Background Recruitment and retention of farm veterinarians have been the focus of recent research. Previous work suggests that a feeling of ‘fit’ is important for students to consider a farm career. The aim of this study was to identify whether students feel that they ‘fit’ in farm practice and reasons for their answer. Methods An online survey was distributed to students at all British and Irish veterinary schools. A mixed methods approach was considered, with thematic analysis on free text answers and regression analysis on demographic variables. Results Thematic analysis identified six themes: career opportunities, nature of farm veterinary work, relationships and interactions, individual experiences, expectations and perceptions, and no perceived barriers. Females, marginalised ethnic groups and those from an urban/suburban background were all identified as having significantly ( p < 0.05) less agreement with the statement ‘I feel able to pursue a career in farm practice’. Limitations Survey limitations include those with a clear bias being likely to respond. However, alignment of the qualitative and quantitative results increased confidence in the findings of this mixed methods approach. Conclusion This study confirms that biases that exist within wider society do have an influence on veterinary undergraduates' intentions to pursue a farm animal career. This is vital to consider both at a university level and when considering students' experiences on placements. Urgent action is required to improve inclusivity in the farm animal veterinary sector.

BACKGROUND Within the production animal sector, it has long been forecast that demand for veterinary services could outstrip supply. This study aims to identify factors influencing veterinary undergraduates' attitudes towards a career in farm animal veterinary practice and how those factors may be influenced by their experiences during their time as an undergraduate. METHODS An online survey was distributed to all vet schools in the UK and Ireland. Thematic analysis and descriptive data analysis were performed on the 1146 responses received. RESULTS Seven themes were identified: relationships, preferences and interest, fit, direct experience, fear, ethics and values and lifestyle. When considering first job choice, extra mural studies (EMS) and personal interest (60% and 75% of respondents respectively) were very influential. Factors that appeal or put off respondents from a career in farm animal varied dependent on anticipated first job (p < 0.001), but working hours and out of hours were consistently identified as barriers. CONCLUSION The results highlight the importance of EMS being more transparent about the profession and using the opportunity to discuss undergraduate concerns regarding farm animal practice.

Abstract Background Heart girth tapes (HGTs) are often used as an alternative to weight scales for calves. This study investigated the accuracy of HGT in estimating bodyweight and daily liveweight gain (DWLG) of pre‐weaned calves, and the impact of inter‐observer variation. Method In Study 1, 119 calves were weighed using HGT and electronic scales on multiple occasions. Mixed‐effects models for both bodyweight and DLWG were used to determine the accuracy of HGT compared to the electronic scales. Simulation data were used to further analyse the accuracy of DLWG estimation including for factors such as the effect of group size on group DLWG estimates. In Study 2, 10 observers weighed 20 pre‐weaned calves, using HGT and electronic scales. Mixed‐effect model was used to investigate the impact of different observers on the accuracy of HGT on measuring bodyweights. Results Mixed‐effects model results suggest HGT provides a relatively accurate estimation of weight (MAE: 2.66 kg) and relatively inaccurate estimation of DLWG (MAE 0.10 kg/d). Simulated data identified associations between time between weight dates and error in DLWG estimation, with MAE of individual DLWG estimation decreasing from 0.43 kg/d when 14 days apart to 0.08 kg/d when 70 days apart. Increased calf numbers reduced error rates of group DLWG estimation, with <0.05 kg/d error achieved in >90% of simulations when 12 calves were weighed 70 days apart. Conclusions HGTs are relatively accurate at estimating individual bodyweights but are unreliable methods for measuring DLWG in individual calves, particularly weighed within a short‐time period. Estimates at group level however are relatively accurate, providing there is a suitable period of time between weigh dates and an appropriate number of calves per group.

Feeding calves milk alongside an oral electrolyte solution might help them recover from diarrhoea faster, compared with feeding an oral electrolyte solution alone. However, the evidence supporting this is weak. One of your dairy clients calls you as he is worried about a few calves starting to scour in the preweaned calf shed. After you have discussed the possible causes of diarrhoea and preventive measures, the farmer asks you whether he should keep feeding milk to these calves or if oral rehydration fluids (electrolytes) alone will be sufficient. He is worried the milk will ‘feed the scour’ and has received conflicting advice. You advise him to keep feeding milk as well as oral rehydration fluids, but you wonder whether there is any evidence that calves fed milk recover faster than calves that are offered oral rehydration fluids alone. In [dairy calves with diarrhoea] does [feeding milk and rehydration fluids compared with rehydration fluids alone] lead to a [faster recovery time]? The search strategy can be viewed at https://bestbetsforvets.org/bet/518, and is also available as a supplement to this article on Vet Record ’s website at https://veterinaryrecord.bmj.com/content/187/9/358 Three hundred and eighty-four papers were found in the Medline search. Three hundred and seventy-one were excluded because they did not answer the question. Ten were excluded because they were review articles, in vitro research or conference proceedings. In total, three relevant papers were obtained. Eight hundred and thirty-six papers were found in the CAB search. Eight hundred and seventeen were excluded because they did not answer the question. Fifteen were excluded because they were review articles, in vitro research or conference proceedings. One was excluded because it was not written in English. In total, three relevant papers were obtained. Overall, three relevant papers were identified. Search last performed: 29 September 2020 As well as the three papers included in the final analysis, two other papers were considered in more detail.1, 2 However, these were discounted as the treatment groups used did not fit the question being investigated in this evidence analysis. In one study, oral electrolytes in water were compared with a milk replacer control.1 In the other, the calves had no access to water and were either given an oral electrolyte solution or a low dose of whey powder.2 Paper 1: The effects of feeding milk to diarrhoeic calves supplemented with oral electrolytes3 Patient group: Diarrhoea was induced in 19 healthy Holstein bull calves, aged between five and eight days, by feeding them a faecal inoculum. The calves were then divided into three groups, and, for four days, they received either electrolytes alone, electrolytes alongside their full milk ration or electrolytes alongside half of their normal milk ration. All calves then received their full milk ration for six days before being euthanased. Study type: Randomised controlled trial. Outcomes: The calves were weighed at the beginning of the experiment and again on days 2, 4, 6, 8 and 10. Each calf was weighed four times on each of these days, and their mean daily weight was calculated. The consistency and estimated volume of the calves’ faeces were scored daily, with clinical diarrhoea being defined as a score above 2.5. A clinical examination was also performed twice daily, and the calves’ demeanour and hydration levels were assessed. At the end of the experiment, a postmortem examination was carried out to determine whether there was any histopathological evidence of concurrent disease. Key results: At the end of the trial, all of the calves were still mildly depressed, diarrhoeic (mean faecal score=3.3) and dehydrated. The progression of the mean daily faecal score over time was similar for all three groups (P>0.1). Study weaknesses: This study involved a very small number of calves, so it is likely to be underpowered. Also, the calves that were included did not have naturally occurring diarrhoea – diarrhoea was instead induced by feeding the calves a faecal inoculum containing multiple pathogens. As such, the results may not accurately reflect what would be seen under field conditions. Limited information is given on the blinding of the assessors, and no information is given on how the calves were assigned to the treatment groups. Other methodological details were also missing, making the study difficult to repeat. Basic data were not adequately described, and the limitations of the study were not discussed. For example, no side effects were discussed. However, four calves were treated with antimicrobials and had to be euthanased before the end of the experiment, five calves received antimicrobials and had evidence of concurrent disease at postmortem examination, and four calves had evidence of concurrent disease but were not treated with antimicrobials. Minimal information is available on the calves that were euthanased and those that received antimicrobials, and we had difficulty following the exclusions from the study to determine whether these were separate from the 19 sample calves. Paper 2: Whole milk and oral rehydration solution for calves with diarrhoea of spontaneous origin4 Patient group: A total of 42 diarrhoeic dairy calves, of mixed sex and breed and with an average age of 10 days, were enrolled in the study. The calves were divided into three treatment groups and received either a partial milk ration plus electrolytes, a full milk ration plus electrolytes or electrolytes only for seven days. Study type: Cohort study. Outcomes: The bodyweight and rectal temperature of the calves were measured at the start of the study and again on days 3 and 7. At the same time points, rectal swabs and blood samples were taken. The swabs were cultured to determine the bacterial species present, and the blood samples were analysed to measure packed cell volume and the serum concentrations of electrolytes and glucose. In addition, faecal consistency was determined at each feeding. Key results: All calves appeared to have recovered fully after seven days of treatment. Overall, there were no significant differences between the three treatment groups for any of the parameters measured. Maintaining calves on milk in addition to an oral electrolyte solution did not appear to worsen or prolong the incidence of diarrhoea when compared with maintaining calves on an oral electrolyte solution alone. Study weaknesses: The sample size was small, and no power calculation was performed. As such, the study is likely underpowered. The method used to allocate the calves to the treatment groups is unclear, and group sizes were not stated. It is not possible to determine if the groups were comparable before treatment, and, as only aggregated results were given, it is somewhat difficult to interpret the findings. The measurements carried out within the study were not clear, no information is provided on the blinding of the assessors and the methods are not described in sufficient detail to enable others to repeat the study. There was also no discussion regarding the possible implications that the study's use of non-saleable milk from cows treated for mastitis might have had on the results. When interpreting the results, P values above the authors’ chosen cut-off value for statistical significance were sometimes discussed as having ‘tendencies’ towards statistical significance. However, this is somewhat misleading. The authors also hint at demonstrating equivalence, but if the aim was to demonstrate equivalence then a non-inferiority trial should have been designed and executed. Patient group: A total of 360 diarrhoeic Holstein-Friesian calves from a single dairy unit were included in the study. The calves were divided into two groups and received either a hypertonic alkalinising oral rehydration therapy containing lecithin-coated citrus fibres (group D) or an isotonic non-alkalinising oral rehydration therapy (group R). Treatment continued until diarrhoea was no longer present. Study type: Randomised controlled trial. Outcomes: Consumption of the electrolyte solution was evaluated at each feeding, with the amount consumed within 10 minutes being estimated. Calves unable to consume their allotted volume within 10 minutes received the remainder of the fluid by oroesophageal intubation. The calves’ were weighed each day, and their hydration status and faecal consistency were scored twice daily. The number of days of treatment required to resolve the diarrhoea was recorded, and any treatment failures (ie, calves with persistent diarrhoea after eight days of treatment) were noted. Any calves that died before weaning were also recorded. Key results: There were no significant differences between the groups in relation to treatment failure or mortality. However, the calves in group D achieved a ‘normal’ faecal score sooner (median days of treatment=7) than the calves in group R (median days of treatment=8) (P=0.0085). Study weaknesses: Although the number of calves included in the study was reasonably large, no power calculation was carried out to support the sample size chosen. The methods are not described in sufficient detail for the trial to be repeated. Furthermore, there were differences in mean serum total protein between the two groups, indicating that more calves in group D received adequate passive transfer than in group R. As such, the two groups may not have been comparable before treatment. All calves were given antibiotics and activated charcoal, which was discontinued when the stool returned to normal or the calf was designated as a treatment failure. This complicates the interpretation of the findings, as it may have masked potential differences between the two treatments. Calves that were designated as treatment failures were removed from the study, as were those that developed concurrent disease. However, we found it difficult to identify how the calves included in the study related to the number of calves that were eligible for inclusion. There appeared to be some calves that were not accounted for. Although two of the papers appraised are more than 25 years old, they were still deemed to be relevant. However, both of these studies3, 4 are likely to be underpowered, which makes it difficult to draw definitive conclusions. Furthermore, an inoculum of pathogens was given to calves in one of these studies3 rather than calves being exposed to pathogens via other animals and the environment. Such experimentally induced diarrhoea may not be directly comparable with naturally occurring diarrhoea. The types of oral electrolyte solution administered, the duration of therapy and the length of time for which milk was withheld were different between the three studies, making them difficult to compare directly. Two of the studies4, 5 also orogastrically tube-fed any of the allocated solutions (milk or oral electrolyte solutions) if they were not drunk within allotted time periods. While orogastric tube feeding is common practice in some commercial farm settings, this is not entirely reflective of what is usually done. There were many other types of literature, particularly expert opinion, that were excluded during the search. In this literature, the two older studies3, 4 were often cited as supporting evidence for continued feeding of milk when treating diarrhoeic calves with oral electrolyte solutions. This could be because of outcomes reported in these papers that were not covered as part of this evidence evaluation (eg, weight gain). There is currently discussion surrounding the osmalality of milk replacer and the effect that oral electrolyte solution has on this, compared with adding additional electrolyte feeds separately. However, this falls outside of the scope of this evidence evaluation. The 'Evaluating The Evidence' section of Vet Record aims to answer specific clinical questions using a systematic approach to identify and succinctly summarise the relevant evidence from the scientific literature. The shortcomings of this evidence are also taken into account, thereby enabling vets to incorporate the best available evidence from the literature when making clinical decisions. Please contact us at vet.research@bmj.com if you have an article you would like us to consider for publication in this section. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

More than 12 years ago, Le Blanc et al (2006) stated that an everbetter understanding of epidemiology and pathophysiology will not in itself reduce the incidence of disease. The ability to translate emerging knowledge into on-farm application and actual prevention of problems requires understanding of the farm as an integrated system, a major component of which is educating and motivating humans to implement well-designed practices. When aiming to improve biosecurity on farm it is important to consider this ‘human’ part of the equation, i.e. the role of the veterinary surgeon and their relationship with the farmer, and several studies have recently provided insights, which are important to consider and guide the direction veterinary surgeons can take to improve biosecurity on farm.