This presentation will provide an overview of nutritional and management strategies that can be used in gilts to maximize their future milking potential. Increasing sow milk yield is most critical because of the current use of hyperprolific sow lines. One important factor affecting milk yield that is often overlooked is mammary development. In swine, there are three periods of rapid mammary development, namely, from 3 months of age until puberty, from 90 days of gestation until farrowing, and during lactation. It is only during these periods that one can attempt to stimulate mammary development. From 90 days of age until puberty, a 20% feed restriction drastically reduces mammary tissue mass whereas decreasing dietary crude protein from 18.7% to 14.4% has no effect on mammary development, and feeding the phytoestrogen genistein increases mammary cell number. During late gestation, feeding very high energy levels (10.5 Mcal ME/d) may have detrimental effects on mammary development and subsequent milk production. On the other hand, increasing SID Lys intake from 18.6 g/d to 26.0 g/d (via the inclusion of additional soybean meal) led to a 44% greater mass of mammary parenchyma. Increasing concentrations of the growth factor IGF-1 via porcine somatotropin injections from days 90 to 110 of gestation increased mammary parenchymal weight by 22%.
Feed intake throughout gestation is important to consider because it affects body condition, and gilts that are too thin (<16 mm backfat thicknes) in late gestation have reduced mammary development. Management of primiparous lactating sows is also important. During the first 2 days of lactation, special care should be taken to ensure that all teats are being suckled because teats that were not previously suckled will produce less milk in second parity.