Abstract
Using swine as a biomedical model, this study examined whether consumption of added protein (red meat) or free sugar (glucose) throughout gestation and lactation will affect milk composition. Multiparous sows were fed an isocaloric supplement in addition to their normal corn-soybean meal base diet starting on day 40 of gestation and throughout lactation: cooked ground beef (BEEF; n = 10); free sugar (SUG; n = 9); a mixture of the BEEF and SUG diet (BEEFSUG; n = 7); or a caloric equivalent of the base diet (CONTROL; n = 8). Milk samples (30 mL) were collected from each sow at days 0, 6, 12, and 18 of lactation by hand-milking teats after intramuscular injection of 1 cc of oxytocin. Milk was frozen at -20 °C until analyzed for percentage of fat, protein, lactose, total solids, other solids, and milk urea nitrogen (MUN). Analyses were conducted using the mixed procedure in SAS. For traits occurring over time, a repeated measures statement was used with sow as the subject and the best fit method based on AICC was chosen. There was a day × treatment interaction (P < 0.01) for fat and lactose. There were no significant treatment effects within a day for fat when evaluating mean separations. While percentages were similar across treatment groups on days 0, 6, and 12 for lactose, SUG sows had decreased lactose on day 18 compared to CONTROL and BEEFSUG sows (P = 0.02 and 0.04), with no other significant differences between treatments. There were no treatment or treatment ×day interactions for protein, MUN, total solids or other solids. There was a main effect of day where protein decreased from day 0 to 12; MUN decreased between days 6 and 18; total solids decreased from day 0 to 6; and other solids increased from day 0 to 6 and further increased on day 12. Consumption of a maternal supplementation may impact the percentage of lactose in milk.