Opinions and practices of wisconsin dairy producers about biosecurity and animal well-being

The objective of this study was to characterize opinions and practices of Wisconsin dairy producers about biosecurity and animal wellbeing. Wisconsin dairy producers were surveyed using a mailed questionnaire and responder herds were categorized based on the number of lactating cows: very small herds (≤50 lactating cows; n = 279); small herds (51 to 100 lactating cows; n = 202); medium herds (101 to 200 lactating cows; n = 42); and large herds (>200 lactating cows; n = 37). Producers from large herds adopted more biosecurity practices than those from small herds, but biosecurity risks were common. Almost half of the responders indicated that they purchased cattle, but few (49.4%) performed diagnostic testing of those cattle. The frequency of diagnostic testing and examination of purchased cattle increased with herd size. Producers generally (80%) believed that they used the “right amount” of antibiotics, but the use of written treatment protocols increased with herd size. Producers from large and medium herds reported much higher usage of computerized (65.7 and 17.5%, respectively) and paper records (42.9 and 22.5%, respectively) compared with producers from smaller herds. Almost all (92.6%) believed that Johne's disease was an important issue for the dairy industry, but only 9% had enrolled in the official Wisconsin control program. Most producers (88.6%) believed that dehorning caused at least a small amount of pain, but the majority (81%) did not use local anesthetics. Producers minimized risks with which they were most familiar. Drinking raw milk was not considered a human health risk by almost half the responders, whereas bovine spongiform encephalopathy was considered “no risk” to only 37%. Raw milk was consumed by more than 60%, but regular consumption of raw milk decreased from 47.7% (very small herds) to 24.3% (large herds); perception of the risk of raw milk increased from 46.2% (very small herds) to 56.8% (large herds) with herd size. Larger farms had more knowledge of personal health risks related to zoonotic pathogens. Overall, most management practices were associated with herd size, but many beliefs regarding important dairy farm issues were consistent.     

Quantifying calf mortality on dairy farms: Challenges and solutions

In the Netherlands, the mortality rate of ear-tagged calves <1 yr is one of the indicators that is continuously monitored in census data and is defined as the number of deceased calves relative to the number of calf-days-at-risk. In 2017, yearly calf mortality rates were published in the lay press and resulted in discussions about the calculation of this parameter among stakeholders because the same parameter appeared to be calculated in many different ways by different organizations. These diverse definitions of calf mortality answered different aims such as early detection of deviations, monitoring trends, or providing insight into herd-specific results, but were difficult to understand by stakeholders. The aim of this study was to evaluate several definitions of calf mortality for scientific validity, usefulness for policymakers, and comprehensibility by farmers. Based on expert consultations, 10 definitions for calf mortality were evaluated that assessed different age categories, time periods, and denominators. Differences in definitions appeared to have a large effect on the magnitude of mortality. For example, with the original mortality parameter, the mortality rate was 16.5% per year. When the first year of life was subdivided into 3 age categories, the mortality rate was 3.3, 4.5, and 3.1% for postnatal calves (≤14 d), preweaned calves (15–55 d), and weaned calves (56 d–1 yr), respectively. Although it was logical that these mortality rates were lower than the original, the sum of the 3 separate mortality rates was also lower than the original mortality rate. The reason was that the number of calves present in a herd and the risk of mortality are not randomly distributed over a calf's first year of life and the conditional nature of mortality rates when calculated for different age categories. Ultimately, 4 parameters to monitor calf mortality in Dutch dairy herds were chosen based on scientific value, usefulness for monitoring of trends, and comprehensibility by farmers: perinatal calf mortality risk (i.e., mortality before, during, or shortly after the moment of birth up to the moment of ear-tagging), postnatal calf mortality risk (≤14 d), preweaned calf mortality rate (15–55 d), and weaned calf mortality rate (56 d–1 yr). Slight differences in definitions of parameters can have a major effect on results, and many factors have to be taken into account when defining an important health indicator such as mortality. Our evaluation resulted in a more thorough understanding of the definitions of the selected parameters and agreement by the stakeholders to use these key indicators to monitor calf mortality.     

Associations between biosecurity practices and bovine digital dermatitis in Danish dairy herds

The relationship between biosecurity and digital dermatitis (DD) was evaluated in 8,269 cows from a convenience sample of 39 freestall dairy herds. The hypothesis was that poor implementation of biosecurity was associated with higher within-herd prevalence of DD. All lactating cows were scored as negative or positive for DD at the hind legs during milking in the milking parlor. Information about biosecurity was obtained through questionnaires addressed to farmers, on-farm observations, and information from the Danish Cattle Database (www.seges.dk). These assessment tools covered potential infection sources of DD pathogens to susceptible cows (e.g., via animals, humans, manure, vehicles, equipment, and facilities). External and internal biosecurity measures were explanatory variables in 2 separate logistic regression models, whereas within-herd DD prevalence was the outcome. Overall DD prevalence among cows and herds were 24 and 97%, respectively; the within-herd DD prevalence ranged from 0 to 56%. Poor external biosecurity measures associated with higher prevalence of DD were recent animal purchase, access to pasture, lack of boots available for visitors, farm staff working at other dairy farms as well, hoof trimming without a professional attending, and animal transporters having access to cattle area. For internal biosecurity, higher DD prevalence were associated with infrequent hoof bathing, manure scraping less than 8 times a day, manure removal direction from cows to heifers, animal pens' exit without water hoses, manure-handling vehicle used in other activities, and water troughs contaminated with manure. These findings showed that improvements on biosecurity may be beneficial for controlling DD in dairy herds. The study is relevant for farmers facing problems with DD, as well as hoof trimmers, advisors, and veterinarians, who can use the results for optimized recommendations regarding biosecurity in relation to DD. Furthermore, our results might be considered by future studies investigating DD pathogen reservoirs and transmission routes.     

An observational analysis of twin births, calf sex ratio, and calf mortality in Holstein dairy cattle

A data set of Holstein calving records from January 1996 to September 2004 comprising 4,103 herds with 2,304,278 calving events representing 1,164,233 cows and 96,069 twin births was extracted from Minnesota Dairy Herd Improvement Association archives to assess reported twinning trends and calf mortality across time. Overall, the reported twinning rate was 4.2%, and twinning increased with parity [1.2% for nulliparous vs. 5.8% for multiparous cows; odds ratio (OR) = 4.9], and with time (3.4% in 1996 to 4.8% in 2004), with a parity by time interaction. Independent of parity, the greatest twinning rate was observed when conception occurred from August to October compared with other seasons (OR = 1.2). Calf mortality was greater after twin births, with 28.2% of twin calving events reporting one or both calves as dead, compared with 7.2% for singleton births (OR = 6.5). Calf mortality for primiparous and multiparous cows was 5.0% after a single birth and 25.5% after twin births, whereas for nulliparous heifers, mortality was 10.4% for singletons and 38.0% for twins (OR = 3.4). Calf sex ratio (male, M; female, F) was 53.3% M and 46.7% F for singleton calves, and 30.1% MM, 43.6% MF, and 26.3% FF for twin calves. Although specific factors cannot be implicated, the increase in twinning across time suggests a concurrent change in one or more causative factors associated with twinning during the 9-yr study period.     

Factors influencing dairy calf and replacement heifer mortality in France

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) and a linear model (mortality risk or rate >0) corrected by the sample bias Heckman method. The same associations were reported for 2005 and 2006. The mortality risks or rates for calves and heifers were positively associated with the proportion of purchased cows or being a Milk Control Program member and negatively associated with adhering to the Good Breeding Practices charter and having an autumn calving peak. The associations between mortality and the breeds or the production areas were positive or negative, depending on the classes of animal. Mortality and having a beef herd in addition to the dairy herd were negatively associated for noncrossed birth to 2-d-old calves, noncrossed 3-d- to 1-mo-old calves, and 3-d- to 1-mo-old heifers. Having a beef herd probably provides specific know-how related to newborn and young calf management that makes it easier to attain low mortality in pure-breed dairy calves. The proportion of males born was positively associated with mortality for the birth to 2-d-old calves (all classes) and for the 3-d- to 1-mo-old beef-crossed calves, but negatively for all classes of heifers. This indicates that heifer management was improved when the availability of newborn heifers decreased, resulting in low mortality. This lower mortality is apparent for all classes of heifers present on the farm during the year when the proportion of males was low, and demonstrates an anticipatory effect. In conclusion, this study shows that the presence of a beef herd in addition to the dairy herd within a farm is associated with decreased dairy calf mortality. It also shows that heifer mortality decreases when the proportion of heifers born decreased. These determinants of dairy calf and heifer mortality are of great importance for farmer advisors, the dairy industry, and the political decision makers.     

Characterizing biosecurity, health, and culling during dairy herd expansions

Our objectives were to investigate strategies for biosecurity, expansion, and culling for expanding dairy herds in the Upper Midwest. Eighteen dairies in Iowa and Wisconsin were visited, and dairy managers and veterinarians were interviewed to characterize five biosecurity practices, herd culling practices, vaccines administered, and ensuing disease status for the herds. The majority of herds that were interviewed failed to employ comprehensive biosecurity programs for incoming cattle. Nearly 60% of herds obtained cattle from sources for which it was difficult to document genetic backgrounds and health histories, fewer than half required health testing for incoming cattle, and approximately 50% quarantined new cattle on arrival. Despite high rates of vaccination for bovine viral diarrhea, all herd owners and managers indicated that herd biosecurity was compromised as a result of expansion. Half of the interviewed herds indicated that bovine viral diarrhea and papillomatous digital dermatitis were notable disease problems. Herds that obtained cattle with unknown backgrounds and health status experienced the largest number of diseases. Before expansion, the most frequently cited reasons for culling were reproductively unsound; low milk production; mastitis, poor udder health, and high SCC; during expansion, the strategic decision to cull cows for low milk production was used less often. In addition, the stochastic simulation model, DairyORACLE, was used to evaluate economic outcomes for several expansion alternatives. Five model scenarios studied were: base scenario (herd size was maintained) and four expansion scenarios--all paired combinations of heifer quality (high, low) and voluntary culling (implemented, not implemented). Culling for low milk production yielded an additional $23.29 annually (6-yr annuity) per cow, but on the basis of purchased replacements, no voluntary culling was most profitable. Purchasing high versus low quality replacement heifers for expansions returned an additional $113.54 annually ($681.24 total net present value) per heifer purchased. Many opportunities exist to improve cattle-related factors for dairy herd expansions, including the use of comprehensive biosecurity programs, realistic planning and budgeting for cattle purchases, and cost effective purchase and culling practices.     

A survey of dairy calf management practices in Canada that affect animal welfare

There is growing interest among the public in farm animal welfare and a need for methods to assess animal welfare on farm. A survey on calf rearing practices that might affect dairy calf welfare was performed via a 1-h interview on 115 dairy farms (mean ± SD: herd size = 52.5 ± 20.9 cows; milk production = 8,697 ± 1,153 L) distributed throughout the province of Quebec. Despite frequent recommendations, many dairy producers continue to use management practices that increase the health risks of milk-fed calves. Major risk factors for poor calf welfare identified were 1) no use of calving pen in 51.3% of herds and low level of surveillance of calvings, especially at nighttime (once every 12 h), 2) no disinfection of newborn's navel in 36.8% of herds, and delayed identification and, hence, calf monitoring (3 d), 3) 15.6% of farms relied on the dam to provide colostrum and none checked colostrum quality or passive transfer of immunity, 4) dehorning and removal of extra teats proceeded at late ages (6.4 wk and 6.7 mo, respectively) and without adequate pain control, 5) use of traditional restrictive milk feeding and waste milk distributed to unweaned calves without precaution in 48.2% of herds, 6) abrupt weaning performed in 16.5% of herds, and 7) calves housed individually in 87.9% of herds, and most inappropriate housing systems (crate = 27.0%, tie-stall = 13.9%, attached against a wall = 5.7%) remained. This risk factor assessment was the first step in an intervention strategy to improve calf welfare on dairy farms.     

An investigation of dairy calf management practices,colostrum quality,failure of transfer of passive immunity,and occurrence of enteropathogens among Australian dairy farms

Calf preweaning morbidity and mortality risks have been reported as high in several countries, with average values approximating 35 and 7%, respectively. However, limited data are available for calf morbidity and mortality risks on Australian dairy farms. The aims of this study were (1) to investigate current calf management practices on dairy farms in Australia and their association with herd-level morbidity and mortality using a questionnaire-based, cross-sectional study; and (2) to estimate the prevalence of common enteropathogens causing diarrhea, the failure of passive transfer of immunity, and poor colostrum quality in a sample of Australian dairy farms. We analyzed 106 completed questionnaires and samples from 23 farms (202 fecal, 253 calf serum, and 221 colostrum samples). Morbidity and mortality risks reported by farmers in preweaned heifers were 23.8 and 5.6%, respectively. These risks were above the Australian dairy industry targets in 75.5 and 66.7% of respondents. The zoonotic pathogens Cryptosporidium spp. and Salmonella spp. were the most prevalent enteropathogens, with a true prevalence of 40.9 and 25.2%, respectively. Salmonella O-group D was present in 67.9% of Salmonella-positive samples, followed by O-groups B (17.9%) and C (10.7%). Failure of transfer of passive immunity (IgG <10 g/L) was observed in 41.9% of calves (mean herd-level prevalence of 36.2%), and only 19.5% of colostrum samples met the standards for immunoglobulin content and microbiological quality. Collectively, these data indicate that there is still considerable room for improvement in calf-rearing practices on Australian dairy farms, particularly with regard to colostrum management and feeding hygiene.     

Passive immunity in Ontario dairy calves and investigation of its association with calf management practices

Adequate passive transfer of maternal immunoglobulin is important for optimal health and performance in newborn dairy calves. From June to October 2003 and January to April 2004, blood samples were collected from 961 dairy calves 0 to 8 d of age on 11 farms in southwestern Ontario. This was followed by a second study conducted from May to October 2004, in which similar samples were taken from 422 calves up to 8 d of age on 119 dairy farms throughout southern Ontario. For each sample collected, serum refractometry was used to evaluate serum total protein (TP) as a measure of passive transfer of maternal immunity. During each study, producers were asked to provide information on calf management practices, including details of colostrum feeding. Data were analyzed to assess the levels of maternal immunity present in the calves, and to investigate whether these were associated with any calf management or colostrum feeding practices used on the farms. Serum TP readings ranged from 3.5 to 9.8 g/dL. Controlling for any effects of variation between farms, we found no statistically significant difference in serum TP levels, or risk of failure of passive transfer (FPT), between heifer and bull calves. The odds of FPT in calves on farms where more than 75% of cows were usually allowed to remain with their calves for more than 3 h after calving were significantly higher than the odds of FPT in calves on farms where dams and calves were separated within 3 h of the birth. Furthermore, an increased volume of colostrum given to calves within 6 h of birth was significantly associated with a reduced risk of FPT in calves. Information from this work provides valuable insight into the efficiency of passive transfer in newborn dairy calves in southern Ontario.     

Quantification of antibiotic use on dairy farms in Pennsylvania

Antibiotic use data are critical for drawing conclusions about the epidemiological connections between antibiotic use in farms animals, antibiotic resistance, animal health, and human health. The goal of this study was to quantitatively and qualitatively characterize antibiotic use on dairy farms in Pennsylvania, the state with second largest number of dairy farms nationally. A survey was sent to 10% of the 6,580 dairy farms registered in Pennsylvania and completed by 235 producers (response rate of 36%). Data on antibiotic use in the previous month and in the previous 6 mo were collected based on farmer self-report, using either recall or treatment records. Two metrics were used to quantify antibiotic consumption: animal-defined daily doses (ADD) and days of therapy (DOT), a metric used in human medicine for purposes of antimicrobial stewardship. Across all farms, 24,444 ADD and 19,029 DOT were reported, representing treatment incidences of 4.2 ADD/1,000 animal-days and 3.3 DOT/1,000 animal-days. These rates were generally lower than those found in other states and countries. The main indication for antibiotic use was mastitis, and first-generation cephalosporins were the most commonly used class of antibiotic for all indications, followed by penicillins and third-generation cephalosporins. Trends in use were similar for ADD and DOT, but the numbers of recorded DOT and associated treatment incidences were generally lower than the number of ADD and associated treatment incidences. Rates of treatment were significantly associated with herd size. This study is the first to quantify antibiotic use on dairy farms in Pennsylvania and the first to use the DOT metric in a dairy setting.     

Farm characteristics and calf management practices on dairy farms with and without diarrhea: A case-control study to investigate risk factors for calf diarrhea

Calf diarrhea is one of the most important problems in calf rearing on dairy farms worldwide. Besides pathogens, several noninfectious management factors, especially management around birth, colostrum management, calf housing, feeding, and hygiene are important in the pathogenesis of diarrhea. To date, few data are available concerning calf rearing management on small and medium-sized dairy farms that are typical for Austria and the alpine region. Consequently, the objectives of this case-control study were to evaluate routine calf management practices on Austrian dairy farms and to examine differences in management between farms with and without the presence of calf diarrhea to identify risk factors. Overall, 100 dairy farms were visited. Of these farms, 50 were chosen based on the history and presence of calf diarrhea (case farms). Another 50 farms with no presence of calf diarrhea were chosen to serve as a standard of comparison (control farms). On farms, management was evaluated by face-to-face interview, and health status and hygiene were surveyed. Several calf rearing management procedures were similar on all of the visited farms, especially in areas regulated by national and European law. These factors include colostrum management and feeding. Consequently, no influence of these factors on the appearance of calf diarrhea could be detected. In contrast, other areas such as hygiene measures differed between farms and showed a partial association with the presence of calf diarrhea on farm. Variables related to diarrhea on farm were farm size; that is, the number of cows on farm. Farms with diarrhea cases were larger (median 40 cows, interquartile range 24.5 to 64.0) compared with farms with no presence of diarrhea (median 28 cows, interquartile range 18.8 to 44.0). Other risk factors that influenced the presence of diarrhea were the presence of other farm animal species on the farm [odds ratio (OR) 26.89, 95% confidence interval (CI): 2.64 to 273.5], frequency of cleaning of the calving area (OR 0.12, 95% CI: 0.02 to 0.79), the placement of individual calf housings (barn vs. outdoors; OR 0.02, 95% CI: 0.00 to 0.47), and the presence of respiratory tract disease (OR 52.49, 95% CI: 1.26 to 2,181.83). The possible influence of these factors on the appearance of calf diarrhea should be considered when farmers are advised.     

An advisory tool to improve management practices affecting calf and heifer welfare on dairy farms

We developed an advisory tool addressing 10 critical areas of calf and heifer management, including calving management, care to newborn calves and painful procedures, colostrum management, cow-calf separation, calf feeding, weaning, calf housing, heifer feeding, heifer housing, and general monitoring. Targets and indicators for each critical area were validated by a panel of experts and maximum scores were assigned based on experts’ opinions and reviews of scientific literature. The tool was tested on 28 Quebec dairy farms for feasibility and repeatability between 2 observers. Farmers were asked to test colostrum quality, measure blood IgG concentrations, and record health events. The on-farm evaluation included an interview on management practices and an evaluation of conditions in the barn. Scorings and recommendations were discussed with producers. The usefulness of our on-farm welfare tool was evaluated by the producers themselves during a final debriefing. We reached the main goals of a successful advisory tool of calf and heifer management to improve welfare on dairy farms. We respected the targeted time limit of a 3-h visit covering all aspects of our tool including data collection on management and environment, scoring, practical demonstration with producers, and debriefing. We had no problems collecting management- and environment-based data and had high repeatability of qualitative environment-based measures (kappa value > 0.6). Our tool helped to detect problems and to discuss these problems with the producers; producers scored below 50% for some targets in calving management, care to newborn calves and painful procedures, colostrum management, and calf feeding. The targets were realistic so producers were not discouraged. All producers were convinced of the usefulness of our tool for identifying areas of calf and heifer management in need of improvement. They were also convinced of the usefulness of our tool as an advisory tool for technical advisors and veterinarians. Six months after the on-farm visit, recommended practices were implemented in many of these areas. Voluntary improvements in animal welfare can be facilitated by using appropriate tools to educate producers and help them change their attitudes toward calf management and animal welfare.     

A cross-sectional study of associations between herd-level calf mortality rates,compliance with legislation on calf welfare,and milk feeding management in Norwegian dairy herds

Our aim was to investigate the associations between management factors, compliance with current legislation, and herd-level calf mortality. In a national calf welfare audit, veterinary inspectors from the Norwegian Food Safety Authority assessed compliance with current legislation on calf welfare (n = 912 herds). Nine criteria were assessed and rated as satisfactory (1) or not satisfactory (0): housing, natural behavior, single pens, colostrum feeding, feeding, water, surveillance, illness/injuries, and <5% mortality rate. In addition, a short questionnaire on milk feeding management for 3-wk-old calves was distributed to all national calf welfare audit herds, and data on mortality and disease recordings were obtained from the Norwegian Dairy Herd Recording System (NDHRS). A herd welfare compliance score (WCS) for each farm was constructed, summarizing the results for the individual criteria. Most herds had a high WCS (median 9.0, range 2–9). Fifty-six percent of the national calf welfare audit herds (508/912) responded to the questionnaire. We performed a cross-sectional study using a data set from 431 herds with available data on recorded disease and mortality events from the NDHRS, recordings from the national calf welfare audit, and the questionnaire. A mixed-effects negative binomial model with Norwegian Food Safety Authority district as the random effect was fitted to the data. Of the 416 herds with available data on calf mortality, 108 (25.9%) reported no mortality in 2016, and the median 6-mo mortality rate was 0.064 (interquartile range 0–0.11) dead calves per 6 calf-months at risk, based on NDHRS recordings. Calf mortality rates were higher in herds whose calves did not have free access to water (incidence rate ratio 1.29; 95% confidence interval 1.02–1.64) and higher in herds that had reported calf disease events (incidence rate ratio 1.31; 95% confidence interval 1.09–1.54). Neither the WCS nor any of the calf milk feeding management factors were associated with mortality, but more than half of producers (59.6%) fed less milk than currently recommended for 3-wk-old calves (8 L/d first 3 to 4 wk). These results indicate that a lack of access to water was associated with higher calf mortality rates. Herds with registered calf disease events had a higher incidence rate ratio of mortality. This finding may be linked to suboptimal calf management, leading to more calf diseases and mortality; or it may be that veterinary consultancy occurs too late or only for the worst cases. There is room for improvement in Norwegian dairy calf management, and water should be provided to young calves.     

Preweaned heifer management on US dairy operations: Part V. Factors associated with morbidity and mortality in preweaned dairy heifer calves

The objective of this study was to evaluate morbidity and mortality in preweaned dairy heifer calves based on different health, feeding, and management practices, as well as environmental factors. This study was conducted as part of the calf component of the National Animal Health Monitoring System's Dairy 2014 study, which included 104 dairy operations in 13 states. The calf component was an 18-mo longitudinal study focused on dairy heifer calves from birth to weaning; data were collected on 2,545 calves. The percentage morbidity for all calves enrolled in the study was 33.9%. Backward elimination model selection was used after univariate screening to determine which management practices and environmental factors significantly affected morbidity and mortality. The final morbidity model included birth weight, serum IgG concentration, ventilation type, and average temperature-humidity index (THI) during the preweaning period. After controlling for other independent variables in the model, calves born at a higher birth weight had a lower predicted risk of morbidity than calves with a lower birth weight. An increase in serum IgG concentration was associated with decreased morbidity. Calves housed in positive- or cross-ventilated systems had a 2.2 times higher odds of developing disease compared with calves housed in natural ventilation systems. Average THI during the preweaning period was inversely correlated with morbidity; as THI increased, the predicted morbidity risk decreased. The percent mortality for all calves enrolled in the study was 5.0%. The final mortality model included birth weight, serum IgG concentration, amount of fat/day in the liquid diet, and morbidity. After controlling for other independent variables in the model, calves born at a higher birth weight had a lower risk of mortality. An increase in serum IgG concentration decreased the risk of mortality. The odds of mortality were 3.1 times higher in calves fed ≤0.15 kg of fat/d in the liquid diet compared with calves fed ≥0.22 kg of fat/d. The odds of mortality were 4.7 times higher in calves that experienced any disease throughout the preweaning period than in calves with no disease. In summary, morbidity and mortality were both associated with birth weight and serum IgG concentration. Additionally, morbidity was associated with ventilation type and average monthly THI, and mortality was associated with amount of fat per day in the liquid diet and morbidity.     

Short communication: Drying-off practices and use of dry cow therapy in Finnish dairy herds

The objective of this study was to survey drying-off practices and use of dry cow therapy (DCT) in Finland through an online questionnaire. The questionnaire was accessible to all dairy farmers of the Finnish dairy herd recording system in 2016 (approximately 5,400 farms). In total, 715 dairy producers across the country, representative of the Finnish dairy industry, participated in the survey. Cows were dried off gradually in most of the farms. Most farms (78%) reported using selective DCT, whereas 9% of farms did not use any DCT, and 13% of farms applied blanket DCT. A significant trend was observed with increasing herd size and proportion of farms using blanket DCT. Percentage of farms using blanket DCT was also higher in farms with automatic milking system. Farmer's own experience was the most commonly reported reason for choosing a particular approach to DCT. Microbiological testing of milk samples at dry-off was the preferred method of selecting cows for DCT; 82 and 64% of farms using selective and blanket DCT approach, respectively, reported testing milk samples before treatment. The second most common criteria for using antibiotic DCT were clinical mastitis history and high somatic cell count. A high number of farms using selective DCT reported treating only up to one-fourth of their cows at dry-off. Information acquired on drying-off practices in Finland allows for future monitoring of prudent antimicrobial usage at dry-off.     

Assessment and promotion of judicious antibiotic use on dairy farms in Washington State

The aims of this study were to describe antibiotic use and biosecurity practices among Washington State dairy producers and to evaluate the effectiveness of a collaborative approach to promoting judicious antibiotic use on dairy farms. In collaboration with a statewide industry group, Washington State dairy producers participated in a written, self-administered survey in 2003. They were then provided several educational interventions followed by a second written survey in 2005. Sixty-five percent (381) of dairy producers completed the 2003 survey. The most commonly cited drugs used for disease treatment were penicillin, ceftiofur, and oxytetracycline. Participants also indicated significant preventive uses with 28% using medicated milk replacer. Most producers appeared to consider intramammary infusion at dry-off to be a treatment rather than a preventative practice. Twenty-three percent of initial respondents indicated at least one extra-label use of antibiotics, yet only half routinely consulted with a veterinarian when doing so. Most agreed that using written protocols for disease treatment could reduce errors, but less than one-third had protocols. After the educational intervention there was a tendency toward reduced use of antibiotic medicated milk replacer: 51% of producers who originally reported using medicated milk replacer discontinued this practice, whereas 12% of producers began using medicated milk replacer between the 2003 and 2005 surveys. Most reported that the resources and educational materials were useful. Areas where additional work is needed include reducing the use of medicated milk replacer, increasing veterinary involvement in antibiotic use decisions, implementing treatment protocols, enhancing biosecurity, and ensuring optimal cow and calf immunity.     

Public perceptions of antibiotic use on dairy farms in the United States

There has been a global push for improved antimicrobial stewardship, including in animal agriculture, due to growing concerns about antimicrobial resistance. However, little is known about the general public's perceptions of antimicrobial use in animal agriculture. The aim of this study was to explore the US public's perceptions of antibiotic use in dairy farming and how these perceptions influence purchasing decisions. Data from the 2017 Cornell National Social Survey developed in collaboration with the Cornell Survey Research Institute were used to assess the public's perceptions. The Survey Research Institute of Cornell University (Ithaca, NY) administered the survey by telephone to a random sample of 1,000 adults in the continental United States. The survey collected information about perceptions of threat to human health posed by antibiotic use in cows on dairy farms and willingness to pay more for milk from cows raised without antibiotics, as well as several presumed explanatory variables, including respondents' knowledge of antibiotics, beliefs regarding cattle treatment in dairy farming, and 18 sociodemographic characteristics. Data were analyzed using logistic regression. Among respondents, 90.7% (n = 892/983) reported that antibiotic use on dairy farms posed some level of threat to human health and 71.5% (n = 580/811) indicated they would be willing to pay more for milk produced from cows raised without antibiotics. Respondents who believed that antibiotic use in dairy farming posed a moderate to high threat to human health were more likely to be female and report willingness to pay more for milk or not purchase milk. Additionally, consumers' willingness to pay more for milk from cattle raised without antibiotics was associated with the belief that antibiotic use posed some threat to human health, the belief that cows are treated better on organic dairy farms, an annual household income of $50,000 or greater, being born outside the United States, having a liberal social ideology, and being currently or formerly married. These results suggest that the general public's decisions as consumers of dairy products are associated with demographic factors in addition to perceptions of antibiotic use and cattle treatment in dairy farming. The rationale behind such perceptions should be further explored to facilitate consumers' informed decision making about antibiotic use in agriculture, links to cattle treatment, and associated willingness-to-pay attitudes.     

Association between bulk-tank milk Salmonella antibody level and high calf mortality in Danish dairy herds

Salmonella enterica ssp. enterica Dublin is the most common Salmonella serotype found in the dairy sector in Denmark. Salmonella antibody level in bulk-tank milk (BTM), indicative of Salmonella Dublin infection in the herd, has been recorded regularly in all Danish dairy herds through a surveillance program since 2002. The objective of this study was to investigate whether high BTM Salmonella antibody level was associated with high calf mortality at herd level. Other risk factors for high calf mortality were also investigated: breed, production type (organic vs. conventional), number of animals purchased, herd size, and number of neighbor herds within a 4.9-km radius. Data from the Danish Cattle Database including the Salmonella surveillance program from September 2007 through August 2008 were used. Dairy herds with more than 20 cows were included (n = 4,337). Because of a highly right-skewed distribution of calf mortality with many zero values, calf mortality had to be dichotomized for the analysis. Therefore, in this study, high calf mortality was defined as calf mortality of more than 6.5% for calves aged 1 to 180 d. A logistic analysis was performed to identify risk factors associated with the probability of a herd having high calf mortality. The following factors were significantly associated with high calf mortality: high BTM Salmonella antibody level, odds ratio (OR) = 2.0 (95% confidence interval = 1.6-2.4), organic production OR = 1.4 (95% confidence interval = 1.1-1.7) for organic versus conventional production, and breed. Purchase of 8 or more animals increased the OR of high calf mortality more than purchase of 1 to 7 animals, which again had a higher OR compared with purchase of 0 animals. Because only 14.3% of the population consisted of herds with high BTM Salmonella status, the estimated proportion of herds with high calf mortality could only be reduced from 38.7 to 36.5% by eradicating Salmonella from the Danish cattle population (i.e., a population attributable risk of 2.2%). This showed that although there is a strong association between BTM Salmonella status and calf mortality, the problem with high calf mortality will not be solved by eradicating Salmonella. All other things equal, a population with more Salmonella-infected herds would gain a larger reduction in calf mortality from a Salmonella control campaign. Nevertheless, individual herds with a high within-herd prevalence of Salmonella are likely to benefit, both economically and regarding animal welfare, from controlling pathogenic Salmonella types in cattle.