Objective estimation of body condition score by modeling cow body shape from digital images.

Body condition score (BCS) is considered an important tool for management of dairy cattle. The feasibility of estimating the BCS from digital images has been demonstrated in recent work. Regression machines have been successfully employed for automatic BCS estimation, taking into account information of the overall shape or information extracted on anatomical points of the shape. Despite the progress in this research area, such studies have not addressed the problem of modeling the shape of cows to build a robust descriptor for automatic BCS estimation. Moreover, a benchmark data set of images meant as a point of reference for quantitative evaluation and comparison of different automatic estimation methods for BCS is lacking. The main objective of this study was to develop a technique that was able to describe the body shape of cows in a reconstructive way. Images, used to build a benchmark data set for developing an automatic system for BCS, were taken using a camera placed above an exit gate from the milking robot. The camera was positioned at 3 m from the ground and in such a position to capture images of the rear, dorsal pelvic, and loin area of cows. The BCS of each cow was estimated on site by 2 technicians and associated to the cow images. The benchmark data set contained 286 images with associated BCS, anatomical points, and shapes. It was used for quantitative evaluation. A set of example cow body shapes was created. Linear and polynomial kernel principal component analysis was used to reconstruct shapes of cows using a linear combination of basic shapes constructed from the example database. In this manner, a cow's body shape was described by considering her variability from the average shape. The method produced a compact description of the shape to be used for automatic estimation of BCS. Model validation showed that the polynomial model proposed in this study performs better (error=0.31) than other state-of-the-art methods in estimating BCS even at the extreme values of BCS scale

Involvement of the digital cushion and the distal phalanx in the development and reoccurrence of claw horn disruption lesions in dairy cattle

Claw horn disruption lesions (CHDLs: sole haemorrhage, sole ulcer and white line disease) cause a large proportion of lameness in dairy cattle and have a high rate of recurrence, yet their aetiopathogenesis remains poorly understood. Untreated CHDLs appear to be associated with trauma within and damage to the internal anatomy of the foot. Chapter 2 explored associations between abnormal bone modelling on the flexor tuberosity of the distal phalanx of cull cows and lameness during life, using a retrospective cohort study design. The hind claws of 72 Holstein dairy cows culled from a research herd were imaged using μ-computed tomography (CT) and lameness and lesion incidence data were available on cows throughout life. Four measures of bone modelling were taken from CT images from the flexor tuberosity of each distal phalanx, in plantar, distal and dorsal planes, and combined within claw. Bone modelling was greater in older cows, in cows with history of CHDL and in cows that had been lame at an increased proportion of locomotion scores during the 12 months preceding slaughter. Further, histological study demonstrated that the bone modelling resembled heterotopic ossification, also termed osteoma, which could have been due to either inappropriate force transfer through the distal phalanx or pathology in the soft tissues with lesion presence. Anatomical damage within the foot does appear to be associated with lameness and CHDLs, and may further predispose lameness. Preventing lameness constitutes a critical component of lameness control, and prophylactic foot trimming is a common management strategy for maintaining claw structure and function. However, over-trimming can cause damage to the foot architecture and lameness. Step 1 of the widely used Dutch Method of foot trimming states to cut the dorsal wall of the hoof to 75 mm. A vertical 5 mm step is left at the toe, therefore based on these recommendations, dorsal wall length would be 82 mm if the toe were trimmed to a point and the dorsal wall extended to the floor (at a toe angle of 50°). Chapter 3 used the CT data to assess the minimum dorsal wall length that would be suitable for trimming each claw. The median length was 76 mm (83 if the toe were trimmed to a point) and ranged from 59 to 86 mm; trimming all claws to 75 mm would have over-trimmed 55 % of claws. In a linear regression model, minimum dorsal wall length increased with age and carcass weight; older and larger cows had bigger claws. However, the vast majority of variation in claw length remained unexplained (only 22 % of the null variance was explained). In order to minimise the number of claws that are over-trimmed, recommendations for foot trimming dimensions should be based on the proportion of claws for which a measurement is suitable, rather than on population means. The minimum lengths that would have been suitable for all claws were 93 mm for cows aged ≥4 years and 86 for cows aged <4 years; 7 mm could be taken from these measurements if a step is left at the toe. CHDLs appear to initially occur through trauma to the germinal epithelium of the sole, and Chapters 4, 5 and 6 present a longitudinal study of how the sole soft tissues (SST; i.e. the digital cushion and corium) alter throughout lactation. The digital cushion is a modified layer of the subcutis that is situated beneath the plantar and distal aspects of the distal phalanx and is considered to be important in dissipating forces during foot strike and to protect the germinal epithelium. The digital cushion contains depots of adipose tissue and recent work has identified that body condition loss is a risk factor for lameness. Previous work found that fatter cows had thicker SST and suggested that fat could be mobilized from the digital cushion and causes it to have decreased biomechanical function. The prospective cohort study assessed the SST of 179 parity 1, 2 3 or 4 cows at 5 assessment points, between 8 weeks pre- and 29 weeks post-calving of one lactation. Lesions present on claws and measures of body fat were recorded at each assessment point, and mobility scoring was performed fortnightly from calving. SST thickness at two sites beneath the distal phalanx were used as outcomes in 4-level mixed effects linear regression models (Chapter 5), and was positively correlated with back fat thickness. However, the effect size was much smaller than reported in previous cross-sectional work and only apparent under some circumstance. SST was thicker when a sole ulcer was present on a claw and was thinner immediately after calving (during the 4-10 days post-calving). The final model left 61 % of the null variance unexplained, of which 48 % remained between repeated measures of the same claw at different assessment points. Chapter 6 presents a series of logistic regression models of survival to first lesion or to first lameness (repeated lameness events were initially tested, but models were discarded due to the high rates of recurrence of both lameness and lesions). Lesion models demonstrate that claws were more likely to develop a lesion if SST was thin, and there was an additional effect of having thin back fat (all animals) or having lost back fat between previous assessment points (parity >1 animals only). Lameness models demonstrated that thin SST on the lateral claw increased the odds of a leg becoming lame, but SST on the medial claw had no effect on lameness. Change in SST thickness did not predispose lesions or lameness; only absolute thinness did. The work suggests that whilst loss of body condition loss may be one variable that contributes towards thinning of SST and subsequent claw horn disruption, many other variables also had a large effect on SST thickness, CHDL and lameness. This thesis presents a sequence of studies of how the anatomy of the foot is related to CHDL incidence, addressing recurrent lameness, mechanisms for the onset of new lameness and the appropriateness of prophylactic foot trimming guidelines as a management tool for lameness. The research literature is deficient in work demonstrating beneficial effects of interventions on lameness, and work throughout this thesis provides novel insights into the aetiopathogenesis of the claw horn disruption lesions. Based on this work, targeted interventions to reduce lameness can be tested

Mechanical properties of hoof horn, sole haemorrhage and lameness in dairy cattle

Merged with duplicate record 10026.1/859 on 27.03.2017 by CS (TIS)The present study aimed to develop a method to measure changes in the mechanical properties of the sole and white line hoof horn that should be used in vivo and to examine the hypothesis that the presence of haemorrhages in the horn would represent a weakening of the structural strength of the horn. Hoof horn samples were collected from the sole and white line areas of the hoof horn of dairy cattle. The maximum punch force, work to fracture, elastic modulus and membrane stress were measured through the use of a punch test and the elastic modulus was measured through the use of a tension test. The elastic modulus of the diaphragm, membrane stress and elastic modulus measured through tension test of the sole and white line areas were found to increase significantly and exponentially (P<0.01, R²adj. = 0.39 to 0.81) and the punch force and work to fracture increased significantly and linearly (P<0.01, R²adj. = 0.37 to 0.89) in relation to the dry matter content of the hoof horn. Sample thickness accounted for 30 to 40 % of the variation of the punch force and work to fracture results, therefore the thickness of the tested area was measured and included as a covariant in the statistical analysis of those tests. Punch force of the sole area of the claw horn decreased significantly (P<0.001) (8.72, 8.53, 8.06, 7.75, 6.08, 4.99 N, sem 0.078 to 0.460) when haemorrhage levels of the tested area increased (0 to 5). In multiparous cows that had higher scores for lesions of the claw horn when compared to the heifers the punch force decreased at day 160 postpartum when the cows had greater lesion scores and was lower in hind claws that had higher lesion scores when compared to the front claws. Lower punch force and elastic modulus were found in heifers with less straight rear legs, lower foot angle, poor HUKI locomotion score, lower scores for the composite trait legs and feet and a higher HUKI final total score. The measurement of the mechanical properties of the hoof horn has contributed to the understanding of the changes occurring during the peripartum period that predispose dairy cows to acquire horn lesions and suffer from lameness and has proven to be a good method for measuring the influence of housing systems and cow conformation on the strength and elasticity of the horn

Involvement of the digital cushion and the distal phalanx in the development and reoccurrence of claw horn disruption lesions in dairy cattle

Claw horn disruption lesions (CHDLs: sole haemorrhage, sole ulcer and white line disease) cause a large proportion of lameness in dairy cattle and have a high rate of recurrence, yet their aetiopathogenesis remains poorly understood. Untreated CHDLs appear to be associated with trauma within and damage to the internal anatomy of the foot. Chapter 2 explored associations between abnormal bone modelling on the flexor tuberosity of the distal phalanx of cull cows and lameness during life, using a retrospective cohort study design. The hind claws of 72 Holstein dairy cows culled from a research herd were imaged using μ-computed tomography (CT) and lameness and lesion incidence data were available on cows throughout life. Four measures of bone modelling were taken from CT images from the flexor tuberosity of each distal phalanx, in plantar, distal and dorsal planes, and combined within claw. Bone modelling was greater in older cows, in cows with history of CHDL and in cows that had been lame at an increased proportion of locomotion scores during the 12 months preceding slaughter. Further, histological study demonstrated that the bone modelling resembled heterotopic ossification, also termed osteoma, which could have been due to either inappropriate force transfer through the distal phalanx or pathology in the soft tissues with lesion presence. Anatomical damage within the foot does appear to be associated with lameness and CHDLs, and may further predispose lameness. Preventing lameness constitutes a critical component of lameness control, and prophylactic foot trimming is a common management strategy for maintaining claw structure and function. However, over-trimming can cause damage to the foot architecture and lameness. Step 1 of the widely used Dutch Method of foot trimming states to cut the dorsal wall of the hoof to 75 mm. A vertical 5 mm step is left at the toe, therefore based on these recommendations, dorsal wall length would be 82 mm if the toe were trimmed to a point and the dorsal wall extended to the floor (at a toe angle of 50°). Chapter 3 used the CT data to assess the minimum dorsal wall length that would be suitable for trimming each claw. The median length was 76 mm (83 if the toe were trimmed to a point) and ranged from 59 to 86 mm; trimming all claws to 75 mm would have over-trimmed 55 % of claws. In a linear regression model, minimum dorsal wall length increased with age and carcass weight; older and larger cows had bigger claws. However, the vast majority of variation in claw length remained unexplained (only 22 % of the null variance was explained). In order to minimise the number of claws that are over-trimmed, recommendations for foot trimming dimensions should be based on the proportion of claws for which a measurement is suitable, rather than on population means. The minimum lengths that would have been suitable for all claws were 93 mm for cows aged ≥4 years and 86 for cows aged <4 years; 7 mm could be taken from these measurements if a step is left at the toe. CHDLs appear to initially occur through trauma to the germinal epithelium of the sole, and Chapters 4, 5 and 6 present a longitudinal study of how the sole soft tissues (SST; i.e. the digital cushion and corium) alter throughout lactation. The digital cushion is a modified layer of the subcutis that is situated beneath the plantar and distal aspects of the distal phalanx and is considered to be important in dissipating forces during foot strike and to protect the germinal epithelium. The digital cushion contains depots of adipose tissue and recent work has identified that body condition loss is a risk factor for lameness. Previous work found that fatter cows had thicker SST and suggested that fat could be mobilized from the digital cushion and causes it to have decreased biomechanical function. The prospective cohort study assessed the SST of 179 parity 1, 2 3 or 4 cows at 5 assessment points, between 8 weeks pre- and 29 weeks post-calving of one lactation. Lesions present on claws and measures of body fat were recorded at each assessment point, and mobility scoring was performed fortnightly from calving. SST thickness at two sites beneath the distal phalanx were used as outcomes in 4-level mixed effects linear regression models (Chapter 5), and was positively correlated with back fat thickness. However, the effect size was much smaller than reported in previous cross-sectional work and only apparent under some circumstance. SST was thicker when a sole ulcer was present on a claw and was thinner immediately after calving (during the 4-10 days post-calving). The final model left 61 % of the null variance unexplained, of which 48 % remained between repeated measures of the same claw at different assessment points. Chapter 6 presents a series of logistic regression models of survival to first lesion or to first lameness (repeated lameness events were initially tested, but models were discarded due to the high rates of recurrence of both lameness and lesions). Lesion models demonstrate that claws were more likely to develop a lesion if SST was thin, and there was an additional effect of having thin back fat (all animals) or having lost back fat between previous assessment points (parity >1 animals only). Lameness models demonstrated that thin SST on the lateral claw increased the odds of a leg becoming lame, but SST on the medial claw had no effect on lameness. Change in SST thickness did not predispose lesions or lameness; only absolute thinness did. The work suggests that whilst loss of body condition loss may be one variable that contributes towards thinning of SST and subsequent claw horn disruption, many other variables also had a large effect on SST thickness, CHDL and lameness. This thesis presents a sequence of studies of how the anatomy of the foot is related to CHDL incidence, addressing recurrent lameness, mechanisms for the onset of new lameness and the appropriateness of prophylactic foot trimming guidelines as a management tool for lameness. The research literature is deficient in work demonstrating beneficial effects of interventions on lameness, and work throughout this thesis provides novel insights into the aetiopathogenesis of the claw horn disruption lesions. Based on this work, targeted interventions to reduce lameness can be tested

Area of hock hair loss in dairy cows : risk factors and correlation to a categorical scale

Data from 3691 dairy cows from 76 farms were used to investigate the risk factors associated with area of hair loss over the lateral aspect of the hock, and the correlation between the area of hair loss as calculated using a hock map and hock lesion scores determined using a pre-existing categorical scale. Six factors were associated with a greater area of hair loss, including cows with locomotion score 3, a cleanliness score (10-18/28), high daily milk yield (25.1 - 58.1 kg), poor body condition score (1-1.5), duration of winter housing (≥41 days) and some combinations of cubicle base and bedding materials. Compared with cows housed in cubicles with a concrete base and whole straw or rape straw bedding, cows housed in cubicles with concrete bases with sand or chopped straw bedding had smaller areas of hair loss and cows housed on a mattress base with whole straw or rape straw bedding had a larger area of hair loss. Area of hair loss, as measured on hock maps, was not significantly different between cows with score 1 (median=23.6 cm2) and score 2 (median=20.3 cm2) on the categorical scale for hock lesions. This suggests that the categorical scale was not reflecting the extent of hair loss and that hock maps are a good alternative for studying the dynamics of hock lesions over time. Further work is required to explore the aetiology of hock lesions and find better ways to control this common condition. Keywords: Hock lesions; Hair loss; Dairy cow; Welfare; Hock map

Development of methods to evaluate hoof conformation and lameness in New Zealand dairy goats and the effects of trimming regimes on goat hoof health : a thesis presented in complete fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University (Manawatu) New Zealand

Two papers in the Proceedings of the New Zealand Society of Animal Production were removed from Appendix Four Conference Proceedings, in accordance with publisher policy. The article in Appendix Three is republished under a CC BY-NC-ND license, and linked to the original article: https://doi.org/10.3168/jds.2019-16264Lameness is a debilitating and painful condition. It is considered a major welfare and economic issue in the dairy industry, due to its high prevalence and associated production losses, and the serious impact it has on individual animals. One major risk factor for lameness is hoof overgrowth and consequently poor hoof conformation. Dairy goats in New Zealand are largely housed indoors; such environments offer limited opportunity for natural hoof wear, therefore hoof overgrowth is likely to be common. However, there are few data in New Zealand evaluating hoof conformation, lameness, or how we can best maintain a normally structured hoof and minimise lameness in commercially housed dairy goats. The overarching aim of this thesis was to examine the hoof conformation and gait of New Zealand dairy goats and to evaluate how these factors are impacted by hoof trimming. Specifically, I aimed to develop and validate a hoof conformation assessment for use in dairy goats, and to develop a reliable gait scoring system that would allow detection of an uneven gait as a potential precursor to clinical lameness. Furthermore, I aimed to use these methods to evaluate the immediate impacts of hoof trimming and the longer-term impacts of early life hoof trimming and subsequent trimming frequency on anatomical (e.g., hoof conformation, joint positions, hoof growth) and behavioural (e.g., lying behaviour, gait) variables. The hoof conformation assessment was determined to be reliable following considerable training of observers; both the objective measures and subjective scores could be used to accurately assess aspects of hoof conformation from photographs. As the subjective scores are less time-consuming and do not require technical equipment, I suggest they should be trialed for on-farm use. A reliable 5-point gait scoring system was developed in a controlled setting at the AgResearch Goat Research Facility. It included an “uneven gait” category, allowing identification of goats which may be predisposed to developing clinical lameness. However, whether it is feasible to detect an uneven gait from live observations on commercial farms is still to be determined. In an observational study conducted on 16 farms (n = 1099 goats; mean ± SD: 64 ± 9 goats/farm), goats that had not been trimmed prior to first mating (8.0 ± 0.70 months) had greater odds of poor hind hoof conformation at that time compared with goats on farms that had already trimmed prior to mating. In the longer term, goats on farms that had not trimmed before first kidding (14.8 ± 0.86 months) had greater odds of having dipped heels on the hind hooves at the end of second lactation (34.1 ± 0.90 months). In contrast, in a controlled experimental study conducted on one farm (n = 80 goats), only minor effects of early life trimming (before first kidding) on hoof conformation were found, and these were not consistent at assessments completed at the end of the first (13 months) and second lactations (25 months). In the experimental study, as poor conformation was observed in both the early and late trimmed treatments, it suggests that the subsequent hoof trimming (3 times per year) was not frequent enough to prevent overgrowth; the early life trimming treatment was not effective at this trimming frequency. In the observational study, trimming frequency following first kidding had no observable effects on hoof conformation. However, differences in the housing environment and management may be strongly impacting hoof conformation across the 16 farms. In the short term, immediate beneficial effects of hoof trimming were observed in the experimental study, with aspects of hoof conformation and joint positions restored to more anatomically correct shapes and positions. There was also some evidence of a transient effect of trimming on lying behaviour, with lying time increasing the day after hoof trimming at 3 out of 4 assessments over the first two years of life. An increase in lying time may be indicative of a pain response. However, daily lying behaviour was highly variable so should be interpreted with caution. High proportions of dipped heels, misshaped claws and splayed claws, particularly in the hind hooves, were recorded on 16 farms in the observational study and before trimming in the goats on the experimental study. Interestingly, on the latter farm, the prevalence of clinical lameness (scored from videos) in the same goats was lower than expected over the 2-year study period, though prevalence of an impaired gait (either uneven gait or clinical lameness) peaked after both kidding events. In addition, the rate of hoof growth changed across the goats’ first two years of life, slowing when the goats were in kid. Overall, my findings suggest that the trimming regimes evaluated in these studies were not adequate to prevent poor hoof conformation in goats housed in indoor environments that do not promote hoof wear. In order to achieve good conformation and long-term hoof health, dairy goat hoof management strategies should include consideration of the timing of first hoof trimming and subsequent trimming frequency, as well as providing an environment that promotes hoof wear

Associations of cow and farm characteristics with cow-level lameness using data from an extensive cross-sectional study across 3 structurally different dairy regions in Germany

The aim of the present study was to evaluate the associations between milk recording data, body condition score (BCS), housing factors, management factors, and lameness in freestall-housed dairy cows in 3 structurally different regions in Germany. These regions substantially vary regarding herd size, breeds, access to pasture, farm management (family run or company owned), and percentage of organic farms. The data used was collected in a large cross-sectional study from 2016 to 2019. A total of 58,144 cows from 651 farms in 3 regions of Germany (North, East, and South) was scored for locomotion and body condition. Additionally, data on milk yield, milk composition, breed, age, as well as information on housing and management were retrieved. One mixed-logistic regression model was fitted per region to evaluate the association of the data with the target variable “lame” and to allow for a comprehensive reflection across different kinds of farming types. In all regions, undercondition (BCS lower than recommended for the lactation stage; North: odds ratio [OR] 2.15, CI 1.96–2.34; East: OR 2.66, CI 2.45–2.88; South: OR 2.45, CI 2.01–2.98) and mid-lactation stage (102–204 d in milk; North: OR 1.15, CI 1.05–1.27; East: OR 1.24, CI 1.17–1.32; South: OR 1.38, CI 1.18–1.62) were associated with higher odds for lameness, whereas overcondition (BCS higher than recommended for the lactation stage; North: OR 0.51, CI 0.44–0.60; East: OR 0.51, CI 0.48–0.54; South: OR 0.65, CI 0.54–0.77) and parity of 1 or 2 was associated with lower odds (parity 1 = North: OR 0.32, CI 0.29–0.35; East: OR 0.19, CI 0.18–0.20; South: OR 0.28, CI 0.24–0.33; parity 2 = North: OR 0.51, CI 0.47–0.46; East: OR 0.41, CI 0.39–0.44; South: OR 0.49, CI 0.42–0.57), irrespective of the regional production characteristics. Low energy-corrected milk yield was associated with higher odds for lameness in South and North (North: OR 1.16, CI 1.05–1.27; South: OR 1.43, CI 1.22–1.69). Further factors such as pasture access for cows (North: OR 0.64, CI 0.50–0.82; and South: OR 0.65, CI 0.47–0.88), milk protein content (high milk protein content = North: OR 1.34, CI 1.18–1.52; East: OR 1.17, CI 1.08–1.28; low milk protein content = North: OR 0.79, CI 0.71–0.88; East: OR 0.84, CI 0.79–0.90), and breed (lower odds for “other” [other breeds than German Simmental and German Holstein] in East [OR 0.47, CI 0.42–0.53] and lower odds both for German Holstein and “other” in South [German Holstein: OR 0.62, CI 0.43–0.90; other: OR 0.46, CI 0.34 – 0.62]) were associated with lameness in 2 regions, respectively. The risk of ketosis (higher odds in North: OR 1.11, CI 1.01–1.22) and somatic cell count (higher odds in East: increased (>39.9 cells × 1,000/mL): OR 1.10; CI 1.03–1.17; high (>198.5 cells × 1,000/mL): OR 1.08; CI 1.01–1.06) altered the odds for lameness in 1 region, respectively. Cows from organic farms had lower odds for lameness in all 3 regions (North: OR 0.18, CI 0.11–0.32; East: OR 0.39, CI 0.28–0.56; South: OR 0.45, CI 0.29–0.68). As the dairy production systems differed substantially between the different regions, the results of this study can be viewed as representative for a wide variety of loose-housed dairy systems in Europe and North America. The consistent association between low BCS and lameness in all regions aligns with the previous literature. Our study also suggests that risk factors for lameness can differ between geographically regions, potentially due to differences in which dairy production system is predominantly used and that region-specific characteristics should be taken into account in comparable future projects