Dr. Denise Beaulieu-Prairie Swine Centre:
The requirements for fetal development change throughout gestation so what we're really trying to do is to feed the animal for her specific needs as she grows or as the requirements change throughout gestation.
Early on in gestation the fetal development is quite slow.
The young piglets developing inside of the sow really aren't growing at a rapid rate of gain however, in the last few weeks of gestation, that's when you see a marked increase so the sow just requires more energy.
However most of that deposit of tissue is primarily protein so the lysine to energy ratio or the lysine to other amino acid ratios actually go up as well.
This is why, when we're phase feeding, we would certainly recommend if a producer can not accommodate different diets at the very least to increase the amount of feed offered to the sow in the last month of gestation but even better than that would be to reformulate the diet and to have one diet throughout most of gestation but a different diet for the last three or four weeks of gestation.
Dr. Beaulieu recommends at least two phases, one in early gestation and one in late, to more precisely match the nutrient content of the diet to the nutrient requirements of the sow for fetal development.
For more on phase feeding during gestation visit the Prairie Swine Centre web site at prairieswine.com.
Source: Farmscape