Jean A. Hall

Dr. Jean Hall
E-Mail: 
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Professor
Small Animal Internal Medicine
Physiology

206 Dryden Hall
541-737-6532 (reception)
541-737-2730 (fax)
cvm.biomed@oregonstate.edu

Professional Awards: 
  • American College of Vet Internal Medicine 1987
  • 1990 Post-doctor Fellowship at OHSU: Lipid Metabolism
  • 1989 PhD Colorado State University: Physiology
  • 1987 MS Colorado State University: Clinical Sciences
  • 1982 DVM Washington State University (summa cum laude)
  • 1981 BS Oregon State University: General Science (with highest scholarship)
Professional and Research Interests: 
  • Nephrology and SDMA
  • Nutrition and immunology
  • Effects of selenium supplementation on immune responses in sheep and cattle
  • Effects of dietary (n–3) fatty acids and antioxidants on immune responses in dogs and cats

Nephrology and SDMA

Chronic kidney disease (CKD) is a common cause of morbidity and mortality in cats and dogs.  Serum concentrations of symmetric dimethylarginine (SDMA) have been shown to detect CKD in cats on average 17.0 months before serum creatinine (Cr) concentration increased above the reference interval, and in dogs on average 9.8 months before serum Cr concentrations increased above the reference interval.

  • SDMA is produced by post-translational methylation of arginine residues in proteins.   Subsequent degradation of proteins containing methylated arginines yields individual methylated arginine amino acids.
  • Free methylarginines are released into the cytosol following proteolysis, and then enter the blood circulation.
  • SDMA is excreted by glomerular filtration and accumulates in patients with renal failure.  We have shown that serum SDMA concentrations are correlated with glomerular filtration rate in dogs and cats.
  • Serum SDMA concentrations are not influenced by lean body mass as is serum Cr concentration. This limits serum Cr utility as a biomarker for monitoring renal function in dogs and cats with decreased lean body mass. 

Now that the utility of using serum SDMA as an early indicator of compromised renal function in pets with CKD has been demonstrated, we find ourselves in the fortunate situation of being able to evaluate benefits of early dietary interventions to improve the outcome of pets with CKD.

  • For example, dietary supplementation of mildly protein-restricted, energy-dense currently available renal protective food with functional lipids (fish oil), antioxidants (lipoic acid), carnitine, increasing concentrations of botanicals (fruits and vegetables), and more bioavailable protein sources reverses the age-associated decline in glomerular filtration rate in healthy geriatric dogs.
  • As a renal biomarker, SDMA was more sensitive for detecting diet-induced changes in glomerular filtration rate than serum Cr.
  • Feeding dogs with IRIS-Stage 1 CKD a renal food for 12 months resulted in improvement in renal biomarker concentrations, in particular decreases in serum SDMA concentration, and owners noted improvement in overall quality of life attributes.

Selenium Supplementation of Oregon Livestock

Selenium (Se) is an essential trace mineral for livestock. White muscle disease, also known as nutritional myodegeneration, results from clinical Se deficiency and was discovered in Oregon in 1958. It is characterized by muscle weakness, heart failure, unthriftiness, and death. Sub-clinical effects of Se deficiency result in poor livestock performance.

  • Selenium deficiency is caused by low Se intake, which correlates to limited Se availability in soils, and thus, forages grown on those soils.
  • Livestock forage, whether range, pasture, or hay, generally reflects the available Se content of the soil on which it is grown.
  • Forage supplemented with Se can be fed to livestock. Concerns about Se toxicity are much less, intake of Se is more consistent, and retention of Se is much greater when feeding a Se-fortified forage.

The potential for using Se as a fertilizer to increase forage-Se concentrations in livestock feeds has been demonstrated by over 15 years of research at Oregon State University.

  • This practice can potentially overcome the inconsistent intake of salt-mineral mix Se supplementation.
  • Supranutritional amounts of Se can be provided safely with Se fertilization.

Our work is focused on establishing guidelines to produce Se-fertilized forage and hay in order to enhance forages fed to ruminants

  • We have shown that sodium selenate is the form of Se most efficiently taken up by plants.
  • The recommended level of application is 5 to 10 grams of actual Se per acre in order to achieve adequate levels in forage. Sodium selenate, for example, is 41% Se.  An application rate of 12 to 24 grams of sodium selenate per acre will provide the recommended 5 to 10 grams of actual Se per acre.

In particular we are studying the effects of Se fertilized forage (thus, increased Se intake) on immune responses, cattle health, and cattle production.  We also have multiple studies in sheep.

Publications

2009
2007
2006
2005