There was no effect of trace mineral source on sow breeding or gestation BW or gestation gains (Table 6). Sows fed organic trace minerals had a somewhat lighter (P < 0.05) weaning BW, but there was no difference in lactation weight change. Lactation feed intake (total or ADFI), estrus rebreeding interval, and milk fat content were similar between trace mineral sources, trace mineral levels, or when the elevated dietary Ca:P levels were fed.As expected, backfat measurements increased as
gestation progressed but declined during lactation. Backfat thicknesses at breeding, 110 d postcoitum, and farrowing were greater (P < 0.05) when sows were
fed inorganic trace minerals. Sows fed the NRC trace mineral level from either mineral source had greater (P < 0.05) backfat thicknesses at breeding, 110 d postcoitum, and at farrowing, resulting in a mineral source × mineral level interaction response