Randy L. Powell

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Exposure to light during the night reduces plasma melatonin levels. A previous study showed that, in response to light, nighttime plasma melatonin levels fell twice as much in a group of acutely ill manic-depressive patients as in a group of normal subjects. The present study compares 11 euthymic manic-depressive patients not taking medications with 24 age-(More)
Milk records from Ayrshire, Brown Swiss, Guernsey, Jersey, and Milking Shorthorn cows that first calved between 18 and 35 mo were combined with scores for linear type traits collected before 43 mo during first lactation to study herd life and lifetime profitability. Profitability (discounted relative net income) was the value of milk, calves, and cow(More)
Genetic evaluations of Holstein bulls for February 1997 through May 1998 were examined to determine the value of more frequent evaluation for quicker identification of bulls with changing predicted transmitting abilities (PTA) and of new bulls of superior genetic merit. Changes in PTA between evaluations that were calculated quarterly rather than(More)
The plastination process using vacuum impregnation replaces tissue fluids with curable polymers and results in dry, non-toxic specimens. We detail a method to produce high quality plastinated specimens using an injection impregnation process. This alternate, non-vacuum method is very low-tech and has minimal start-up costs. We were able to successfully use(More)
Cows with superior genetic merit, based on an economic index for milk, fat, and yields (milk-fat-protein dollars), have been designated as elite by USDA. Because of the concern that adjustment for heterogeneous variance may have resulted in inequitable state representation for elite cows, the percentages of US cows with elite status were compared by state(More)
Canadian and US genetic evaluations for July 1991 were combined for 3304 Holstein bulls evaluated in Canada that had US progeny or a cross-reference code. Canadian evaluations of the bulls and their sires and dams were converted to US PTA. Combined PTA were weighted averages of progeny information from both countries and parent average. Parent average was(More)
Genetic evaluations for milk, fat, and protein from 1995 through August 2003 for 17,987 Holstein bulls in active artificial insemination (AI) service were examined for changes to the November 2003 evaluation. Evaluations for active AI bulls at each of 31 evaluation dates showed mean declines to November 2003. No evidence was seen of a worsening situation(More)
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