Genetic analysis of clinical lameness in dairy cattle

Measurement of joint angles for the objective assessment of limb conformation in dairy calves

Poor limb conformation in cattle is believed to be closely associated with claw and limb disorders. Limb conformation is part of genetic evaluation and is assessed visually. In this descriptive study, the assessment of conformation in calves was evaluated objectively using joint angle measurements. A total of 100, 30- to 90-d-old, heifer calves of the Brown Swiss (n = 50) and Holstein (n = 50) breeds were photographed from both sides and the front and rear. Carpal, tarsal, autopodium and fetlock joint angles of the fore- or hind limbs were measured on the images using anatomic reference points and the ImageJ/Fiji® program. Each angle was measured 3 times, and the mean was used for analysis. Values from both sides were pooled. Deviations from defined standard angles were classified as slight or moderate. The positions of the front and hind feet were measured and scored. On average, the calves had moderate "knock-kneed" carpal conformation, and the autopodium of the front limb had a slight lateral deviation. In the rear view, the calves had slight, but close to moderate, "cow-hocked" tarsal conformation, and the autopodium of the hind limbs was parallel, but close to slightly deviated. Holstein calves were moderately, and Brown Swiss calves were slightly "cow-hocked". A moderate lateral deviation occurred in the metacarpal-digit angle in the front view and a slight lateral deviation occurred in the metatarsal-digit angle in the rear view. The front feet position score was >17° in 69% of the calves, and the hind feet position score was <17° in 90% of the calves. In the side views, the calves were slightly "over at the carpus" and slightly "straight-hocked" and had average fetlock conformation. In the mean values, most measured joint angles did not correspond to the straight or parallel classifications in our calves; moderate "knock-kneed" and slight "cow-hocked", and "toed-out" classifications were most common. The limb angles measured were based on anatomical features and therefore are unlikely to change substantially with increasing age. These aspects should be considered when assessing linear traits and investigating the relationship between limb conformation and claw diseases.

Invited review: Prevalence, risk factors, treatment, and barriers to best practice adoption for lameness and injuries in dairy cattle-A narrative review

Lameness and leg injuries are both painful and prevalent across the dairy industry, and are a major welfare concern. There has been a considerable amount of research focused on investigating the risk factors associated with lameness and injuries and how they might be prevented and treated. The objectives of this narrative review were to summarize herd-level prevalence estimates, risk factors, strategies for prevention, control, and treatment of these conditions, and the barriers to best practice adoption for lameness and injuries on dairy farms. There is a relatively high within-herd prevalence of lameness on dairy farms globally, with a recent systematic review estimating the mean prevalence at 22.8%. Similarly, there is a relatively high prevalence of hock injuries, with within-herd estimates ranging from 12% to 81% of cows affected. Knee and neck injuries have been reported to be less common, with 6% to 43% and 1% to 33%, respectively. Numerous risk factors have been associated with the incidence of lameness, notably housing (e.g., access to pasture, bedding depth, bedding type, flooring type, stall design), management (e.g., stall cleanliness, frequency of trimming, holding times, stocking density), and cow-level (e.g., body condition, parity, injured hocks) factors. Risk factors associated with hock injuries can be similarly classified into housing (e.g., bedding type and depth, outdoor access, parlor type, stall design), management (e.g., bedding depth, cleanliness), and cow (e.g., parity, days in milk, lameness) factors. Key preventative approaches for lameness include routine preventative and corrective hoof trimming, improving hoof cushioning and traction through access to pasture or adding rubber flooring, deep-bedded stalls, sand bedding, ensuring appropriate stocking densities, reduced holding times, and the frequent use of routine footbaths. Very little research has been conducted on hock, knee, and neck injury prevention and recovery. Numerous researchers have concluded that both extrinsic (e.g., time, money, space) and intrinsic (e.g., farmer attitude, perception, priorities, and mindset) barriers exist to addressing lameness and injuries on dairy farms. There are many diverse stakeholders in lameness and injury management including the farmer, farm staff, veterinarian, hoof trimmer, nutritionist, and other advisors. Addressing dairy cattle lameness and injuries must, therefore, consider the people involved, as it is these people who are influencing and implementing on-farm decisions related to lameness prevention, treatment, and control.

Repeatability of Health and Welfare Traits and Correlation with Performance Traits in Dairy Goats Reared under Low-Input Farming Systems

The objectives of the study were to estimate the repeatability of health and welfare traits and investigate their association with performance in three breeds of dairy goats reared under low-input farming systems in Greece. A total of 1210 goats of Eghoria (n = 418), Skopelos (n = 429), and Damascus (n = 363) breeds were assessed. Udder health, parasitic resistance, welfare, milk yield and quality, and body condition score were recorded monthly for two milking periods. Udder health records included somatic cell count (SCC) and total viable count (TVC). Based on combinations of SCC and TVC and thresholds set at >106 cells/mL and >2 × 104 cfu/mL, respectively, additional udder health phenotypes were defined. Parasitism included myiasis, tick infestation, gastrointestinal nematode (GIN) and cestode faecal egg count (FEC), and lungworm faecal larval count (FLC). Infection with each of the endoparasites was defined based on FEC/FLC. Welfare assessment parameters included the presence of ear and horn injuries, ocular and nasal discharge, body and udder abscesses, injury and lesions on the skin of different regions, diarrhoea, hernias, overgrown hooves, arthritis, lameness, and udder asymmetry. Trait repeatability and animal correlations were estimated. Significant (p < 0.05) repeatability was reported for all udder health and most welfare traits in all breeds, GIN and cestode FEC, and GIN and lungworm infection in Eghoria, and myiasis in Skopelos. Correlations of health and most of welfare traits with performance were non-significant or favourable. Overall, results demonstrate potential to improve health and welfare of the studied breeds without compromising performance.

Improving the accuracy of predictions for cow survival by multivariate evaluation model

Context Cow survival measures the ability of cows to survive from the current to subsequent lactation. In addition to economic gain, genetic selection for survival could improve animal welfare by increasing the adaptability and resilience of the cows to both environmental and health challenges. However, survival is a complex trait because it results from a diverse range of reasons for culling of cows from the herd. Consequently, the accuracy of genetic predictions of direct survival are often low. Aims Our aim was to increase the accuracy of predictions of survival in Holstein and Jersey sires by including important predictor traits in multi-trait evaluation models. Methods Phenotypic and genetic correlations between survival trait deviations (TDs) and 35 routinely measured traits (including milk yield, fertility and type traits) were estimated using bivariate sire models. Survival TDs for 538 394 Holstein and 63 839 Jersey cows were used in our study; these cows or their close relatives also had milk, fertility and type traits records between 2002 and 2019. These genetic parameters were required to assess the potential usefulness of predictor traits for the prediction of survival. Key results Survival was genetically correlated with milk, fat and protein yields, overall type, composite mammary system and fertility TDs in both Holstein and Jersey. Further, most of the type traits related to feet and legs, and rump, were also correlated with survival TDs in Jersey. For sires, the accuracy of predictions for survival increased by 0.05 for Holsteins (from 0.54 to 0.59) and for Jerseys (from 0.48 to 0.53) through the use of multivariate models compared with univariate models. Conclusions Survival was genetically associated with traits affecting voluntary and involuntary culling and when included in multi-trait genetic evaluation models, they moderately improved the accuracy of genetic prediction of survival. Implications Predictor traits can be used to increase the accuracy of predictions of survival through the use of multi-trait models. The inclusion of breed-specific predictor traits should be considered, especially for Jerseys in genetic evaluations of survival.

Association of BoLA-DRB3.2 alleles with fusobacteriosis in cows

The Major Histocompatability Complex (MHC) determines the immune response to pathogens, and its genes are promising candidates for the search of associations with diseases. A special role is played by BoLA-DRB3 gene, the product of which directly participates in the binding of alien antigens and conditions the specificity of the immune response. The second exon of this gene codes β1-domain of class II antigens, which is necessary for binding a broad spectrum of alien antigens. Exon 2 of BoLA-DRB3 gene is extremely polymorphic, giving the possibility to search the associations of its alleles with various diseases. The article provides the results of the study on polymorphism of alleles of BoLA-DRB3.2 gene for detection of its associations with sensitivity to fusobacteriosis (necrobacteriosis) of cows. The survey was performed using PCR-RFLP method with DNA of blood from 176 cows of two herds of Ukrainian black-and-white dairy breed. As a result of the studies, in the first herd, 25 BoLA-DRB3.2 alleles were found. In the selections of nectobacteriosis susceptible and resistant cows, we found 22 and 21 variants respectively. In the second herd, in the general selection and group of healthy animals, 27 alleles were typed, and 22 in the group of susceptible cows. BoLA-DRB3.2*22 allele was the commonest in both herds in both general selections and groups of nectobacteriosis-resistant cows. In the selection of susceptible animals, the commonest was the variant BoLA-DRB3.2*16. We determined statistically significant associations of BoLA-DRB3.2 alleles with sensitivity to nectobacteriosis of cattle. BoLA-DRB3.2*03 and *22 alleles associate with nectobacteriosis-resistant, while *16 and *23 – with nectobacteriosis-susceptible cows of the both studied groups. Also, in the first herd, another allele was found – *24, indicating close relationship with the disease. The studies of polymorphism of BoLA-DRB3 gene expand the knowledge about genetic peculiarities of the Ukrainian black-and-white dairy breed. The identified molecular-genetic markers could be useful for breeders whose work is oriented towards the formation of herds which are resistant to diseases of the limbs in cattle.

Assessing selection signatures within and between selected lines of dual-purpose black and white and German Holstein cattle

The aim of this study was to detect selection signatures considering cows from the German Holstein (GH) and the local dual-purpose black and white (DSN) population, as well as from generated sub-populations. The 4654 GH and 261 DSN cows were genotyped with the BovineSNP50 Genotyping BeadChip. The geographical herd location was used as an environmental descriptor to create the East-DSN and West-DSN sub-populations. In addition, two further sub-populations of GH cows were generated, using the extreme values for solutions of residual effects of cows for the claw disorder dermatitis digitalis. These groups represented the most susceptible and most resistant cows. We used cross-population extended haplotype homozygosity methodology (XP-EHH) to identify the most recent selection signatures. Furthermore, we calculated Wright's fixation index (F_ST ). Chromosomal segments for the top 0.1 percentile of negative or positive XP-EHH scores were studied in detail. For gene annotations, we used the Ensembl database and we considered a window of 250 kbp downstream and upstream of each core SNP corresponding to peaks of XP-EHH. In addition, functional interactions among potential candidate genes were inferred via gene network analyses. The most outstanding XP-EHH score was on chromosome 12 (at 77.34 Mb) for DSN and on chromosome 20 (at 36.29-38.42 Mb) for GH. Selection signature locations harbored QTL for several economically important milk and meat quality traits, reflecting the different breeding goals for GH and DSN. The average F_ST value between GH and DSN was quite low (0.068), indicating shared founders. For group stratifications according to cow health, several identified potential candidate genes influence disease resistance, especially to dermatitis digitalis.

Quantitative Trait Loci Mapping for Lameness Associated Phenotypes in Holstein-Friesian Dairy Cattle

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

A 100-Year Review: Identification and genetic selection of economically important traits in dairy cattle

Over the past 100 yr, the range of traits considered for genetic selection in dairy cattle populations has progressed to meet the demands of both industry and society. At the turn of the 20th century, dairy farmers were interested in increasing milk production; however, a systematic strategy for selection was not available. Organized milk performance recording took shape, followed quickly by conformation scoring. Methodological advances in both genetic theory and statistics around the middle of the century, together with technological innovations in computing, paved the way for powerful multitrait analyses. As more sophisticated analytical techniques for traits were developed and incorporated into selection programs, production began to increase rapidly, and the wheels of genetic progress began to turn. By the end of the century, the focus of selection had moved away from being purely production oriented toward a more balanced breeding goal. This shift occurred partly due to increasing health and fertility issues and partly due to societal pressure and welfare concerns. Traits encompassing longevity, fertility, calving, health, and workability have now been integrated into selection indices. Current research focuses on fitness, health, welfare, milk quality, and environmental sustainability, underlying the concentrated emphasis on a more comprehensive breeding goal. In the future, on-farm sensors, data loggers, precision measurement techniques, and other technological aids will provide even more data for use in selection, and the difficulty will lie not in measuring phenotypes but rather in choosing which traits to select for.

Relationships between energy balance and health traits of dairy cattle in early lactation

Data were records of daily food intake and milk production, periodic measures of milk composition and all health and reproductive information from 140 multiparous Holstein cows involved in various experiments at the Agriculture Canada dairy research station in Lennoxville, Quebec. Energy concentrations of the total mixed rations were also available. Daily energy balance was calculated by multiplying the food intake by the concentration of energy in the diet and then subtracting from this quantity the expected (National Research Council) amount of energy required for maintenance (based on parity and body weight) and for milk production (based on yield and concentrations of fat, protein and lactose). Four energy balance traits were defined: (1) average daily energy balance within the first 10 to 100 days of lactation, (2) minimum daily energy balance, (3) days in negative energy balance and (4) total energy deficit during the period of negative energy balance. Health traits were the numbers of incidences of each of the following: (1) all udder problems, (2) mastitis, (3) all locomotive problems, (4) laminitis, (5) digestive problems and (6) reproductive problems. Reproductive traits were the number of days to first observed oestrous and number of inseminations. Phenotypic relationships between energy balance and health were investigated by regressing the energy balance traits on each health trait. Parity and treatment (according to the research trial that the cow was involved with) were also included in the model. Genetic parameters were estimated with restricted maximum likelihood and a model that included effects of parity, treatment and animal. Phenotypically, several significant (P<0.10) relationships between energy balance and health were observed. Cows with longer periods of negative energy balance had increased digestive problems. Cows with greater total energy deficit had more digestive problems and laminitis. Estimates of heritabilities for energy intake and milk energy were 0.42 and 0.12, respectively but estimates of heritability for all energy balance traits were zero. The low estimates for these traits may have been due to (1) low true additive genetic variance, (2) small amount of data, or (3) relatively few genetic ties among cows.

Farm-specific economic value of automatic lameness detection systems in dairy cattle: From concepts to operational simulations

Although prototypes of automatic lameness detection systems for dairy cattle exist, information about their economic value is lacking. In this paper, a conceptual and operational framework for simulating the farm-specific economic value of automatic lameness detection systems was developed and tested on 4 system types: walkover pressure plates, walkover pressure mats, camera systems, and accelerometers. The conceptual framework maps essential factors that determine economic value (e.g., lameness prevalence, incidence and duration, lameness costs, detection performance, and their relationships). The operational simulation model links treatment costs and avoided losses with detection results and farm-specific information, such as herd size and lameness status. Results show that detection performance, herd size, discount rate, and system lifespan have a large influence on economic value. In addition, lameness prevalence influences the economic value, stressing the importance of an adequate prior estimation of the on-farm prevalence. The simulations provide first estimates for the upper limits for purchase prices of automatic detection systems. The framework allowed for identification of knowledge gaps obstructing more accurate economic value estimation. These include insights in cost reductions due to early detection and treatment, and links between specific lameness causes and their related losses. Because this model provides insight in the trade-offs between automatic detection systems' performance and investment price, it is a valuable tool to guide future research and developments.

Linear and threshold model genetic parameters for disease, fertility and milk production in dairy cattle

This study provides estimates of genetic parameters for various diseases, fertility and 305-day milk production traits in dairy cattle using data from a UK national milk recording scheme. The data set consisted of 63891 multiple lactation records on diseases (mastitis, lameness, milk fever, ketosis and tetany), fertility traits (calving interval, conception to first service, number of services for a conception, and number of days to first service), dystocia and 305-day milk, fat and protein yield. All traits were analysed by multi-trait repeatability linear animal models (LM). Binary diseases and fertility traits were further analysed by threshold sire models (TM). Both LM and TM analyses were based on the generalized linear mixed model framework. The LM included herd-year-season of calving (HYS), age at calving and parity as fixed effects and genetic, permanent environmental and residual effects as random. The TM analyses included the same effects as for LM, but HYS effects were treated as random to avoid convergence problems when HYS sub-classes had 0 or 100% incidence. Because HYS effects were treated as random, herd effects were fitted as fixed effects to account for effect of herds in the data. The LM estimates of heritability ranged from 0•389 to 0•399 for 305-day milk production traits, 0•010 to 0•029 for fertility traits and 0•004 to 0•038 for diseases. The LM estimates of repeatability ranged from 0•556 to 0•586 for 305-day milk production traits, 0•029 to 0•086 for fertility traits and 0•004 to 0•100 for diseases. The TM estimates of heritabilities and repeatabilities were greater than LM estimates for binary traits and were in the range 0•012 to 0•126 and 0•013 to 0•168, respectively. Genetic correlations between milk production traits and fertility and diseases were all unfavorable: they ranged from 0•07 to 0•37 for milk production and diseases, 0•31 to 0•54 for milk production and poor fertility and 0•06 to 0•41 for diseases and poor fertility. These results show that future selection programmes should include disease and fertility for genetic improvement of health and reproduction and for sustained economic growth in the dairy cattle industry.

A High Percentage of Beef Bull Pictures in Semen Catalogues Have Feet and Lower Legs that Are Not Visible

Simple Summary

When cattle breeders purchase semen from a website, the only way they can visually appraise a bull’s conformation is by looking at his photograph. Correct foot and leg structure is important to help reduce lameness. Only 19.4% of the bull pictures on four major websites had fully visible feet and lower legs. A possible explanation for this may be deliberate covering of feet and legs with photo editing software to cover up conformation defects. Visibility of feet and lower legs would help semen buyers avoid bulls with obvious feet or leg problems.

Abstract

A total of 1379 beef bull pictures were surveyed to determine visibility of feet and legs from four American semen company websites. Five different breeds were represented: Angus, Red Angus, Hereford (polled and horned), Simmental, and Charolais. In addition to visibility, data on other variables were collected to establish frequencies and correlations. These included breed, color, material that obscured visibility, such as grass, picture taken at livestock show or outside, semen company, photographer, video, and age of bull. A foot and leg visibility score was given to each bull picture. Only 19.4% of the pictures had fully visible feet and legs. Both the hooves and dewclaws were hidden on 32.5% of the pictures. Correlation between bull’s birthdate and the first four visibility scores was statistically significant (P < 0.0001). As age increased the feet and legs were more likely to be visible in the bull’s picture. This may possibly be due to greater availability of both photo editing software and digital photography. One positive finding was that 6% of the bulls had a video of the bull walking which completely showed his feet and legs.

Digital Dermatitis in Dairy Cows: A Review of Risk Factors and Potential Sources of Between-Animal Variation in Susceptibility

Simple Summary

Dairy cow lameness is a major problem for the industry, causing reduced animal welfare and economic loss. Digital dermatitis (DD) is a bacterial disease causing painful lesions, generally on the heels of the rear feet, and is an important cause of lameness. There appears to be individual variation between animals in susceptibility to this disease. Particular physical, physiological and behavioural factors might influence individual susceptibility, but further work is required to clarify the influence of these factors and to determine how this information could be used to develop breeding and management strategies to reduce DD prevalence.

Abstract

Digital dermatitis (DD) is a bacterial disease that primarily affects the skin on the heels of cattle. It is a major cause of lameness in dairy cows and a significant problem for the dairy industry in many countries, causing reduced animal welfare and economic loss. A wide range of infection levels has been found on infected farms, prompting investigations into both farm level and animal level risk factors for DD occurrence. There also appears to be individual variation between animals in susceptibility to the disease. The identification of factors affecting individual variation in susceptibility to DD might allow changes in breeding policies or herd management which could be used to reduce DD prevalence. Factors mentioned in the literature as possibly influencing individual variation in susceptibility to DD include physical factors such as hoof conformation and properties of the skin, physiological factors such as the efficacy of the immune response, and behavioural factors such as standing half in cubicles. Further work is required to determine the influence of these factors, identify the genetic basis of variation, clarify the level of heritability of DD susceptibility and to determine how this is correlated with production and health traits currently used in breeding programmes.

Short communication: Genetic characterization of digital cushion thickness

Dairy cow lameness is a serious animal welfare issue. It is also a significant cause of economic losses, reducing reproductive efficiency and milk production and increasing culling rates. The digital cushion is a complex structure composed mostly of adipose tissue located underneath the distal phalanx and has recently been phenotypically associated with incidence of claw horn disruption lesions (CHDL); namely, sole ulcers and white line disease. The objective of this study was to characterize digital cushion thickness genetically and to investigate its association with body condition score (BCS), locomotion score (LOCO), CHDL, and milk production. Data were collected from 1 large closely monitored commercial dairy farm located in upstate New York; 923 dairy cows were used. Before trimming, the following data were collected by a member of the research team: BCS, cow height measurement, and LOCO. Presence or not of CHDL (sole ulcer or white line disease, or both) was recorded at trimming. Immediately after the cows were hoof trimmed, they underwent digital sonographic B-mode examination for the measurement of digital cushion thickness. Factors such as parity number, stage of lactation, calving date, mature-equivalent 305-d milk yield (ME305MY), and pedigree information were obtained from the farm's dairy management software (DairyCOMP 305; Valley Agricultural Software, Tulare, CA). Univariate animal models were used to obtain variance component estimations for each studied trait (CHDL, BCS, digital cushion thickness average, LOCO, height, and ME305MY) and a 6-variate analysis was conducted to estimate the genetic, residual, and phenotypic correlations between the studied traits. The heritability estimate of DCTA was 0.33±0.09, whereas a statistically significant genetic correlation was estimated between DCTA and CHDL (-0.60±0.29). Of the other genetic correlations, significant estimates were derived for BCS with LOCO (-0.49±0.19) and ME305MY (-0.48±0.20). Digital cushion thickness is moderately heritable and genetically strongly correlated with CHDL.

Profile and genetic parameters of dairy cattle locomotion score and lameness across lactation

This study investigated the profile of locomotion score and lameness before the first calving and throughout the first (n=237) and second (n=66) lactation of 303 Holstein cows raised on a commercial farm. Weekly heritability estimates of locomotion score and lameness, and their genetic and phenotypic correlations with milk yield, body condition score, BW and reproduction traits were derived. Daughter future locomotion score and lameness predictions from their sires��� breeding values for conformation traits were also calculated. First-lactation cows were monitored weekly from 6 weeks before calving to the end of lactation. Second-lactation cows were monitored weekly throughout lactation. Cows were locomotion scored on a scale from one (sound) to five (severely lame); a score greater than or equal to two defined presence of lameness. Cows��� weekly body condition score and BW was also recorded. These records were matched to corresponding milk yield records, where the latter were 7-day averages on the week of inspection. The total number of repeated records amounted to 12 221. Data were also matched to the farm���s reproduction database, from which five traits were derived. Statistical analyses were based on uni- and bivariate random regression models. The profile analysis showed that locomotion and lameness problems in first lactation were fewer before and immediately after calving, and increased as lactation progressed. The profile of the two traits remained relatively constant across the second lactation. Highest heritability estimates were observed in the weeks before first calving (0.66 for locomotion score and 0.54 for lameness). Statistically significant genetic correlations were found for first lactation weekly locomotion score and lameness with body condition score, ranging from ���0.31 to ���0.65 and from ���0.44 to ���0.76, respectively, suggesting that cows genetically pre-disposed for high body condition score have fewer locomotion and lameness issues. Negative (favourable) phenotypic correlations between first lactation weekly locomotion score/lameness and milk yield averaged ���0.27 and ���0.17, respectively, and were attributed to management factors. Also a phenotypic correlation between lameness and conception rate of ���0.19 indicated that lame cows were associated with lower success at conceiving. First-lactation daughter locomotion score and/or lameness predictions from sires��� estimated breeding values for conformation traits revealed a significant linear effect of rear leg side view, rear leg rear view, overall conformation, body condition score and locomotion, and a quadratic effect of foot angle.

Genetic parameters for body condition score, locomotion, angularity, and production traits in Italian Holstein cattle

The objectives of this research were to estimate genetic parameters for body condition score (BCS) and locomotion (LOC), and to assess their relationships with angularity (ANG), milk yield, fat and protein content, and fat to protein content ratio (F:P) in the Italian Holstein Friesian breed. The Italian Holstein Friesian Cattle Breeders Association collects type trait data once on all registered first lactation cows. Body condition score and LOC were introduced in the conformation scoring system in 2007 and 2009, respectively. Variance (and covariance) components among traits were estimated with a Bayesian approach via a Gibbs sampling algorithm and an animal model. Heritability estimates were 0.114 and 0.049 for BCS and LOC, respectively. The genetic correlation between BCS and LOC was weak (-0.084) and not different from zero; therefore, the traits seem to be genetically independent, but further investigation on possible departures from linearity of this relationship is needed. Angularity was strongly negatively correlated with BCS (-0.612), and strongly positively correlated with LOC (0.650). The genetic relationship of milk yield with BCS was moderately negative (-0.386), and was moderately positive (0.238) with LOC. These results indicate that high-producing cows tend to be thinner and tend to have better locomotion than low-producing cows. The genetic correlation of BCS with fat content (0.094) and F:P (-0.014) was very weak and not different from zero, and with protein content (0.173) was weak but different from zero. Locomotion was weakly correlated with fat content (0.071), protein content (0.028), and F:P (0.074), and correlations were not different from zero. Phenotypic correlations were generally weaker than their genetic counterparts, ranging from -0.241 (BCS with ANG) to 0.245 (LOC with ANG). Before including BCS and LOC in the selection index of the Italian Holstein breed, the correlations with other traits currently used to improve type and functionality of animals need to be investigated.

Short communication: genetic evaluation of mobility for Brown Swiss dairy cattle

Genetic parameters were estimated for mobility score and 16 linear type traits of Brown Swiss dairy cattle. Mobility is an overall assessment trait that measures a cow's ability to move, as well as the structure of her feet, pasterns, and legs. Scores from 50 to 99 were assigned by appraisers for the Brown Swiss Cattle Breeders' Association of the USA beginning in June 2007. Only scores made before 69 mo of age were used. After edits, 32,710 records were available for 19,472 cows in 819 herds. The model included fixed effects for the interaction of herd and appraisal date (2,109 groups), appraisal age within parity (46 groups), and lactation stage within parity (21 groups), as well as random effects for animal, permanent environment, and residual error. A multi-trait analysis was conducted using canonical transformation, multiple diagonalization, and a decelerated expectation-maximization REML algorithm. Heritability was estimated to be 0.21 for mobility and ranged from 0.06 to 0.37 for the other 16 type traits. The traits with the highest genetic correlation with mobility were final score (0.78), rear legs (rear view; 0.74), rear udder width (0.52), and foot angle (0.51). Predicted transmitting ability (PTA) for mobility was calculated using the Brown Swiss multi-trait type evaluation system but included only appraisals for which all traits had been scored. For the 1,868 bulls evaluated, PTA for mobility ranged from 1.6 to -1.8 with a standard deviation of 0.5 and was most highly correlated with PTA for final score (0.88), rear legs (rear view; 0.77), rear udder height (0.70), and rear udder width (0.69), as expected from the trait correlations. When matched with official US national evaluations from August 2011, PTA mobility had moderately high correlations with PTA for milk, fat, and protein yields, as well as productive life (0.31-0.41). The mobility trait may provide a more accurate assessment of the structural soundness required for longevity than does the feet-legs composite.

Genetics of behavioural adaptation of livestock to farming conditions

Behavioural adaptation of farm animals to environmental changes contributes to high levels of production under a wide range of farming conditions, from highly controlled indoor systems to harsh outdoor systems. The genetic variation in livestock behaviour is considerable. Animals and genotypes with a larger behavioural capacity for adaptation may cope more readily with varying farming conditions than those with a lower capacity for adaptation. This capacity should be exploited when the aim is to use a limited number of species extensively across the world. The genetics of behavioural traits is understood to some extent, but it is seldom accounted for in breeding programmes. This review summarizes the estimates of genetic parameters for behavioural traits in cattle, pigs, poultry and fish. On the basis of the major studies performed in the last two decades, we focus the review on traits of common interest in the four species. These concern the behavioural responses to both acute and chronic stressors in the physical environment (feed, temperature, etc.) and those in the social environment (other group members, progeny, humans). The genetic strategies used to improve the behavioural capacity for adaptation of animals differ between species. There is a greater emphasis on responses to acute environmental stress in fish and birds, and on responses to chronic social stress in mammals.

Determining the heritable component of dairy cattle foot lesions

Lameness and hoof health affect dairy cows as an animal welfare issue, in decreased milk production, and in premature culling. Selection schemes for dairy cattle focus on sire contribution to milk production, with little consideration of the cow's physical structure or disease probability. On 3 commercial California dairies, 6 phenotypic binary hoof traits that contribute to lameness were recorded: white line disease, sole ulcer, other claw horn lesions, foot rot (interdigital phlegmon), foot warts (digital dermatitis), and other lesions. Monthly lactation records were collected from December 2006 to April 2009 with weekly observations of hoof lesions for lame and dry cows. In addition to hoof lesion information, data on cows (n=5,043) included parentage, birth date, freshening date, lactation number, and date of lameness diagnosis. The prevalence of hoof lesions ranged from a low of 2.2% (foot rot) to a high of 17.1% (foot warts). The farm environment increased the odds ratio depending upon the lesion. Lameness was more common in early lactation and as lactation number increased. Using a threshold model, heritabilities and repeatabilities were estimated for each binary trait. The heritability for risk varied by lesion, with the higher estimates being 0.40 (95% confidence interval: 0.20-0.67) for digital dermatitis and 0.30 (95% confidence interval: 0.08-0.63) for sole ulcer. Including terms to account for cow productivity on either a 305-d mature-equivalent basis or a per-lactation basis had minimal effect on the heritability estimates, suggesting that selection for hoof health is not correlated with response to selection for greater milk production and that improvement could be made for both traits. The genetic component lends support for further genetic studies to identify loci contributing to some of the lesion phenotypes such as foot warts or sole ulcers, 2 of the top 3 causes of lameness in dairy cattle.

The effect of hindclaw height differential and subsequent trimming on lameness in large dairy cattle herds in Canterbury, New Zealand

AIMS

To determine if inequality in height between claws within each hindlimb of dairy cattle is a risk factor for the development of lameness and to determine the effect of preventive trimming of these claws on the subsequent risk of lameness.

METHODS

Cows (n=2,695) on three dairy farms in Canterbury, New Zealand, were examined and the height differential between their hind claws on each limb was measured. Cows were blocked by age, then breed and grouped by height differential, before being randomly assigned to either treatment or control groups. Cows in the control group were not trimmed, whilst cows in the treatment group were all trimmed according to the 'Dutch Trimming' method by an experienced foot trimmer. All subsequent clinical incidences of lameness were identified, recorded and classified according to five categories. The overall incidence of lameness, the effect of claw height differential on the incidence of lameness and the effect of trimming on the incidence of lameness were assessed using both GEE modelling and survival analysis.

RESULTS

The incidence of lameness identified in any untrimmed hindlimb irrespective of diagnosis, measured at a limb level and assessing the first incidence of lameness only, was 10.0% for a 6-month period from November to drying off. The predominant lesion identified was white line disease (WLD; 7.9% incidence and 78.6% of all lameness). The overall incidence of hindlimb lameness measured at cow level for the same period was 14.5%. The risk of lameness was influenced by breed (p=0.016), age (p=0.002) and claw height differential (p=0.026). There were no significant interactions. The risk of lameness was lowest where the claw height differential was 0-2 mm. The incidence of lameness in the first 70 days following trimming was higher in older cows than in younger cows (p<0.001). Trimming did not affect lameness incidence (p=0.185). The Cox proportional hazard model demonstrated that farm (p<0.001), trimming group (p=0.021); and age (p=0.021) significantly affected the median days to lameness in the first 70 days following trimming.

CONCLUSIONS AND CLINICAL RELEVANCE

Hind feet with lower height differentials between claws had a lower incidence of lameness. Trimming of these feet to remove the height differential did not reduce their overall incidence of lameness, but did increase days to first lameness.

Genetic analysis of feet and leg traits of Australian Angus cattle using linear and threshold models

The advantages of using a univariate threshold animal model (TAM) over the conventional linear animal model (AM) in the development of a genetic evaluation system for feet and leg traits of Angus cattle were explored. The traits were scored on a scale of 1–9 with scores 5 and 6 being the most desirable. The genetic parameters and estimated breeding values for front feet angle (FA), rear feet angle (RA), front feet claw set (FC), rear feet claw set (RC), rear leg hind view (RH) and rear leg side view (RS) were compared from AM and TAM. In order to predict breeding values to identify the animals with intermediate optimum, the scores were categorised to form three groups to differentiate the desirable group (5–6) from the other two groups with less desirable feet and leg appearances (1–4 and 7–9). The AM and TAM were used to estimate genetic parameters for the grouped data as well as the original score data. A TAM using the group data was used to predict the probability and breeding value for the desirable intermediate group. For the original score data, estimated heritabilities on the underlying scale, using TAM, were 0.50, 0.46, 0.35, 0.44, 0.32 and 0.22 for FA, FC, RA, RC, RH and RS, respectively, and were 0.01–0.18 higher than the heritabilities estimated using AM. Genetic correlation between the six traits using a bivariate TAM with all scores ranged from 0.02 to 0.50 with front and rear angles had the highest genetic correlation at 0.50. For all six traits, proportion in the intermediate desirable group was higher than the other two groups combined. The low annual genetic change observed for all six traits over the 10 years of data recording reflected the lack of directional selection to improve the traits in Angus cattle. For genetic evaluation of feet and leg traits with an intermediate optimum, TAM is a preferred method for estimating genetic parameters and predicting breeding values for the desirable category. The TAM has now been implemented for regular estimated breeding value analysis of feet and leg traits of Angus cattle.

Genetics of animal health and disease in cattle

There have been considerable recent advancements in animal breeding and genetics relevant to disease control in cattle, which can now be utilised as part of an overall programme for improved cattle health. This review summarises the contribution of genetic makeup to differences in resistance to many diseases affecting cattle. Significant genetic variation in susceptibility to disease does exist among cattle suggesting that genetic selection for improved resistance to disease will be fruitful. Deficiencies in accurately recorded data on individual animal susceptibility to disease are, however, currently hindering the inclusion of health and disease resistance traits in national breeding goals. Developments in 'omics' technologies, such as genomic selection, may help overcome some of the limitations of traditional breeding programmes and will be especially beneficial in breeding for lowly heritable disease traits that only manifest themselves following exposure to pathogens or environmental stressors in adulthood. However, access to large databases of phenotypes on health and disease will still be necessary. This review clearly shows that genetics make a significant contribution to the overall health and resistance to disease in cattle. Therefore, breeding programmes for improved animal health and disease resistance should be seen as an integral part of any overall national disease control strategy.

The impact of genetic selection for increased milk yield on the welfare of dairy cows

Milk yield per cow has more than doubled in the previous 40 years and many cows now produce more than 20,000 kg of milk per lactation. The increase in production should be viewed with concern because: i) the increase in milk yield has been accompanied by declining fertility, increasing leg and metabolic problems and declining longevity; ii) there are unfavourable genetic correlations between milk yield and fertility, mastitis and other production diseases, indicating that deterioration in fertility and health is largely a consequence of selection for increased milk yield; and iii) high disease incidence, reduced fertility, decreased longevity and modification of normal behaviour are indicative of substantial decline in cow welfare. Improving welfare is important as good welfare is regarded by the public as indicative of sustainable systems and good product quality and may also be economically beneficial. Expansion of the Profitable Lifetime Index used in the UK to include mastitis resistance and fertility could increase economic response to selection by up to 80%, compared with selection for milk production alone. In the last 10 years, several breeding organisations in Europe and North America followed the example of Nordic Countries and have included improving fertility and reducing incidence of mastitis in their breeding objectives, but these efforts are still timid. A multi-trait selection programme in which improving health, fertility and other welfare traits are included in the breeding objective, and appropriately weighted relative to production traits, should be adopted by all breeding organisations motivated in their goal of improving welfare.

Effects of breed and production system on lameness parameters in dairy cattle

The aim of the present study was to assess the effects of Holstein-Friesian (HF) and Norwegian (N) dairy cattle genotypes on lameness parameters in dairy cattle within different production systems over the first 2 lactations. Following calving, HF (n = 39) and N (n = 45) heifers were allocated to 1 of 3 systems of production (high level of concentrate, low level of concentrate, and grass-based). High- and low-concentrate animals were continuously housed indoors on a rotational system so that they spent similar amounts of time on slatted and solid concrete floors. Animals on the grass treatment grazed from spring to autumn in both years of the study, so that most animals on this treatment grazed from around peak to late lactation. Claw health was recorded in both hind claws of each animal at 4 observation periods during each lactation as follows: 1) -8 to 70 d postcalving, 2) 71 to 150 d postcalving, 3) 151 to 225 d postcalving, and 4) 226 to 364 d postcalving. Sole lesions, heel erosion, axial wall deviation, sole length of the right lateral hind claw (claw length), right heel width, and right lateral hind heel height were recorded as well as the presence of digital dermatitis. The N cows had lower (better) white line and total lesion scores than HF cows. Cows on the high- and low-concentrate treatments had better sole and total lesion scores than cows on the grass treatment. The HF cows had better locomotion scores than N cows. Breed and production system differences were observed with respect to claw conformation, including claw length, heel width, and heel height. Digital dermatitis was associated with worse sole lesion scores and interacted with production system to influence white line lesion scores and maximum heel erosion scores. This study shows that genetic, environmental, and infectious factors are associated with hoof pathologies in dairy cows.

Prevalence and severity of foot lesions in Danish Holstein heifers through first lactation

Several studies have shown that foot lesions and clinical lameness occur before first calving and develop further during the lactation period. Lameness may cause production losses, but the relationship between foot lesions, particularly in the claw horn, and lameness in heifers is unclear. The objectives of this study were to describe the development of and evaluate the relationship between lameness and foot lesions in Danish Holsteins before and after first calving. In a longitudinal study, 147 heifers were examined for lameness and foot lesions 2-5 times over an 18-month period. Lameness was assessed by means of a visual locomotion score and foot lesion severity was recorded. The prevalence of a locomotion score 3 was 25% before calving, and 90% at approximately 250 days in milk (DIM). Prevalence of moderate to severe sole haemorrhage (SH) was 27% before calving and 56% at 250 DIM, and that of moderate to severe white line lesion (WLL) 44% before calving with a peak of 70% at 200 DIM. There was one case of white line abscess but SH was seen throughout the entire study period. Digital dermatitis (DD) was prevalent prior to first calving (15%) and peaked at 39% at 0-100 DIM. Heel horn erosion (HHE) occurred in almost all cows (93-100%) and was strongly correlated with DD (r=0.51). The correlation coefficient between SH and WLL was also high (0.42). The relatively high correlations between WLL and both DD and HHE were more surprising (0.38 and 0.35, respectively), those between SH and both DD and HHE were moderate (around 0.18). Interdigital dermatitis was significantly correlated with both HHE and DD, but completely unrelated to SH and WLL. The overall average locomotion score increased by about one-half of a score unit from 1 month prior to calving until 250 DIM, with a large difference between herds, although this was unsurprising as cows may alter their locomotion pattern with management factors (e.g. floor properties). DD and WLL were both associated with a locomotion score > or = 3 but of the cows with severe WLL there was no clear association between a locomotion score > or = 3 and DD. The highest locomotion scores occurred among cows with DD but without WLL.

Conformation of hind legs and lameness in Danish Holstein heifers

Lameness causes major financial losses and welfare problems in dairy herds. Prevention of foot lesions may suffice in the majority of lameness cases. The objectives of this longitudinal study were to describe the dynamics and associations between abnormal hind leg conformation, asymmetric claws, lameness, and foot lesions in 122 Danish Holstein heifers from an average of 41 d before first calving until dry off or culling. The cattle were housed either in a free-stall system with cubicles or in deep-bedded straw yard. The claws of all cattle were examined on up to 5 occasions. The associations between foot lesions, lameness, symmetry of the claws, shape of the dorsal toe-wall, and the conformation of the hind legs were examined statistically using mixed models. A large proportion (81%) of the heifers had cow-hocked conformation, with wide-based stance, hocks together, and lateral rotation of the foot before calving, and 25% of the heifers had locomotion scores above 2, indicating signs of lameness, before calving. Our results indicate that lameness, abnormal conformation, and lesions acquired precalving persist throughout the first lactation. Thinner cows were more cow-hocked, and cow-hocked cows had a higher frequency of sole hemorrhages. Increased severity of white line lesion was associated with greater claw asymmetry. More severe lameness and sole hemorrhages were found in symmetric claws.

Estimation of genetic parameters and prediction of breeding values for multivariate threshold and continuous data in a simulated horse population using Gibbs sampling and residual maximum likelihood

Simulated horse data were used to compare multivariate estimation of genetic parameters and prediction of breeding values (BV) for categorical, continuous and molecular genetic data using linear animal models via residual maximum likelihood (REML) and best linear unbiased prediction (BLUP) and mixed linear-threshold animal models via Gibbs sampling (GS). Simulation included additive genetic values, residuals and fixed effects for one continuous trait, liabilities of four binary traits, and quantitative trait locus (QTL) effects and genetic markers with different recombination rates and polymorphism information content for one of the liabilities. Analysed data sets differed in the number of animals with trait records and availability of genetic marker information. Consideration of genetic marker information in the model resulted in marked overestimation of the heritability of the QTL trait. If information on 10,000 or 5,000 animals was used, bias of heritabilities and additive genetic correlations was mostly smaller, correlation between true and predicted BV was always higher and identification of genetically superior and inferior animals was - with regard to the moderately heritable traits, in many cases - more reliable with GS than with REML/BLUP. If information on only 1,000 animals was used, neither GS nor REML/BLUP produced genetic parameter estimates with relative bias <or=25% and BV correlation >50% for all traits. Selection decisions for binary traits should rather be based on GS than on REML/BLUP breeding values.

Genetic Parameters and Evaluation of Rear Legs (Rear View) for Brown Swiss and Guernseys

Genetic parameters were estimated for rear legs (rear view; RLRV) and 15 current linear type traits of Brown Swiss and Guernsey dairy cattle. The Brown Swiss Cattle Breeders' Association of the USA and the American Guernsey Association began scoring RLRV in 2004. For Brown Swiss, 8,502 records were available for 7,676 cows in 417 herds; Guernsey data included 5,437 records for 4,749 cows in 229 herds. Nine unknown-parent groups were defined for each breed, each with 2 birth years. The model included fixed effects for the interaction of herd, appraisal date, and parity; appraisal age within parity; and lactation stage within parity and random effects for animal, permanent environment, and residual error. The multitrait analysis for RLRV and the 15 linear type traits used canonical transformation, multiple diagonalization, and a decelerated expectation-maximization REML algorithm. For Brown Swiss, heritability was 0.102 for RLRV and ranged from 0.099 for rear legs (side view) to 0.453 for stature. For Guernseys, heritability ranged from 0.078 for RLRV to 0.428 for stature. For Brown Swiss, the highest genetic correlation with RLRV was 0.71 for rear udder width; the most negative correlation was -0.19 with rump angle. For Guernseys, the highest genetic correlations with RLRV were 0.43 for rear udder width and 0.42 for body depth; the most negative correlation was -0.46 with rear legs (side view). With heritability near 0.10, RLRV should be useful in selection for improved locomotion. Release of genetic evaluations for RLRV began in May 2006 for Brown Swiss and Guernseys.

Genetic and Phenotypic Relationships Among Locomotion Type Traits, Profit, Production, Longevity, and Fertility in Spanish Dairy Cows

The phenotypic and genetic relationships of 3 locomotion traits with profit, production, longevity, and fertility traits were studied to determine the importance of locomotion traits for dairy producers. Two data sets including official milk records and type classification scores of 62,293 cows, and reproductive records of 24,561 cows from the Basque and Navarra Autonomous Regions were analyzed. Higher scores for feet and legs (FL), foot angle (FA), and rear legs set (RLS) were positively related to production and functional traits, whereas fertility was not significantly affected. The cows that scored the highest for FL were $213/yr more profitable, produced 575 kg more milk per year, and remained in the herd for 307 more functional days than the cows scoring the lowest. Feet and legs was the trait most genetically correlated to profit, although a low value (0.10) was obtained, whereas RLS was the trait most correlated to milk production (0.12). Genetic correlations among FL, FA, RLS, and longevity traits (from -0.10 to 0.05) were low. Quadratic curves were the best fit for both profit and functional herd life for EBV of each of the 3 locomotion traits. Further studies dealing with profitability and lameness, instead of using conformation traits, could be performed directly if a larger data pool of lameness was routinely recorded.

Genetic parameters of claw and foot disorders estimated with logistic models

The primary aim of this study was to estimate heritabilities for different types of claw and foot disorders and the genetic relationship of disorders with milk yield and selected conformation traits by applying logistic models in Holstein dairy cattle. The study included data from 5634 Holstein cows kept on large-scale dairy farms in Eastern Germany. Dichotomous response variables were the presence or absence of the disorder in 2003. Cows that were present in herds for <6 wk in 2003 were excluded from the analysis. Incidences, disregarding repeated measurements, for digital dermatitis (DD), sole ulceration (SU), wall disorder (WD), and interdigital hyperplasia (IH) in rear legs were 13.2, 16.1, 9.6, and 6.3%, respectively. The herd effect was highly significant for all disorders. Incidences increased with increasing parities for SU and WD, but were highest among heifers for DD. High milk yield at the first 2 test d after calving was associated with a greater risk for claw and foot disorders in the same lactation. Estimates of heritability were 0.073 for DD, 0.086 for SU, 0.104 for WD, and 0.115 for IH. Genetically, health problems appear to occur in clusters (i.e., a cow showing one disease has an increased genetic risk of showing another claw disease). This phenomenon was also observed between claw and foot disorders and the somatic cell score. Genetic correlations between milk yield in early lactation and disorders were 0.240 for DD, 0.057 for SU, 0.270 for WD, and 0.336 for IH, indicating a physiological antagonism. Correlations between breeding values for claw and foot disorders of bulls and official breeding values for functional type traits were mostly favorable. Routine recording of claw data will offer a new chance to improve claw health within the population as was elaborated by different scenarios applying selection index procedures.

Genetic Parameters for Claw Disorders in Dutch Dairy Cattle and Correlations with Conformation Traits

Impaired claw health is one of the major problems causing production loss and reduced animal welfare in dairy cattle. In response, the Dutch Animal Health Service (GD) Ltd. initiated this study, in which claws of lactating and near-term cows and heifers in 430 herds were trimmed by hoof trimmers and the health status of the rear claws recorded. Only herds with >75% of the animals having feet trimmed were considered, resulting in records on 21,611 animals. Eight claw disorders were scored: digital dermatitis (DD), interdigital dermatitis/heel horn erosions (IDHE), sole hemorrhage (SH), chronic laminitis (CL), sole ulcer (SU), white line disease (WLD), interdigital hyperplasia (HYP), and interdigital phlegmona (IP). The prevalence varied from 0.6% (IP) to 39.9% (SH). More than 70% of the animals had at least one claw disorder. Conformation traits and locomotion were recorded once during the animal's first lactation by trained classifiers of the Royal Dutch Cattle Syndicate and completely independent of the moment of claw trimming. Heritabilities were estimated using a sire model, and ranged from <0.01 (IP) to 0.10 (DD and HYP). Genetic correlations of incidences of claw disorders with locomotion were variable, ranging from 0.13 (SH) to -0.91 (CL). Genetic correlations with the rear leg conformation traits were lower, ranging from 0.04 (ID with rear leg side view) to -0.69 (IP with rear leg rear view).

Genetic selection for health traits using producer-recorded data. I. Incidence rates, heritability estimates, and sire breeding values

The objective of this study was to determine the feasibility of genetic selection for health traits in dairy cattle using data recorded in on-farm herd management software programs. Data regarding displaced abomasum (DA), ketosis (KET), mastitis (MAST), lameness (LAME), cystic ovaries (CYST), and metritis (MET) were collected between January 1, 2001 and December 31, 2003 in herds using Dairy Comp 305, DHI-Plus, or PCDART herd management software programs. All herds in this study were either participants in the Alta Genetics (Watertown, WI) Advantage progeny testing program or customers of the Dairy Records Management Systems (Raleigh, NC) processing center. Minimum lactation incidence rates were applied to ensure adequate reporting of these disorders within individual herds. After editing, DA, KET, MAST, LAME, CYST, and MET data from 75,252 (313), 52,898 (250), 105,029 (429), 50,611 (212), 65,080 (340), and 97,318 (418) cows (herds) remained for analysis. Average lactation incidence rates were 0.03, 0.10, 0.20, 0.10, 0.08, and 0.21 for DA, KET, MAST, LAME, CYST, and MET (including retained placenta), respectively. Data for each disorder were analyzed separately using a threshold sire model that included a fixed parity effect and random sire and herd-year-season of calving effects; both first lactation and all lactation analyses were carried out. Heritability estimates from first lactation (all lactation) analyses were 0.18 (0.15) for DA, 0.11 (0.06) for KET, 0.10 (0.09) for MAST, 0.07 (0.06) for LAME, 0.08 (0.05) for CYST, and 0.08 (0.07) for MET. Corresponding heritability estimates for the pooled incidence rate of all diseases between calving and 50 d postpartum were 0.12 and 0.10 for the first and all lactation analyses, respectively. Mean differences in PTA for probability of disease between the 10 best and 10 worst sires were 0.034 for DA, 0.069 for KET, 0.130 for MAST, 0.054 for LAME, 0.039 for CYST, and 0.120 for MET. Based on the results of this study, it appears that genetic selection against common health disorders using data from on-farm recording systems is possible.