lactose. There were no differences in ADG, ADFI, final BW or carcass characteristics. Pigs fed diets with increasing liquid lactose had marginally significant increased (quadratic, P=0.070) G:F. Overall, liquid lactose and molasses improved PDI, without negatively influencing growth performance in nursery pigs and marginally improving G:F in finishing pigs.