Nutritional indices and helminth fauna of ring-necked pheasants in the Texas High Plains
Dowell, James Howard
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Gizzard fat (GF), wing fat (WF), eviscerated body weight (BW) spleen weight, and thyroid weights were analyzed in ring-necked pheasants (Phasianus colchicus) to determine area, sex, and seasonal variations. Birds were collected from 2 study areas in the Texas Panhandle during 4 seasons. Area differences in major grain crops were not reflected in the nutritional indices examined. However, differences in pheasant densities between areas were detected. Thus, pheasants appear to adapt population size rather than individual nutritional status to food availability. Gizzard fat and WF were greater in hens than in cocks. Highest values for GF and BW occurred in February; lowest values occurred in August. In May, a drastic decline in WF and GF occurred in cocks, probably reflective of reproductive/territorial activities. Spleen weights were greatest in males and in August. In juveniles, no differences between sexes in WF were detected, but GF was greater in hens than cocks. Sex X Month and Area X Month interactions were detected in the GF analysis. Helminth parasitism, also was analyzed by area, sex, age, and seasonal variations. Two nematode and 1 cestode species were recovered from 18 of 84 (21%) birds examined. Heterakis spp. (H. gallinarum or _H. isolonche) were found during August, November and February but with very low prevalence. Choanotaenia infundibulum was the most common helminth with specimens found during February, May and August. The highest incidence occurred during the warm season with prevalence of 7/16 and 6/23 and abundance of 2.4 and 1.7 for May and August, respectively.