Addition of chromic oxide to creep feed as a fecal marker for selection of creep feed-eating suckling pigs

Objective-To determine whether the addition of chromic oxide (Cr2O3) to creep feed could be used as a visual marker in feces for selection of creep feed-eating suckling pigs. Animals-20 suckling pigs. Procedures-Via syringe, 5 pigs (2 to 3 days old on day 0; 1 pig/treatment) from each of 4 litters received oral administrations of 10, 20, 30, or 40 g of creep feed containing 10 g of Cr2O3 center dot kg(-1) on each of 2 consecutive days (days 20 and 21) or 30 g of creep feed containing 10 g of Cr2O3 center dot kg(-1) on day 20 and 30 g of Cr2O3 free creep feed on day 21. On days 21 through 24, 6 fecal samples were collected from each pig at regular intervals between 8:00 Am and 6:00 Pm. Green-colored feces were considered indicative of creep feed consumption (eaters). Data analyses were based on single and multiple fecal samples. Results-On day 22, evaluation of 1 fecal sample/pig and multiple fecal samples per pig resulted in identification of as many as 40% and only 15% of the feed-treated pigs wrongly as noneaters, respectively. Repeated sampling over multiple days would identify 99% of eaters accurately. Pigs erroneously identified as noneaters were those administered either low amounts of Cr2O3 supplemented creep feed for 2 days or Cr2O3 supplemented creep feed on only 1 day. Conclusions and Clinical Relevance-Data suggest that addition of Cr2O3 to creep feed enables selection of individual creep feed-eating suckling pigs via examination of feces, provided that repeated fecal samples are evaluated.