Title: Influence of Daily Grit Consumption Rate and Diet on Gizzard Grit Counts
Abstract:We evaluated the relationship between the number of grit particles in gizzards and the grit consumption rate. House sparrows (Passer domesticus) were given, via oral gavage, doses of 9, 18, 36, 72, 14...We evaluated the relationship between the number of grit particles in gizzards and the grit consumption rate. House sparrows (Passer domesticus) were given, via oral gavage, doses of 9, 18, 36, 72, 144, 288, or 576 particles/day, and northern bobwhites (Colinus virginianus) were given 9, 18, 36, 72, 144, or 288 particles/day. Test birds were fed either a hard food (wild bird seed mix) or soft food (canned dog food) diet and were given equal numbers of grit particles from 3 different size classes (house sparrows: 0.2-0.4, 0.6-0.8, and 1.2-1.4 mm; northern bobwhites: 0.6-0.8, 1.4-1.7, and 2.4-2.8 mm). For both species, the number of grit particles in gizzards increased as dose increased, but the percentage that the gizzard grit count constituted of the daily grit dose decreased at higher doses. The fact that the birds eliminated large amounts of grit at the higher dose levels but retained most of the grit at lower levels suggests that birds need a certain target amount of grit in their gizzards. As daily grit dose increased, house sparrows on a hard diet had more small and medium-size grit in their gizzards than did house sparrows on a soft diet; the amount of large grit was similar between diets. As the daily grit dose increased, northern bobwhites had more small and medium-size grit in their gizzards than large grit. The high grit counts for some northern bobwhites may have resulted from incomplete flushing of the gizzard grit before dosing began. Our study improved upon previous efforts to evaluate the relationship between gizzard grit counts and grit consumption rates and provides information useful in assessing the potential for avian exposure to granular pesticides.Read More
Publication Year: 2002
Publication Date: 2002-04-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 9
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