Effect of ractopamine feeding strategies during the first lactation on sow performance

摘要

During the first lactation, excessive mobilisation of sow body reserves, particularly protein, significantly impairs subsequent reproduction. Dietary ractopamine (RAC; Paylean~R) increased lean growth in finisher pigs (Apple et al, 2007), with lactation live weight loss also reduced in primiparous sows receiving a RAC-supplemented diet (van Wettere et al., 2009). In finisher pigs, the growth response to RAC is affected by ractopamine inclusion rate, with some studies also reporting further improvements when RAC concentrations are stepped up after 14 days (Apple et al, 2007). Two studies were conducted to test the hypothesis that altering RAC inclusion rate, and the period of inclusion relative to farrowing, in the diet of first lactation sows woulddifferentially affect the mobilisation of body reserves and subsequent reproduction.