1a.Objectives (from AD-416):
A review of published literature and discussions with nutritional colleagues indicate that both "day" and "marker-to-marker" fecal and urine collection methods are utilized in nutrient digestibility and balance studies. The ultimate purpose of either method is to obtain a specific time period output from the animal from which to conduct digestibility and balance studies to determine the nutritional value of various feed ingredients, including the numerous by-products generated from the biofuels industry. To date, however, no data can be obtained which directly compares these two methods relative to nutrient digestibility or retention data. This data is important in that nutritional digestibility and balance studies need to have no bias towards the final digestibility or retention data so that the nutritional and economic evaluation of feed ingredients reflects the true value to the growing animal.
1b.Approach (from AD-416):
For the "day" method, urine and feces will be collected for four 24-hour periods (exact timing), starting at 7 a.m. on day eight and ending at 7 a.m. on day 12. For the "marker-to-marker" method, urine would be collected as for the "day" method, while feces would be collected starting when the marker first appears and ending when the second marker appears (first marker added on day eight at 7 a.m.; second marker added on day 13 at 7 a.m.), where it is assumed that marker "appearance" will be approximately 24 hour post meal addition. Two diets will be utilized consisting of a typical corn-soybean meal and a corn-distillers dried grains with solubles to determine if the type has a determination on which collection method is warranted. The trial will be a completely randomized design and the individual pig will be the experimental unit. There will be a minimum of nine observations per treatment by method combination.
The objective of the research was to determine the effect of collection method (day versus marker-to-marker) on nutrient digestibility and balance in growing pigs and if the method of collection differs due to diet type. All animal experimentation, laboratory analysis, and statistical analysis have been completed with the data obtained by the University of Nebraska having been received by the ARS. In summary, the data indicates that the use of either the "day" or "marker-to-marker" method for collection of manure from pigs has little impact on nutrient digestibility or dietary energy estimates, suggesting that either method is suitable for animal experimentation.