Dust emissions in cattle feedlots

Dust emissions were measured at three Texas cattle feedlots on 15 occasions in 1987 to determine concentrations of total suspended particulate matter (TSP) and dust with 10 microns or less aerodynamic particle size (PM-10). Net feedlot dust concentrations (downwind minus upwind) ranged from 15.7 to 1,700.1 micrograms per m3 and averaged 412.4 +/- 271.2 micrograms per m3, which is about 37 per cent less than was determined in feedlot dust research in California approximately 17 years earlier. Upwind concentrations averaged 22 per cent of the downwind concentrations. Feedlot dust concentrations were generally highest in early evening and lowest in early morning. Using the Wedding and Andersen-321A PM-10 samplers, the PM-10 dust concentrations were 19 and 40 per cent, respectively, of mean TSP concentrations in direct comparisons. There was good correlation between PM-10 and TSP concentrations. Although dust concentrations decreased with increasing moisture, the correlation coefficients were relatively low. Odor intensity appeared to increase with decreasing net dust concentrations, perhaps due to moisture influences. Mean particle sizes of feedlot dust were 8.5 to 12.2 microns on a particle volume basis and 2.5 to 3.4 microns on a population basis. Respirable dust (below 2 microns) represented only 2.0 to 4.4 per cent of total dust on a particle volume basis. Under conditions of these experiments, the feedlots often exceeded both state and federal (U.S. Environmental Protection Agency) standards for TSP concentrations and for PM-10 concentrations measured using the Andersen-321A sampler. However, feedlots were below the new U.S. Environmental Protection Agency standards when the Wedding PM-10 sampler was used for measuring dust emissions.     

Diseases and pathogens associated with mortality in Ontario beef feedlots.

This study determined the prevalence of diseases and pathogens associated with mortality or severe morbidity in 72 Ontario beef feedlots in calves that died or were euthanized within 60 days after arrival. Routine pathologic and microbiologic investigations, as well as immunohistochemical staining for detection of bovine viral diarrhea virus (BVDV) antigen, were performed on 99 calves that died or were euthanized within 60 days after arrival. Major disease conditions identified included fibrinosuppurative bronchopneumonia (49%), caseonecrotic bronchopneumonia or arthritis (or both) caused by Mycoplasma bovis (36%), viral respiratory disease (19%), BVDV-related diseases (21%), Histophilus somni myocarditis (8%), ruminal bloat (2%), and miscellaneous diseases (8%). Viral infections identified were BVDV (35%), bovine respiratory syncytial virus (9%), bovine herpesvirus-1 (6%), parainfluenza-3 virus (3%), and bovine coronavirus (2%). Bacteria isolated from the lungs included M. bovis (82%), Mycoplasma arginini (72%), Ureaplasma diversum (25%), Mannheimia haemolytica (27%), Pasteurella multocida (19%), H. somni (14%), and Arcanobacterium pyogenes (19%). Pneumonia was the most frequent cause of mortality of beef calves during the first 2 months after arrival in feedlots, representing 69% of total deaths. The prevalence of caseonecrotic bronchopneumonia caused by M. bovis was similar to that of fibrinosuppurative bronchopneumonia, and together, these diseases were the most common causes of pneumonia and death. M. bovis pneumonia and polyarthritis has emerged as an important cause of mortality in Ontario beef feedlots.     

Antimicrobial susceptibility patterns of Salmonella isolates from cattle in feedlots

OBJECTIVE: To evaluate the antimicrobial susceptibility patterns of Salmonella isolates from feedlot cattle. DESIGN: Cross-sectional study. SAMPLE POPULATION: 263 Salmonella isolates. PROCEDURES: Fecal samples were collected from the floor of 2 pens in each of 100 feedlots. Two hundred eighty Salmonella isolates were recovered after bacteriologic culture from 38 pens. Of these, 263 isolates were available for antimicrobial susceptibility testing to 16 antimicrobials, using microbroth dilution breakpoint plates. RESULTS: Less than 5% of isolates were resistant to any of the antimicrobials tested, with the exception of sulfamethoxazole (15; 5.7%) and tetracycline (61; 23.2%). Most isolates (197; 74.9%) were susceptible to all antimicrobials tested, whereas 18 (6.8%) were resistant to 2 or more antimicrobials. The percentage of isolates with resistance to any antimicrobial varied by serotype. The percentage of isolates resistant to various antimicrobials was not related to concurrent use of antimicrobials in the feed. CONCLUSIONS AND CLINICAL RELEVANCE: With the exception of tetracycline and sulfamethoxazole, resistance of Salmonella isolates to any of the antimicrobials was uncommon. Most isolates were susceptible to all antimicrobials tested. Antimicrobial resistance was not related to the presence of antimicrobials in the ration being fed at the time of sample collection.     

Prevalence of sucking and chewing lice on cattle entering feedlots in southern Alberta

Beef calves from 2 sources entering southern Alberta feedlots in the winters of 1997-98 and 1998-99, were surveyed for the presence of lice. A random sample of multiple source (MS), that is, auction market-derived, calves entering commercial feedlots and single source (SS) calves entering a backgrounding feedlot were examined for the presence of lice at entry to the feedlot. A standardized examination, which involved hair-part examination of 8 louse predilection sites, was conducted on each selected calf to determine prevalence and intensity of infestation. The long-nosed sucking louse, Linognathus vituli, was the most commonly encountered species. This species infested from 57.8% to 95.6% of the calves selected from both MS and SS calves during both winters. Louse index values, indicating intensity of infestation, for L. vituli ranged from 1 to 243 lice per animal. The chewing louse, Bovicola bovis, was present on MS and SS calves only in the winter of 1998-99. The louse index values for B. bovis ranged from 1 to 230 lice per animal. Mixed infestations of the L. vituli and B. bovis were common. The little blue cattle louse, Solenopotes capillatus, was present only on the SS calves in the winter of 1997-98. The short-nosed sucking louse, Haematopinus eurysternus, was present at very low intensities, 1-2 lice per animal, on 2.6% to 4.4% of the MS calves during both winters. Comparison of results from the current study with published literature suggests that efforts to determine the economic impact of louse infestations are confounded by the lack of a uniform method to assess louse population levels.     

In vitro study of the biochemical origin and production limits of odorous compounds in cattle feedlots.

Livestock odors are closely correlated to airborne concentrations of volatile organic compounds (VOC), which are a complex mixture of carbon-, sulfur-, and nitrogen-containing compounds produced primarily during the incomplete anaerobic fermentation of animal manure by microorganisms. Volatile fatty acids, alcohols, and aromatic ring compounds comprise a substantial fraction of VOC, yet very little is known about their biochemical origin and environmental factors controlling their production. The anaerobic production of fermentation products and consumption of substrates (CP, starch, and nonstarch carbohydrate) were analyzed in slurries of fresh (< 24 h) and aged (> 1 d) cattle manure over several weeks. Ethanol, acetate, propionate, butyrate, lactate, and H2 were the major products of fermentation. Aged cattle manure produced twice the concentration of VFA during incubation produced by the fresh manure (P < 0.001). Aromatic compounds (phenols, indoles, and benzoates) remained unchanged in both manures. Production of VFA from fresh manure was inhibited when the pH fell below 4.5. It is likely that the presence of calcareous soil, which has a high buffering capacity, and lactate-consuming microorganisms minimized acidification in the aged manure slurries. Low starch content limited VFA production in the aged manure. Starch was the likely biochemical source for fermentation products in both manures based on the strong negative correlations between fermentation product and starch content (r = -0.944 and -0.773) and ratio of fermentation products produced to starch consumed (r = 0.64 and 0.72) for fresh and aged manure, respectively. Nonstarch carbohydrate served an indeterminate role in the production of fermentation products. Nonstarch carbohydrate decreased by 4.7 and 23.4 g/L in the fresh and aged manure, respectively, whereas the starch content decreased by 18.6 and 22.4 g/L in the fresh and aged manure, respectively. The concentration of CP did not change, which suggests a balance between protein consumption and new bacterial biomass production. We conclude that the types of substrates in cattle manure and the feedlot soils where they are deposited are significant factors in the production of odors.     

Renal percent clearance ratios in cattle

Renal percent clearance ratios for various electrolytes were determined on nine clinically normal Holstein heifers. Endogenous creatinine serum and urine levels were used to calculate the ratios. The average percent clearance ratios and standard deviations of Na, K, Cl, P, and Ca were 1.97+/-0.63, 49.3+/-9.2, 3.16+/-1.l2, 15.6+/-14.3, and 1.38+/-1.41, respectively. The correlation between Na and Cl percent clearance ratios within a sample was 0.92. A very strong direct correlation of urine creatinine and urine specific gravity was demonstrated.     

Embryonic mortality in cattle

Inhalt: Embryonaler Fruchttod beim Rind In der vorliegenden Arbeit werden Ursachen und neue Aspekte des embryonalen Fruchttodes beim Rind sowie verschiedene geeignete Kriterien und Untersuchungs-methoden an Hand von Literaturhinweisen und eigenen Arbeiten diskutiert. Das Arbeiten mit Schlachttieren ermöglicht danach die exaktesten Angaben im Zusammenhang mit hormonanalytischen und biochemischen Untersuchungen. Der kritische Zeitpunkt für die embryonale Mortalität bei Tieren, die wiederholt umrindern, ist der 6./7. Tag nach der Insemination in Gegensatz zu Tieren mit normaler Fertilität, hier tritt der embryonale Fruchttod nicht vor dem 16. Tag auf. Wiederholt umrindernde Tiere mit degenerierten Embryonen, sieben Tage nach der Befruchtung, zeigten, verglichen mit Tieren mit normal entwickelten Embryonen, zwar gleiche Plasmaprogeste-ronwerte, aber Unterschiede sowohl im Plasmaöstrogenspiegel als auch in der Gesamt-proteinkonzentration und dem Phosphor-, Kalium-, Zink- und Kulziumgehalt der Uterusflüssigkeit.     

Calf mortality in crossbred dairy cattle

Summary Information is given on crossbred calves between birth and 6 months of age belonging to 6 genetic groups—3 with 50% inheritance from Holstein, Jersey and Brown Swiss and the other 3 with 75% inheritance from 1 or 2 temperate dairy breeds.The mortality rate in 1,059 calves born was 3·87, 2·84 and 1·22% respectively under 1 month, from 1 to 3 and from 3 to 6 months of age. The mortality rate was lower in halfbreds than in crosses with 75% inheritance from temperate breeds. Season of birth, sex of the calf and birth weight did not show any significant association with mortality rate but the latter showed a definite decline with advancing age.No significant association of cause of mortality with age, genetic group and season of birth of the calves was observed. Percentage mortality was largely due to respiratory diseases in the birth to 1 month age group while diseases affecting the digestive system resulted in more deaths in the 3 to 6 months age group.

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Mortalidad De Terneros En Ganado Lechero Cruzado

Resumen Se hace un informe detallado sobre terneros cruzados desde el nacimiento hasta los 6 meses de edad, pertenecientes a 6 grupos genéticos; 3 con 50% herencia de Holstein, Jersey y Pardo Suizo y de otros 3 con 75% herencia de 1 o 2 razas lecheras de áreas templadas.La tasa de mortalidad en 1,059 terneros nacidos fué de 3.87, 2.84 y 1.22% respectivamente, en animales menores de 1 mes, de 1 a 3 y de 3 a 6 meses de edad. La tasa se mortalidad fué más baja en animales media sangre, que en cruces con 75% herencia de razas lecheras de áreas templadas. La época de nacimiento, sexo del ternero y peso al nacer, no tuvo relación con la tasa de mortalidad, la cual disminuzó progresivamente con la edad. A mayor edad menos mortalidad.No se observó relación directa entre causas de mortalidad, edad, grupos genéticos y estación al nacer. El porcentaje de mortalidad fué superior en el grupo estudiado desde el nacimiento hasta el mes de edad, debido a causas respiratorias. Las enfermedades gastrointestinales causaron más mortalidad en el grupo de 3 a 6 meses.

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Mortalite Des Veaux Chez Le Betail Laitier Ameliore

Résumé Les auteurs donnent des informations concernant des veaux métis entre leur naissance et l'âge de six mois appartenant à six groupes génétiques différents: trois groupes à 50 p. 100 d'Holstein, de Jersiais et de Suisse Brune et les trois autres groupes à 75 p. 100 de dominance de une à deux races laitières.Pour 1 059 veaux, le taux moyen de mortalité a été de 3,87, 2.84 et 1,22 p. 100 au-dessous de un mois d'âge, de 1 à 3 mois et de 3 à 6 mois.Le taux de mortalité a été plus bas chez les demi-sangs que chez les métis ayant 75 p. 100 de sang d'animaux de races tempérées.La saison de naissance, le sexe du veau et la poids à la naissance n'ont pas montré de relations significatives avec le taux de mortalité, mais il a été constaté par la suite que ce taux déclinait au fur et à mesure que les veaux prenaient de l'âge.Aucune association de nature significative entre les causes de mortalité avec l'âge, le groupe génétique et la saison de naissance n'a été observée.Dans le groupe des animaux de O à 1 mois d'âge ce sont les maladies respiratoires qui ont été le plus largement observées alors que ce sont les affections du système digestif qui ont causé le plus grand nombre de morts dans le groupe des animaux entre 3 et 6 mois d'âge.

     

Protecting US cattle. The role of national biosecurity programs.

The bovine practitioner has a critical role to play in promoting biosecurity at both the farm level and the national level. Successful exclusion of exotic diseases, biocontainment of endemic diseases, and emergency preparedness rest soundly on bovine practitioners as part of the national biosecurity team. Bovine practitioners must voice their opinions on the strengths and weaknesses of existing and proposed national biosecurity programs. Healthy debate about national biosecurity programs and consideration of biosecurity issues by national veterinary organizations provide valuable feedback for the continual improvement of the programs and enhance their credibility. The health and productivity of US agriculture depend on national biosecurity.     

Effects of body weight loss during transit from sale barns to commercial feedlots on health and performance in feeder cattle cohorts arriving to feedlots from 2000 to 2008

Body weight loss during transport or shrink (SHK) is a common occurrence in feeder cattle that results from a physiological, complex process. Previous studies have assessed the effects of environmental and dietary stressors on transport-associated BW loss; however, data on associations between shrink and subsequent health and performance parameters in feeder cattle are limited. Operational data from 13 U.S. commercial feedlots (n = 16,590 cattle cohorts) were used to quantify how SHK was associated with bovine respiratory disease (BRD) morbidity and overall mortality risks, HCW and ADG in feeder cattle cohorts arriving to feedlots during 2000 to 2008. Multivariable mixed-effects negative binomial and linear regression models were employed to determine these associations while accounting for other cohort-level demographic variables. The median SHK among the study cohorts was 3.0% with a mean (± SEM) of 2.4 ± 0.02%. The mean (± SEM) cumulative BRD morbidity was 10.0% ± 0.09% (median = 5.8%; range 0 to 100%) and the mean (± SEM) overall cumulative mortality was 1.3% ± 0.01% (median = 0.9%; range: 0 to 25.6%). The mean and median number of days on feed of cohorts experiencing initial BRD cases was 143 and 150 d (range = 23 to 288 d). The effects of SHK were significantly (P < 0.05) associated with BRD morbidity, overall mortality, HCW and ADG, and these effects were significantly (P < 0.05) modified by gender, season and mean arrival BW of the cohort. Combining data on BW loss during transport with cohort demographics could allow a more precise prediction of health and performance of feedlot cattle.     

Trends in bovine viral diarrhoea in Scottish cattle

Review of bovine viral diarrhoea virus-related disease, 1996 to 2009. Diverse range of respiratory diseases diagnosed in cattle. Caseous lymphadenitis confirmed in a Suffolk ram lamb aged only four months. Extramedullary haematopoiesis of unknown cause in a pig. Coccidiosis diagnosed frequently in pheasants and partridges. These are among matters discussed in the disease surveillance report for July from SAC Consulting: Veterinary Services (SAC C VS).     

Congenital Neospora caninum infection in dairy cattle and associated calfhood mortality.

A prospective cohort study was undertaken on two central California dairies, A and B, to estimate prevalence of congenital infection with Neospora caninum, to characterize temporal variation in prevalence, to determine if occurrence of congenital infection was associated with specific dam and calf attributes, and to estimate the effect of congenital infection on calfhood mortality. Of the 405 calves enrolled over a period of 2 1/2 y on dairy A and dairy B, 30.6% (85/278) and 53.5% (68/127), respectively, were seropositive precolostrally to N. caninum, as determined by an ELISA test. Adult cow seroprevalence at calving was 36.0% (82/228) for dairy A, and 57.9% (33/57) for dairy B. No evidence was found for a significant increasing or decreasing trend in adult and precolostral seroprevalence through the study period (P > or = 0.26). For both herds combined, 81% of seropositive cows (93/115) and 5% of seronegative cows (8/170) had congenitally infected calves. Seroprevalence did not increase with cow age on either dairy (P > or = 0.47). The probability of a calf being congenitally infected was not associated with dam age, dam lactation number, dam history of abortion, calf gender, or length of gestation (P > or = 0.11). High dam ELISA values at calving were significantly associated (P < or = 0.001) with an increased probability of congenital infection in her calf. Results of survival analyses of female calves available for follow-up indicated a consistently greater survivorship to 90 d in congenitally infected calves than in noninfected calves on both dairies, which was significant for dairy A (P = 0.07, n = 186) but not for dairy B (P = 0.69, n = 72), thus indicating that congenital infection does not necessarily have a detrimental effect on calf health. The findings of a similar magnitude in congenital infection rate and adult cow prevalence, the lack of increasing seroprevalence with cow age, the lack of an effect of dam age on precolostral seropositivity, and the constant seroprevalences during the study period, suggest that, in the two dairies studied, congenital transmission constituted a substantial amount of infection and was likely the major mode of transmission of N. caninum.     

Owner survey of schitosomiasis mortality in sudanese cattle

The estimated mortality in six- to 30-month-old cattle due to presumptive schistosomiasis was 7.1% for 155 interviews conducted in the White Nile Province in 1981. This mortality was higher for those herds under sedentary management than for migratory herds (9.4% vs 3.6%). The interviews were done through an informal visit technique by a veterinarian living in the area. The approximate number (19,000) of cattle over six months old estimated to be owned by those interviewed represents about 1% of the population in that province. The mortality from all causes in the six- to 30-month age group was 9.2%; in the over 30-month age group it was 1.8%. The authors judge the schistosomiasis mortality to be somewhat upwardly biased but the mortality due to all causes (9.2%) is consistent with the few reports available.