نتایج جستجو برای: beef calves
تعداد نتایج: 29320 فیلتر نتایج به سال:
To determine the prevalence of Giardia duodenalis in weaned beef calves on cow-calf operations in the United States, fecal specimens were collected from 819 calves (6-18 months of age) from 49 operations. After cleaning and concentration procedures to maximize recovery of cysts from feces, DNA was extracted from each of the 819 specimens. The presence of G. duodenalis was determined by nested P...
BACKGROUND Mortality and morbidity are hardly documented in the white veal industry, despite high levels of antimicrobial drug use and resistance. The objective of the present study was to determine the causes and epidemiology of morbidity and mortality in dairy, beef and crossbred white veal production. A total of 5853 calves, housed in 15 production cohorts, were followed during one productio...
The 2002 USDA Consensus of Agriculture reported a total of 160 beef cow/calf ranches in the US with greater than 2,500 cows. Of these 160 ranches, 60% reside in just four states with Florida, Texas, Nebraska and New Mexico possessing 38, 28, 19, and 10, respectively. These results illustrate a significant anomaly when considering the fate of weaned feeder calves from these major calf producing ...
The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) o...
Herd-level risk factors for dairy calf and heifer mortality in France were identified by calculating herd-level variables (including mortality risk or rate) using the National Bovine Identification Database (2005 and 2006). Eleven dairy production areas representing different livestock systems were also included. Statistical analyses were based on a probit model (mortality risk or rate=0 or >0)...
BACKGROUND In the less-sensitive mouse model, Shiga toxin-producing Escherichia coli (STEC) challenges result in shedding that reflect the amount of infection and the expression of virulence factors such as Shiga toxins (Stx). The purpose of this study was to characterize the contribution of STEC diversity and Stx expression to shedding in beef feeder calves and to evaluate the effectiveness of...
In PNAS, Eshel et al. (1) present a novel methodology for calculating a suite of ecological impacts from livestock and poultry production in the United States. The authors acknowledge two complementary and valuable approaches in ecological accounting: bottom up and top down. Top-down analyses, however, are only valuable insofar as they adequately represent the structure of the study system. By ...
The emergence of infections caused by antimicrobial resistant microorganisms (ARMs) is currently one of the most important challenges to public health and medicine. Though speculated to originate at least partially from the overuse of antibiotics during food animal production, we hypothesized that cattle are exposed to ARMs in the environment. In this cohort study, a herd of beef calves with no...
This study was designed to compare the quality of veal produced from 'Tudanca×Charolais' cross (n=6) and Limousin (n=6) breeds when allowed to feed freely on mountain pastures and suckle naturally from birth to 7 months of age. After 80 days of age calves also had access to concentrate (maximum of 3 kg/day), while mothers did not. At slaughter, Limousin calves were heavier (P<0.01) and provided...
This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean ...
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