Assessment of the Iron Status of Young Pigs in a Confinement Herd

Iron deficiency in swine became a problem with the transition from outdoor operations to confinement systems. Pigs raised outdoors would naturally obtain iron via rooting in the dirt. However, in confinement, pigs are provided iron primarily via an injection soon after birth to augment the low amount in tissues and the small quantity they receive from sow milk. This experiment was conducted to determine if the iron supplemented at birth is sufficient for piglets throughout the nursey phase. A total of 124 pigs from 13 sows were used. Pigs were weighed at day 1, weaning, and day 21 and 35 postweaning. Blood samples were also collected at the different time points. Each piglet received a 1.5 mL IM injection of iron dextran supplying approximately 75 mg iron, immediately after blood collection on day 1. After collection of the weaning blood samples, at about 21 days of age, the pigs were moved to a nursery site and housed 4 pigs per pen. The nursery diet was supplemented with 33 ppm iron as ferrous sulfate. Iron status was assessed by levels of hemoglobin concentration and hematocrit percentage in the piglets. The results indicated that hemoglobin concentration was a more sensitive measure of iron status than hematocrit percentage. At weaning, hemoglobin concentration (y) had a negative relationship with BW (y = -0.9411 BW+20.639, = 0.097). The 21-day post wean hemoglobin concentration also had a negative relationship with BW (y = -0.0228 BW+14.759, = 0.007). The 35-day post wean hemoglobin concentration, had a positive relationship with BW (y = 0.0583 BW+12.278, = 0.058). Using an industry standard hemoglobin concentration to indicate iron deficiency g/dL), Figure 1 indicates at weaning around 13% of the pigs would be considered iron deficient. However, at day 21 and day 35 post wean all pigs were above that critical value. In conclusion, under conditions similar to this confinement herd, a portion of pre-wean piglets seem to outgrow the day one iron injection; however, by day 21 in the nursery there are no apparent issues with iron deficiency.