Raymond W. Loan

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OBJECTIVE To determine the effect of transportation stress on serum concentrations of oxidative stress biomarkers of calves. ANIMALS 105 crossbred beef steer calves (mean [+/-SD] body weight, 207 +/- 21.2 kg). PROCEDURE Calves were assembled at 1 location in Tennessee, and pretransit (day -3) blood samples were collected. Calves were allotted randomly(More)
The 5′-AMP-activated protein kinase (AMPK) family is an ancient stress response system whose primary function is regulation of cellular ATP. Activation of AMPK, which is instigated by environmental and nutritional stresses, initiates energy-conserving measures that protect the cell by inhibition and phosphorylation of key enzymes in energy-consuming(More)
Respiratory tract infections with viruses and Pasteurella spp. were determined sequentially among 26 cattle that died during two severe epizootics of shipping fever pneumonia. Nasal swab and serum samples were collected prior to onset of the epizootics, during disease progression, and after death, when necropsies were performed and lung samples were(More)
OBJECTIVES To follow incidence of Pasteurella haemolytica (PH) in the upper respiratory tract of healthy calves at the farm and through the marketing process, and to determine the effect of vaccination on PH colonization of the upper respiratory tract and on the incidence of respiratory tract disease (RTD). ANIMALS 2- to 5-month-old calves (n = 104) from(More)
OBJECTIVE To identify cytocidal viruses and Pasteurella spp that could be isolated from cattle involved in 2 natural outbreaks of shipping fever. ANIMALS 105 and 120 castrated male 4- to 8-month-old feedlot cattle involved in 1997 and 1998 outbreaks, respectively. PROCEDURES Nasal swab specimens and blood samples were collected, and cattle were(More)
OBJECTIVE To determine the effect of tilmicosin treatment on number of Pasteurella haemolytica (PH) organisms in nasal secretion specimens of calves with respiratory tract disease. ANIMALS 206 British mixed-breed beef calves, 2 to 5 months old. PROCEDURE In 2 separate studies of outbreaks, calves (study 1, n = 101; study 2, n = 105) that developed(More)
Fusobacterium necrophorum (Sphaerophorus necrophorus) and Bacteroides melaninogenicus were the predominant bacteria isolated from biopsy specimens of lesions in cattle affected with foot rot. Mixed inoculums of the 2 bacteria, applied to the scarified interdigital skin or inoculated intradermally into the interdigital skin of test cattle, induced typical(More)
An epidemiologic study of Pasteurella haemolytica serovar 1 (Ph1) in market-stressed feeder calves from 7 farms in eastern Tennessee was conducted. The nasal mucus of each calf was cultured sequentially at the farm of origin (day 0), at an auction market (day 133), and at a feedyard in Texas (days 141, 148, 155, and 169). Of the 103 calves tested, 77 were(More)
A live Pasteurella haemolytica serotype 1 vaccine was used in an efficacy trial conducted on 100 lightweight feeder calves purchased from a Florida ranch. Forty-one calves were inoculated with the vaccine intradermally in the neck. Fifty-nine calves served as nonvaccinated controls. Fourteen days later, the calves were shipped to an order buyer in eastern(More)