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The study aimed to describe growth parameters and to quantify the association between linear body measurements as predictors of liveweight (LW) of Holstein-Friesian (HF), and HF crossbred dairy calves in Queensland. A secondary objective was to quantify the effect of disease events on LW change.Longitudinal study.Fortnightly LW, hip height (HH), hip width (HW) and heart girth (HG) measurements were recorded from 16 male and 28 female HF calves from birth until weaning. The association between linear body measurement and the effect of a disease event on LW change were explored using linear mixed-effects modelling with random intercepts and random slopes.HG was the best body measure used individually as a predictor of calf LW (R2 = 82%; P0.001), while the combined use of HG, HW and HH was the most accurate predictor of calf LW between birth and weaning (R2 = 90%; P0.001). HW, average feed intake and total feed intake were significantly affected by disease events (P0.05). On average, total average LW loss associated with a single pneumonia event was estimated at 14.6 kg (95% CI = 10.5 to 18.7 kg; P 0.05).Calves of this study performed at a level consistent with the previously published reports. Growth performance was significantly compromised by pneumonia. HW was found to be the least predictive individual measure, and the combined use of HH, HW and HG had the most accurate prediction of calf liveweight from birth to weaning.

Porcine circovirus type 2 (PCV2), an important pig viral pathogen, can cause porcine circovirus-associated disease (PCVAD), resulting in economic losses associated with decreased growth and mortalities. The diagnosis of PCVAD is complex requiring clinical, pathological and virological approaches. This study assessed PCV2 infection using histopathology and immunohistochemistry (IHC) on tissue samples and quantitative polymerase chain reaction (qPCR) on serum samples from 47 grower-finisher pigs allocated in three clinical groups in the Philippines. Typical PCV2 histopathological lesions were observed in mediastinal lymph nodes (MLN) of eight of 47 pigs. Lymphoid depletion was seen in all eight pigs and granulomatous inflammation in one of these pigs. Four of these eight pigs were PCV2 positive by both IHC and qPCR. IHC revealed PCV2 antigen in 8 pigs in at least one of the following tissues: MLN (5/8), spleen (3/8), tonsils (4/8) and lungs (5/8). PCV2 antigen was observed in 3/8 MLN with lymphoid depletion and in one MLN with depletion and granulomatous inflammation. The qPCR test showed that 33 sera had a non-detectable level, twelve had 106 PCV2 DNA copies/ml serum. One pig with lymphoid depletion had > 106 PCV2 DNA copies/ml serum, and another pig without MLN lesions also had > 106 PCV2 DNA copies/ml serum. These findings suggest that PCVAD is present in the Philippines and confirm the challenges of PCVAD diagnosis as different patterns of results were obtained from the different tests.

Urinary bladder diseases are common in dogs and cats; however, there is little published work on urinary bladder disease in Australian pets. We identified pathology records of Australian dogs and cats with urinary bladder tissue submitted to the University of Queensland Veterinary Laboratory Service during 1994–2016 ( n = 320). We described the proportion of bladder diseases in dogs and cats, and applied the less-commonly used logistic regression procedure to quantify associations between signalment variables and disease diagnosis that were evident using descriptive statistics alone. After preliminary analysis, both species were combined because of similar results. Spayed/castrated animals were 74% less likely to be diagnosed with cystitis compared with intact animals. Animals 4–11 y old were also at lower risk of being diagnosed with cystitis compared with younger or older animals. Male animals were at increased risk of neoplasia compared to females, which contrasts with reports from North America and Europe. There was increased risk for developing neoplasia with progressive age, with up to 20 times higher odds in the > 11-y age group. Logistic regression modeling provided unique insight into proportionate morbidity of urinary bladder diseases in Australian dogs and cats.

The aim of this study was to appraise the available evidence on the effectiveness of probiotic treatment on mature cattle immunity, inflammation, and disease prevention. A systematic review with meta-analysis was conducted to analyse studies that were eligible to answer the following research question: “in cattle of at least 6-months of age, is the use of probiotics associated with immunomodulatory and inflammatory responses, and clinical disease outcomes?” Our literature search yielded 25 studies that fit the inclusion criteria. From these studies, only 19 were suitable for inclusion in the meta-analysis due to data limitations and differences in study population characteristics. Included studies were assessed for bias using a risk assessment tool adapted from the Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. GRADE guidelines were used to assess the quality of the body of evidence at the outcome level. The meta-analysis was performed using Review Manager and R. The overall quality of evidence at the outcome level was assessed as being very low. On average, the treatment effect on immunoglobulin G (IgG), serum amyloid A (SAA), haptoglobin (Hp) and β-hydroxybutyrate (BoHB) for cows receiving probiotics did not differ from control cows. Exposure to probiotics was not associated with reduced risk of reproductive disorders (pooled RR = 1.02 95 % CI = 0.81–1.27, P = 0.88). There is insufficient evidence to support any significant positive effects of probiotics on cattle immunity and disease prevention. This lack of consistent evidence could be due to dissimilarities in the design of the included studies such as differences in dosage, dose schedule, diet composition and/or physiological state of the host at the time of treatment.

Simple Summary Modern technology has allowed researchers to track the movement patterns of cattle with increasing accuracy in order to gain a greater understanding of both overt and subtle activity trends. The aim of this study was to describe and analyze movement patterns displayed by recently weaned and healthy dairy calves. Three movement pattern clusters were identified, and calves in this study were more active in the afternoon and at night. There was a correlation between the rate of movement, linearity ratio, and the distance traveled. However, turning angles do not have any influence on the distance traveled and the rate of movement across the three cluster-type movements. The findings reported in this study could be used to further develop the interpretation of movement and behavior patterns of calves in order to establish an early detection system for poor health and welfare on dairy farms. Abstract Animals display movement patterns that can be used as health indicators. The movement of dairy cattle can be characterized into three distinct cluster types. These are cluster type 1 (resting), cluster type 2 (traveling), and cluster type 3 (searching). This study aimed to analyze the movement patterns of healthy calves and assess the relationship between the variables that constitute the three cluster types. Eleven Holstein calves were fitted with GPS data loggers, which recorded their movement over a two week period during spring. The GPS data loggers captured longitude and latitude coordinates, distance, time and speed. It was found that the calves were most active during the afternoon and at night. Slight inconsistencies from previous studies were found in the cluster movements. Cluster type 2 (traveling) reported the fastest rate of movement, whereas cluster type 1 (resting) reported the slowest. These diverse movement patterns could be used to enhance the assessment of dairy animal health and welfare on farms.

There is a critical need to ensure that all cattle undergoing surgical husbandry procedures are provided effective pain relief. Non-steroidal anti-inflammatory drugs (NSAIDs) are most commonly used, and typically are administered by intramuscular (IM) injection. However, administration of NSAIDs via this route to large numbers of cattle which are handled only once or twice a year, typical of many rangeland beef production systems, presents significant occupational health and safety and mis-administration risks. To address this, a novel transdermal (TD) formulation of ketoprofen was developed, and its efficacy assessed in a study of 36 Holstein&ndash, Friesian calves which were assigned to a placebo (n = 10), a TD ketoprofen (n = 10), an IM ketoprofen (n = 10) and sham dehorned group (n = 6). TD ketoprofen significantly reduced plasma cortisol concentrations between 1 to 4 h after dehorning compared to placebo treated calves, with concentrations at 2 and 4 h being very similar to those for sham dehorned calves. The expected log count of positively associated pain variables (ear flick, tail wag, ruminating, head shake, lying down, grooming and neck extending) in the TD group was reduced by 42%, compared to placebo calves, with an overall significant (p &lt, 0.05) treatment effect. The IM group exhibited similar responses and both TD and IM cattle had a higher BW gain at 2 and 5 (p &lt, 0.05) weeks post-dehorning, compared to placebo. This study has shown that TD administered ketoprofen was at least as effective as IM to control pain associated with dehorning and facilitates the administration of analgesic drugs prior to the surgical husbandry procedures being performed.

Anatomic pathology is a vital component of veterinary medicine but as a primarily subjective qualitative or semiquantitative discipline, it is at risk of cognitive biases. Logistic regression is a statistical technique used to explain relationships between data categories and outcomes and is increasingly being applied in medicine for predicting disease probability based on medical and patient variables. Our aims were to evaluate histologic features of canine and feline bladder diseases and explore the utility of logistic regression modeling in identifying associations in veterinary histopathology, then formulate a predictive disease model using urinary bladder as a pilot tissue. The histologic features of 267 canine and 71 feline bladder samples were evaluated, and a logistic regression model was developed to identify associations between the bladder disease diagnosed, and both patient and histologic variables. There were 102 cases of cystitis, 84 neoplasia, 42 urolithiasis and 63 normal bladders. Logistic regression modeling identified six variables that were significantly associated with disease outcome: species, urothelial ulceration, urothelial inflammation, submucosal lymphoid aggregates, neutrophilic submucosal inflammation, and moderate submucosal hemorrhage. This study demonstrated that logistic regression modeling could provide a more objective approach to veterinary histopathology and has opened the door toward predictive disease modeling based on histologic variables.

Streptococcus uberis is one of the most frequent mastitis-causing pathogens isolated from dairy cows. Further understanding of S. uberis genetics may help elucidate the disease pathogenesis. We compared the genomes of S. uberis isolates cultured from dairy cows located in distinctly different geographic regions of Australia. All isolates had novel multi locus sequence types (MLST) indicating a highly diverse population of S. uberis. Global clonal complexes (GCC) were more conserved. GCC ST86 and GCC ST143 represented 30% of the total isolates (n = 27) and were clustered within different geographic regions. Core genome phylogeny revealed low phylogenetic clustering by region, isolation source, and MLST. Identification of putative sortase (srtA) substrates and generation of a custom putative virulence factor database revealed genes which may explain the affinity of S. uberis for mammary tissue, evasion of antimicrobial efforts and disease pathogenesis. Of 27 isolates, four contained antibiotic resistance genes including an antimicrobial resistance cluster containing mel/mef(A), mrsE, vatD, lnuD, and transposon-mediated lnuC was also identified. These are novel genes for S. uberis, which suggests interspecies lateral gene transfer. The presence of resistance genes across the two geographic regions tested within one country supports the need for a careful, tailored, implementation and monitoring of antimicrobial stewardship.

The aims of this study were to undertake a systematic review and meta-analysis of the types of probiotic formulations that are commercially available and to critically appraise the available evidence for the effectiveness of probiotics in improving the health and productivity of calves. Relevant papers were identified to answer the question: ‘In calves aged between birth to one year, is the use of probiotics associated with changes in haematological or biochemical parameters, faecal bacteria counts, average daily live weight gain, dry matter intake, or feed conversion ratio?’ The search of the literature yielded 67 studies that fit the primary screening criteria. Included studies were assessed for bias and confounding using a predefined risk assessment tool adapted from the Cochrane Collaboration's tool for assessing risk of bias in randomised trials and GRADE guidelines. Meta-analysis was performed using Review Manager and R. Random sequence generation was low in more than 59 % of studies. Risk of allocation concealment and performance bias were largely unclear in over 68 % of studies. Calves fed probiotics had increased average daily live weight gains (ADG) from birth to weaning (mean difference [MD] = 83.14 g/d 95 % CI = 58.36–107.91, P < 0.001) compared with calves on a control diet. Calf age reduced the level of heterogeneity of the effect of probiotics on ADG for calves between one to three weeks of age (τ = 73.15; I = 4%; P = 0.40) but not for calves older than three weeks of age (τ = 2892.91; I = 73 %; P < 0.001). Feed conversion ratio (FCR) was lower for calves on probiotics (MD = −0.13 kg of dry matter intake (DMI) to kg of live weight (LW) gain, 95 % CI = −0.17 to −0.09, P < 0.001), and the heterogeneity of effect was large in younger aged calves (τ = 0.05; I = 78 %; P = 0.03). The risk of bias regarding the methodology in the included studies was high. The quality of evidence for each outcome was categorised as moderate. There is sufficient data to support the effectiveness of probiotic use in some applications such as for the improvement of performance and productivity parameters of calves. However, the evidence is weak for other potential probiotic uses in calves such as improved health and reduced risk of disease. Therefore, the existing data are inconclusive and do not support the use of probiotics as an alternative to antimicrobials to improve calf health and productivity.

Q fever is a zoonotic disease caused by infection with Coxiella burnetii transmitted from animals including, but not limited to, cattle, sheep and goats. The infection in cattle is typically sub-clinical with some evidence suggesting associated reproductive loss. There is currently limited data on the true prevalence and distribution of coxiellosis in beef cattle across northern Australia. During this study, 2,012 sera samples from beef cattle managed on commercial farms located in Queensland and the Northern Territory were tested using an indirect immunofluorescent assay (IFA) for serological evidence of IgG antibodies against C. burnetii. Bayesian latent class models were used to estimate the true prevalence, adjusted for diagnostic test sensitivity and specificity and incorporating the hierarchical structure of the cattle within farms and regions. In this study, cattle in the Northern Territory had lower estimated true prevalence than cattle within most regions of Queensland with the exception of south-east Queensland. Results from this study have described the geographic distribution and estimated the true prevalence of antibodies to C. burnetii in a sample of extensively managed beef cattle located across the tropical grazing regions of northern Australia.

The current coronavirus disease 2019 (COVID-19) pandemic is largely driven by community transmission, after 2019 novel Coronavirus (2019-nCoV or SARS-CoV-2) crosses the borders. To stop the spread, rapid testing is required at community clinics and hospitals. These rapid tests should be comparable with the standard PCR technology. Isothermal amplification technology provides an excellent alternative that is highly amenable to resource limited settings, where expertise and infrastructure to support PCR are not available. In this review, we provide a brief description of isothermal amplification technology, its potential and the gaps that need to be considered for SARS-CoV-2 detection. Among this emerging technology, loop-mediated amplification (LAMP), recombinase polymerase amplification (RPA) and Nicking enzyme-assisted reaction (NEAR) technologies have been identified as potential platforms that could be implemented at community level, without samples referral to a centralized laboratory and prolonged turnaround time associated with the standard COVID-19 RT-PCR test. LAMP, for example, has recently been shown to be comparable with PCR and could be performed in less than 30 min by non-laboratory staff, without RNA extractions commonly associated with PCR. Interestingly, NEAR (ID NOW™ COVID-19 (Abbott, IL, USA) was able to detect the virus in 5 min. More so, isothermal platforms are cost effective and could easily be scaled up to resource limited settings. Diagnostics developers, scientific community and commercial companies could consider this alternative method to help stop the spread of COVID-19.

Foot lesions causing lameness in dairy cows are important economic and welfare issues. Prompt and correct detection and diagnosis are critical for improving economic and welfare outcomes. Few tests are currently available to aid the dairy farmer in the detection and diagnosis of foot lesions. The objectives of this systematic review were to identify those tests that have been investigated for the detection and diagnosis of foot lesions causing lameness in dairy cows, evaluate the methodological quality of the studies investigating the identified tests, compare the accuracy of the identified test, and determine which tests can be recommended for implementation on the farm based on accuracy and practicality for use by dairy farmers. A comprehensive literature search resulted in 2137 papers. After removing duplicates and performing relevance screening, 12 papers with 20 studies met the inclusion criteria. Pertinent data from each study were extracted using a standardised form. Eligible studies were grouped based on the objective of the test under investigation, resulting in the following groups of disorders: lameness, foot lesions, sole ulcer, and digital dermatitis. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool which includes four domains: animal selection, index test, reference test and flow and timing. Incomplete reporting in the studies limited the assessment of methodological quality. The animal selection domain was particularly poorly reported. No single study could be classified as being at low risk of bias across all domains of the QUADAS-2 tool. One automated test was identified, while all others were manually operated. No studies reported the cost of the test in question and only two studies reported the time taken to carry out the procedures involved with using the test in question. It was not possible to compare the accuracy of these tests or recommend which tests are suitable for implementation on the farm. This was due to incomplete reporting of information and significant risk of bias in all studies.

There is limited knowledge of the true prevalence and distribution of coxiellosis in dairy and beef cattle populations in Australia. For this to occur, apparent prevalence estimates need to be reliably adjusted, accounting for diagnostic sensitivity (DSe) and diagnostic specificity (DSp) of the test used. However, there are few tests available with known diagnostic specifications suitable to inform screening and surveillance activities in the Australian context. We initially modified and optimised a human indirect immunofluorescence assay (IFA) test for the detection of IgG antibodies against phase I and/or phase II Coxiella burnetii in bovine sera and determined an optimal screening dilution cut-off to be 1:160. Direct comparison of the modified IFA with the commercial IDEXX enzyme-linked immunosorbent assay (ELISA) kit (Q Fever Ab Test IDEXX Laboratories, United States of America) was performed by testing 458 serum samples from four distinct cattle populations across the east coast of Australia and New Zealand. Cross classified test results were then analysed using Bayesian latent class modelling, to validate the tests in the absence of a gold standard reference test. Results from this analysis indicate that the IFA, at a 1:160 serum dilution, has an estimated DSe of 73.6% (95% Credible Interval (CrI) 61.1, 85.9) and DSp of 98.2% (95% CrI 95.1, 99.7). The commercial IDEXX ELISA kit was found to have a higher DSe of 87.9% (95% CrI 73.9, 96.4) and similar DSp of 97.7% (95% CrI 93.2, 99.7). Evaluation of the diagnostic performance of the IFA and ELISA methods, specifically for use in cattle will enable more accurate interpretation of prevalence estimates of C. burnetii exposure to be reported for cattle in Australia and other countries.

Probiotics intended to improve plant health and productivity of pastures grazed by dairy cow are becoming commercially available in Australia. Great Land (GL; Terragen Biotech Pty Ltd., Coolum Beach, QLD, Australia) is one such biologic soil conditioner and spray-on probiotic with a label claim of “acting to improve plant health and productivity.” The objective of this study was to quantify the effect of GL on the milk quality of cows grazing pasture top-dressed with GL. Lactating dairy cows of mixed age and breed (primarily Holstein-Friesian), in their second lactation or greater, and at least 80 d in milk were enrolled and randomly allocated into 1 of 2 study groups: a treatment cow group (n = 98; cows grazed pasture that was top-dressed with GL according to the product label) and a control cow group (n = 114; cows grazed untreated pasture). As required, both groups were supplemented at the same rate with a mixed ration during the grazing period. Composite milk samples were collected weekly from each cow during the study and analyzed to determine milk components. Milk volumes were recorded at each milking using the herd management software of the study farm. Mean differences in the milk component variables were compared using mixed-effects linear regression models. After controlling for the effect of days in milk, cow lactation, and time since a cow entered the study, the treatment cows produced an average of 1.21 L/cow per day more milk (95% confidence interval: 0.34–2.08 L/cow per day) and more milk protein (0.03 kg/d; 95% confidence interval: 0.01–0.05 kg/d) than the control cows. Pasture cover and pasture consumption did not differ between the GL-treated and the untreated study paddocks grazed by the treatment or control cows. A limited amount of published data have examined the effect of probiotic pasture treatment on the milk quality of dairy cows. This study suggests that application of such products may be beneficial. The mechanisms associated with this type of outcome remain to be investigated.

The goal of the study was to evaluate alternative student-centered approaches that could replace autopsy sessions and live demonstration and to explore refinements in assessment procedures for standardized cardiac dissection. Simulators and videos were identified as feasible, economical, student-centered teaching methods for technical skills training in medical contexts, and a direct comparison was undertaken. A low-fidelity anatomically correct simulator approximately the size of a horse's heart with embedded dissection pathways was constructed and used with a series of laminated photographs of standardized cardiac dissection. A video of a standardized cardiac dissection of a normal horse's heart was recorded and presented with audio commentary. Students were allowed to nominate a preference for learning method, and students who indicated no preference were randomly allocated to keep group numbers even. Objective performance data from an objective structure assessment criterion and student perception data on confidence and competency from surveys showed both innovations were similarly effective. Evaluator reflections as well as usage logs to track patterns of student use were both recorded. A strong selection preference was identified for kinesthetic learners choosing the simulator and visual learners choosing the video. Students in the video cohort were better at articulating the reasons for dissection procedures and sequence due to the audio commentary, and student satisfaction was higher with the video. The major conclusion of this study was that both methods are effective tools for technical skills training, but consideration should be given to the preferred learning style of adult learners to maximize educational outcomes.

Probiotics are genetically identifiable, live microorganisms that when administered in adequate amounts, confer appropriately sized health benefit (e.g. correcting dysbiosis, immunomodulatory effect) on a target host. In cattle, probiotics have shown promising results and long-term benefits in productivity when used on animals under stress. The health and production benefits of probiotics were attributed to improvement in fermentation in rumen and intestine, the stabilisation of rumen pH, and improvements in the intestinal barriers. In the bovine udder, a dysbiosis of the commensal intramammary microbiota and the presence of mastitis causing-bacteria has been linked to increased intramammary infections. Probiotic bacteria capable of biofilm formation inside the udder either serve as a barrier against pathogens or disrupt and replace biofilms formed by pathogens. Over the past two decades, several types of probiotics have been used as feed additives; however, the effect of probiotic use on disease prevention and cattle health and performance indicators, and characterisation of the immunomodulatory association between probiotic microbiota and host target system microbiota are yet to be quantified or documented.

A cross-sectional study was conducted between October 2011 and March 2012 in two major pig producing provinces in the Philippines. Four hundred and seventy one pig farms slaughtering finisher pigs at government operated abattoirs participated in this study. The objectives of this study were to group: (a) smallholder (S) and commercial (C) production systems into patterns according to their herd health providers (HHPs), and obtain descriptive information about the grouped S and C production systems; and (b) identify key HHPs within each production system using social network analysis. On-farm veterinarians, private consultants, pharmaceutical company representatives, government veterinarians, livestock and agricultural technicians, and agricultural supply stores were found to be actively interacting with pig farmers. Four clusters were identified based on production system and their choice of HHPs. Differences in management and biosecurity practices were found between S and C clusters. Private HHPs provided a service to larger C and some larger S farms, and have little or no interaction with the other HHPs. Government HHPs provided herd health service mainly to S farms and small C farms. Agricultural supply stores were identified as a dominant solitary HHP and provided herd health services to the majority of farmers. Increased knowledge of the routine management and biosecurity practices of S and C farmers and the key HHPs that are likely to be associated with those practices would be of value as this information could be used to inform a risk-based approach to disease surveillance and control.

Dairy herd managers have attempted to increase and maintain profits by selectively breeding dairy cattle for high production. Selection for milk production may have resulted in a tendency for greater liveweight (LW) loss postpartum. This study aimed to: (1) determine if excessive LW loss and milk yield in the first 50 days in milk (DIM) was associated with the development of lameness after 50 DIM, and (2) estimate the incidence risk of lameness in this herd attributable to excessive liveweight loss. The dataset comprised details from 564 mixed age cows from a single, seasonally calving, pasture fed dairy herd in New Zealand. After adjusting for the confounding effects of parity, LW at calving, breed, the presence of specified disease events in the first 50 DIM and milk yield, LW loss in the first 50 DIM increased the risk of lameness after 50 DIM by a factor of 1.80 (95% CI 1.00–3.17). The risk of lameness was greatest for high yielding cows that lost excessive LW (risk ratio 4.36, 95% CI 4.21–8.19), but the effect LW loss on lameness risk at the herd level was relatively small. Based on data accumulated during the study we estimate that for this herd, there would be a 3% (95% CI 1–6%) reduction in the incidence risk of lameness if excessive LW loss was prevented. Twenty three percent of the incidence of lameness in this herd was attributable to excessive LW loss. We conclude that policies and interventions to reduce the rate and amount of LW loss in the first 50 DIM will have a non-negligible impact on the incidence risk of lameness in this herd.

This was a prospective cohort study of 930 lactations in 595 mixed aged dairy cows that calved between 1 July and 24 October of 2008 and 1 July and 24 October 2009 in a single dairy herd in the lower North Island of New Zealand. Parametric accelerated failure time models based on the log-normal distribution were used to identify and quantify the effect of factors influencing the time it took for cows to conceive after the Planned Start of Mating (PSM) date. A focus of this study was to quantify the effect of liveweight change in the first 4 weeks after calving ( ΔLW PP ) and liveweight change in the period from PSM—21 days to PSM ( ΔLW BPSM ) on PSM to conception intervals. Parity, calving to PSM interval, ΔLW BPSM , milk protein percentage, breed, clinical mastitis, the presence of a fertility treatment and season was associated with PSM to conception intervals. PSM to conception intervals for cows with zero or positive ΔLW BPSM was 74% of those for cows with negative ΔLW BPSM (TR 0.74, 95% CI 0.48 to 1.00; P = 0.05). The findings of this study are consistent with those reported in the literature and better define the impact of long- and short-term liveweight changes on reproductive performance, providing the opportunity to design feeding programmes to minimise the impact of LW loss (used as a proxy for negative energy balance) on reproductive failure in pasture fed dairy herds.

To compare the sensitivity, specificity, predictive values and accuracy of detection of oestrus using a novel oestrus detection strip (ODS) and a camera-software device (CSD) with typical farm management practices of visual observation and use of tail paint in dairy cattle at pasture.Dairy cows (n = 480) in a seasonal-calving herd managed at pasture under typical commercial conditions in New Zealand were stratified by age, body condition score and days in milk, then randomly allocated to one of two groups prior to the planned start of mating (PSM). Tail paint was applied to all cows and oestrus detected by visual observation of oestrous behaviour and removal of paint, by farm staff. One group (n = 240) was fitted with ODS and also monitored for signs of oestrus using a CSD, while the Control group (n = 240) was monitored using tail paint and visual observations only. Cows detected in oestrus were artificially inseminated (AI), and pregnancy status determined using rectal palpation and ultrasonography, 51-52 days after the end of a 55-day A period. Results of pregnancy diagnosis were used to confirm the occurrence of oestrus, and the sensitivity, specificity, predictive value and accuracy of detection of oestrus compared between oestrus detection methods.The sensitivity and accuracy of oestrus detection in the Control group, using visual observation and tail paint, were low. Compared with the Control group, detection of oestrus using the ODS and CSD resulted in greater sensitivity (85% vs 78%; p = 0.006), specificity (99.6% vs 98.0%; p0.001), positive predictive value (PPV; 88% vs 51%; p0.001) and overall accuracy (99.0% vs 98.0%; p0.001). Negative predictive value (NPV) did not differ significantly between groups (99.4% vs 99.3%; p = 0.28). Pregnancy rate to first service was higher in the CSD group than in the Control group (72% vs 39%; p0.05). Use of the CSD significantly increased the cumulative proportion of cows pregnant to AI over the breeding period (p = 0.044).The ODS and CSD was satisfactory for detection of oestrus in seasonal calving dairy herds grazing on pasture and could improve the sensitivity and accuracy of detection of oestrus in herds where these are low.

This was an observational study of 828 lactations in 542 mixed-age dairy cows that calved seasonally in a single, pasture-fed herd in New Zealand in 2008 and 2009. The study objectives were to: (i) document daily liveweight change (∆LW) before and after observed oestrus for cows subsequently diagnosed pregnant or non-pregnant and (ii) quantify the sensitivity and specificity of ∆LW as a test for oestrus. The sensitivity and specificity of ∆LW when combined with other commonly used oestrous detection methods was also evaluated. In cows that conceived as a result of service at detected oestrus, liveweight loss began 1 day before the day of detection and was greatest on the day of detection (−9.6 kg, 95% CI −11.3 kg to −7.8 kg; p < 0.01) compared with LW recorded 2 days before the day of detection. In cows that did not conceive to a service at a detected oestrus, the lowest liveweights were recorded 1 day before the day oestrus was detected (−4.3 kg, 95% CI −7.7 to −0.8 kg; p = 0.02) compared with LW recorded 4 days before the day of detection. The sensitivity and specificity of ∆LW as a means of oestrous detection were 0.42 (95% CI 0.40–0.45) and 0.96 (95% CI 0.95–0.97), respectively. When ∆LW was combined with tail paint and visual observation, the oestrous detection sensitivity and specificity were 0.86 and 0.94, respectively. Monitoring LW change holds promise to enhance the sensitivity and specificity of oestrous detection in combination with other oestrous detection methods.

Estimates of point prevalence suggest that locomotion scoring identifies three times as many lame cows than when estimated by farmers. The aim of this study was to ascertain the impact of this under-recognition on the interval between identification of lameness (using locomotion score) and treatment. The study was undertaken on a 463-cow, spring-calving, pasture-fed herd in the lower North Island of New Zealand. All cows were locomotion scored (using a 1-5 scale) weekly during one milking season (July 2008 to May 2009). Survival analyses were then used to quantify the number of days between identification of a specific locomotion score and presentation, by farm staff, of a cow for lameness treatment. All cows which had a locomotion score of >3 were presented for lameness treatment subsequently, although >40% were treated more than 3 weeks after being identified. Only 75% of events where cows had a locomotion score of 3 were followed by treatment with >65% of those treatments occurring >3 weeks after the first score of 3. Improving the recognition of lameness by farm staff is thus likely to appreciably reduce the interval between reduced mobility and lameness treatment.

This study investigated the effect of lameness on liveweight (LW) in pasture-fed dairy cattle. The data comprised 222,446 averaged daily LW measurements from 828 lactations of 542 mixed-age cows in a seasonally calving, pasture-fed New Zealand dairy herd. The LW measurements for individual cows were aggregated into weekly averages and analyses conducted to evaluate the effect of a diagnosis of lameness on LW change after controlling for the effect of week in milk, parity, LW at calving, breed, calendar month, and season. In lame cows, LW decreased for up to 3 wk before lameness was diagnosed and for up to 4 wk after treatment. Total LW loss arising from a single lameness episode was, on average, 61 kg (95% confidence interval: 47 to 74 kg). The results from this study demonstrate how LW records for individual animals can be used to enhance a herd manager's ability to detect lame cows and present them for treatment. The methods presented here show how daily LW monitoring might be used as a tool for early detection of lameness in dairy cattle.

The effect of lameness on the fertility of dairy cattle is well recognized. But, the effect of lameness on the fertility of seasonally breeding cattle in pasture-based systems is less well characterized. This prospective cohort study of 463 cows on 1 farm in the lower North Island of New Zealand was designed to assess the effect of clinical lameness, as identified by farm staff, on the hazard of conception after the planned start-of-mating date. A Cox proportional hazards model with time-varying covariates was used. After controlling for the effect of parity, breed, body weight at calving, and calving-to-planned start of mating interval, the daily hazard of conception for cows identified as lame was 0.78 (95% confidence interval: 0.68–0.86) compared with non-lame cows. Lame cows took 12d longer to get pregnant compared with their non-lame counterparts.

Daily walkover liveweight (WoLW) records (n=79,697) from 463 pasture-fed dairy cows from a single dairy herd in the lower North Island of New Zealand were recorded over the first 100 d of lactation. The aims of this study were to (1) describe LW records retrieved by a standalone automatic Wo daily weighing system; (2) describe the frequency and nature of outlier LW records measured by the system and develop an approach for excluding identified outlier LW records; (3) quantify the agreement between cow LW measured using the Wo system and those measured statically; and (4) describe the autocorrelation between daily LW measurements to provide an indication of how frequently management decisions need to be reviewed to effectively monitor cow LW change in the early-lactation period. The standard deviation of daily LW measurements across parities was 17kg, on average. A near perfect association between LW measured statically and WoLW (concordance correlation coefficient 0.99, 95% CI 0.99–1.0) was observed. After controlling for the effect of LW at calving and long-term LW change using a mixed-effects linear regression model, the autocorrelation between WoLW recorded on successive days was 0.21, decaying to zero by 8 d. This study shows that by using a standalone automatic Wo weighing system positioned in the exit race of a rotary milking parlor, it was possible to record LW of individual cows on a daily basis and, with controlled cow flow over the weighing platform (allowing for sufficient succession distance to prevent congestion), results were similar to those recorded using conventional, static weighing techniques using the same scales. Based on the autocorrelation analyses, we recommend that LW are recorded on a daily basis to allow changes in physiological status such as the onset of acute illness or estrus to be detected. For managerial purposes, such as using LW change as a guide for adjusting the herd feeding program, we recommend a 7-d decision interval to effectively monitor significant changes in cows' recorded daily LW measurements.