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Biomedical subjects

J Dorsey

Publications and source records attributed to J Dorsey.

6 recordsLinked to original sources
PubMed2000

Lamb production and forage quality under a forage system consisting of AU Triumph tall fescue and Tifton 44 bermudagrass.

The lamb production potential and forage quality of a forage system consisting of AU Triumph fescue and Tifton 44 bermudagrass was studied over a period of two consecutive years. Each spring, 60 yearling Suffolk ewes and 40 wethers were divided into two groups and allowed to graze two replicated 1ha AU Triumph paddocks continuously. At the end of the spring grazing season, both groups were transferred to two replicated 1ha Tifton 44 paddocks for summer grazing. Body weight was recorded fortnightly and composite forage samples analyzed for chemical composition, in vitro dry matter disappearance (IVDMD) and in vitro organic matter disappearance (IVOMD) at the end of the study. Mean crude protein (CP), ether extract (EE), ash, neutral-detergent fiber (NDF), acid-detergent fiber (ADF), cellulose, lignin, IVDMD and IVOMD contents of AU Triumph fescue were 13.26, 1.86, 7.38, 69.4, 36.37, 29.2, 6.81, 64.44 and 62.88%, respectively. The corresponding values for Tifton 44 bermudagrass were 7.5, 1.01, 5.2, 78.3, 41.0, 28.3, 8.8, 56.97 and 55.61%. Average daily gain (ADG) and lamb gain per hectare on AU Triumph fescue were 142.1g and 412.59kg/ha, respectively. However, lamb ADG started to decline and remained low when they were transferred from AU Triumph to Tifton 44 bermudagrass resulting in a low ADG and lamb gain per hectare of only 18.2g and 84.09kg/ha, respectively. In contrast, Tifton 44 yielded higher post grazing residual DM, suggesting that the decline in performance of the lambs grazing Tifton 44 to be related to poor forage quality rather than availability. The results indicate that low nutritive value of Tiftton 44 bermudagrass is a limiting factor to lamb production in the forage system studied. To prevent the observed decline in lamb performance, it might be necessary to fertilize Tifton 44 at a higher rate or replace it with a better quality warm season forage.

Journal Article↗
PubMed1993

Correlates of the Woodcock-Johnson Reading Comprehension and Kaufman Brief Intelligence Test in a forensic psychiatric population.

Assessing the forensic psychiatric patient remains an ongoing challenge. This study assessed the intellectual status of lower-functioning incarcerated adult males with the Woodcock-Johnson Reading Comprehension subtest and the Kaufman Brief Intelligence Test. The results of this study have led the authors to argue for a broad-based assessment model that focuses on the demands and constraints of the dispositional setting.

Adult↗
PubMed1991

Postnatal changes in plasma 1,25-dihydroxyvitamin D3 in sheep: role of altered clearance.

The ontogeny of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] production and metabolic clearance rates (PR and MCR, respectively) was determined in chronically catheterized fetal (postconceptional age of 127 days; term = 145 days), neonatal (10 +/- 1 and again at 24 +/- 1 days postnatal), and adult (3 yr of age) sheep. Plasma concentrations of 1,25(OH)2D3 were more than twofold higher in fetuses than in adults and were increased by 78% during the 1st 24 days postnatally. In contrast, compared with values in fetuses, the MCR of 1,25(OH)2D3 was reduced by 40% in 10-day-old neonates and by 58% in 24-day neonates, although 24-day neonatal values were still 75% higher than adult values. In contrast, the PR of 1,25(OH)2D3 did not demonstrate an ontogenic change during development and remained at all times approximately ninefold the adult value. The finding, by regression analysis of an inverse relationship between the MCR and the plasma concentration of 1,25(OH)2D3, is interpreted to suggest that increased plasma concentrations are the result of a reduced MCR. We conclude that increases in plasma concentrations of 1,25(OH)2D3 in the perinatal period can occur by a mechanism that is independent of enhanced endogenous synthesis, namely a reduction in the MCR of the hormone.

Analysis of Variance↗
PubMed1989

Rapid analytical technique for the assessment of cell metabolic activity in marine microalgae.

A standard method for the assessment of cell viability has been developed for marine phytoplankton using an inexpensive stain, fluorescein diacetate (FDA), at .75 microM for 10 min. A flow cytometer was used as the fluorescence detector, providing an assessment of viability for each individual particle. Cell size and chlorophyll fluorescence per cell were assessed simultaneously, permitting an assignment of viability to specific subpopulations, thus increasing the power of the technique. A reasonable correspondence between FDA mean fluorescence intensity per cell and an independent metabolic indicator, photosynthetic capacity measured by 14C, was found. Both FDA mean fluorescence intensity and photosynthetic capacity vary as a function of cell volume. Recovery after extended periods of darkness indicate that cells that are FDA negative may not be dead, but merely quiescent or inactive.

Eukaryota↗