title: Evaluation of the Captec chrome controlled-release device for the estimation of fecal output by grazing sheep.
abstract: Three grazing experiments were conducted to compare actual fecal output (FO) by sheep, determined with fecal collection bags, to fecal output predicted using Captec chromic oxide (Cr2O3) controlled-release capsules. In Exp. 1, 14 crossbred wethers dosed with controlled-release Cr2O3 capsules rotationally grazed four paddocks of alfalfa (Medicago sativa L.) for 18 d. Total fecal collection and grab samples were taken daily from each animal; feces were dried and assayed for Cr. From d 5 to 12 after dosing, mean actual FO (429 +/- 9.6 g of DM/d) differed (P less than .001) from FO predicted by the capsule (463 +/- 12.8 g of DM/d). The correlation between actual and predicted FO was r = .59. When data were averaged by day, the correlation increased to .82. In Exp. 2, Tifton 44 bermudagrass (Cynodon dactylon [L.] Pers.) was strip-grazed for 30 d by the same 14 wethers used in Exp. 1. Mean actual FO (369 +/- 5.1 g of DM/d) differed (P less than .0001) from predicted FO (415 +/- 9.3 g of DM/d), with a correlation of .60. In Exp. 3, 72 crossbred lambs were blocked by weight (light and heavy) and assigned to six groups of eight wethers (four with fecal bags) and four ewes, allotted randomly to three stocking rates (74, 99, and 148 sheep/ha). Sampling occurred from d 6 to 10 after dosing (Period 1) and d 20 to 24 after dosing (Period 2).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh.
authors.forename: S E
authors.initials: SE
authors.lastname: Buntinx
authors.forename: K R
authors.initials: KR
authors.lastname: Pond
authors.forename: D S
authors.initials: DS
authors.lastname: Fisher
authors.forename: J C
authors.initials: JC
authors.lastname: Burns
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002214:Capsules; D002857:Chromium / Q000008:administration & dosage; D017608:Chromium Compounds; D003672:Defecation; D003692:Delayed-Action Preparations; D005069:Evaluation Studies as Topic; D005260:Female; D008297:Male; D011237:Predictive Value of Tests; D011897:Random Allocation; D012756:Sheep / Q000502:physiology*
chemical_list: D002214:Capsules; D017608:Chromium Compounds; D003692:Delayed-Action Preparations; D002857:Chromium; C023600:chromic oxide