Cattle Shipments Research Articles

The Cattle Trading Network and Its Effect on the Spread of Brucellosis in Paraná, Brazil

This study analyzed the cattle trade network in Paraná, Brazil, for the years 2018 and 2019 to identify potential movement patterns that could contribute to the spread of brucellosis among farms. The brucellosis statuses of 1757 farms were incorporated into the analysis. Network parameters of farms with a known brucellosis infection status were statistically compared between infected and non-infected farms using traditional techniques and the quadratic assignment procedure. A multilinear regression model (MLR) was used to consider known risk factors for brucellosis infection in conjunction with the network parameters. The cattle trade network in Paraná during the study period comprised 115,296 farms linked by 608,807 cattle shipments. The movement pattern was marked by a high concentration of movements to and from a small percentage of farms. The existence of such highly connected farms could facilitate the transmission of communicable diseases via the cattle trade in Paraná. The trading communities in Paraná exhibited a spatial pattern, with proximate farms more likely to engage in trade. Brucellosis-infected farms traded more frequently than non-infected farms (odds ratio [OR] 3.61), supplied cattle to other farms more often than the regional average (OR 2.12), and received more cattle (OR 2.78). The in-degree and out-degree were associated with brucellosis infection on the farm. The mean shortest path between infected farms was significantly shorter than that between non-infected farms (4.14 versus 4.49, p = 0.004, OR 1.39). In the MLR, a higher out-degree was positively associated with infected farms after accounting for previously identified risk factors. This novel information offers insights into the factors driving the current endemic situation in the study area and can inform the development of targeted animal health policies.

Modeling nation-wide U.S. swine movement networks at the resolution of the individual premises

The spread of infectious livestock diseases is a major cause for concern in modern agricultural systems. In the dynamics of the transmission of such diseases, movements of livestock between herds play an important role. When constructing mathematical models used for activities such as forecasting epidemic development, evaluating mitigation strategies, or determining important targets for disease surveillance, including between-premises shipments is often a necessity. In the United States (U.S.), livestock shipment data is not routinely collected, and when it is, it is not readily available and mostly concerned with between-state shipments. To bridge this gap in knowledge and provide insight into the complete livestock shipment network structure, we have developed the U.S. Animal Movement Model (USAMM). Previously, USAMM has only existed for cattle shipments, but here we present a version for domestic swine. This new version of USAMM consists of a Bayesian model fit to premises demography, county-level livestock industry variables, and two limited data sets of between-state swine movements. The model scales up the data to simulate nation-wide networks of both within- and between-state shipments at the level of individual premises. Here we describe this shipment model in detail and subsequently explore its usefulness with a rudimentary predictive model of the prevalence of porcine epidemic diarrhea virus (PEDv) across the U.S. Additionally, in order to promote further research on livestock disease and other topics involving the movements of swine in the U.S., we also make 250 synthetic premises-level swine shipment networks with complete coverage of the entire conterminous U.S. freely available to the research community as a useful surrogate for the absent shipment data.

A model exploration of carrier and movement transmission as potential explanatory causes for the persistence of foot-and-mouth disease in endemic regions.

Foot-and-mouth disease (FMD) is a virulent and economically important disease of livestock, still endemic in many areas of Asia and sub-Saharan Africa. Transmission from persistently infected livestock, also known as carriers, has been proposed as a mechanism to support the persistence of FMD in endemic regions. However, whether carrier livestock can infect susceptible animals is controversial; recovered virus is infectious and there are claims of field transmission, but it remains undemonstrated experimentally. Alternate hypotheses for persistence include the movement of livestock within and between regions, and fomite contamination of the environment. Using a stochastic compartmental ordinary differential equation (ODE) model, we investigate the minimum rates of carrier transmission necessary to contribute to the maintenance of FMD in a region, and compare this to the alternate mechanism of persistence through cattle shipments. We find that carrier transmission can theoretically support persistence even at transmission rates much lower than the highest realistic rates previously proposed, and that the parameters with the most effect on the feasibility of carrier-mediated persistence are the average duration of both the carrier phase and natural immunity. However, shipment-mediated persistence remains a viable alternate mechanism for persistence without carrier transmission.

Welfare during pre-slaughter handling and carcass lesions of beef cattle submitted to different loading densities

ABSTRACT: Inadequate pre-slaughter handling conditions can compromise animal welfare and productivity. This study aimed to evaluate the animal welfare (AW) indexes during pre-slaughter handling and quantify the carcass lesions of beef cattle submitted to different loading densities. A total of 270 Nellore cattle, at 30 months of age, from three farms were used in the study. Each farm presented a different loading density: higher density (500kg/m2), intermediate density (450kg/m2), and lower density (420kg/m2). Three shipments of cattle from each farm with 30 animals each were used in the AW analysis. Ten animals from each shipment were considered for quantification of carcass bruises. The AW indexes were classified according to the five-freedom criterion (physiological, environmental, sanitary, behavioral, and psychological). After slaughter, the carcasses were inspected in the routine line and evaluated for the presence of lesions. Statistically significant differences (p<0.001) were found for all variables studied as a function of AW and bruises. The best AW index and the lowest mean weight of lesions were found at the loading density of 450kg/m2. The highest carcass weight was observed at the loading density of 500kg/m2. Lesions were found in 100% of the animals at the loading densities of 500 and 420kg/m2. In conclusion, the best AW indexes and the smallest occurrence of bruises were verified at the loading density of 450kg/m2. This study confirmed the importance of adequate pre-slaughter handling to ensure cattle welfare and, consequently, greater profitability for producers and slaughterhouses.

Estimating and exploring the proportions of inter- and intrastate cattle shipments in the United States

Mathematical models are key tools for the development of surveillance, preparedness and response plans for the potential events of emerging and introduced foreign animal diseases. Creating these types of plans requires data; when data are incomplete, mathematical models can help fill in missing information, provided they are informed by the data that are available. In the United States, the most complete national-scale data available on cattle shipments are based on Interstate Certificates of Veterinary Inspection, which track the shipment of cattle between states; data on intrastate cattle shipments are lacking. Here we develop four new datasets on intrastate cattle shipments in the U.S., including an expert elicitation survey covering 19 states and territories and three state-level brand inspection data sets. The expert elicitation survey provides estimates on the proportion of shipments that travel interstate over multiple regions of the U.S. These survey data also identify differences in shipment patterns between regions, cattle commodity types, and sectors of the cattle industry. These survey data cover more states than any other source of intrastate data; however, one limitation of these data is the small number of participating experts in many of the states, only seven of the 19 responding states and territories had a group size of three or larger. The brand data sets include origin and destination information for both intra- and interstate shipments. These data, therefore, also provide detailed information on the proportion of interstate shipments in three Western states, including the temporal and geographic variation in shipments. Because the survey and brand data overlap in the Western U.S., they can be compared. We find that in the Western U.S. the expert estimates of the overall proportion of cattle shipments matched the brand data well. However, the experts estimated that there would be larger differences in beef and dairy shipments than the brand data show. This suggests the cattle industries in the West may be sending similar proportions of commodity specific cattle shipments over state lines. We additionally used the expert survey data to explore how differences in the proportion of interstate shipments can change predictions about cattle shipment patterns using the example of model-guided suggestions for targeted surveillance in Texas. Together these four data sets are the most extensive and geographically comprehensive information to date on intrastate cattle shipments. Additionally, our analyses on predicted shipment patterns suggest that assumptions about intrastate shipments could have consequences for targeted surveillance.

Model-guided suggestions for targeted surveillance based on cattle shipments in the U.S.

Risk-based sampling is an essential component of livestock health surveillance because it targets resources towards sub-populations with a higher risk of infection. Risk-based surveillance in U.S. livestock is limited because the locations of high-risk herds are often unknown and data to identify high-risk herds based on shipments are often unavailable. In this study, we use a novel, data-driven network model for the shipments of cattle in the U.S. (the U.S. Animal Movement Model, USAMM) to provide surveillance suggestions for cattle imported into the U.S. from Mexico. We describe the volume and locations where cattle are imported and analyze their predicted shipment patterns to identify counties that are most likely to receive shipments of imported cattle. Our results suggest that most imported cattle are sent to relatively few counties. Surveillance at 10 counties is predicted to sample 22–34% of imported cattle while surveillance at 50 counties is predicted to sample 43%–61% of imported cattle. These findings are based on the assumption that USAMM accurately describes the shipments of imported cattle because their shipments are not tracked separately from the remainder of the U.S. herd. However, we analyze two additional datasets – Interstate Certificates of Veterinary Inspection and brand inspection data – to ensure that the characteristics of potential post-import shipments do not change on an annual scale and are not dependent on the dataset informing our analyses. Overall, these results highlight the utility of USAMM to inform targeted surveillance strategies when complete shipment information is unavailable.

Mapping U.S. cattle shipment networks: Spatial and temporal patterns of trade communities from 2009 to 2011

The application of network analysis to cattle shipments broadens our understanding of shipment patterns beyond pairwise interactions to the network as a whole. Such a quantitative description of cattle shipments in the U.S. can identify trade communities, describe temporal shipment patterns, and inform the design of disease surveillance and control strategies. Here, we analyze a longitudinal dataset of beef and dairy cattle shipments from 2009 to 2011 in the United States to characterize communities within the broader cattle shipment network, which are groups of counties that ship mostly to each other. Because shipments occur over time, we aggregate the data at various temporal scales to examine the consistency of network and community structure over time. Our results identified nine large (>50 counties) communities based on shipments of beef cattle in 2009 aggregated into an annual network and nine large communities based on shipments of dairy cattle. The size and connectance of the shipment network was highly dynamic; monthly networks were smaller than yearly networks and revealed seasonal shipment patterns consistent across years. Comparison of the shipment network over time showed largely consistent shipping patterns, such that communities identified on annual networks of beef and diary shipments from 2009 still represented 41–95% of shipments in monthly networks from 2009 and 41–66% of shipments from networks in 2010 and 2011. The temporal aspects of cattle shipments suggest that future applications of the U.S. cattle shipment network should consider seasonal shipment patterns. However, the consistent within-community shipping patterns indicate that yearly communities could provide a reasonable way to group regions for management.

The Impact of Movements and Animal Density on Continental Scale Cattle Disease Outbreaks in the United States

Globalization has increased the potential for the introduction and spread of novel pathogens over large spatial scales necessitating continental-scale disease models to guide emergency preparedness. Livestock disease spread models, such as those for the 2001 foot-and-mouth disease (FMD) epidemic in the United Kingdom, represent some of the best case studies of large-scale disease spread. However, generalization of these models to explore disease outcomes in other systems, such as the United States’s cattle industry, has been hampered by differences in system size and complexity and the absence of suitable livestock movement data. Here, a unique database of US cattle shipments allows estimation of synthetic movement networks that inform a near-continental scale disease model of a potential FMD-like (i.e., rapidly spreading) epidemic in US cattle. The largest epidemics may affect over one-third of the US and 120,000 cattle premises, but cattle movement restrictions from infected counties, as opposed to national movement moratoriums, are found to effectively contain outbreaks. Slow detection or weak compliance may necessitate more severe state-level bans for similar control. Such results highlight the role of large-scale disease models in emergency preparedness, particularly for systems lacking comprehensive movement and outbreak data, and the need to rapidly implement multi-scale contingency plans during a potential US outbreak.

A national-scale picture of U.S. cattle movements obtained from Interstate Certificate of Veterinary Inspection data

We present the first comprehensive description of how shipments of cattle connect the geographic extent and production diversity of the United States cattle industry. We built a network of cattle movement from a state-stratified 10% systematic sample of calendar year 2009 Interstate Certificates of Veterinary Inspection (ICVI) data. ICVIs are required to certify the apparent health of cattle moving across state borders and allow us to examine cattle movements at the county scale. The majority of the ICVI sample consisted of small shipments (<20 head) moved for feeding and beef production. Geographically, the central plains states had the most connections, correlated to feeding infrastructure. The entire nation was closely connected when interstate movements were summarized at the state level. At the county-level, the U.S. is still well connected geographically, but significant heterogeneities in the location and identity of counties central to the network emerge. Overall, the network of interstate movements is described by a hub structure, with a few counties sending or receiving extremely large numbers of shipments and many counties sending and receiving few shipments. The county-level network also has a very low proportion of reciprocal movements, indicating that high-order network properties may be better at describing a county's importance than simple summaries of the number of shipments or animals sent and received. We suggest that summarizing cattle movements at the state level homogenizes the network and a county level approach is most appropriate for examining processes influenced by cattle shipments, such as economic analyses and disease outbreaks.

World Developments in Buiatrics

Buiatrics is the study of cattle and their diseases. This paper considers a selection of areas in which remarkable changes have occurred since the foundation of the World Association for Buiatrics in the 1960s. These areas range from surgical procedures, including for example Caesarean section and surgical correction of displaced abomasa, to the nutrition of cattle and the wide range of diseases, mainly viral, that present in them. The links between genetics and breeding, global trade and animal welfare are discussed. Examples include the shipment of cattle and sheep from Australia to Middle Eastern countries, the illegal import of 1.5 million cattle from India to Bangladesh and the ever increasing milk production of cows.

Results of a survey to estimate cattle movements and contact rates among beef herds in California, with reference to the potential spread and control of foot-and-mouth disease

To estimate contact rates and movement variables for shipments of beef cattle to and from producer premises in California. Cross-sectional survey. 583 beef producers in California. Questionnaires were developed and distributed to beef cattle producers in California. The study period was from April 20, 2005, through September 7, 2006. Data from completed questionnaires were entered manually into an electronic format. Descriptive statistical analyses were performed. Median number of interstate animal movements (movement of cattle into or out of California) was 0.17/mo; on the basis of this median, beef cattle were moved interstate > 2 times/y. Respondents kept beef cattle at up to 5 locations throughout the year. More than 40% of the movements from the respondents' premises were to a sale yard or auction facility. Frequency of animal movements in this statewide study differed from values in another study of monthly shipments of animals to and from beef operations in 3 counties of California. The survey reported here revealed more frequent movements of animals to and from beef operations of all sizes. In addition, there were more high-risk indirect contacts on beef operations than has been reported previously. However, the number of low-risk indirect contacts was similar for small beef operations but less for large beef operations than has been reported elsewhere. Epidemic simulation models for California based on data in earlier studies likely underpredicted disease transmission involving beef herds.

Effects of on-arrival versus delayed clostridial or modified live respiratory vaccinations on health, performance, bovine viral diarrhea virus type I titers, and stress and immune measures of newly received beef calves1

Stress, commonly associated with weaning, marketing, and shipment of feeder cattle, can compromise immune function, and vaccine administration during immunosuppression may reduce vaccine efficacy and calf growth. Four treatments were compared in a 2 x 2 factorial arrangement to evaluate the effect of on-arrival (d 0) vs. delayed (d 14) administration of clostridial (CLOS) and respiratory (RESP) vaccines on health, performance, bovine viral diarrhea virus (BVDV) antibody titers, and physiological immune measurements of high-risk, newly received calves. Crossbred bull and steer calves (n = 263) were weighed (239 +/- 1.2 kg), stratified by sex, and randomly assigned to vaccination treatment: 1) arrival CLOS, arrival RESP (ACAR); 2) arrival CLOS, delayed RESP (ACDR); 3) delayed CLOS, arrival RESP (DCAR); and 4) delayed CLOS, delayed RESP (DCDR). Body weight and blood samples were collected on d 0, 14, 28, 42, and 56. Average daily gain did not differ (P > or = 0.34), averaging 0.98, 0.93, 0.95, and 0.91 kg/d for ACAR, ACDR, DCAR, and DCDR, respectively, for the entire 56-d trial. Vaccination timing did not affect morbidity (P > or = 0.23); however, there tended to be a CLOS timing effect (P = 0.07) and RESP timing effect (P = 0.09) on days to initial bovine respiratory disease (BRD) treatment. Average days to initial BRD treatment were less for ACAR (6 +/- 0.8 d) compared with DCDR (8 +/- 0.8 d; P = 0.01). Greater white blood cell counts were observed for DCDR than ACDR (P = 0.01), with ACAR and DCAR being intermediate. Serum cortisol concentrations were greater on d 0 than d 14 (P < 0.01) or d 28 (P = 0.01) but no treatment x day interaction (P = 0.21) was observed. Timing of RESP administration affected (P = 0.001) serum BVDV type I titers, with greater (P < 0.01) levels in calves receiving RESP vaccine on arrival. Delaying CLOS or RESP vaccination did not affect BW gain or morbidity in high risk, newly received stocker calves. Calves administered RESP vaccine on d 0 developed antibody titers to BVDV type I earlier than delayed RESP treatments. Total white blood cell count was greatest when RESP and CLOS vaccination were delayed (DCDR).

Effects of on-arrival versus delayed modified live virus vaccination on health, performance, and serum infectious bovine rhinotracheitis titers of newly received beef calves1

Stress commonly associated with weaning, marketing, and shipment of feeder cattle can temporarily compromise immune function, thereby reducing the effective response to vaccination intended to control bovine respiratory disease (BRD). Two vaccination timing treatments were used to evaluate the effect of timing of a multivalent modified live virus (MLV) BRD vaccine on health, performance, and infectious bovine rhinotracheitis (IBR) antibody titers of newly received stocker cattle. Crossbred bull and steer calves (n = 528) were weighed (197 +/- 2.4 kg) and randomly assigned to MLV vaccination treatment: 1) MLV vaccination upon arrival (AMLV), or 2) delayed (14 d) MLV vaccination (DMLV). All cattle were processed similarly according to routine procedures, with the exception of the initial MLV vaccination timing. Subsequently, BW were recorded on d 14, 28, and 42. Blood samples were collected on d 0, 14, 28, and 42 to determine serum IBR titers, and comparisons were made between treatments on a receiving-day basis and an equivalent postvaccination day basis. Daily BW gains were greater (P < or = 0.05) for DMLV calves from d 0 to 14 (1.16 vs. 0.88 +/- 0.22 kg/d) and from d 0 to 42 (0.75 vs. 0.65 +/- 0.09 kg/d). Days to first treatment, total treatment cost, percentage death loss, and pasture ADG after the 42-d receiving period did not differ (P > or = 0.15). Morbidity rates for BRD were high for both AMLV and DMLV (71.5 and 63.5%, respectively) and did not differ (P = 0.12). Positive IBR titer seroconversion was greater (P < or = 0.03) for DMLV calves on d 42 of the study, and for the 28- and 42-d equivalent postvaccination basis. Delaying vaccination by 14 d may increase ADG during the receiving period compared with AMLV, and seroconversion to IBR was greater in DMLV calves, indicating a possible improvement in acquired immune response when MLV vaccination is delayed.

A Plant Virus as a Bioherbicide for Tropical Soda Apple, &lt;I&gt;Solanum Viarum&lt;/I&gt;

© 2007. Research Information Ltd. All rights reserved DOI: 10.1564/18aug07 Tropical soda apple (Solanum viarum, Figure 1; abbreviated: TSA) is an exotic, thorny, perennial shrub that has become a highly invasive weed in the southern USA. TSA is native to Brazil, but has spread to several countries of South and Central America, the Caribbean, Africa, and the Indian subcontinent. In Florida, improved pastures, cattle feedlots, citrus groves, ditches, sod farms, and natural areas are seriously affected by this weed (Ferrell & Mullahey 2007, Mullahey et al. 1993). TSA has been reported to occur also in Alabama, Georgia, Mississippi, Louisiana, Texas, North Carolina, South Carolina, Tennessee, and Pennsylvania (NAPIS, 2003). While some of these infestations have been eradicated, the threat of continued influx has not diminished because cattle, deer, wild hogs, birds, and contaminated hay help to disseminate the seed. TSA has the potential to spread throughout the continental USA (Patterson 1996). The realization of the threat posed by TSA has led to its designation as a “noxious weed” under the Federal and Florida noxious weed statutes. In efforts to stop the weed at its source, namely, the infestations in Florida, all potentially effective methods of control, including biological control, are being examined (DOACS-Florida 2007). TSA infestations in pastures cause the cattle stocking rates to be lowered due to the reduced access and available area for grazing. The livestock production costs go up, and out-of-state cattle shipments face a regulatory dilemma since the cattle are partly implicated in spreading the weed to their destinations. Although TSA foliage is inedible due to the presence of sharp thorns on all parts of the shoot, livestock, feral hogs, deer, raccoons, and birds eat the fruits and disperse the seeds (Coile 1993). Contaminated equipment, hay, grass seed, composted manure, and sod from TSA-infested areas also disperse the seeds. TSA seed is highly viable even after passage through animals’ digestive tracts and is the principal means of initial establishment as well as secondary increases in TSA populations. Mature plants can also sucker and re-establish following mowing and chemical treatment. Besides its weediness, TSA is a potential reservoir of several cropdamaging insects and pathogens (McGovern et al. 1994). A PLANT VIRUS AS A BIOHERBICIDE FOR TROPICAL SODA APPLE, SOLANUM VIARUM

Trailer-mounted RFID reader scans EID tags during cattle shipments (2007)

One of the challenges regarding implementation of a national animal identification system is the logistics of reading and reporting EID (electronic identification) tag numbers as cattle move through the production cycle. Many small producers would have difficulty justifying the investment required to install an RFID (radio frequency identification) reader system that would only be used seasonally to track relatively small numbers of cattle that are entering commerce. A proposed solution to this issue is to install an RFID reader on commercial cattle trailers so that cattle can have EID tags read as they are loaded and unloaded during transport from one premise to the next. With such an arrangement, the RFID equipment would be used often by a small number of highly trained people in the transport sector and the cost could be spread over a large number of cattle hauled over the life of the reader. The goal of this study was to evaluate the performance of a trailer-mounted RFID reader, in one location, using four prominent brands of commercially available EID tags.

Regional risk of exporting cattle seropositive for bluetongue virus from the United States.

To create a stochastic model to quantify the risk that shipments of cattle from regions within the United States would contain animals seropositive for bluetongue virus and to determine shipment-level accuracy of serologic testing by use of a competitive ELISA (c-ELISA). 19,216 shipments containing 528,918 cattle and calves. Data were obtained on number of animals and state of origin of cattle in export shipments originating within the United States between January 1994 and March 2002. Probability distributions for size of export shipments were determined for all states within the United States, and distributions for agar gel immunodiffusion and c-ELISA accuracy (sensitivity and specificity) were determined from expert opinion and review of the literature. The model simulated selection of a shipment and then determined the probability that a threshold number or percentage of cattle within that shipment would have a positive c-ELISA result. Shipment-level sensitivity, specificity, positive-predictive value, and negative-predictive value were calculated. Substantial differences were evident in the regional probability of a shipment being declared positive, with shipments from northeastern states having the lowest probability and shipments from southwestern states having the highest probability. The c-ELISA had variable predictive values at the shipment level, depending on the threshold used and the prevalence of antibody-positive cattle within the region. Results from this study will aid importers in making scientifically based decisions regarding risk of importing antibody-positive cattle.

Prevalence, antibiotic susceptibility, and genetic diversity of Salmonella, Campylobacter, and Escherichia coli O157:H7 collected at four Kansas beef cattle feedyards over 13 months (1998)

Salmonella, Campylobacter, and Eschericia Escherichia coli O157:H7 isolates will help to coli O157:H7 are important foodborne pathogens, determine 1) their feedyard sources, 2) which but longitudinal studies of their prevalence in beef antibiotics could be effective for cattle therapy, 3) cattle feedyards have not been done. Our longsources that have greatest resistance, 4) whether term study involved 24,556 samples taken from some genetically identical isolates are developing beef cattle feedyards found overall prevalences of resistance over time, and 5) seasonal resistance 4.87% for Salmonella, 20.1% for Campylobacter patterns for each antibiotic tested. Knowing the in hospital pen fecal samples, and 0.20% for E. genetic diversity of organisms such as E. coli coli O157:H7. Yard and pen differences (P<0.05) O157:H7 aids investigators in determining if were detected. All 53 E. coli O157:H7 isolates contamination is due primarily to resident or were resistant to Talmicosin and Erythromycin, transient isolates and could help trace the source two antimicrobials used in food animal medicine. of disease outbreaks. Monitoring the prevalence, Their genetic diversity was high and did not antibiotic susceptibility, and genetic diversity of indicate the presence of resident strains at the foodborne pathogens at cattle feedyards is imporyards studied. Salmonella, Campylobacter, and tant for producers designing production animal E. coli O157:H7 were probably brought into the (preharvest) Hazard Analysis Critical Control yards by shipments of new cattle. Many of these Points (HACCP) programs for pathogen reducorganisms were susceptible to antibiotics comtion. monly used to treat beef cattle.

The Impact of Forward Contracting on Fed Cattle Transaction Prices

Beef packers have vertically integrated into the cattle feeding sector. This study examines the impacts of beef packer forward contracting on cash cattle transaction prices in southwest Kansas. From late May through November 1990, average fed cattle cash transaction prices were estimated to be $0.15/cwt to $0.31/cwt lower as a result of forward contract cattle shipments. The impact of the level of forward contracting on cash prices was variable across time: cash prices were as much as $0.34/cwt lower at times when contract shipments were large, and prices were statistically unaffected at times when forward contract shipments were low.

Cattle Shrinkage During Overseas Shipment on a Cargo Ship

ABSTRACT A shipment of market-weight cattle was made in the spring of 1978 from Portland, Oregon, to Yokohama, Japan. The cattle were transported in holding pens on the top deck of a cargo ship. Weight loss from point of origin in South Dakota to Japan was estimated to be 1.3 kg/head/day.

Use of a fluorometric immunoassay to determine antibody response to Pasteurella haemolytica in vaccinated and nonvaccinated feedlot cattle.

A retrospective study of the antibody response to Pasteurella haemolytica was conducted by using sera from 368 feedlot cattle divided among five experiments. In three experiments, live vaccines or a bacterin were administered to some of the cattle and others were left as nonvaccinated controls. In two experiments, cattle were not vaccinated. Clinical signs of disease with subsequent recovery developed in 48.0% of the cattle, and 10.3% of the cattle died. Vaccination had no apparent effect on morbidity or mortality. At the time of purchase, 78% of the cattle had low antibody titers (less than 25) as measured by a quantitative fluorometric immunoassay. In most groups of cattle (both vaccinated and nonvaccinated), there was a significant rise in mean antibody titers between the time of purchase and days 28 to 32 in the feedlot. The antibody titers at the time of shipment and health status of cattle. The antibody ratios were significantly greater for cattle that became sick and then recovered compared with those of cattle that remained healthy. Although significance could not be established, antibody titers at the time of shipment were higher for cattle that remained healthy compared with cattle that became sick and then recovered.