Using animal-mounted sensor technology and machine learning to predict time-to-calving in beef and dairy cows.

Worldwide, there is a trend towards increased herd sizes, and the animal-to-stockman ratio is increasing within the beef and dairy sectors; thus, the time available to monitoring individual animals is reducing. The behaviour of cows is known to change in the hours prior to parturition, for example, less time ruminating and eating and increased activity level and tail-raise events. These behaviours can be monitored non-invasively using animal-mounted sensors. Thus, behavioural traits are ideal variables for the prediction of calving. This study explored the potential of two sensor technologies for their capabilities in predicting when calf expulsion should be expected. Two trials were conducted at separate locations: (i) beef cows (n = 144) and (ii) dairy cows (n = 110). Two sensors were deployed on each cow: (1) Afimilk Silent Herdsman (SHM) collars monitoring time spent ruminating (RUM), eating (EAT) and the relative activity level (ACT) of the cow, and (2) tail-mounted Axivity accelerometers to detect tail-raise events (TAIL). The exact time the calf was expelled from the cow was determined by viewing closed-circuit television camera footage. Machine learning random forest algorithms were developed to predict when calf expulsion should be expected using single-sensor variables and by integrating multiple-sensor data-streams. The performance of the models was tested using the Matthew's correlation coefficient (MCC), the area under the curve, and the sensitivity and specificity of predictions. The TAIL model was slightly better at predicting calving within a 5-h window for beef cows (MCC = 0.31) than for dairy cows (MCC = 0.29). The TAIL + RUM + EAT models were equally as good at predicting calving within a 5-h window for beef and dairy cows (MCC = 0.32 for both models). Combining data-streams from SHM and tail sensors did not substantially improve model performance over tail sensors alone; therefore, hour-by-hour algorithms for the prediction of time of calf expulsion were developed using tail sensor data. Optimal classification occurred at 2 h prior to calving for both beef (MCC = 0.29) and dairy cows (MCC = 0.25). This study showed that tail sensors alone are adequate for the prediction of parturition and that the optimal time for prediction is 2 h before expulsion of the calf.

Use of novel sensors combining local positioning and acceleration to measure feeding behavior differences associated with lameness in dairy cattle.

Time constraints for dairy farmers are an important factor contributing to the under-detection of lameness, resulting in delayed or missed treatment of lame cows within many commercial dairy herds. Hence, a need exists for flexible and affordable cow-based sensor systems capable of monitoring behaviors such as time spent feeding, which may be affected by the onset of lameness. In this study a novel neck-mounted mobile sensor system that combines local positioning and activity (acceleration) was tested and validated on a commercial UK dairy farm. Position and activity data were collected over 5 consecutive days for 19 high-yield dairy cows (10 lame, 9 nonlame) that formed a subset of a larger (120 cow) management group housed in a freestall barn. A decision tree algorithm that included sensor-recorded position and accelerometer data was developed to classify a cow as doing 1 of 3 categories of behavior: (1) feeding, (2) not feeding, and (3) out of pen for milking. For each classified behavior the mean number of bouts, the mean bout duration, and the mean total duration across all bouts was determined on a daily basis, and also separately for the time periods in between milking (morning = 0630-1300 h; afternoon = 1430-2100 h; night = 2230-0500 h). A comparative analysis of the classified cow behaviors was undertaken using a Welch t-test with Benjamini-Hochberg post-hoc correction under the null hypothesis of no differences in the number or duration of behavioral bouts between the 2 test groups of lame and nonlame cows. Analysis showed that mean total daily feeding duration was significantly lower for lame cows compared with non-lame cows. Behavior was also affected by time of day with significantly lower mean total duration of feeding and higher total duration of nonfeeding in the afternoons for lame cows compared with nonlame cows. The results demonstrate how sensors that measure both position and acceleration are capable of detecting differences in feeding behavior that may be associated with lameness. Such behavioral differences could be used in the development of predictive algorithms for the prompt detection of lameness as part of a commercially viable automated behavioral monitoring system.

Investigating the value dairy farmers place on a reduction of lameness in their herds using a willingness to pay approach.

A survey was conducted to elicit dairy farmers' willingness to pay (WTP) to reduce the prevalence of lameness in their herds. A choice experiment questionnaire was administered using face-to-face interviews of 163 farmers in England and Wales. Whole herd lameness assessments by trained researchers recorded a mean lameness prevalence of nearly 24% which was substantially higher than that estimated by farmers. Farmers' responses to a series of attitudinal questions showed that they strongly agreed that cows can suffer a lot of pain from lameness and believed that they could reduce lameness in their herds. Farmers' mean WTP to avoid lameness amounted to UK£411 per lame cow but with considerable variation across the sample. Median WTP of UK£249 per lame cow was considered a better measure of central tendency for the sample. In addition, the survey found that farmers had a substantial WTP to avoid the inconvenience associated with lameness control (a median value of UK£97 per lame cow) but that they were generally prepared to incur greater inconvenience if it reduced lameness. The study findings suggest that farmers need a better understanding of the scale and costs of lameness in their herds and the benefits of control. To encourage action, farmers need to be convinced that lameness control measures perceived as inconvenient will be cost effective.

Reducing lameness in dairy herds--overcoming some barriers.

Incomplete detection, high tolerance of lameness, and shortage of time and labour have been identified as barriers to reducing lameness in dairy herds. The effects of farmer participation in a project aimed at reducing lameness in dairy cattle on these factors were investigated. Over the course of the project farmers' detection of lameness improved and tolerance decreased. On farms entering the study with lameness prevalence below the median of 35%, improved detection was correlated with a reduction in lameness prevalence, but this was not the case for farms entering above the median prevalence. Lowered tolerance of lameness was correlated with reduced lameness regardless of initial prevalence. A greater importance given to lack of time as an initial barrier to progress was correlated with a greater reduction in lameness over the course of the project, suggesting that farmers who recognised limited time as a barrier were able to overcome this to some extent.

Promoting farmer engagement and activity in the control of dairy cattle lameness.

Many 'influencers' allied to the agricultural industry support farmers to implement management changes that affect animal welfare. Developing approaches to working with farmers that achieve both engagement and subsequently management changes is critical. As an example, the generation of action points and implementation of change to control dairy cattle lameness is reported and discussed here. Action plans were generated on farms receiving both lameness monitoring and intervention support (MS group; n=117) as part of a 3 year intervention project. At the start of year 1, MS farmers received action planning advice from a veterinary surgeon, and then at the start of years 2 and 3, farmers generated their own lameness control action plans with facilitator support. Engagement was achieved with 114 MS farmers who generated 692 action points in total. Two hundred and sixteen of these resulted from veterinary advice and 476 were generated by the farmers with facilitator support. In terms of activity, MS farms implemented a mean of 8.22 changes per farm as compared to 6.77 on farms which only received annual lameness monitoring (MO group; n=72). While these levels of change were similar, fewer changes implemented on the MS farms (8.5%) were judged 'likely to increase the risk of lameness' compared to the MO farms (16.5%). Farmers generated substantial numbers of lameness control action points for their own farms aided by a facilitator and, crucially, veterinary or facilitator involvement reduced changes that were likely to compromise lameness control.

Evaluating an intervention to reduce lameness in dairy cattle.

Lameness in dairy cattle remains a significant welfare concern for the UK dairy industry. Farms were recruited into a 3-yr study evaluating novel intervention approaches designed to encourage farmers to implement husbandry changes targeted toward reducing lameness. All farms completing the study were visited at least annually and received either monitoring only (MO, n=72) or monitoring and additional support (MS, n = 117) from the research team. The additional support included traditional technical advice on farm-specific solutions, facilitation techniques to encourage farmer participation, and application of social marketing principles to promote implementation of change. Lameness prevalence was lower in the MO (27.0 ± 1.94 SEM) and MS (21.4 ± 1.28) farms at the final visit compared with the same MO (38.9 ± 2.06) and MS (33.3 ± 1.76) farms on the initial visit. After accounting for initial lameness, intervention group status, and year of visit within a multilevel model, we observed an interaction between year and provision of support, with the reduction in lameness over time being greater in the MS group compared with the MO group. Farms in the MS group made a greater number of changes to their husbandry practices over the duration of the project (8.2 ± 0.39) compared with those farms in the MO group (6.5 ± 0.54). Because the lameness prevalence was lower in the MS group than the MO group at the start of the study, the contribution of the additional support was difficult to define. Lameness can be reduced on UK dairy farms although further work is needed to identify the optimum approaches.

Sampling strategies for monitoring lameness in dairy cattle.

Evaluating the prevalence of lameness within herds of dairy cattle is important for management and certification purposes; however, sampling strategies that could reduce the time taken for an assessment would be valuable. The prevalence of lame and severely lame cows on 224 United Kingdom dairy farms was available for analysis. Presence of more than 1 severely lame cow on a farm was a useful indication of a lameness problem. The vast majority (80%) of the 182 farms that had > or = 1 severely lame cow present had an overall lameness prevalence >25%, whereas only 24% of the 42 farms that had no severely lame cows had an overall prevalence >25%. Information was available on individual milking order through the parlor on the day of the lameness assessment. On 37 farms where cows were housed in a group, lameness prevalence was 11.9% greater in the last third compared with the first third of the milking order. For 36 herds that were larger than 100 cows, sampling a maximum of 100 cows from the middle of the milking order produced an estimate of prevalence within 5% of the true prevalence on 83% of farms. A reasonable sampling strategy may, therefore, be to observe up to 100 cows from the middle of the milking order. Also, presence of severely lame cows at the end of milking may be useful for identifying those farms likely to benefit from further support.

Working towards a reduction in cattle lameness: 2. Understanding dairy farmers' motivations.

Reducing lameness in dairy herds requires farmers to adapt or change existing practices or resources. Those who seek to improve animal welfare by influencing the actions of farmers need to understand farmers' motivations. To investigate why farmers see lameness as a problem and what motivates their efforts to reduce lameness, a questionnaire was carried out with 222 UK dairy farmers. Farmers considered pain and suffering for the cows to be an important outcome of lameness, but reduced performance by lame cows was also seen as a considerable problem. The motivator most commonly given high importance was pride in a healthy herd. Factors incorporating accreditation issues, public image and costs of treatment were generally seen to be of some, but lesser importance. Advisors need to take all these areas into consideration when working to encourage farmers to act to reduce lameness and thereby improve animal welfare.

Working towards a reduction in cattle lameness: 1. Understanding barriers to lameness control on dairy farms.

On 222 dairy farms, the farmer's perception of the scale of the herd lameness problem was compared with the prevalence detected by observation of the milking herd, and a questionnaire explored the barriers to lameness reduction. Ninety percent of farmers did not perceive lameness to be a major problem on their farm, although the average prevalence of lameness was 36%. For 62% of the sample, lameness was not the top priority for efforts made to improve herd health. Time and labour were important limiting factors for lameness control activities and financial constraints prevented farmers taking action on advice in 30% of cases. Farmers' understanding the implications of lameness for the farm business was limited. Lameness reduction is restricted by farmers' perception of lameness, but also by time, labour and finance; these issues need to be addressed at the industry level to support animal welfare improvement.

Assessment of lameness prevalence and associated risk factors in dairy herds in England and Wales.

Visits were made to 205 dairy farms in England and Wales between October 2006 and May 2007 by 1 or more of 4 researchers. At each visit, all milking cows were locomotion scored (lameness scored) using a 4-point scale (0=sound locomotion, 1=imperfect locomotion, 2=lame, 3=severely lame). The mean prevalence of lameness (scores 2 and 3) across the study farms was 36.8% (range=0-79.2%). On each farm, the presence within the housing and grazing environments of commonly reported risks for increased lameness was recorded. Each farmer was interviewed to gauge the ability of the farm staff to detect and treat lameness. A multivariable linear regression model was fitted. Risk factors for increased lameness were the presence of damaged concrete in yards, cows pushing each other or turning sharply near the parlor entrance or exit, cattle grazing pasture also grazed by sheep, the use of automatic scrapers, not treating lame cows within 48h of detection, and cows being housed for 61 d or longer at the time they were locomotion scored by the visiting researcher. Having a herd consisting entirely of a breed or breeds other than Holstein-Friesian was associated with a reduction in lameness prevalence compared with having a herd consisting entirely of Holstein-Friesians.

Risk factors for increased rates of sole ulcers, white line disease, and digital dermatitis in dairy cattle from twenty-seven farms in England and Wales.

Claw lesion treatment records were recorded by farmers on 27 dairy farms (3,074 cows, 36,432 records) in England and Wales between February 2003 and February 2004. These were combined with farm environment and management data collected using a combination of direct observations, interviews with farmers, and milk recording data. Multilevel models were constructed for the 3 most frequently reported lesions related to lameness, namely, sole ulcers, white line disease, and digital dermatitis. Risks associated with an increased incidence of sole ulcers were parity 4 or greater, the use of roads or concrete cow tracks between the parlor and grazing, the use of lime on free stalls, and housing in free stalls with sparse bedding for 4 mo or more. The risks for white line disease were increasing parity and increasing herd size, cows at pasture by day and housed at night, and solid grooved concrete floors in yards or alleys. Solid grooved flooring was also associated with an increased risk of digital dermatitis, and cows 6 or more months after calving had a decreased risk of a first case of digital dermatitis. These results improve our understanding of the specific risks for 3 important lesions associated with bovine lameness and could be used as interventions in future clinical studies targeted at the reduction of specific lesions.

Associations between sole ulcer, white line disease and digital dermatitis and the milk yield of 1824 dairy cows on 30 dairy cow farms in England and Wales from February 2003-November 2004.

The milk yields of 1824 cows were used to investigate the effect of lesion-specific causes of lameness, based on farmer treatment and diagnosis of lame cows, on milk yield. A three-level hierarchical model of repeated test day yields within cows within herds was used to investigate the impact of lesion-specific causes of lameness (sole ulcer, white line disease, digital dermatitis and other causes) on milk yield before and after treatment compared with unaffected cows. Cattle which developed sole ulcer (SU) and white line disease (WLD) were higher yielding cattle before they were diagnosed. Their milk production fell to below that of the mean of unaffected cows before diagnosis and remained low after diagnosis. In cattle which developed digital dermatitis (DD) there was no significant difference in milk yield before treatment and a slightly raised milk yield immediately after treatment. The estimated milk loss attributable to SU and WLD was approximately 570 and 370 kg, respectively. These results highlight that specific types of lameness vary by herds and within herds they are associated with higher yielding cattle. Consequently lesion-specific lameness reduction programmes targeting the cow and farm specific causes of lameness might be more effective than generic recommendations. They also highlight the importance of milk loss when estimating the economic impact of SU and WLD on the farms profitability.

Management factors associated with impaired locomotion in dairy cows in England and Wales.

Forty-nine farms in England and Wales were visited on 4 occasions between February 2003 and March 2004. A total of 21,693 scores of locomotion were assigned to 7,722 cattle. Locomotion was assessed on a 3-point scale by observing the posture of a cow's back while standing and walking (1 = sound, 2 = not sound, 3 = lame). Data on measurable factors potentially associated with locomotion were collected from all farms using direct observations of the farm environment and a comprehensive farmer interview. The mean herd locomotion score was 1.77 +/- 0.02. There was no significant difference in mean herd locomotion scores between 5 herds housed in straw yards (1.72 +/- 0.02) and 44 herds housed in free stalls (1.78 +/- 0.02), possibly because of lack of power. A GLM was produced using data from the 44 herds housed in free stalls, with the mean farm locomotion score of all cows examined on all 4 visits as the outcome variable. Factors associated with an elevated locomotion score were dry cows kept in straw yards compared with free stalls (increase in locomotion score = 0.06 +/- 0.03), pregnant heifers kept with milking cows in winter compared with being kept with dry cows (increase in locomotion score = 0.09 +/- 0.03), aisle widths of < 3 m compared with widths of > or = 3 m (increase in locomotion score = 0.06 +/- 0.02), a curb height of < or = 15 cm compared with a height of > 15 cm (increase in locomotion score = 0.07 +/- 0.03), routine trimming of hooves of all cows by a hoof trimmer or by the farmer compared with no routine hoof trimming (increase in locomotion score = 0.18 +/- 0.04 and 0.13 +/- 0.03 respectively), feeding corn silage to milking cows compared with feeding other forage types (increase in locomotion score = 0.10 +/- 0.03), and the use of automatic scrapers in the free-stall barn compared with tractor scrapers (increase in locomotion score = 0.10 +/- 0.03). These variables were correlated with many other management variables. The use of automatic scrapers was correlated with the use of sawdust on rubber mats in free stalls. Curb height was negatively correlated with increasing distance of the neck rail from the front (head end) of the free stall. These putative risk factors support the hypothesis that locomotion score is linked to management factors; in particular, the combination of sawdust on rubber mats with automatic scrapers was associated with elevated locomotion scores.

Risk factors for reduced locomotion in dairy cattle on nineteen farms in The Netherlands.

A 3-point locomotion scoring system was used that incorporated the position of the back of cows while standing and when walking to investigate risk factors for elevated locomotion scores of 1,450 dairy cows on 19 farms in The Netherlands. Each of the farms was visited twice in an 18-mo period from February 2003 to July 2004. At each visit, all milking and dry cows were scored for locomotion by a single observer. Two multivariable regression models were constructed to identify factors associated with elevated mean locomotion score (increased abnormality) and the percentage of cows with the highest score (score 3). Risk factors for increased locomotion score were having a hoof-trimming stall with foot-lifting apparatus compared with not having such apparatus (increase in locomotion score = 0.15), presence of a footbath at the parlor exit or other site compared with not having a footbath on the farm (increase in locomotion score = 0.17 and 0.19, respectively), not providing supplemental vitamins and minerals to lactating cows compared with supplementing animals (increase in locomotion score = 0.17) and feeding corn silage to heifers compared with not doing so (increase in locomotion score = 0.10). The results provide a framework for hypotheses for future investigations of risk factors for high locomotion scores.