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

Quantifying multiple burdens of dairy cattle production diseases and reproductive inefficiency: current knowledge and proposed metrics

The economic burden of diseases and reproductive inefficiency in dairy cattle is evident and has been quantified. Dairy diseases and reproductive inefficiency are however associated with other issues as well, including animal welfare, environmental pressure, and public health risks. Quantifying these other issues is becoming important to help farmers making decisions. Quantification of the non-economic burdens of diseases and reproductive inefficiency is rare and lacks an overview of approaches and metrics. The first aim of this paper is to provide trends for associating diseases and reproductive inefficiency with economic and non-economic burdens of disease. The second aim is to provide a review of approaches and metrics used to quantify the non-economic burdens of disease and reproductive inefficiency. For the economic burden of diseases and reproductive performance, only an overview of the approaches used to quantify the burden is provided. The final aim is to propose approaches and metrics for future quantification of non-economic burdens caused by individual diseases. A literature search was conducted in Web of Science to identify scientific articles on mastitis, lameness, metabolic disorders and reproductive inefficiency in dairy cows. The search was restricted to articles published between 1 January 2010 and 31 December 2022 and resulted in 7,565 articles. The total number of articles that mentioned the economic, animal welfare, public health, and environmental burden was 1,253, 428, 291, and 77, respectively. An increase in the percentage of articles mentioning the economic, animal welfare, and public health burden is observed between 2010 and 2022. Despite the 2,049 articles that mentioned one of the burdens, the results showed that approximately 10% of the articles quantified one or more of these burdens. The economic burden of diseases and reproductive inefficiency has been quantified in 154 articles and very few articles quantified the non-economic burdens (9 articles for environment, 29 articles for public health and 2 articles for animal welfare). Eleven articles were identified that quantified multiple burdens, and in all these studies the economic burden was combined with a non-economic burden through a modeling approach (mainly simulation). We propose to link the non-economic burdens to biological simulation models, and thus develop bio-burden simulation models. Well-established approaches and metrics can be used to quantify economic, environmental, and public health burdens. For the economic impact, costs per cow per year can be assessed. A life cycle assessment can be performed for environmental impact and the public health impact can be assessed by a defined daily dose for antimicrobial use and disability-adjusted life years for zoonotic diseases. Regarding animal welfare, approaches and metrics to quantify the welfare impact of a diseased animal are not well established. For animal welfare, we propose a welfare-adjusted life years approach. The mentioned approaches and metrics are a proposal, and it is up to the scientific community to use them or, based on empirics and research experience, propose changes so that we will end up with robust approaches and metrics that enable us to compare research results and provide more evidence for animal health decision makers.

Public awareness, risk perceptions and behaviour towards antibiotic use in food-producing animals and antimicrobial resistance in Malaysia: A cross-sectional study

Antimicrobial resistance (AMR) is a growing global public health problem, particularly in low- and middle-income countries, including Malaysia. Understanding risk perceptions on antimicrobial use (AMU) in food-producing animals from the general public perspective is an essential component in addressing AMR. However, little is known about public risk perceptions of AMU and AMR in food-producing animals in Malaysia. The objectives of this study were to assess the level of awareness, risk perceptions, and behaviour regarding antibiotic use in food-producing animals and antimicrobial resistance and to examine the factors associated with risk perceptions and the relationship between knowledge, awareness, risk perceptions and behaviour among the general public in Malaysia. A cross-sectional survey was used. Both descriptive and analytical statistics were used to analyse data and present results. Correlation and regression analyses were conducted to examine the factors associated with risk perceptions and the relationship between risk perceptions and behaviour. A total of 416 individuals participated in the study. The majority of the participants (69.2 %) had low knowledge of antibiotics and antibiotic use in food-producing animals. The levels of awareness of antibiotic use and the perceived route of antibiotic resistance transfer were moderate. Participants had a high level of general risk perception (GRP) of antibiotic use, a moderate level of personal-level risk perception (PRP) of antibiotic resistance transmission, and a high level of societal-level risk perception (SRP) of antibiotic resistance transmission. Awareness of antibiotic use was a significant predictor of GRP (β = 0.27, 95 %CI: 0.12-0.31, P < 0.001). Awareness of route of resistance transfer was a significant predictor of PRP (β = 0.54, 95 %CI: 0.32-0.44, P < 0.001) and SRP (β = 0.47, 95 %CI: 0.32-0.46, P < 0.001). PRP is the only significant predictor of behavioural changes towards antibiotic use and antibiotic resistance (OR = 1.45 [1.02-2.07], P = 0.041). Overall, there is a general lack of knowledge and little awareness of antibiotic use and antibiotic resistance in food-producing animals in Malaysia. Risk perceptions were moderate to high and were significantly predicted by awareness of antibiotic use and route of resistance transfer. Personal-level risk perception was a significant predictor of behavioural changes aimed at reducing the risk of AMU and AMR. It is imperative to raise public awareness and understanding of the risks associated with AMU in food-producing animals. Risk communication should be emphasised to ensure the translation of public risk perceptions into behavioural changes.

The effect of information provision on consumers' risk perceptions of, support for a ban, and behavioral intention towards the preventive use of antibiotics in food animals

BACKGROUND

Antibiotics have been widely used in feed and drinking water for food animals to prevent them from getting sick. Such preventive use of antibiotics has become a contributor to increasing antibiotic resistance and thus poses threats to human health. However, consumers have little knowledge about this practice and the associated health risks of increasing transmission of antibiotic residues and antibiotic resistant bacteria. This study aimed to examine the effect of information provision on consumers' risk perceptions, support for a ban, and behavioral intention regarding the preventive use of antibiotics in food animals. Especially, the study sought to test two competing hypotheses which were informed by two theoretical perspectives of fear appeal theory - the linear model and the plateau effect model. The former suggested that providing information on the health risks of both antibiotic residues and antibiotic resistant bacteria would have a stronger effect compared to providing information on only one of them, while the latter posited that providing information on both risks might not have additional influence, as the effect of information on either risk could reach the plateau.

METHODS

An experimental study with four conditions was conducted where participants read different information on the health risks associated with the preventive use first and then answered questions regarding consumers' risk perceptions, support for a ban, and behavioral intention regarding the preventive use. Condition 1 was the control condition, where basic information about antibiotics, antibiotic resistance, and the preventive use was provided. Condition 2 and Condition 3 further added information on the health risk of antibiotic residues (Condition 2) and antibiotic resistant bacteria (Condition 3) due to the preventive use, respectively. Condition 4 provided all information contained in the first three conditions.

RESULTS

The results showed that compared to participants in the control condition, participants in Conditions 2-4 reported higher risk perceptions, stronger support for a ban on the preventive use, and a higher intention to buy meat produced without the preventive use of antibiotics. However, there were no significant differences in these factors between Conditions 2-4, indicating that providing information on the health risk of either antibiotic residues, or antibiotic resistant bacteria, or both, has similar effect on these variables. That is, the hypothesis based on the plateau effect model was supported.

CONCLUSIONS

The findings suggested that informing the public with the health risk of either antibiotic residues or antibiotic resistant bacteria associated with the preventive use is effective enough to reach plateau effect in increasing risk perceptions, support for a ban, and behavioral intention, which has important implications for policymakers and livestock industries to develop effective communication strategies to promote responsible antibiotic use in food animals.

Emerging Parameters Justifying a Revised Quality Concept for Cow Milk

Milk has become a staple food product globally. Traditionally, milk quality assessment has been primarily focused on hygiene and composition to ensure its safety for consumption and processing. However, in recent years, the concept of milk quality has expanded to encompass a broader range of factors. Consumers now also consider animal welfare, environmental impact, and the presence of additional beneficial components in milk when assessing its quality. This shifting consumer demand has led to increased attention on the overall production and sourcing practices of milk. Reflecting on this trend, this review critically explores such novel quality parameters, offering insights into how such practices meet the modern consumer's holistic expectations. The multifaceted aspects of milk quality are examined, revealing the intertwined relationship between milk safety, compositional integrity, and the additional health benefits provided by milk's bioactive properties. By embracing sustainable farming practices, dairy farmers and processors are encouraged not only to fulfill but to anticipate consumer standards for premium milk quality. This comprehensive approach to milk quality underscores the necessity of adapting dairy production to address the evolving nutritional landscape and consumption patterns.

Perceptions of dairy cow-handling situations: A comparison of public and industry samples

Inappropriate cattle handling poses a reputational threat to the dairy industry. To enhance social sustainability, handling practices must resonate with societal values about animal care. However, it has yet to be determined to what extent industry and public stakeholders differ in their perception of common cattle handling situations. We administered an online survey to samples of dairy industry (IND) and public (PUB) stakeholders to examine how they perceive a variety of cow-handling scenarios ranging from positive to negative in terms of effects on animal welfare. Participants were presented with 12 brief videos depicting a range of realistic cow-handling situations and responded to measures designed to assess their attitudes and beliefs about each scenario, their perception of the emotional response of the cows depicted in each scenario, as well as their own personal emotional response. Preexisting beliefs about cow treatment on US dairy farms and demographic data, including self-reported dairy consumption, were also collected and analyzed. Before viewing the videos, 52.9% of PUB (vs. 79.0% of IND) believed cows were treated well while 27.2% (vs. 9.0% of IND) believed cows were treated badly. Within IND, believing cows were treated badly was more common among nonwhites, those with greater formal education, more liberal politics, or from urban or suburban environments. In PUB, female and younger participants were more likely to believe cows were treated badly before viewing the videos. In both samples, participants with more positive preexisting beliefs about dairy cow treatment in the US reported consuming dairy products more frequently. In both PUB and IND, scenarios which were rated more positively for attitudes or for the cows' or respondents' emotional experiences were also perceived as more common. Within a given cow-handling scenario, qualitative attitudes (i.e., a positive, negative, or neutral valence) did not differ between the samples. In both samples, at the participant level, overall attitudes toward cow-handling scenarios were highly correlated with both their personal emotional response to the scenario and their perception of the cows' emotional responses. Although the participants' overall personal emotional responses did not differ between the samples, IND rated cows as experiencing more negative emotions overall. The consensus between industry and public stakeholders around dairy cow-handling practices observed in this study could provide a common starting point for addressing other, more contentious animal welfare issues.

Randomized, noninferiority trial evaluating the efficacy of a novel teat sealant in pasture grazed dairy cows

The intramammary infusion at the end of lactation of a bismuth subnitrate internal teat sealant (ITS), with no antibiotic component has been shown to be an effective means of reducing new intramammary infections over the dry period. There has, however, been very few comparative studies between different brands of ITS under grazed pasture conditions. The objectives of this study were, therefore, to determine if a new bismuth subnitrate internal teal sealant (ShutOut, MSD Animal Health) was noninferior to Teatseal (Zoetis) regarding end-points such as (a) detection of the ITS product after calving, (b) clinical mastitis during the dry period and early lactation, and (c) subclinical mastitis at 30 to 60 d in milk. A total of 1,105 mixed-age cattle were enrolled across 2 farms comparing 2 ITS products for detection of the ITS at calving and prevention of clinical and subclinical mastitis. Both ITS contained 65% (2.6 g) bismuth salts emulsified in ≤ 1.4 g of mineral oil (ShutOut as investigational product, IVP; Teatseal as control product, CPT). At dry-off, treatment was allocated to every second cow. All cows met industry best practice criteria for using ITS treatment without antibiotics. Outcomes included detection of ITS at first stripping of the udder by the farmer, clinical mastitis (CM) from dry-off to 30 d following calving and subclinical mastitis at 30 to 60 d following calving. For ITS detection, a generalized mixed linear regression model was used to model the data, with clustering of quarters within cow accounted for by including cow as a random intercept. Clinical mastitis was analyzed at the cow-level using a Fisher's exact test, and SCC was modeled using a negative binomial distribution. The IVP was noninferior to the CPT for ITS detection following calving. There were 1344/1800 (71.5%) of quarters with ITS detection in the IVP in comparison to 1076/1604 (67.1%) of quarters in the CPT treated group. The quarter-level CM incidence risk was low (45 cases out 4,324 quarters; 1.04%). The overall cow-level CM risk was 4.1% (44/1081), with 20/540 (3.7%) cases in animals in the IVP group and 24/541 (4.4%) cases in animals in the CPT group. The IVP was noninferior to the CPT for cow-level mastitis incidence. The median SCC for all animals was 23,000 cells/mL, with a mean of 92,000 cells/mL. The back-transformed estimated marginal mean estimated SCC was 84,800 (95% CI 75,200-95,600) cells/mL for animals in the IVP group, and 98,800 (95% CI 87,600-111,300) cells/mL for animals in the CPT group. The IVP was, therefore, noninferior for all outcomes measured.

Variation in partial direct costs of treating clinical mastitis among 37 Wisconsin dairy farms

The objective of this observational study was to describe variations in partial direct costs of clinical mastitis (CM) treatments among 37 dairy herds using data obtained from herd management records. Animal health and drug purchase records were retrospectively collected from 37 Wisconsin dairy herds for a period of 1 yr. Each farm was visited to verify case definitions, recording accuracy, and detection criteria of CM cases. Descriptive statistics were used to summarize cost of drugs and milk discard. Differences in costs among protocols, intramammary (IMM) products, parities, days in milk, and recurrence were analyzed using ANOVA. Of 20,625 cases of CM, 31% did not receive antimicrobial treatment. The average cost of drugs and milk discard (including cases that were not treated) was $192.36 ± 8.90 (mean ± SE) per case and ranged among farms from $118.13 to $337.25. For CM cases treated only with IMM antimicrobials, milk discard accounted for 87% of total costs and was highly influenced by duration of therapy. Differences in costs were observed among parities, recurrence, and stage of lactation at case detection. Eight different treatment protocols were observed, but 64% of cases were treated using only IMM antimicrobials. Treatment costs varied among protocols; however, cases treated using both IMM and injectable antimicrobials as well as supportive therapy had the greatest costs as they were also treated for the longest duration. Ceftiofur was used for 82% of cases that received IMM antimicrobials while ampicillin was used for 51% of cases treated using injectable antimicrobials. With the exception of ceftiofur and pirlimycin IMM products, many IMM products were given for durations that exceeded the maximum labeled duration. For cases treated using only IMM therapy, as compared with observed costs, we estimated that partial direct costs could be reduced by $65.20 per case if the minimum labeled durations were used. Overall, partial direct costs per case varied among herds, cow factors, and treatment protocols and were highly influenced by the duration of therapy.

Community involvement in addressing the antibiotic crisis

Increasing student interest and success in STEM education is a top priority for many postsecondary educational institutions. One well-documented approach to both priorities is to have students participate in a Course Undergraduate Research Experience (CURE). Faculty from several technical colleges and universities in Wisconsin teamed up with the Tiny Earth organization to offer a CURE to address the search for new antibiotics. Students enrolled in undergraduate microbiology courses engaged in research and participated in community outreach. To involve the community, faculty from various institutions joined an NFL team, the Green Bay Packers, and created the Tiny Earth in Titletown symposium. Here, students presented their work via scientific posters, to community and industry members, and networked with other scientists from around the region. The Tiny Earth in Titletown symposium started in 2018, was held again in 2019, and returned in 2022 following a 2-year hiatus due to the COVID-19 pandemic. Record attendance in 2022 suggests that community outreach and education may be helping restore trust in science that was lost during the pandemic.

Right on the money? U.S. dairy farmers' varied understanding of consumer preferences and attitudes towards animal health, welfare and biotechnology

This Research Communication investigates how well U.S. dairy farmers understand the voting behaviour and willingness to pay of consumers for products with production traits relevant to animal health, welfare and biotechnology. Accurately understanding consumer behaviour is key to making sound production decisions and reducing risks. Comparing survey data with the literature shows that U.S. dairy farmers correctly assess consumer attitudes and behaviour over animal welfare practices like pain-controlled dehorning but could improve knowledge of attitudes towards antibiotic use and novel biotechnologies like gene editing.

Lactational performance, rumen fermentation, nutrient use efficiency, enteric methane emissions, and manure greenhouse gas-emitting potential in dairy cows fed a blend of essential oils

The objective of this experiment was to investigate the effects of an essential oil (EO) blend on lactational performance, rumen fermentation, nutrient utilization, blood variables, enteric methane emissions and manure greenhouse gas-emitting potential in dairy cows. A randomized complete block design experiment was conducted with 26 primiparous and 22 multiparous Holstein cows. A 2-wk covariate and a 2-wk adaptation periods preceded a 10-wk experimental period used for data and sample collection. Treatments were: (1) basal diet supplemented with placebo (CON); and (2) basal diet supplemented with a blend of EO containing eugenol and geranyl acetate as main compounds. Supplementation with EO did not affect dry matter intake, milk and energy-corrected milk yields, and feed efficiency of cows, compared with CON. Milk fat and lactose concentrations were increased, and milk total solids (TS) concentration and milk fat yield tended to be increased by EO. Multiparous cows supplemented with EO tended to have slightly decreased dry matter and crude protein digestibility compared with CON multiparous cows. There was a tendency for increased ruminal pH by EO, whereas other rumen fermentation variables did not differ between treatments. Daily methane emission was not affected by EO supplementation, but methane emission intensity per kg of milk fat was decreased by 8.5% by EO. Methane emission intensity per kg of milk lactose and milk TS were decreased and methane emission intensity per kg of milk yield tended to be decreased by up to 10% in EO multiparous cows, but not in primiparous cows. The greenhouse gas-emitting potential of manure was not affected by EO supplementation. Compared with CON, fecal nitrogen excretion was increased by EO supplementation in multiparous, but not in primiparous cows, and milk nitrogen secretion (as a % of nitrogen intake) tended to be increased in EO supplemented cows. Blood variables were not affected by EO supplementation in the current study. Overall, dietary supplementation of EO did not affect lactational performance of the cows, although milk fat and lactose concentrations were increased. Most enteric methane emission metrics were not affected, but EO decreased methane intensity per kg of milk fat by 8.5%, compared with the control.

Apparent prevalence and selected risk factors of methicillin-resistant Staphylococcus aureus and non-aureus staphylococci and mammaliicocci in bulk tank milk of dairy herds in Indiana, Ohio, and Michigan

The purpose of this study was to determine the apparent prevalence and risk factors of methicillin-resistant Staphylococcus aureus and non-aureus staphylococci and mammaliicocci (NASM) in bulk tank milk (BTM) obtained from 300 dairy farms that belong to a cooperative collecting milk from Indiana, Michigan, and Ohio. Dairy field personnel recorded information about selected farm level risk factors and collected and froze BTM samples (n = 300) that were sent to Michigan State University researchers. Milk samples were thawed at room temperature and pre-enriched by adding 1 to 4 mL of Mueller-Hinton broth supplemented with 6.5% NaCl and incubated at 37°C for 24 h. Subsequently, 10 µL was plated on mannitol salt agar and Mueller-Hinton agar supplemented with 2.5% NaCl containing 2 mg/L oxacillin and 20 mg/L aztreonam. Colonies that grew on the selective media were subcultured on blood agar and identified using MALDI-TOF mass spectrometry. Phenotypic methicillin resistance was tested using cefoxitin disk diffusion. Conventional PCR was used to detect mecA and mecC in phenotypically resistant isolates. Of 550 isolates that were obtained from mannitol salt agar plates and 10 isolates from Mueller-Hinton agar plates, 16 species of NASM accounted for 84% of staphylococci, while S. aureus accounted for the remaining 16%. Among S. aureus, 4 isolates from 4 farms (1.3%) demonstrated phenotypic resistance to methicillin resistance but none carried mecA or mecC genes. Among NASM, 45 isolates from 40 farms (13.3%) demonstrated phenotypic resistance to methicillin. However, only 13 NASM isolates (7 Mammaliicoccus sciuri, 2 Staphylococcus haemolyticus, 1 Mammaliicoccus fleuretti, 1 Staphylococcus epidermidis, 1 Staphylococcus saprophyticus, and 1 Staphylococcus hyicus) from 13 farms were positive for mecA, whereas all were negative for mecC. Thus, the prevalence of mecA-positive NASM in BTM was 4.3%. Based on molecular results, this study demonstrated a low prevalence of methicillin resistance NASM from BTM samples collected from farms in the Upper Midwest. Dairy farms that contained ≤200 lactating cows and had swine located on the farm had a higher prevalence of methicillin-resistant NASM than smaller farms that did not contain swine.

Consumer Preferences and Attitudes towards Antibiotic Use in Food Animals

Antimicrobial resistance (AMR) is one of the major challenges faced by society, with the real threat of the failure of many medical procedures. Antibiotics are also used in livestock production and provide a potential pathway to increasing AMR. The central challenge involves ensuring animal health and welfare while securing the long-term effectiveness of antibiotics. This paper reports the results of a survey of 5693 respondents from the customer panels of four major UK supermarkets regarding preferences and attitudes towards antibiotic use in food animals, and their perspectives on how the balance between animal welfare and human benefit can be achieved. The results of these surveys are consistent with those from other countries that found that consumers generally have limited knowledge about antibiotic use in agriculture and AMR, with around 50% responding "don't know" to many questions. There was agreement about the benefits of antibiotics outweighing harm, with 40% agreeing that, overall, the use of antibiotics to treat disease in farm animals delivers more benefit than harm. However, 44% neither agreed nor disagreed, indicating a high level of uncertainty and a situation that is potentially unstable. The seriousness of the AMR challenge is such that continued action for the more discriminating use of antibiotics must continue.

Graduate Student Literature Review: Reducing mortality and morbidity in transported preweaning dairy calves: Colostrum management and pretransport nonsteroidal anti-inflammatory drug administration

Currently, mortality and morbidity rates for preweaning calves in the US dairy industry are high, with the major cause being digestive disorders and respiratory diseases. One of the most important management practices that can reduce calf mortalities and morbidities is the feeding of colostrum, provided its quantity, quality, and cleanliness, and timing of feeding are according to recommendations. However, other management practices similar to transportation, can also compromise calf health and production performance. When preweaning calves are transported, stressors similar to physical restraint, commingling, dehydration, bruising, and pain may lead to an inflammatory response and immunosuppression, which has been seen in older cattle, and could increase susceptibility to digestive disorders and respiratory diseases. One strategy that could potentially reduce transport-related negative outcomes is the pretransport administration of nonsteroidal anti-inflammatory drugs, such as meloxicam. This review provides a brief background on preweaning mortality and morbidity, colostrum management, transport-related stress, use of nonsteroidal anti-inflammatory drugs in transported calves, and highlights some of the current knowledge gaps.

A Survey of knowledge, attitude, and practices surrounding antimicrobial use by family dairy farmers to mastitis control

This study determined the family dairy farmers' knowledge, attitudes, and practices regarding the management strategy of mastitis, antibiotic use, and antimicrobial resistance in dairy farms in Türkiye. A total of 455 dairy farmers participated in face-to-face surveys from the villages of Çanakkale in Türkiye. A total of 62 questions that were divided into 5 categories were asked of the participants. Farmers (252/455; 55.4%) noted that they had not heard of any term about the expression of microbial resistance. They believe that antibiotic residues (156/455; 34,3%) do not pass into the soil and environment with animal wastes, and diseases such as mastitis (173/455; 38%) cannot be cured without antibiotics. Farmers indicated that they used antibiotic therapy in the treatment of udder diseases such as mastitis at a rate of 44.8%. Moreover, most dairy farmers (78.2%) decided to start antibiotic treatment with the decision of the veterinarian. Farmers believe that the barn environment is not as clean as necessary at a rate of 23.5%, and the necessary hygiene conditions are not followed in animal care 23.4% as the cause of mastitis. They highlighted that they detected mastitis from the redness or swelling of the udder at a rate of 38.2%. 55.8% of the farmers participating in the study had undergone analysis for the diagnosis of mastitis disease. On the other hand, 57.4% of farmers tried natural products such as olive oil, soft soap, vinegar, clay soil, honey, soapy, and yogurt, instead of antibiotics treatment for mastitis diseases. They have been relying mostly on veterinarian recommendations for AU. The use of culture and susceptibility test results for antimicrobial selection should be expanded among veterinarians. All stakeholders should be included in periodic training programs on topics such as AU, AR, preventive treatments for mastitis, vaccination, public health, and environmental health. Surveillance systems are needed to monitor AU and AR in animals, as in human medicine.

In vitro effects of cinnamon, oregano, and thyme essential oils against Escherichia coli and Trueperella pyogenes isolated from dairy cows with clinical endometritis

Clinical endometritis causes serious economic losses in dairy farms, mainly due to its negative health impact on fertility and milk production, as well as the additional costs of medicines used to treat the affected animals. The therapy for uterine diseases is principally performed with antibiotic treatment; however, its indiscriminate use in dairy herds can favor the increase in the resistance of pathogenic bacteria, leading to treatment failures. In this regard, the use of unconventional treatment may be a good option to reduce the use of antimicrobials in milk production. The objective of the present study was to evaluate the antibacterial activity of cinnamon, oregano, and thyme essential oils, and their combinations, against bovine uterine pathogens. The antibacterial activities of these essential oils were evaluated by the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), and Fractional Inhibitory Concentration (FIC) indices against Escherichia coli and Trueperella pyogenes, which were isolated from dairy cows with clinical endometritis. Among the essential oils evaluated, the lowest MIC and MBC values observed were obtained with cinnamon essential oil alone. The association among essential oils showed different kinds of interactions, and in some situations, antagonism was observed. This study demonstrated a promising antimicrobial activity of cinnamon's essential oil, indicating that it has excellent potential to be explored as a possible alternative in the treatment of clinical endometritis in dairy cows.

Realities, Challenges and Benefits of Antimicrobial Stewardship in Dairy Practice in the United States

The use of antimicrobials for the treatment of food-producing animals is increasingly scrutinized and regulated based on concerns about maintaining the efficacy of antimicrobials used to treat important human diseases. Consumers are skeptical about the use of antibiotics in dairy cows, while dairy producers and veterinarians demonstrate ambivalence about maintaining animal welfare with reduced antimicrobial usage. Antimicrobial stewardship refers to proactive actions taken to preserve the efficacy of antimicrobials and emphasizes the prevention of bacterial diseases and use of evidence-based treatment protocols. The ability to broadly implement antimicrobial stewardship in the dairy industry is based on the recognition of appropriate antimicrobial usage as well as an understanding of the benefits of participating in such programs. The most common reason for the use of antimicrobials on dairy farms is the intramammary treatment of cows affected with clinical mastitis or at dry off. Based on national sales data, intramammary treatments comprise < 1% of overall antimicrobial use for food-producing animals, but a large proportion of that usage is a third-generation cephalosporin, which is classified as a highest-priority, critically important antimicrobial. Opportunities exist to improve the use of antimicrobials in dairy practice. While there are barriers to the increased adoption of antimicrobial stewardship principles, the structured nature of dairy practice and existing emphasis on disease prevention provides an opportunity to easily integrate principles of antimicrobial stewardship into daily veterinary practice. The purpose of this paper is to define elements of antimicrobial stewardship in dairy practice and discuss the challenges and potential benefits associated with these concepts.

Invited review: Selective use of antimicrobials in dairy cattle at drying-off

Administering intramammary antimicrobials to all mammary quarters of dairy cows at drying-off [i.e., blanket dry cow therapy (BDCT)] has been a mainstay of mastitis prevention and control. However, as udder health has considerably improved over recent decades with reductions in intramammary infection prevalence at drying-off and the introduction of teat sealants, BDCT may no longer be necessary on all dairy farms, thereby supporting antimicrobial stewardship efforts. This narrative review summarizes available literature regarding current dry cow therapy practices and associated impacts of selective dry cow therapy (SDCT) on udder health, milk production, economics, antimicrobial use, and antimicrobial resistance. Various methods to identify infections at drying-off that could benefit from antimicrobial treatment are described for selecting cows or mammary quarters for treatment, including utilizing somatic cell count thresholds, pathogen identification, previous clinical mastitis history, or a combination of criteria. Selection methods may be enacted at the herd, cow, or quarter levels. Producers' and veterinarians' motivations for antimicrobial use are discussed. Based on review findings, SDCT can be adopted without negative consequences for udder health and milk production, and concurrent teat sealant use is recommended, especially in udder quarters receiving no intramammary antimicrobials. Furthermore, herd selection should be considered for SDCT implementation in addition to cow or quarter selection, as BDCT may still be temporarily necessary in some herds for optimal mastitis control. Costs and benefits of SDCT vary among herds, whereas impacts on antimicrobial resistance remain unclear. In summary, SDCT is a viable management option for maintaining udder health and milk production while improving antimicrobial stewardship in the dairy industry.

Astragalus membranaceus Additive Improves Serum Biochemical Parameters and Reproductive Performance in Postpartum Dairy Cows

The purpose of the study was to assess the recovery, immune function, and breeding efficiency of postpartum dairy cows fed Astragalus membranaceus (AM) as a feed additive. The experiment used a completely randomized design. Cows were randomly assigned to two groups: (1) Control group fed total mixed ration (TMR; CON group, n = 15); (2) AM group fed TMR and AM (AM group, n = 15). The AM group was fed 675 g/day. The experimental results showed that compared with the CON group. The breeding interval of the AM group of dairy cows had a tendency to shorten (0.05 < p < 0.1). Plasma viscosity (PV), Plasma fibrinogen (FIB), the red cell aggregation index (TRCAI), Calcitonin (CT), Immunoglobulin M (IgM), and Luteinizing hormone (LH) results of AM group showed a time-treatment interaction (p < 0.05). Furthermore, the result of the study revealed that feeding AM as feed additives to dairy cows during the postpartum period had positive effects on wound recovery, immune function, endocrine regulation, and breeding efficiency.

Effect of Cistanche deserticola on Rumen Microbiota and Rumen Function in Grazing Sheep

For a long time, veterinary drugs and chemical additives have been widely used in livestock and poultry breeding to improve production performance. However, problems such as drug residues in food are causing serious concerns. The use of functional plants and their extracts to improve production performance is becoming increasingly popular. This study aimed to evaluate the effect of Cistanche deserticola in sheep feed on rumen flora and to analyze the causes to provide a theoretical basis for the future use of Cistanche deserticola as a functional substance to improve sheep production performance. A completely randomized experimental design was adopted using 24 six-month-old sheep males divided into four groups (six animals in each group) which were fed a basic diet composed of alfalfa and tall fescue grass. The C. deserticola feed was provided to sheep at different levels (0, 2, 4, and 6%) as experimental treatments. On the last day (Day 75), ruminal fluid was collected through a rumen tube for evaluating changes in rumen flora. The test results showed that Prevotella_1, Lactobacillus, and Rikenellaceae_RC9_gut_group were the dominant species at the genus level in all samples. Lactobacillus, Rikenellaceae_RC9_gut_group, Ruminococcaceae_NK4A214_group, Butyrivibrio_2, and Christensenellaceae_R-7_group differed significantly in relative abundance among the treatment groups. The polysaccharides in C. deserticola was the major factor influencing the alteration in rumen flora abundance, and had the functions of improving rumen fermentation environment and regulating rumen flora structure, etc. Hence, C. deserticola can be used to regulate rumen fermentation in grazing sheep to improve production efficiency.

Effects of Milk Feeding Strategy and Acidification on Growth Performance, Metabolic Traits, Oxidative Stress, and Health of Holstein Calves

Effects of milk feeding strategy and acidification on calf growth, metabolic traits, oxidative stress, and health were evaluated in the first 78 days of life. Holstein calves (N = 48; 12 calves/treatment) were assigned to 1 of the 4 treatments in a 2 × 2 factorial arrangement of milk feeding strategy [6 L/d (MOD) or 12 L/d (HIGH) of milk] and acidification [non-acidified milk (NAM) or acidified milk (ACM)] on day 2. Calves were bucket-fed milk as follows: 6 L/d from days 2 to 49 for MOD and 6 L/d from days 2 to 49, 12 L/d from days 7 to 42, and 8 L/d from days 43 to 49 for HIGH calves. All calves were then fed 4 L/d from days 50 to 56. Starter and water were available ad libitum, while hay was fed at 5% of starter from day 64. Calves were weighed, measured, and blood (except days 14, 42 and 56) sampled on days 2, 14, 28, 42, 49, 56, 63 and 78. Data were analyzed using Mixed PROC of SAS with time as repeated measurements. Fecal scores, checked daily, were examined by the logistic regression using a binomial distribution in GLIMMIX procedure. There were no three-way interactions observed for all the parameters. We detected a milk feeding strategy × time interaction for starter intake, body weight, ADG, ADG/ME, FE, structural measurements, and glucose. Although, overall (558.0 vs. 638.6 g/d), HIGH calves tended to consume less starter compared to MOD, significant differences were only observed in week 8. The HIGH calves had greater ADG during days 2–14 (1.12 vs. 0.75 kg/d) and tended to have greater ADG on days 15–28 (0.79 vs. 0.55) and 29–42 (0.86 vs. 0.60) and lower on days 57–63 (0.11 vs. 0.38) compared to MOD calves. The HIGH calves had greater BW from days 28 to 78 compared to MOD, while NAM were bigger compared to ACM calves from days 49 to 78. The HIGH calves had lower overall feed and metabolizable energy efficiencies compared to MOD. Except for BW and heart girth, no milk acidification × time interaction was observed for starter intake, ADG, FE, or ADG/ME. Blood glucose in calves fed NAM-HIGH and ACM-HIGH were greater compared to those fed moderate milk volumes on day 28 only. Albeit, feeding strategy had no effect, calves fed ACM had lower likelihood of experiencing diarrhea (odds ratio = 1.32; 95% confidence interval: 1.018–1.698) compared to those fed NAM. Overall milk feeding strategy had no effect on growth, while milk acidification reduced growth in calves, despite lowering the likelihood of experiencing diarrhea.

Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR): An On-Farm Surveillance System

Canada has implemented on-farm antimicrobial resistance (AMR) surveillance systems for food-producing animals under the Canadian Integrated Program for Antimicrobial Resistance (CIPARS); however, dairy cattle have not been included in that program yet. The objective of this manuscript was to describe the development and implementation of the Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR). An Expert Panel (EP) of researchers was created to lead the development of the dairy surveillance system. The EP initiated a draft document outlining the essential elements of the surveillance framework. This document was then circulated to a Steering Committee (SC), which provided recommendations used by the EP to finalize the framework. CaDNetASR has the following components: (1) a herd-level antimicrobial use quantification system; (2) annually administered risk factor questionnaires; and (3) methods for herd-level detection of AMR in three sentinel enteric pathogens (generic Escherichia coli, Campylobacter spp., and Salmonella spp.) recovered from pooled fecal samples collected from calves, heifers, cows, and the manure pit. A total of 144 dairy farms were recruited in five Canadian provinces (British-Columbia, Alberta, Ontario, Québec, and Nova-Scotia), with the help of local herd veterinarians and regional field workers, and in September 2019, the surveillance system was launched. 97.1 and 94.4% of samples were positive for E. coli, 63.8, and 49.1% of samples were positive for Campylobacter spp., and 5.0 and 7.7% of samples were positive for Salmonella spp., in 2019 and 2020, respectively. E. coli was equally distributed among all sample types. However, it was more likely that Campylobacter spp. were recovered from heifer and cow samples. On the other hand, it was more common to isolate Salmonella spp. from the manure pit compared to samples from calves, heifers, or cows. CaDNetASR will continue sampling until 2022 after which time this system will be integrated into CIPARS. CaDNetASR will provide online access to farmers and veterinarians interested in visualizing benchmarking metrics regarding AMU practices and their relationship to AMR and animal health in dairy herds. This will provide an opportunity to enhance antimicrobial stewardship practices on dairy farms in Canada.

Consumer perceptions of antimicrobial use in animal husbandry: A scoping review

Antimicrobial use in animal agriculture is often perceived to play a role in the emerging threat of antimicrobial resistance. Increased consumer awareness of this issue places pressure on animal husbandry to adopt policies to reduce or eliminate antimicrobial use. We use a scoping review methodology to assess research on consumer perceptions of antimicrobial drugs in meat products in the United States, Canada, or the European Union. Evaluating peer-reviewed and grey literature, we included studies for assessment if they met these topical and geographic requirements, involved primary data collection, and were originally published in English. Our screening process identified 124 relevant studies. Three reviewers jointly developed a data charting form and independently charted the contents of the studies. Of the 105 studies that measured consumer concern, 77.1% found that consumers were concerned about antimicrobial use in meat production. A minority of studies (29.8% of all studies) queried why consumers hold these views. These studies found human health and animal welfare were the main reasons for concern. Antimicrobial resistance rarely registered as an explicit reason for concern. A smaller group of studies (23.3%) measured the personal characteristics of consumers that expressed concern about antimicrobials. Among these studies, the most common and consistent features of these consumers were gender, age, income, and education. Regarding the methodology used, studies tended to be dominated by either willingness-to-pay studies or Likert scale questionnaires (73.64% of all studies). We recommend consideration of qualitative research into consumer views on this topic, which may provide new perspectives that explain consumer decision-making and mentality that are lacking in the literature. In addition, more research into the difference between what consumers claim is of concern and their ultimate purchasing decisions would be especially valuable.

New York State dairy veterinarians' perceptions of antibiotic use and resistance: A qualitative interview study

Antimicrobial resistance (AMR) limits the ability to prevent and treat infection, making AMR one of the foremost threats to human and animal health. Animal agriculture's large use of antibiotics in food animals is an important factor in AMR. As such, policies to reduce antibiotic use and combat AMR in animal agriculture in the United States (US) have been in place or are developed. One key to the success of these policies in the US is understanding how a major stakeholder - veterinarians treating dairy cattle - perceive the scale of antibiotic use, the threat of AMR and the utility of antibiotic use policies. We interviewed 9 dairy veterinarians in New York State and conducted an iterative thematic analysis of their responses, through which five themes were identified: 1. veterinarians' views of the frequency and reasons for antibiotic misuse, 2. their ideas on reducing antibiotic use, 3. perceptions of AMR within the dairy industry, 4. view of organic farming and how it relates to animal welfare, and 5. the impact of consumers' beliefs on the dairy industry. Participants viewed antibiotic overuse as largely due to farmers' concern for the welfare of their cattle and desire to treat ailments swiftly. Interviewees believed that it was possible to reduce antibiotic use through regulation, such as the Veterinary Feed Directive and improved herd management activities, such as better colostrum management, culture-based mastitis treatment, and improved housing conditions. They did not view the dairy industry as a significant contributor to AMR, particularly when compared to the human medical industry. Interviewees also offered their (unsolicited) opinion on organic dairy farming in the US and expressed frustration with the limited treatment options available in organic dairy farming and how this dynamic may potentially compromise animal welfare. Finally, they commented on the impact of consumers' beliefs on the dairy industry, expressing frustration with how misinformation about the dairy industry has led to consumer driven changes. As consumer beliefs have an impact on the dairy industry, this influence could be leveraged to further decrease antibiotic use. These findings can help guide future efforts in veterinarian-client communication and the development and implementation of effective policies in New York State. These results also highlight the need for more quantitative research on antibiotic use in the dairy industry, as without this data it will be difficult to ascertain the true impact of policy interventions.

How does public perception of antibiotic use on dairy farms contribute to self-reported purchasing of organic?

The United States regulates the use of antibiotics in agricultural settings to address the global antibiotic resistance problem. Conventional dairy cows treated with antibiotics are kept in the herd and after the withholding period milk is harvested. On organic farms, the US organic standard on antibiotic use requires sick dairy cows to be treated, but treated cows must be removed from the herd and their milk can never again be sold as certified organic. This study investigated the US public's perceptions of the organic dairy farming, antibiotic use on dairy farms, and whether these perceptions affect consumer's self‐reported purchasing behavior for organic. We used a nationally representative phone‐based survey of 1000 US adults and characterized participants’ self‐reported (i) knowledge of the legality of antibiotic use on dairy farms (conventional and organic) and (ii) frequency of purchasing organic instead of conventional dairy products, as well as several demographic and other variables. The results indicated that participants’ knowledge about antibiotic use practices in dairy farming have no effect on their self‐reported purchasing behavior for organic or conventional dairy products. However, respondents who were familiar with the regulations of antibiotic use on dairy farms were more likely to oppose the US organic standard on antibiotic use in dairy farming and thought that past antibiotic use should not permanently remove a cow's organic status. These findings contribute to understanding of public perceptions that shape the US dairy organic market.

Practical Application

Income, employment, health and political values, but not consumers’ knowledge about antibiotic use in dairy farming, affect self‐reported purchasing behavior for organic dairy products. However, consumers who are familiar with the regulations of antibiotic use on US dairy farms disagree with the US organic standard on antibiotic use mandating loss of organic status for any cattle treated with antibiotics. These findings may be useful to organic markets.

Application of enzyme probiotic drug developed based on microorganisms of the rumen of reindeer (Rangifer tarandus) in feeding cows

In the current conditions of intense technologies of milk production, the feeding of dairy cows is aimed at providing fast rates of growth and maximum productivity over a short period. However, such systems of diets often have negative effects on the health of the animals as a result of metabolism malfunctioning. The present study was conducted to assess the influence of the enzyme probiotic preparation Rumit, developed based on cellulolytic bacteria isolated from the rumen of reindeer, on dairy activity, food intake, density of ciliate fauna of the rumen, feeding activity, and also metabolic profile and the level of natural resistance of newly-calved heifers. To conduct the experiment, we composed two groups (control and experimental) of first-calf heifers with 12 individuals in their first 100 days of lactation after calving. The first-calf heifers of the experimental group, in addition to the main diet, received the preparation in the amount of 50 g per individual daily in the lunch time feeding for 90 days. Inclusion of the probiotic increased the dairy productivity, particularly a 3.1 kg increase in the average yield of daily 4%-fat milk, 9.6 kg in the butterfat output, and 7.7 kg in that of dairy protein. With increase in dairy productivity, a 0.09 EFU (energy fodder units, equals 10 MJ) decrease was observed in energy expenditure for 1 kg of milk. Intake of the probiotic led to increase in the index of nutritional activity by 0.03 units and increase in the density of ciliates by 155, 900 individuals/mL. Use of the biopreparation had a positive effect on the metabolic processes in the organism of heifers. The animals of the experimental group were observed to have an increase in the content of the total protein in the blood, 12.5% decrease in the urea, and glucose concentration reached the normative values. In the first-calf heifers that had received the food supplement in addition to their diet, the physiological parameters of health normalized and the protective abilities of the organism activated, the pulse and respiration frequencies increased (by 3.8% and 6.6%), the phagocytic index grew by 30.2%, and the absorptive ability of neutrophils increased by 40%. Thus, enzyme probiotic preparation Rumit confirmed its efficiency when fed to newly-calved heifers.