Farm management and husbandry practices associated with spontaneous humeral fractures in New Zealand dairy heifers.

AIMS: To use a farm-based survey to identify characteristics of the New Zealand dairy system associated with the risk of spontaneous humeral fracture in dairy heifers. METHODS: A questionnaire was designed and made available in print and online to collect information from dairy farmers and/or veterinarians, across New Zealand, about the management and nutrition of cows from birth to first lactation. Data were collected from July 2019 to March 2020 from farms that either had recorded (case farms) or not recorded (control farms) cases of humeral fractures in dairy heifers. RESULTS: A total of 68 completed questionnaires were returned, with 35 responses from case farms and 33 responses from control farms. Twenty-six responses (38%) were from the South Island (13 case farms and 13 control farms) and 38 responses (56%) were from the North Island (20 case farms and 18 control farms). For four questionnaires (6%) farm location was not given. Adjusting for the effect of age when calves accessed pasture, case farms had increased odds of having Holstein-Friesian Jersey crossbreed cows as the predominant breed (OR = 9.7; 95% CI = 3.1-36.0; p < 0.001). Adjusting for the effect of breed, allowing calves access to pasture a week later decreased the odds of being a case farm (OR = 0.68; 95% CI = 0.47-0.90; p = 0.006). CONCLUSIONS: Cows being Holstein-Friesian Jersey crossbreed was identified as a possible risk factor associated with spontaneous humeral fracture in dairy heifers in New Zealand. Given the small sample size, the likely multifactorial aetiology for humeral fractures, and the non-randomised survey, this risk factor, and the possible association between age at turn out and herd production with humeral fractures, all require further investigation.

A prospective cohort study examining the association of claw anatomy and sole temperature with the development of claw horn disruption lesions in dairy cattle.

Foot characteristics have been linked to the development of sole lesions (sole hemorrhage and sole ulcers) and white line lesions, also known as claw horn disruption lesions (CHDL). The objective of this study was to examine the association of claw anatomy and sole temperature with the development of CHDL. A cohort of 2,352 cows was prospectively enrolled from 4 UK farms and assessed at 3 time points: before calving (T1-precalving), immediately after calving (T2-calving), and in early lactation. At each time point body condition score was recorded, a thermography image of each foot was taken for sole temperature measurement, the presence of CHDL was assessed by veterinary surgeons, and an ultrasound image was taken to retrospectively measure the digital cushion and sole horn thickness. Additionally, at the postcalving time point, foot angle and heel depth were recorded. Four multivariable logistic regression models were fit to separately examine the relationship of precalving and postcalving explanatory variables with the development of either white line lesions or sole lesions. Explanatory variables tested included digital cushion thickness, sole horn thickness, sole temperature, foot angle, and heel depth. Farm, parity, body condition score, and presence of lesion at the time of measurement were also included in the models. A thicker digital cushion shortly after calving was associated with decreased odds of cows developing sole lesions during early lactation (odds ratio [OR]: 0.74, 95% confidence interval [CI]: 0.65-0.84). No association was found between digital cushion thickness and development of white line lesions. Sole temperature after calving was associated with increased odds of the development of sole lesions (OR: 1.03, 95% CI: 1.02-1.05), and sole temperature before and after calving was associated with the development of white line lesions (T1-precalving OR: 1.04, 95% CI: 1.01-1.07; T2-calving OR: 0.96, 95% CI: 0.93-0.99). Neither foot angle nor heel depth was associated with the development of either lesion type. However, an increased sole horn thickness after calving reduced the odds of cows developing sole lesions during early lactation (OR: 0.88, 95% CI: 0.83-0.93), highlighting the importance of maintaining adequate sole horn when foot trimming. Before calving, animals with a lesion at the time of measurement and a thicker sole were more likely to develop a sole lesion (OR: 1.23, 95% CI: 1.09-1.40), compared with those without a sole lesion. The results presented here suggest that white line and sole lesions may have differing etiopathogenesis. Results also confirm the association between the thickness of the digital cushion and the development of sole lesions, highlight the association between sole horn thickness and sole lesions, and challenge the potential importance of foot angle and heel depth in the development of CHDL.

Prevalence and risk factors for hair loss in outdoor-wintered beef cattle under cold weather conditions.

Keeping cattle outdoors year-around is considered an attractive alternative to indoor winter-housing, due to lower investment costs and better welfare. However, hair loss, attributed to lice, may impair cattle's thermal balance during harsh winters. During the winters of 2019-2021, outdoor cattle in Sweden were studied for the prevalence and development of hair loss, while surveys were conducted among the farmers on their perceptions and attitudes around hair loss. Of the 463 groups of cattle from 75 farms enrolled in a welfare control program issued by the Swedish Board of Agriculture, 25.7% (n = 119) had at least one animal with hair loss. When we followed up a subset of animals (n = 3673) which did not receive prophylactic delousing, 15.7% developed hair loss. Hair loss occurrence increased between visits within each winter in these animals, suggesting a contagious etiology. Logistic regression analyses, using the information collected in the control program and the hair loss outcome, showed that preventive delousing before November was effective, alongside keeping animals clean and the group size small. Meanwhile, being older (>2 years) and having access to bedding materials was shown to increase the risk at an animal-level. Some groups (n = 34) had no hair loss despite receiving no prophylactic delousing. Based on the survey conducted among the farmers (n = 15), groups with lower hair loss prevalence belonged to farmers who were more observant of hair loss and gave prompt treatment. This study provides knowledge useful to limit delousing interventions without compromising animal welfare.

Pelvic dimensions and occurrence of dystocia in Black-and-White and Holstein-Friesian heifers.

The Black-and-White (BW) breed, which until recently had dominated in Europe, was replaced by the Holstein-Friesian (HF) breed. As a result, the incidence of dystocia has increased. Dystocia occurs most frequently in heifers, and it is associated with high calf weight and/or too narrow pelvic openings in heifers. The aim of this study was to evaluate retrospectively the effects of pelvic dimensions and rump angle on calving ease in two cattle breeds. The research was carried out in four barns where BW and HF cattle were used. The course of parturition was evaluated in 317 heifers (BW, n=169; HF, n=148) based on direct observations. Calves were weighed, external and internal pelvic measurements were performed (using the Rice pelvimeter), and rump angle was determined in heifers. Based on the course of parturition, heifers of both breeds were divided into easy calving (EC) and difficult calving (DC) groups. The frequency of DC was 24.3% in HF heifers and 13.1% in BW heifers. In comparison with DC heifers, EC heifers had a larger pelvic area, in particular the internal dimensions of the bony pelvis, and a higher rump angle. In comparison with BW heifers, HF heifers had a smaller rump angle, a narrower pelvis and a lower ratio of pelvic area to calf weight. High dystocia rates in HF heifers could result from a relatively large fetus size and a less preferable pelvic size and rump angle. High variation in the internal pelvic dimensions in HF heifers indicates that the incidence of dystocia can be reduced through selection for a larger pelvic size and the optimal rump angle.

A system dynamics approach to model heat stress accumulation in dairy cows during a heatwave event.

Climate change is expected to increase the number of heat wave events, leading to prolonged exposures to severe heat stress (HS) and the corresponding adverse effects on dairy cattle productivity. Modelling dairy cattle productivity under HS conditions is complicated because it requires comprehending the complexity, non-linearity, dynamicity, and delays in animal response. In this paper, we applied the System Dynamics methodology to understand the dynamics of animal response and system delays of observed milk yield (MY) in dairy cows under HS. Data on MY and temperature-humidity index were collected from a dairy cattle farm. Model development involved: (i) articulation of the problem, identification of the feedback mechanisms, and development of the dynamic hypothesis through a causal loop diagram; (ii) formulation of the quantitative model through a stock-and-flow structure; (iii) calibration of the model parameters; and (iv) analysis of results for individual cows. The model was successively evaluated with 20 cows in the case study farm, and the relevant parameters of their HS response were quantified with calibration. According to the evaluation of the results, the proposed model structure was able to capture the effect of HS for 11 cows with high accuracy with mean absolute percent error <5%, concordance correlation coefficient >0.6, and R2 > 0.6, except for two cows (ID #13 and #20) with R2 less than 0.6, implying that the rest of the nine animals do not exhibit heat-sensitive behaviour for the defined parameter space. The presented HS model considered non-linear feedback mechanisms as an attempt to help farmers and decision makers quantify the animal response to HS, predict MY under HS conditions, and distinguish the heat-sensitive cows from heat-tolerant cows at the farm level.

Attributing Ethiopian animal health losses to high-level causes using expert elicitation.

The Global Burden of Animal Diseases programme is currently working to estimate the burden of animal health loss in Ethiopia. As part of this work, structured expert elicitation has been trialled to attribute the proportion of animal health losses due to three independent and exhaustive high-level causes (infectious, non-infectious, and external). Separate in-person workshops were conducted with eight cattle, nine small ruminant, and eight chicken experts. Following the Investigate-Discuss-Estimate-Aggregate protocol for structured expert elicitation, estimates were obtained for the proportion of animal health loss due to high-level causes in different combinations of health loss, species, age-sex class, and production system. Three-point questions were used to inform beta-pert distributions and capture uncertainty in estimates. Individual expert estimates were aggregated by quantile mean to produce average distributions. Random samples from these average distributions estimated that infectious causes inflict the highest proportion of health loss in Ethiopia, with at least 40 % of health losses estimated to be due to infectious causes in all categories. This study provides a rapid, simple, and engaging method to attribute the burden of animal health loss at a high-level. Results are informative, however will become increasingly useful once they can be compared with results from more sophisticated, data-driven models.

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves - Part 2: Temperature, relative humidity and bedding.

Bovine respiratory disease (BRD) is a challenge in all housed farming systems that raise calves. Farm to farm variation in BRD prevalence can be partially attributed to variation in host immunity, pathogens and housing environment. Unlike host immunity and BRD pathogens, housing environment has not been well investigated. The objective of this systematic review was to identify the measurable environmental variables associated with BRD in housed preweaned calves. Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion publications had to be published in English, before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection. In total 12 publications were included in this review. In this second part of the systematic review the environmental variables identified were; temperature (9 publications); relative humidity (8 publications); bedding (5 publications); ventilation (1 publication); air CO2 concentration (1 publication) and air velocity (4 publications). Of the publications that were examined a statistically significant relationship to BRD was identified in 4/9 publications examining temperature, 3/8 examining relative humidity, 2/4 examining air velocity, 2/5 examining bedding, 0/1 examining ventilation rates and 0/1 examining CO2 concentration. From this review it is clear high airspeed at calf level should be avoided as should deep, wet pack bedding. The relationship between BRD prevalence and both high and low temperature requires more investigation to identify temperature thresholds associated with increased risk of BRD as well as the most influential modifiers. An optimal environment for housed calves could not be clearly identified in this review.

Risk factors associated with enzootic bovine leukosis in Boyacá and Cundinamarca municipalities, Colombia.

Background: Enzootic bovine leukosis (EBL) is a lymphoproliferative disorder caused by the bovine leukemia virus (BLV), a virus of the Retroviridae family. The infection is distributed worldwide, and a high percentage of animals infected by the BLV are asymptomatic and act as carriers of the virus in many cattle populations. Aim: To identify the risk factors associated with EBL in the municipalities of Boyacá and Cundinamarca (Colombia). Methods: A simple descriptive cross-sectional study with random sampling was conducted. A total of 1,140 blood samples were taken from cattle (females and males) from the municipalities of Chiquinquirá, Ubaté, and San Miguel de Sema of different breeds and age groups. The samples were processed using the commercial ELISA SERELISA® BLV Ab Mono Blocking kit (sensitivity 97%, specificity 98%). The data were processed with the statistical programs WinEpi and Epi Info® version 7.2.4.0, estimating the prevalence ratio, implementing the chi-square test (p ≤ 0.05) and logistic regression. Results: A true prevalence (TP) and apparent prevalence (AP) of 23.61% and 22.7% in Ubaté, 19.22% and 18.1% in Chiquinquirá, and 15.61% and 14.3% in San Miguel de Sema, respectively, were established. Bovines 2-4 years old were the most prevalent in Ubaté and Chiquinquirá (37.5% and 21.21%, respectively), while in San Miguel de Sema individuals >4 years had the highest percentage of antibodies (18.3%). The Holstein breed had a higher prevalence in Ubaté and San Miguel de Sema (26.02% and 19.67%), and crossbreeds were more BLV-seroprevalence in Chiquinquirá (20.20%). In Ubaté, re-use of needles was identified as a risk factor, contaminated blood in needles is considered one of the main routes of transmission. On the other hand, manual milking was identified as a risk factor in San Miguel de Sema. Conclusion: The non-implementation of an individual needle per animal in Ubaté; the Holstein breed and manual milking in San Miguel de Sema were identified as risk factors for the presence of antibodies against the disease. EBL prevention and control plans should be established that focus on the implementation of management and sanitary practices based on herd biosecurity.

Hematological differentiation of bladder rupture and complete/partial urethral obstruction in castrated Hanwoo (Korean indigenous cattle) with urolithiasis.

This case report describes the hematological and radiological examination of urinary bladder rupture and complete urethral obstruction. associated with urolithiasis in Hanwoo. Hyponatremia, hypochloremia, azotemia, and hyperglycemia were observed in both urethral obstruction and urinary bladder rupture. However, cattle with urethral obstruction showed hyperkalemia and mild hyperglycemia, whereas cattle with bladder rupture showed marked hyperglycemia and normal potassium levels. In ultrasonography, the urethral obstruction showed a dilated bladder with a thick bladder wall. In contrast to previous literature, in this study, severe electrolyte changes such as severe hyponatremia, hypochloremia, and hyperkalemia occurred in a case of complete urethral obstruction.

Association between dam and calf measurements with overall and fetopelvic dystocia in Holstein heifers.

We investigated the relationship between dam's pelvic and calf's dimensions with dystocia due to fetopelvic disproportion in the Holstein breed and estimated risk factors and dystocia probability. For this purpose, external pelvic measurements were performed in 402 heifers 15 ± 11 (1-38) days ante-partum and specific conformation measurements were obtained from their calves 1.7 ± 1.2 post-partum. Dystocia was defined as the inability of the heifer to complete parturition spontaneously within 120 min after the appearance of the amnion with normal presentation, position and posture or as having definite obstetrical obstacles within 60 min. Overall and fetopelvic disproportion dystocia incidence was 10.4% and 5.2%, respectively. Heifer measurements mainly influenced overall dystocia, whereas calf conformation was related solely with fetopelvic dystocia. Specifically, heifers with a small pelvis (hip width <49.95 cm, pelvic inlet area <333.2 cm2, pelvic volume <7799.2 cm3) had 2.8 to 3.5 times greater incidence of overall dystocia (19.0-20.8%) compared to heifers with a larger pelvis (incidence of 7.0-7.6%). Regarding calf factors, sex (male calves), body weight, chest circumference and fetlock joint circumference significantly increased the odds of experiencing dystocia due to fetopelvic disproportion compared with female, lighter or smaller calves. In a backward elimination model with independent variables treated as continuous, an area under the ROC curve of 0.66 regarding the prediction of overall dystocia based on heifer pelvic length, and of 0.64 for the prediction of fetopelvic dystocia based on fetlock joint circumference was found. The combination of the two variables in one model improved the ROC area to 0.71 regarding dystocia due to fetopelvic disproportion, reaching acceptable level of discrimination. Our findings indicate that dystocia due to fetopelvic disproportion in heifers is mainly influenced by the fetal side. Additionally, the estimation of pelvic dimensions of the dam before parturition and specific conformation characteristics of the calf during parturition, especially fetlock joint circumference, could aid obstetricians and herdsmen regarding dystocia probability and parturition surveillance.

Review: Reproductive consequences of whole-body adaptations of dairy cattle to heat stress.

Heat stress has far-reaching ramifications for agricultural production and the severity of its impact has increased alongside the growing threats of global warming. Climate change is exacerbating the already-severe consequences of seasonal heat stress and is predicted to cause additional losses in reproductive performance, milk production and overall productivity. Estimated and predicted losses are staggering, and without advancement in production practices during heat stress, these projected losses will threaten the human food supply. This is particularly concerning as the worldwide population and, thus, demand for animal products grows. As such, there is an urgent need for the development of technologies and management strategies capable of improving animal production capacity and efficiency during periods of heat stress. Reproduction is a major component of animal productivity, and subfertility during thermal stress is ultimately the result of both reproductive and whole-body physiological responses to heat stress. Improving reproductive performance during seasonal heat stress requires a thorough understanding of its effects on the reproductive system as well as other physiological systems involved in the whole-body response to elevated ambient temperature. To that end, this review will explore the reproductive repercussions of whole-body consequences of heat stress, including elevated body temperature, altered metabolism and circulating lipopolysaccharide. A comprehensive understanding of the physiological responses to heat stress is a prerequisite for improving fertility, and thus, the overall productivity of dairy cattle experiencing heat stress.

Associated risk factors for skin alterations in dairy cattle kept on small scale mountain farms.

The objective of this study was to determine the risk factors for skin alterations at herd and cow level on dairy farms with different housing systems in South Tyrol (Northern Italy). A cross-sectional study was conducted on 204 farms (111 free stalls and 93 tie stalls) from March to October 2019 assessing the level of animal welfare using resource-based and animal-based indicators. A total number of 1,891 dairy cows were evaluated, of which 43.5% were reared in tie stalls and 56.5% in free stalls. A logistic regression model identified the herd and cow level risks factors for neck and leg skin alterations in the two different systems. There was a higher prevalence for skin lesions on the neck (Odd Ratio (OR) = 2.36) and hock (OR = 2.82) for tie stalls. Irrespective of the housing system the soft-based stall mattresses had a lower prevalence for knee and hock lesions of 0.48 and 0.54, respectively, compared to wood base stalls for both knee (OR = 2.19) and hock (OR = 2.47) consecutively. The prevalence of skin alterations on the knee (OR = 0.42) and hock (OR = 0.33) decreased by the presence of sawdust as bedding material. Similarly, straw (OR = 0.61) and lime-straw-water bedding (OR = 0.59) reduced the prevalence for skin alterations on the hock. Access to pasture reduced the prevalence of skin alterations on the neck (OR = 0.34), the knee (OR = 0.77), and on the hock (OR = 0.46) regardless of the housing system. In conclusion, the assessment of risk factors of different skin alterations in different housing systems can contribute to the improvement of overall animal welfare in traditional small scale mountain dairy systems.

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.

Genesis of clinical and subclinical endometritis in dairy cows.

In brief: Clinical and subclinical endometritis are different manifestations of reproductive tract inflammatory disease in dairy cows. This review addresses the genesis of clinical and subclinical endometritis considering metabolic stress, innate immune dysfunction, and shifts in the composition of the uterine microbiota in the postpartum period. Abstract: Up to half of dairy cows may develop one or more types of reproductive tract inflammatory disease within 5 weeks after calving. Clinical endometritis (CE) results from uterine bacterial dysbiosis with increased relative abundance of pathogenic bacteria associated with luminal epithelial damage. These bacteria cause endometrial stromal cell lysis, followed by massive polymorphonuclear neutrophil (PMN) migration, and pyogenesis. CE is defined as endometrial inflammation accompanied by purulent discharge. Purulent discharge is not always accompanied by uterine inflammation (being (rarely) vaginitis or (commonly) cervicitis), hence referred to as purulent vaginal discharge (PVD). Subclinical endometritis (SCE) is an asymptomatic uterine disease defined by a threshold of PMN on cytology that is associated with worse reproductive performance; it has not been linked with bacterial dysbiosis. Current evidence suggests that SCE is a result of metabolic and inflammatory dysfunction that impairs innate immune function and the ability of endometrial PMN to undergo apoptosis, necrosis, and ultimately achieve resolution of inflammation. CE and SCE are diagnosed between 3 and 5 weeks postpartum and commonly overlap, but they are considered distinct manifestations of reproductive tract inflammatory disease. This review addresses the genesis of CE and SCE in postpartum dairy cows considering metabolic stress, innate immune dysfunction, and shifts in the composition of the uterine microbiota.

[Risk factors for infectious foot -disorders on two Swiss cattle -mountain pastures]. / Risikofaktoren für infektiöse Zehen­erkrankungen auf zwei Schweizer ­Rinderalpen.

INTRODUCTION: In the present study, risk groups for infectious foot disorders were identified on two large Swiss cattle mountain pastures by analyzing animal and treatment data of a total of 3256 animals of the bovine species. Both mountain pastures were part of the Federal Office for Agriculture (FOAG) consultancy project «Healthy animals, attractive herdsmen positions and less medication on large cattle mountain pastures¼. The project was launched in 2020 following the increased incidence of lameness on these mountain pastures. Bacteriological and histological analyses were to provide information as to whether the most common foot disorder was interdigital phlegmon (IP) or whether digital dermatitis also occurred. Further, the temporal distribution of cases over the mountain pasture season and the influence of mountain pasture and year were investigated and interpreted for the project years 2020 to 2022, and treatment incidences were compared between years. Multiple treatment cycles in the same individual were classified into persistent infections and new infections. Nineteen of 394 first-treated cattle were clinically examined, 12 of them were additionally sampled for bacteriological and histological analyses. All cases examined showed, both clinically and following laboratory analyses, typical characteristics for IP. In contrast, there was no specific evidence for the presence of digital dermatitis. No persistent infections occurred during treatment with benzylpenicillin. Multivariate logistic regression analyses identified > 365-730-day-old cattle (odds ratio OR 8,29), as well as inseminated (OR 5,30) and non-inseminated (OR 7,85) heifers as risk groups for the disease studied (p < 0,05). Association with the oestrus activity of non-inseminated heifers and a generally higher locomotor activity in heifers compared to cows - with a correspondingly increased risk of injury - is conceivable. Meat breeds had a reduced risk compared to dairy breeds (OR 0,29). Breed differences in behavior and/or the effectiveness of the local immune response might have an impact. Knowing about these risk groups can be put to use in the future when selecting animals to be taken to the mountain pastures and/or when planning pasture management in order to reduce the prevalence of infectious foot disorders and thereby the use of antibiotics.

INTRODUCTION: Dans la présente étude, nous avons identifié, grâce à l'analyse des données concernant les animaux et les traitements d'un total de 3256 animaux de l'espèce bovine, des groupes à risque pour les maladies infectieuses des onglons sur deux grands alpages bovins en Suisse. Les deux alpages faisaient partie du BLW-projet de conseil «Animaux sains, postes de bergers attractifs et moins de médicaments sur les grands alpages bovins¼. Le projet a débuté en 2020 suite à l'accumulation de problèmes de boiteries sur ces alpages. Des analyses bactériologiques et histologiques devaient fournir des indications afin de savoir si la maladie des onglons majoritaire était le phlegmon interdigité (PI) ou si la dermatite digitale était également présente. La répartition temporelle des cas de maladies durant la saison d'estivage et l'influence de l'alpage et de l'année pour les années de projet 2020 à 2022 ont été évaluées et interprétées, et les incidences des traitements comparées entre les années. Les cycles de traitement multiples chez le même individu ont été répartis en deux groupes: les infections persistantes et les nouvelles infections. Dix-neuf des 394 bovins primo-traités ont été évalués cliniquement. Douze de ces 19 animaux ont également été soumis à un échantillonnage bactériologique et histologique. Tous les cas étudiés présentaient, aussi bien cliniquement que suite à l'analyse technique en laboratoire, les caractéristiques typiques d'un PI. Par contre, il n'y a pas eu d'indication quant à la présence de dermatite digitale. Aucune infection persistante n'a été constatée après traitement avec de la Benzylpénicilline. Les bovins âgés > 365­730 jours (OR 8.29), ainsi que les génisses inséminées (odds ratio OR 5.30) et non inséminées (OR 7.85) ont été identifiés, suite à une analyse de régression logistique multivariée, comme faisant partie de groupes à risque pour la maladie étudiée (p < 0.05). Un lien avec l'activité en période de chaleurs des génisses non inséminées et une activité locomotrice généralement plus intensive des génisses par rapport aux vaches ­ avec par conséquent un risque accru de blessures ­ est concevable. Le risque était réduit pour les races à viande par rapport aux races laitières (OR 0.29). Des différences de comportement et/ou d'efficacité de l'immunité locale entre les races pourraient avoir une influence. Le fait de connaître ces groupes à risque pourrait être mis à profit à l'avenir lors de la sélection des animaux à monter à l'alpage et/ou lors de la planification de la gestion des prairies, afin de diminuer la prévalence des maladies infectieuses des onglons et ainsi l'utilisation d'antibiotiques.

Associations between days in the close-up group and milk production, transition cow diseases, reproductive performance, culling, and behavior around calving of Holstein dairy cows.

The objective of experiment I was to evaluate the association between days in the close-up group (DINCU) and milk production, early lactation diseases, reproductive performance, and culling. In experiment II behavioral changes associated with DINCU were evaluated using a neck-mounted sensor (Smarttag neck, Nedap Livestock Management, Groenlo, the Netherlands). Cow-lactations of 28,813 animals from 14,155 individual cows of 2 farms in northern Germany and western Slovakia, calving between January 2015 and December 2020, were included in the study. After exclusion of cows with a gestation length <262 and >292 d and cows with >42 DINCU data from 8,794 and 19,598 nulliparous and parous cows, respectively, were available for final statistical analyses. To analyze the association between DINCU and second test-d 305-d mature-equivalent milk projection, linear mixed models were calculated. Binary data (i.e., clinical hypocalcemia, hyperketonemia, retained placenta [RP], acute puerperal metritis [APM], mastitis, left displaced abomasum [LDA], first service pregnancy risk) were analyzed using logistic regression models. To analyze the association between DINCU and culling or death during the first 300 DIM Cox proportional hazards were used. To analyze the association between DINCU and behavior 7 d before to 7 d after calving (i.e., activity, inactivity, eating, ruminating time), linear mixed models were calculated. Nulliparous cows with a short (<10 DINCU) and a long stay (>30 DINCU) in the close-up group had a lower milk production an increased risk for hyperketonemia, RP, and APM compared with nulliparous cows with DINCU between 21 to 28 d. Parous cows with a short (<10 DINCU) and a long stay (>30 DINCU) in the close-up group had a lower milk production, an increased risk for RP and mastitis, a reduced first service pregnancy risk, and an increased culling risk, compared with parous cows with DINCU between 21 to 28 d. Furthermore, the risk for clinical hypocalcemia and LDA was increased in parous cows with >30 DINCU compared with parous cows with <30 DINCU. The risk for APM was increased in parous cows with <10 DINCU compared with parous cows with >10 DINCU. In nulliparous cows no association was found between DINCU and the risk for left displaced abomasum and mastitis. In experiment II, cows with 7 and 35 DINCU had an impaired behavior around calving compared with cows with 14, 21, and 28 DINCU. During the last 7 d before parturition, these cows were more inactive and had a reduced eating and ruminating time. After calving, cows with 7 DINCU spent less time eating. In conclusion, cows with <10 DINCU and cows with >30 DINCU had a lower milk production, a higher risk to incur diseases and an impaired behavior, especially before calving.

Invited review: Bovine abortion-Incidence, risk factors and causes.

The true incidence of bovine abortion (42-260 days of gestation) is unknown because of under-reporting. This is particularly true of the first half of gestation when most abortions occur. From research studies, it is estimated that the animal-level incidence of abortion between day 45 and term is approximately 10%, being lower in suckler than in dairy cows. While wide variation exists in herd-level incidence, up to 30%, it is estimated that less than 5% of farmers report high (>5%) observed abortion rates. Given these figures, veterinary practitioners and farmers tend to use investigation thresholds close to these values, ≥5 and ≥3%, respectively. Most of the risk factors for abortion are animal-level factors (e.g. parity), but there are also herd-level factors (e.g. enterprise type). Of the many risk factors for bovine abortion, only a small number are modifiable. While the causes of bovine abortion are often classified as noninfectious or infectious, in reality, this means diagnosis not reached (DNR) or infectious. Approximately 40% of abortions are diagnosed as infectious and the remaining 60% as DNR; DNR includes both infectious and noninfectious causes not diagnosed. Increasingly, genetic causes are being diagnosed and changes to current national genetic selection indices may be warranted. Of the infectious causes, Neospora caninum is now the most commonly diagnosed abortifacient internationally, followed by Trueperella pyogenes, BVDv and fungi. Both national eradication programmes and effective vaccination programmes can reduce the burden of some infectious abortifacients, but the control of sporadic, noninfectious and Neospora-associated abortions remains challenging.

Clinical management of pregnancy-related problems between days 28 and 60 in the dairy cow.

The biological and economic impacts of pregnancy loss in dairy herds are well recognized. This review examines clinical aspects of late embryonic/early fetal loss of non-infectious cause in the dairy cow. The period of interest spans from shortly after observation of at least one embryo with a heartbeat upon pregnancy diagnosis, at around Day 28 of pregnancy (late embryonic period), until approximately Day 60 of pregnancy (early fetal period). This last time point is when pregnancy is firmly established and beyond which the risk of pregnancy loss is greatly reduced. We particularly focus on the role of the clinician in managing a pregnancy and discuss findings to predict the viability of a pregnancy, available therapies for expected pregnancy problems and possible implications of the newer technologies.

Hepatic Lipidosis in Ruminants.

Hepatic lipidosis (ie, fatty liver) occurs primarily during the first weeks of lactation in dairy cows because of excessive lipolysis overwhelming the concomitant capacity for beta-oxidation and hepatic export of triglycerides. Besides economic losses due to reduced lactational and reproductive performance, close associations with concomitantly occurring infectious and metabolic health disorders, in particular ketosis, exist. Hepatic lipidosis is not only a consequence from the postpartal negative energy balance but also acts as a disease component for further health disorders.

A multistate modeling approach to investigate long-term effects of claw horn disruption lesions and early lesion development in dairy cows.

Claw horn disruption lesions (CHDL) are a leading cause of lameness in dairy cattle, and the development, effect, and pathology of these lesions remains an open area of interest within dairy cattle health. Current literature typically attempts to measure the effect of risk factors on the development of CHDL over a relatively short time period. Further understanding of the interaction of CHDL and the long-term effect of early CHDL in a cow's life remains an important area of research which is so far mostly unexplored. In this study 57,974 cows from 1,332 herds were selected and their regular claw trimming records containing important claw health information were used to model the long-term effect of lesions in a cow's lifetime in a 6-state multistate model. A multistate model predicts the time before transition from any one state to another and the probability of transition to a future state. The 6 lesion states that were modeled were as follows: never had a lesion, first recorded lesion event, no recorded lesion after first lesion event, second or subsequent recorded lesion event, no recorded lesion after second or subsequent lesion event, and culled. The effect of various cow level covariates on the transition probabilities between various states was tested. For the first time, this study shows the importance and effect of the first lesion and other cow level factors on long-term claw health. Model results showed that the timing and severity of the first recorded lesion event significantly influenced the likelihood of a future lesion being present. Cows with CHDL present within the 180 d of first calving had a short-term increased risk and long-term decreased risk of a future lesion, compared with cows that present with CHDL later than 180 d of first lactation. Moreover, presence of a severe first lesion increased a cow's risk of a future lesion being present. The model was used to evaluate the relative difference between high-risk cows (age of first calving ≥793 d, breeding values in the lowest quartile) and low-risk cows (age of first calving ≤718 d, breeding values in the highest quartile). Our results indicated that these low-risk cows present with a lesion on an average 3 mo later than high-risk cows. Furthermore, results from the model evaluation of a simulated herd with cows with breeding values in the higher quartile indicated that cows present with a CHDL on an average 7.5 mo later compared with a herd where cows have breeding values distributed in a lower quartile.