J. I. Alawneh

The effect of lameness on the fertility of dairy cattle in a seasonally breeding pasture-based system

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 12 d longer to get pregnant compared with their non-lame counterparts.

Interval between detection of lameness by locomotion scoring and treatment for lameness: a survival analysis.

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.

Description of the pig production systems, biosecurity practices and herd health providers in two provinces with high swine density in the Philippines

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.

Comparison of a camera-software system and typical farm management for detecting oestrus in dairy cattle at pasture

Abstract AIM: 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. METHODS: 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 AI 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. RESULTS: 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%; p<0.001), positive predictive value(PPV;88% vs 51%;p<0.001) and overall accuracy (99.0% vs 98.0%; p<0.001). 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%; p<0.05). Use of the CSD significantly increased the cumulative proportion of cows pregnant to AI over the breeding period (p=0.044). CONCLUSION AND CLINICAL RELEVANCE: 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.

The effect of clinical lameness on liveweight in a seasonally calving, pasture-fed dairy herd

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 managers 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 effects of liveweight loss and milk production on the risk of lameness in a seasonally calving, pasture fed dairy herd in New Zealand

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.

Prevalence and risk factors associated with gross pulmonary lesions in slaughtered pigs in smallholder and commercial farms in two provinces in the Philippines

A cross-sectional study of lungs from 1,887 randomly selected pigs from 471 farms from two provinces in the Philippines was carried out to estimate the prevalence of gross pathological lesions, identify potential risk factors and spatial clustering associated with high lung or pleurisy score farms. Lungs from pigs were scored at slaughter. Interviews with the farm managers were conducted to collect information about farm management and biosecurity practices. Of lungs examined, 48% had a lung score above 6 (maximum was 55) and 22% showed pleurisy. When data were aggregated at the farm level, commercial farms were at higher risk of being high lung score farms and high pleurisy farms compared to smallholder farms (P < 0.01). Variables that were associated with an increased risk of a farm being a high lung score farm included the presence of a market pen on the farm, not vaccinating against hog cholera and the presence of another piggery within 500 m. Practicing “feedback” (feeding pig manure, viscera or aborted material to pigs), presence of another piggery within 500 m, and allowing commercial livestock vehicles on farm were all associated with an increased risk of being a high pleurisy farm. Spatial analyses revealed a primary 9.6 km-radius cluster of 39 farms with high lung and pleurisy scores in the southeast of Bulacan province. High lung and pleurisy score farms could be targeted to improve on-farm disease control programs to reduce the risk of respiratory diseases. Clusters of high scoring farms could be prioritized for further investigations or for coordinating intervention efforts.

A systematic review of tests for the detection and diagnosis of foot lesions causing lameness in dairy cows

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.

Functionality and Interfaces of a Herd Health Decision Support System for Practising Dairy Cattle Veterinarians in New Zealand

Decision-making processes to assess and improve the health of dairy herds are often unstructured due to the complexity of interactions that exist between the health and productivity of the herd, for which there are no ready to hand solutions. Decisions made in the face of these complex herd health problems are often based on the experience and perceptions of what might be a quick or the easiest solution. To shift from this unstructured process to semistructured decision-making requires a more holistic understanding of potential health problems and access to herd productivity information and to analytical methods suitable for examining and evaluating such data. Technological advances in agriculture have made the development of such information technology systems both possible and relatively accessible to decision makers working with dairy herds (e.g., veterinarians). The timely access and appropriate analysis of herd productivity data provides the herd health advisor with the opportunity to track and benchmark the performance of dairy herds. Thus, a decision support system (DSS) will use best available evidence to guide the allocation of resources to specific, most promising herd health interventions. This article presents an example of a DSS-based on collection of data and algorithm of analysis.

Technical Skills Training for Veterinary Students: A Comparison of Simulators and Video for Teaching Standardized Cardiac Dissection

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 horses 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 horses 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.