Lameness represents a major welfare and health problem for the dairy industry across all farming systems. Visual mobility scoring, although very useful, is labour-intensive and physically demanding, especially in large dairies, often leading to inconsistencies and inadequate uptake of the practice. Technological and computational advancements of artificial intelligence (AI) have led to the development of numerous automated solutions for livestock monitoring. The objective of this study was to review the automated systems using AI algorithms for lameness detection developed to-date. These systems rely on gait analysis using accelerometers, weighing platforms, acoustic analysis, radar sensors and computer vision technology. The lameness features of interest, the AI techniques used to process the data as well as the ground truth of lameness selected in each case are described. Measures of accuracy regarding correct classification of cows as lame or non-lame varied with most systems being able to classify cows with adequate reliability. Most studies used visual mobility scoring as the ground truth for comparison with only a few studies using the presence of specific foot pathologies. Given the capabilities of AI, and the benefits of early treatment of lameness, longitudinal studies to identify gait abnormalities using automated scores related to the early developmental stages of different foot pathologies are required. Farm-specific optimal thresholds for early intervention should then be identified to ameliorate cow health and welfare but also minimise unnecessary inspections.

Monitoring body condition score (BCS) is a useful management tool to estimate the energy reserves of an individual cow or a group of cows. The aim of this study was to develop and evaluate the performance of a fully automated 2 -dimensional imaging system using a machine learning algorithm to generate real-time BCS for dairy cows. Two separate datasets were used for training and testing. The training dataset included 34,150 manual BCS (MAN_BCS) assigned by 5 experienced veterinarians during 35 visits at 7 dairy farms. Ordinal regression methods and deep learning architecture were used when developing the algorithm. Subsequently, the testing dataset was used to evaluate the developed BCS prediction algorithm on 4 of the participating farms. An experienced human assessor (HA1) visited these farms and performed 8 whole -milking -herd BCS sessions. Each farm was visited twice, allowing for 30 d (+/- 2 d) to pass between visits. The MAN_BCS assigned by HA1 were considered the ground truth data. At the end of the validation study, MAN_BCS were merged with the stored automated BCS (AI_BCS), resulting in a testing dataset of 9,657 single BCS. A total of 3,817 cows in the testing dataset were scored twice 30 d (+/- 2 d) apart, and the change in their BCS (ABCS) was calculated. A subset of cows at one farm were scored twice on consecutive days to evaluate the within -observer agreement of both the human assessor and the system. The manual BCS of 2 more assessors (HA2 and HA3) were used to assess the interobserver agreement between humans. Finally, we also collected ultrasound measurements of backfat thickness (BFT) from 111 randomly selected cows with available MAN_BCS and AI_BCS. Using the testing dataset, intra- and interobserver agreement for single BCS and ABCS were estimated by calculating the simple percentage agreement (PA) at 3 error levels and the weighted kappa (K w ) for the exact agreement. A Bland -Altman plot was constructed to visualize the systematic and proportional bias. The association between MAN_BCS and AI_BCS and the BFT was assessed with Passing-Bablok regressions. The system had an almost perfect repeatability with a K w of 0.99. The agreement between MAN_BCS and AI_BCS was substantial, with an overall K w of 0.69. The overall PA at the exact, +/- 0.25 -unit, and +/- 0.50unit BCS error range between MAN_BCS and AI_BCS was 44.4%, 84.6%, and 94.8%, respectively, and greater than the PA obtained between HA1 and HA3. The Bland -Altman plot revealed a minimal systematic bias of -0.09 with a proportional bias at the extreme scores. Furthermore, despite the low K w of 0.20, the overall PA at the exact and +/- 0.25 -unit of BCS error range between MAN_BCS and AI_BCS regarding the ABCS was 45.7 and 88.2%, respectively. A strong linear relationship was observed between BFT and AI_BCS (rho = 0.75), although weaker than that between BFT and MAN_BCS (rho = 0.91). The system was able to predict single BCS and ABCS with satisfactory accuracy, comparable to that obtained between trained human scorers.

The objectives of this observational cohort study were to assess the effect of body condition score change, back fat depth change, and muscle diameter change on the time to commencement of luteal activity and first estrus in commercial pedigree Holstein cows. A total of 140 of 200 commercial pedigree Holstein cows were enrolled in one dairy herd in Somerset, UK, over 52 wk in 2021 to 2022. The herd used 4 automatic milking machines with in-line progesterone measurement capability to determine commencement of luteal activity and time to first estrus. Cows were followed until at least 60 d postpartum, and milk progesterone was measured daily starting from 10 DIM. Body condition scoring and ultrasound measurements of back fat depth and longissimus dorsi muscle diameter were performed on cows twice, within 7 d of both calving and 60 DIM. Other explanatory variables assessed included parity, 60-d and 305-d milk yield, and subclinical ketosis (β-hydroxybutryate ≥1.2 mmol/L). Occurrence of clinical disease <60 DIM was forced into all models as a binary variable. Data were analyzed using multivariable Cox proportionate survival analyses. Muscle loss was associated with commencement of luteal activity and time to first estrus. A reduction in muscle diameter by 1.5 to 5 mm was associated with the shortest time to the start of luteal activity and first estrus. A reduction in muscle diameter >8 mm was associated with the longest times to luteal activity and first estrus. In addition to being affected by muscle loss, commencement of luteal activity was delayed by subclinical ketosis, clinical disease, and failure to gain body condition to 60 DIM. Cows that had a BCS loss of 0.25 or more between calving and 60 DIM were at least 52 ± 22% less likely to have commenced luteal activity compared with those that gained BCS. Interestingly, cows that had no change in body condition score commenced luteal activity later than those that gained body condition score. Muscle loss was associated with time to first estrus irrespective of clinical disease status. Cows that lost >8 mm of muscle diameter showed estrus behavior later than cows that lost 1.5 to 5 mm. In conclusion, our findings indicate that extensive muscle loss postpartum was associated with a delayed start to luteal activity and first estrus, irrespective of body condition change, clinical disease, and subclinical ketosis. Marginal muscle loss and a gain in body condition, however, were associated with an earlier start to luteal activity and first estrus.

IntroductionLameness is a major welfare challenge facing the dairy industry worldwide. Monitoring herd lameness prevalence, and early detection and therapeutic intervention are important aspects of lameness control in dairy herds. The objective of this study was to evaluate the performance of a commercially available video surveillance system for automatic detection of dairy cattle lameness (CattleEye Ltd).MethodsThis was achieved by first measuring mobility score agreement between CattleEye and two veterinarians (Assessor 1 and Assessor 2), and second, by investigating the ability of the CattleEye system to detect cows with potentially painful foot lesions. We analysed 6,040 mobility scores collected from three dairy farms. Inter-rate agreement was estimated by calculating percentage agreement (PA), Cohen’s kappa (κ) and Gwet’s agreement coefficient (AC). Data regarding the presence of foot lesions were also available for a subset of this dataset. The ability of the system to predict the presence of potentially painful foot lesions was tested against that of Assessor 1 by calculating measures of accuracy, using lesion records during the foot trimming sessions as reference.ResultsIn general, inter-rater agreement between CattleEye and either human assessor was strong and similar to that between the human assessors, with PA and AC being consistently above 80% and 0.80, respectively. Kappa agreement between CattleEye and the human scorers was in line with previous studies (investigating agreement between human assessors) and within the fair to moderate agreement range. The system was more sensitive than Assessor 1 in identifying cows with potentially painful lesions, with 0.52 sensitivity and 0.81 specificity compared to the Assessor’s 0.29 and 0.89 respectively.DiscussionThis pilot study showed that the CattleEye system achieved scores comparable to that of two experienced veterinarians and was more sensitive than a trained veterinarian in detecting painful foot lesions.

BACKGROUND:There is a lack of literature concerning dairy farmers' use of veterinary services and how satisfied they are with them. This study aimed to fill this gap for seasonal calving UK herds, with a focus on fertility, and included farmer perceived barriers to veterinary involvement.METHODS:A cross-sectional questionnaire (convenience sample), with 166 useable responses.RESULTS:Opportunities exist for further veterinary involvement in seasonal herds. Areas vets are least involved in currently are nutrition, breeding and genetics, growth rate monitoring and infrastructure changes. Current veterinary input was rated neutral or poor value by 21% of respondents. Over 90% of farmers want vets to ask questions to elicit their needs. Frequently mentioned barriers were 'lack of veterinary knowledge of our system', 'not enough cost-benefit of veterinary involvement' and 'we get our fertility information elsewhere'. Along with clinical ability and being approachable, 'understanding our system' and being 'proactive' were qualities participants most valued in a vet. After cost, 'pushing sales and interventions' were the least liked.CONCLUSION:Findings highlight the critical importance of clearly demonstrating the full cost-benefit of veterinary services to farmers. The results contain many details concerning farmer perceptions and values that can help veterinary businesses to strengthen existing services and develop new services.

Excessive periparturient fat mobilisation and its association with dairy cattle health and fertility is well documented; however, the role of muscle mobilisation has not been studied extensively. The objectives of this study were to (i) investigate the changes in the thickness of the longissimus dorsi muscle in high producing dairy cows during the periparturient period, (ii) identify factors associated with these changes, and (iii) describe their possible associations with cattle reproductive performance. Data were collected from a total of 500 lactations from 455 cows on three different UK farms. Muscle thickness (MT) (Longissimus dorsi) and back fat thickness (BFT) measurements were collected at three different time-points during the periparturient period using ultrasonography. Body condition score (BCS) was also assessed at the same time-points and blood samples were collected for the measurement of non-esterified fatty acids. Farm fertility records were used and genomically estimated breeding values were also available. Associations between variables were analysed with the use of multivariable linear and logistic regression models; Cox proportional hazard analysis was used for fertility outcomes. Muscle thickness decreased pre- to post-calving on all three farms, though they were notable between farm differences. Those animals with a lower BCS pre-calving had a higher MT loss; significant fat mobilisation occurred between the calving and early lactation period. Muscle thickness changes and fat mobilisation were not associated in this study. An increased time to first service was described for those animals that mobilised more muscle tissue. Our study advances the understanding of periparturient muscle tissue mobilisation in dairy cattle and highlights its potential associations with cattle fertility.

AbstractBackgroundThe study aim was to characterise issues faced by farmers and veterinary surgeons when making end‐of‐life decisions for dairy cattle.MethodsOnline surveys were distributed to British dairy farmers and veterinary surgeons for 20 weeks from November 2020.ResultsThere were 83 responses (37 farmers, 46 veterinary surgeons). Among youngstock, the risk of unassisted/natural death (2.6% ± 0.3%) was almost double the risk of euthanasia (1.4% ± 0.3%; p = 0.003). The opposite, however, was true in the milking herd: the risk of euthanasia (2.3% ± 0.3%) was greater than unassisted/natural death (1.6% ± 0.2%; p = 0.05). A fallen stock collector (62%) typically performed euthanasia and most farms (66%) did not have anyone trained to perform euthanasia. Most deaths within the milking herd were attributed to ‘unknown or not recorded’ (median 15% of deaths). The factors that farmers most frequently reported as strongly influencing their decision of when to euthanase an animal relative to the onset of disease were ‘failure to respond to treatment’ (89%), ‘veterinary advice’ (89%) and ‘severity of disease’ (88%). On average, veterinarians had moderate or high confidence that 60% of dairy farm clients ‘are performing euthanasia in a timely manner so as to prevent unnecessary suffering’. Veterinary surgeons had variable agreement on the time to euthanasia for various conditions.ConclusionsThe survey highlighted end‐of life decision‐making successes and areas for improvement on dairy farms. An evidence‐based, decision‐support framework may help end‐of‐life decision‐making, particularly for complex diseases.

It is economically essential, but challenging, for dairy farmers to manage bovine fertility. Vets can help farmers to improve fertility, and this is cost-effective bringing benefits for production, animal health and welfare, and the environment. However, the extent to which vets are involved in fertility varies considerably between farms, for reasons that are unclear. This study investigated the motivators and barriers that vets perceive when trying to increase their involvement with fertility management on UK dairy farms. Interviews were conducted with 20 vets and four themes identified. The first, “clinical baggage,” highlighted vets' disillusionment due to past experiences of low uptake of their advice by farmers. Consequently, some vets made assumptions about farmer needs and behaviours, and exhibited ageist stereotyping. These issues, along with concerns and fatigue associated with repeatedly offering the same advice which was not acted upon, negatively influenced vets' engagement with farmers. The second theme “stuck in the comfort zone” revealed a loss of enthusiasm by some senior vets, whilst others lacked confidence to engage due to perceived gaps in their knowledge. Vets also reported farmers not perceiving their problems and lack of farm data or facilities, as barriers. The “vet-farmer relationship” theme highlighted building trust and developing strong relationships which were key drivers for vets to proactively engage and to “go the extra mile” for their clients. The final theme “money matters” explored vets' motivations to improve their clients' profitability and included the future sustainability of their own businesses. Our themes provide useful insight into the challenges vets face and provide key areas that can be targeted in future interventions to improve veterinary involvement in fertility management. For example, post-graduate training and support for vets needs to consider factors such as reflection, mentorship, stereotyping, relationships, communication, and leadership skills. This type of postgraduate support is currently limited for vets and requires investment from stakeholders if improvements in production, animal health and welfare, and the environment are to be achieved. Our findings are informative for facilitating veterinary involvement in any disease context, and are relevant for stakeholders including governments, educators, charities, farmer representatives, environmentalists, and veterinary leaders.

The environment contributes to production diseases that in turn badly affect cow performance, fertility and culling. Oestrus intensity is lower in lame cows, and in all cows 26% potential oestrus events are not expressed (to avoid getting pregnant). To understand these trade-offs, we need to know how animals react to their environment and how the environment influences hypothalamus-pituitary-adrenal axis (HPA) interactions with the hypothalamus-pituitary-ovarian axis (HPO). Neurotransmitters control secretion of GnRH into hypophyseal portal blood. GnRH/LH pulse amplitude and frequency drive oestradiol production, culminating in oestrus behaviour and a precisely-timed GnRH/LH surge, all of which are disrupted by poor environments. Responses to peripheral neuronal agents give clues about mechanisms, but do these drugs alter perception of stimuli, or suppress consequent responses? In vitro studies confirm some neuronal interactions between the HPA and HPO; and immuno-histochemistry clarifies the location and sequence of inter-neurone activity within the brain. In both species, exogenous corticoids, ACTH and/or CRH act at the pituitary (reduce LH release by GnRH), and hypothalamus (lower GnRH pulse frequency and delay surge release). This requires inter-neurones as GnRH cells do not have receptors for HPA compounds. There are two (simultaneous, therefore fail-safe?) pathways for CRH suppression of GnRH release via CRH-Receptors: one being the regulation of kisspeptin/dynorphin and other cell types in the hypothalamus, and the other being the direct contact between CRH and GnRH cell terminals in the median eminence. When we domesticate animals, we must provide the best possible environment otherwise animals trade-off with lower production, less intense oestrus behaviour, and impaired fertility. Avoiding life-time peri-parturient problems by managing persistent lactations in cows may be a worthy trade-off on both welfare and economic terms - better than the camouflage use of drugs/hormones/feed additives/intricate technologies? In the long term, getting animals and environment in a more harmonious balance is the ultimate strategy.

Bovine digital dermatitis (BDD), an infectious disease of the bovine foot with a predominant treponemal etiology, is a leading cause of lameness in dairy and beef herds worldwide. BDD is poorly responsive to antimicrobial therapy and exhibits a relapsing clinical course; an effective vaccine is therefore urgently sought. Using a reverse vaccinology approach, the present study surveyed the genomes of the three BDD-associatedTreponemaphylogroups for putative β-barrel outer membrane proteins and considered their potential as vaccine candidates.

Background: In the UK, quarterly Johne's disease milk antibody ELISAs (JD-mELISAs) are commonly used to classify animals which are likely to be infectious, termed "red cows". "Red cows" are classified following two positive results from the previous four tests (e.g.+ - - +). All cattle are also regularly screened for bovine tuberculosis using intradermal avian and bovine tuberculin, and it is advised to maintain a 60 day interval between a tuberculosis test and JD-mELISA. Aims: To evaluate the impact of bovine tuberculosis testing on JD-mELISAs, and to quantify the impact of test specificity and "red cow" classification test pattern on the probability of infection. Methods: Four years of individual cow milk records with JD-mELISA results were collated from 735 dairy farms and matched to tuberculosis testing records. A two-level multivariable logistic regression model quantified the effect of tuberculosis testing on JD-mELISA result. The specificity and age-dependent sensitivity of a single JD-mELISA were estimated and used to calculate likelihood ratios following each test. Using Bayes' theorem, the posterior probability of infection with Johne's disease was calculated for different specificities, ages of cow, and patterns of test results. Results: There were increased odds of a positive JD-mELISA if it was <= 30 days (OR: 2.1) or 31-60 days (OR: 1.2) after a tuberculosis test, compared to >90 days. A larger avian skin reaction at the tuberculosis test was also associated with increased odds of a positive JD-mELISA. The proportion of cows which tested exclusively negative after their first positive JD-mELISA was higher if that JD-mELISA was <= 30 days after a tuberculosis test compared to >90 days. The posterior probability of infection reduced substantially when the test specificity was slightly reduced. In "red cows" classified following two consecutive positive tests, if the test specificity was reduced to 0.95, then the posterior probability of infection was only >95 % if the prior probability was >13 %. If the "red cow" classification was due to two non-consecutive positive tests (+ - - +), the posterior probability of infection was only >95 % if the prior probability was >43 %. Conclusions: Testing for Johne's disease within 60 days of a tuberculosis test is associated with a higher chance of a positive JD-mELISA and this may reflect a reduction in the ELISA specificity. Relatively small reductions in JD-mELISA specificity can markedly reduce the posterior probability of infection which also depends on the pattern of test results which classifies "red cows".

The aim of this study was to estimate the prevalence of macroscopic reproductive tract abnormalities in a sample of female cattle in the UK. To our knowledge, this type of post-mortem survey has not been conducted in the UK since the 1970s. Over the last 40 years significant changes have occurred with respect to management and genetics. Moreover, there have been changes in growth rates in beef animals, elevated milk yields and a decline in fertility in dairy cattle. It was hypothesised that differences may exist in the extent and type of lesions occurring compared with previous studies. Between May and July 2017, the reproductive tracts of cattle (Bos taurus) were examined post-mortem at an abattoir in the north west of England. All female cattle slaughtered on visit days were eligible. In total 680 tracts were examined, constituting 88% of those eligible. Macroscopic abnormalities were recorded using a standard format and definitions. The majority of cattle were a dairy breed (73%) with Holstein-Friesian accounting for over half of these. Median age at slaughter for dairy breeds was 5.1 years (range 1.7-13.8 years) and 3.9 years (0.92-16.8 years) for beef breeds. A total of 141 out of the 680 reproductive tracts examined exhibited at least one lesion, giving an overall prevalence of abnormalities of 20.7%, with 95% confidence interval (Cl) 17.9-23.9%. This is double the last similar UK-based study carried out in the late 1970s. There were 20 different types of abnormality identified, with 207 individual lesions in 141 abnormal tracts. The ovary was the most common anatomical location displaying abnormalities, accounting for 70.2% of all abnormal tracts. Ovaro-bursal adhesions were the most common abnormality found at 5.3% (CI 3.9-7.2%) and half of these were classified as severe. The second most common lesion was follicular cystic ovarian disease at 4.6% (CI 3.2-6.4%), followed by anoestrus at 4.1% (CI 2.9-5.9%). Double the prevalence of macroscopic reproductive tract lesions is a concern. Greater use of post-mortem material for disease surveillance and further studies into risk factors, especially for the most prevalent lesions, is warranted.

Lameness represents a significant challenge for the dairy cattle industry, resulting in economic losses and reduced animal health and welfare. The existence of underlying genomic variation for lameness associated traits has the potential to improve selection strategies by using genomic markers. Therefore, the aim of this study was to identify genomic regions and potential candidate genes associated with lameness traits. Lameness related lesions and digital cushion thickness were studied using records collected by our research team, farm records, and a combination of both. Genome-wide analyses were performed to identify significant genomic effects, and a combination of single SNP association analysis and regional heritability mapping was used to identify associated genomic regions. Significant genomic effects were identified for several lameness related traits: Two genomic regions were identified on chromosome 3 associated with digital dermatitis and interdigital hyperplasia, one genomic region on chromosome 23 associated with interdigital hyperplasia, and one genomic region on chromosome 2 associated with sole haemorrhage. Candidate genes in those regions are mainly related to immune response and fibroblast proliferation. Quantitative trait loci (QTL) identified in this study could enlighten the understanding of lameness pathogenesis, providing an opportunity to improve health and welfare in dairy cattle with the addition of these regions into selection programs.

Increasing levels of antimicrobial resistance in human and veterinary medicine have raised concerns over the irresponsible use of antimicrobials. The role of administering antimicrobials in food producing animals most frequently falls to the farmer, therefore it is essential that their use of antimicrobials is both optimal and responsible. This study sought in-depth information on the drivers behind antimicrobial use behaviors and farmer attitudes to responsible use using a mixed-methodological approach. Initially, in-depth semi-structured interviews were conducted with a purposively selected sample of farmers (n = 22). A thematic analysis approach was taken to identify key themes from these qualitative data. The generalizability and variation of these themes was then tested on a larger randomly selected sample of pig farmers through a questionnaire study (n = 261). The influences behind antimicrobial use were complex with multiple drivers motivating decisions. There was no consensual opinion on what farming systems resulted in either a low or high antimicrobial requirement however, farmers reported that good management practices, low stocking densities, and a high health status were associated with low antimicrobial use. Farmers expressed desire to avoid the long-term use of in-feed antimicrobials, but identified barriers to discontinuing such behaviors, such as pig morbidity, mortality, and economic losses. The high cost of antimicrobials was described as a motivation toward seeking alternative methods of controlling disease to prophylactic use; however, this expense was balanced against the losses from an increased burden of disease. The high financial costs involved in pig production alongside the economic uncertainty of production and pressure from retailers, were identified as limiting the scope for improvements in pig accommodation and facilities which could reduce the antimicrobial requirements on farm. Long-term, sustainable and economically stable relationships between retailers and farmers may allow farmers to make necessary investments in improving management and housing in order to reduce antimicrobial use. Greater use and more widespread deployment of effective vaccinations were highlighted by farmers as being a feasible alternative to antimicrobial use in preventing disease.

Clinical and subclinical hypocalcaemia are common in dairy cows, yet evidence in the literature assessing their impact on fertility is inconsistent. The aim of this prospective cohort study was to examine associations between blood ionised calcium concentration at calving and fertility outcomes in dairy cattle. Blood samples were taken from 137 Holstein cows from four commercial dairy herds within 24 hours of calving and analysed for blood ionised calcium using an Epocal Point of Care Analyser (Epocal, Ottawa, Canada). Data collected from routine veterinary fertility examinations and herd records were used to investigate the association of ionised calcium with the outcomes: time to first service, time to conception and endometritis. There were significant negative associations between blood ionised calcium concentration and time to first service (HR 1.33, P=0.001) and blood ionised calcium concentration and time to conception (HR 1.16, P=0.04). There was no significant association between blood ionised calcium concentration and endometritis. The results of this study imply that management policies that minimise the reduction in blood ionised calcium concentration in the periparturient dairy cow are likely to improve reproductive outcomes and should be considered as part of the multifactorial approach to optimising dairy cow fertility.

In studying the efficiency of a variety of methods for estrus detection in a large dairy herd, we suspected a definite sequence of estrus signs. Consequently, we observed a subset of animals continuously between 0400 and 2400 h, making a note of the precise timing and frequency of each sexual behavior. Sixteen Holstein-Friesian cows, >20 d postpartum, were equipped with motion activity-sensing neck collars and had milk progesterone profiles monitored simultaneously. The duration between the first and last observed estrus behavior was (mean ± SE) 14.0 ± 1.9 h, with a range 8.5 to 28.75 h. The duration of standing to be mounted (STBM) was 4.68 ± 1.49 h, with a range of 0.25 to 18.25 h. Sniffing the vulva of another cow occurred on average 5.5 ± 1.3 h (range = 0.25-18.25 h) before the first STBM. By ranking the first appearance of each behavior, we established that sniffing was followed by the active behaviors of mounting another cow and not accepting a mount, as well as the passive behaviors of being sniffed and STBM by another cow. Chin resting occurred before not accepting a mount and STBM. All these behaviors were observed in the reverse order after the last STBM. The mean profile of motion activity revealed an increase in motion activity with the onset of exploratory behaviors, and highest values occurred within the period of STBM. Such distinct behavioral sequences may be controlled by changes in peripheral progesterone and estradiol concentrations, as well as by subtle independent mechanisms via pheromones in differing concentrations or divergent composition.

Lactation records from 396,534 pedigree Holstein and Holstein-Friesian primiparous cows from 6,985 UK milk recorded herds, calving for the first time during the period between the 1st of January 2006 and the 31st of December 2008, were examined in order to determine the associations between age at first calving (AFC) and subsequent production, udder health, fertility and survivability parameters. Heifers were grouped by AFC into single month classes ranging from 21 to 42 months. Mixed effects multivariable regression modelling was used for data analysis. Mean and median AFC were 29.1 and 28 months respectively. Within the study, only 48,567 heifers (12.3% of the studied population) calved for the first time at 24 months of age or younger. 162,157 heifers (40.9%) were 30 months or older at their first calving. An increased AFC was associated with increased first lactation milk, fat and protein yields. The lowest predicted mean 305-day yield (6,617kgs; 95% confidence interval (CI): 6,546-6,687 kgs) was recorded for the 21 month AFC class, significantly lower than any other class. The 36 month AFC class had the highest predicted mean (7,774 kgs; 95% CI: 7,737-7,811 kgs). However, an increased AFC was also associated with increased calving interval and increased first lactation somatic cell count (SCC). Animals calving at 21 months had a predicted mean lactation SCC of 72,765 (95% CI: 68427-77378). Animals calving at 36 months of age had a predicted mean lactation SCC of 86,648 (95% CI: 84,499-88,853). Importantly, an increased AFC was also associated with decreased lifetime daily milk yield and decreased likelihood of calving for a second successive time. Animals calving at 22 months of age had a predicted mean daily lifetime milk yield of 15.24 kgs (95% CI: 15.06-15.35); animals calving at 36 months of age had a predicted mean daily lifetime milk yield of 12.83 kgs (95% CI: 12.76-12.91). Our results highlight the importance of achieving a lower age at first calving which was here associated with improved udder health, increased lifetime daily milk yield, improved reproductive performance and increased likelihood of calving for a second time.

We have previously established that the efficiency of identifying oestrus with activity-sensing devices can be compromised by common production diseases; the present study was undertaken to determine how these diseases may affect device readings. A total of 67 Holstein-Friesian cows, >20 days postpartum, were equipped with activity-sensing neck collars and pedometers, and simultaneous milk progesterone profiles were also monitored twice a week. The influences of common production stressors on maximum activity and progesterone values were analysed. Approximately 30% potential oestrus events (low progesterone value between two high values) remained unrecognised by both activity methods, and progesterone values in these animals were higher on the potential day of oestrus when both activity methods did not detect an event (0.043 ± 0.004 versus 0.029 ± 0.004 ng/mL; P = 0.03). Data from a subset of 45 cows (two events each) were subjected to mixed models and multiple regression modelling to investigate associations with production diseases. Cow motor activity was lower in lame cows. Maximum progesterone concentrations prior to oestrus increased as time postpartum and body condition score (BCS) increased. There were also fewer days of low progesterone prior to oestrus associated with increases in BCS and maximum progesterone concentrations prior to oestrus. In conclusion, lameness was associated with lower activity values, but this suppression was insufficient to account for lowered oestrus detection efficiency of either device. However, associations were identified between production diseases and progesterone profiles.

Veterinary RecordVolume 183, Issue 6 p. 195-196 Letters and notices Using BVA policy to improve farm animal health and welfare Paddy Gordon, Corresponding Author Paddy Gordon paddy.gordon@sheptonvets.com Shepton Veterinary Group, Allyn Saxon Drive, Shepton Mallet, Somerset, BA4 5QHe-mail: paddy.gordon@sheptonvets.comSearch for more papers by this authorRobert Smith, Robert Smith Department of Livestock Health and Welfare, Institute of Veterinary Science, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TESearch for more papers by this author Paddy Gordon, Corresponding Author Paddy Gordon paddy.gordon@sheptonvets.com Shepton Veterinary Group, Allyn Saxon Drive, Shepton Mallet, Somerset, BA4 5QHe-mail: paddy.gordon@sheptonvets.comSearch for more papers by this authorRobert Smith, Robert Smith Department of Livestock Health and Welfare, Institute of Veterinary Science, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TESearch for more papers by this author First published: 11 August 2018 https://doi.org/10.1136/vr.k3363Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume183, Issue6August 2018Pages 195-196 RelatedInformation

Increasing levels of antimicrobial resistance in human and veterinary medicine have raised concerns around the issue of overprescribing and the indiscriminate use of antimicrobials. Their use in food producing animals is under scrutiny due to the perceived risk from the zoonotic transfer of resistant pathogens from animals to humans. This study aimed to explore UK veterinary surgeons antimicrobial prescribing behaviours, their attitudes to antimicrobial resistance and their perceptions of responsibility of antimicrobial use in pigs through a questionnaire study on a census sample of 261 veterinary surgeons in England, Wales and Scotland who had a clinical caseload which included commercial pigs. The questionnaire had a useable response rate of 34.1% (n = 61/179) in eligible veterinary surgeons. Overall, veterinary surgeons reported personal confidence that their prescribing decisions were responsible however, there was concern that the prescribing behaviours of other veterinary surgeons and physicians in human medicine may be less responsible; a sociological concept known as 'othering'. In parallel, veterinary surgeons seldom identified that treatment failure was a consequence of antimicrobial resistance in their own clinical caseload, however they considered it an issue for other veterinary surgeons and for human prescribers. Veterinary surgeons consulted a wide spectrum of resources on antimicrobial use in pigs which, on occasion, contained conflicting guidance on what was defined as responsible prescribing. The decision over whether or not to prescribe an antimicrobial was influenced by numerous factors relating to the veterinary surgeons' experience and the clinical situation presented, but maintaining pig welfare was a high priority. There was a shared desire to seek alternative methods to prevent disease to antimicrobial use, however the use of diagnostics to support prescribing decisions was an infrequently reported behaviour and could play a more significant role in prescriber decisions if more cost effective and rapid tests were available. Future interventions to optimise antimicrobial use in pigs needs to focus on the evolution of antimicrobial use practices in a changing political and scientific landscape whilst also considering individual motivations and justifications for use.