Normal hematologic and biochemical values for prelaying greater sage grouse (Centrocercus urophasianus) and their influence on chick survival.

TitleNormal hematologic and biochemical values for prelaying greater sage grouse (Centrocercus urophasianus) and their influence on chick survival.
Publication TypeJournal Article
Year of Publication2005
AuthorsDunbar MR, Gregg MA, Giordano MR, Davis DM, Byrne MW, Crawford JA, Tornquist SJ
JournalJournal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians
Volume36
Issue3
Pagination422-9
Date Published2005 Sep
ISSN1042-7260
KeywordsAnimal Nutritional Physiological Phenomena, Animals, Animals, Newborn, Blood Chemical Analysis, Blood Glucose, Blood Proteins, Calcium, Female, Galliformes, Hematologic Tests, Logistic Models, Nutritional Status, Phosphorus, Predictive Value of Tests, Reference Values
Abstract

Declines in greater sage grouse (Centrocercus urophasianus) productivity and population numbers throughout their range demand a better understanding of how nutrition influences sage grouse populations. During March and April 1999-2001, blood samples were collected from 158 female (73 adult, 85 yearling), free-ranging, prelaying, greater sage grouse from an area in northwestern Nevada, USA, and southeastern Oregon, USA. These blood samples were evaluated to establish normal blood values for sage grouse and ascertain if certain blood parameters, as indices of nutrition, are useful for predicting if sage grouse hens would raise at least one chick to 1 August. Results of logistic regression indicated that three of six blood parameters analyzed--glucose, total plasma protein, and calcium: phosphorus ratio-affected the probability of a female sage grouse raising at least one chick to late summer. Ranking of the standardized estimates revealed that glucose and total plasma protein had the greatest impact on the likelihood of a female successfully raising chicks. Odds ratios indicated that a 1-unit increase in glucose (1 mg/dl) and plasma protein (0.1 g/dl) would result in a 4% and 113% positive increase, respectively, in the predicted odds of at least one chick surviving until 1 August. Odds ratios for calcium : phosphorus ratio revealed a 70% decline in the predicted odds of at least one chick surviving until 1 August if the level of this parameter increased one unit (e.g., 3:1 to 4:1). Based on these analyses, values of some blood parameters used as indices of nutrition, especially glucose, total plasma protein, and calcium : phosphorus ratio, can be successfully used to predict reproductive success of sage grouse. These parameters are not only indicative of the nutritional status of prelaying hens but may be associated with nutritional quality of the habitat and therefore have important management significance.

Alternate JournalJ. Zoo Wildl. Med.