Cows with diverging haplotypes show differences in differential milk cell count, milk parameters and vaginal temperature after S. aureus challenge but not after E. coli challenge.

BACKGROUND: In dairy cattle, mastitis causes high financial losses and impairs animal well-being. Genetic selection is used to breed cows with reduced mastitis susceptibility. Techniques such as milk cell flow cytometry may improve early mastitis diagnosis. In a highly standardized in vivo infection model, 36 half-sib cows were selected for divergent paternal Bos taurus chromosome 18 haplotypes (Q vs. q) and challenged with Escherichia coli for 24 h or Staphylococcus aureus for 96 h, after which the samples were analyzed at 12 h intervals. Vaginal temperature (VT) was recorded every three minutes. The objective of this study was to compare the differential milk cell count (DMCC), milk parameters (fat %, protein %, lactose %, pH) and VT between favorable (Q) and unfavorable (q) haplotype cows using Bayesian models to evaluate their potential as improved early indicators of differential susceptibility to mastitis. RESULTS: After S. aureus challenge, compared to the Q half-sibship cows, the milk of the q cows exhibited higher PMN levels according to the DMCC (24 h, p < 0.001), a higher SCC (24 h, p < 0.01 and 36 h, p < 0.05), large cells (24 h, p < 0.05) and more dead (36 h, p < 0.001) and live cells (24 h, p < 0.01). The protein % was greater in Q milk than in q milk at 0 h (p = 0.025). In the S. aureus group, Q cows had a greater protein % (60 h, p = 0.048) and fat % (84 h, p = 0.022) than q cows. Initially, the greater VT of S. aureus-challenged q cows (0 and 12-24 h, p < 0.05) reversed to a lower VT in q cows than in Q cows (48-60 h, p < 0.05). Additionally, the following findings emphasized the validity of the model: in the S. aureus group all DMCC subpopulations (24 h-96 h, p < 0.001) and in the E. coli group nearly all DMCC subpopulations (12 h-24 h, p < 0.001) were higher in challenged quarters than in unchallenged quarters. The lactose % was lower in the milk samples of E. coli-challenged quarters than in those of S. aureus-challenged quarters (24 h, p < 0.001). Between 12 and 18 h, the VT was greater in cows challenged with E. coli than in those challenged with S. aureus (3-h interval approach, p < 0.001). CONCLUSION: This in vivo infection model confirmed specific differences between Q and q cows with respect to the DMCC, milk component analysis results and VT results after S. aureus inoculation but not after E. coli challenge. However, compared with conventional milk cell analysis monitoring, e.g., the global SCC, the DMCC analysis did not provide refined phenotyping of the pathogen response.

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.

In vitro effects of lipopolysaccharides on bovine uterine contractility.

Metritis is an important disorder in dairy cows during the early postpartum period. Myometrial contractility is a prerequisite for uterine involution; however, very scanty literature is available about the effect of metritis on this process and endocrine responsiveness. This study was aimed to evaluate the effect of inflammation on uterine contractility in vitro, and the inflammation was induced by incubating myometrial strips with lipopolysaccharides (LPS). Myometrial samples were collected from 17 healthy Holstein Friesian cows during caesarean section. Eight longitudinal strips from each cow were incubated in organ baths with LPS concentrations of 0 (LPS0 ), 0.1 (LPS0.1 ), 1 (LPS1 ) and 10 µg/ml (LPS10 ). Spontaneous contractility and contractility induced by increasing concentrations of oxytocin (10-10 - 10-7  mol/L) were recorded during nine 30-min intervals (T1 to T9). The minimum amplitude (minA), maximum amplitude (maxA), mean amplitude (meanA) and area under the curve (AUC) were calculated for each time interval. LPS had an effect (p ≤ .05) on maxA, meanA and AUC. In T1, myometrial strips incubated with LPS0.1 and LPS1 had higher (p ≤ .05) maxA, meanA and AUC than the strips incubated with LPS0 . In T9 without oxytocin, LPS0 led to higher (p ≤ .05) maxA, meanA and AUC than LPS0.1 and LPS1 . In T8 and T9 with oxytocin, LPS1 had lower (p ≤ .05) maxA, meanA and AUC than the other LPS concentrations. Interestingly, the results show that LPS has a transient positive effect on myometrial contractility in vitro and that this effect is dependent on LPS concentration and duration of incubation.

Influence of two different feeding strategies in the dry period on dry matter intake and plasma protein peroxidative and antioxidative profile during dry period and early lactation.

BACKGROUND: Dairy cows undergo dramatic changes in endocrine and metabolic status around parturition and in early lactation. Meeting the nutritional requirements of transition dairy cows is important for animal health, production and animal wellbeing. Dry cow feeding and managing play an essential role in this. The changes in metabolism of periparturient cows also lead to a rise in the production of oxidising agents, leading to oxidative stress. The relationship between dry cow diet composition and oxidative stress has received little research attention so far. In the present study, the influence of two different dry cow feedings (single diet with medium energy content over the whole dry period versus traditional two-phase diet with a low-energy "far-off" ration and a high energy "close-up" ration) on dry matter intake, energy intake and plasma protein peroxidative and antioxidative profile was investigated. RESULTS: The examined parameters revealed a dynamic profile within the experimental period. Dry matter intake (DMI) did not differ between groups. However, there was a time and a group x time interaction effect: Group 1 ("one-phase") had a very constant DMI with a slow and even decrease until calving. In Group 2 ("two-phase"), an initial increase in DMI two weeks antepartum (a.p.) was followed by a sharp drop at week 1 a.p.. The highest total antioxidant capacity and sulfhydryl residue concentration was noted at partus. In contrast, concentration of formylokinurenine and bityrosine bridges as representatives of protein peroxidation were lowest at parturition. The time course of formylokinurenine and bityrosine bridges showed parallels to the DMI. The contents of sulfhydryl groups, formylokinurenine and total antixoxidant capacity did not differ between groups. In contrast, concentration of bityrosine bridges was always higher in Group 2 compared with Group 1 and these differences were statistically significant at week 3 a.p., week 2 a.p., week 1 a.p. and at parturition. CONCLUSION: The results of our study suggest time-related changes of pro- and antioxidative plasma parameters. Different dry cow feeding affected antepartal DMI. Furthermore, DMI and diet compositions seemed to have an influence on plasma protein peroxidative profile and activity of antioxidative defence.

Activity of selected glycosidases and availability of their substrates in bovine placenta during pregnancy and parturition with and without retained foetal membranes.

The activity of glycosidases is crucial for the function and biological activity of proteins conjugated with sugar moieties, which play an important role in adhesion of cells during attachment and detachment of the foetal membranes. The aim of study was to describe the ability of bovine placental tissues to break down O-glycosidic bonds in different glycoproteins by the determination of activity of ß-galactosidase, α-l-fucosidase, ß-N-acetyl-hexosaminidase and sialidase in early-mid-pregnancy as well as at parturition with released and retained foetal membranes. Moreover, the availability of substrates for these glycosidases in placental homogenates was evaluated. Placental samples were collected from pregnant (2-4 months) cows in slaughterhouse (n = 8) as well as during Caesarean section and divided into released foetal membranes (n = 8) and retained foetal membranes (n = 8). Tissue homogenates were subjected to spectrofluorimetric and spectrophotometric determinations of enzyme activities as well as electrophoretic separations. Enzyme activities expressed changes within examined time with significant (p < .05) differences between pregnancy and physiological parturition in ß-N-acetyl-hexosaminidase and α-l-fucosidase in foetal part of placenta while in maternal part only in the latter one. Decreasing tendency in enzyme activity was noticed in foetal part of retained samples in comparison with released ones with significant (p < .05) differences in α-l-fucosidase activity. The analysis of staining of sugar moieties attached to selected proteins depicted availability of sugar molecules in examined tissues, but their patterns differed between samples. In conclusion, sugar moieties in conjugated proteins express changes in the course of pregnancy which is reflected by the alterations in activities of placental glycosidases.

Development and evaluation of a milk protein transcript depletion method for differential transcriptome analysis in mammary gland tissue.

BACKGROUND: In the mammary gland transcriptome of lactating dairy cows genes encoding milk proteins are highly abundant, which can impair the detection of lowly expressed transcripts and can bias the outcome in global transcriptome analyses. Therefore, the aim of this study was to develop and evaluate a method to deplete extremely highly expressed transcripts in mRNA from lactating mammary gland tissue. RESULTS: Selective RNA depletion was performed by hybridization of antisense oligonucleotides targeting genes encoding the caseins (CSN1S1, CSN1S2, CSN2 and CSN3) and whey proteins (LALBA and PAEP) within total RNA followed by RNase H-mediated elimination of the respective transcripts. The effect of the RNA depletion procedure was monitored by RNA sequencing analysis comparing depleted and non-depleted RNA samples from Escherichia coli (E. coli) challenged and non-challenged udder tissue of lactating cows in a proof of principle experiment. Using RNase H-mediated RNA depletion, the ratio of highly abundant milk protein gene transcripts was reduced in all depleted samples by an average of more than 50% compared to the non-depleted samples. Furthermore, the sensitivity for discovering transcripts with marginal expression levels and transcripts not yet annotated was improved. Finally, the sensitivity to detect significantly differentially expressed transcripts between non-challenged and challenged udder tissue was increased without leading to an inadvertent bias in the pathogen challenge-associated biological signaling pathway patterns. CONCLUSIONS: The implementation of selective RNase H-mediated RNA depletion of milk protein gene transcripts from the mammary gland transcriptome of lactating cows will be highly beneficial to establish comprehensive transcript catalogues of the tissue that better reflects its transcriptome complexity.

Case-control study on factors associated with a decreased milk yield and a depressed health status of dairy herds in northern Germany.

BACKGROUND: In the past years, it became apparent that health status and performance differ considerably within dairy farms in Northern Germany. In order to obtain clues with respect to possible causes of these differences, a case-control study was performed. Case farms, which showed signs of health and performance problems, and control farms, which had none of these signs, were compared. Risk factors from different areas such as health management, housing, hygiene and nutrition were investigated as these are known to be highly influential. The aim of this study was to identify major factors within these areas that have the strongest association with health and performance problems of dairy herds in Northern Germany. RESULTS: In the final model, a lower energy density in the roughage fraction of the diet, more pens with dirty lying areas and a low ratio of cows per watering spaces were associated with a higher risk for herd health problems. Moreover, case farms were affected by infections with intestinal parasites, lungworms, liver flukes and Johne's Disease numerically more often than control farms. Case farms more often had pens with raised cubicles compared to the deep bedded stalls or straw yards found in control farms. In general, the hygiene of the floors and beddings was worse in case farms. Concerning nutrition, the microbiological and sensory quality of the provided silages was often insufficient, even in control farms. Less roughage was provided to early lactating cows and the feed was pushed to the feeding fence less frequently in case farms than in control farms. CONCLUSIONS: The results show that milk yield and health status were associated with various factors from different areas stressing the importance of all aspects of management for good animal health and performance. Moreover, this study confirmed well-known risk factors for health problems and performance losses. These should better be taken heed of in herd health management.

Diversity of Clostridium perfringens toxin-genotypes from dairy farms.

BACKGROUND: Clostridium (C.) perfringens is the causative agent of several diseases in animals and humans, including histotoxic and enteric infections. To gain more insight into the occurrence of its different toxin-genotypes in dairy herds, including those toxin genes previously associated with diseases in cattle or humans, 662 isolates cultivated from feces, rumen content and feed collected from 139 dairy farms were characterized by PCR (detecting cpa, cpb, iap, etx, cpe, and both allelic variants of cpb2). RESULTS: Isolates from feces were assigned to type A (cpa positive, n = 442) and D (cpa and etx positive, n = 2). Those from rumen content (n = 207) and feed (n = 13) were all assigned to type A. The consensus and atypical variants of the cpb2 gene were detected in 64 (14.5 %) and 138 (31.22 %) of all isolates from feces, and 30 (14.5 %) and 54 (26.1 %) of all isolates from rumen content, respectively. CONCLUSION: Both allelic variants of cpb2 occurred frequently in animals without signs of acute enteric disease, whereby the atypical variant dominated. Five (0.8 %) of all type A isolates were positive for the cpe gene. Therefore, the present study indicates that dairy cows are no primary source for potentially human pathogenic enterotoxin gene positive strains.

Detection of Clostridium botulinum neurotoxin genes (A-F) in dairy farms from Northern Germany using PCR: A case-control study.

Classical botulism in cattle mainly occurs after ingestion of feed contaminated with preformed toxin. In 2001 a form of botulism ("visceral botulism") was postulated to occur after ingestion of Clostridium (C.) botulinum cells or spores, followed by colonization of the intestine, and local production of botulinum neurotoxin (BoNT) causing chronic generalized disease. To verify the potential role of C. botulinum in the described syndrome, a case-control study was conducted, including 139 farms. Fecal samples, rumen content, water and silage samples were collected on each farm. Real time BoNT gene PCR assays were conducted after enrichment in RCM (Reinforced Clostridial Medium) at 37 °C and conventional PCRs after enrichment in MCM (Modified Cooked Meat Medium) at 30 °C. Furthermore, a direct detection of BoNT genes without prior enrichment was attempted. BoNT A, B, C, D, E and F genes were detected in animal samples from 25 (17.99%), 3 (2.16%), 0 (0.0%), 2 (1.44%), 1 (0.72%), and 3 (2.16%) farms, respectively. Eleven feed samples were positive for BoNT A gene. By enrichment a significant increase in sensitivity was achieved. Therefore, this should be an essential part of any protocol. No significant differences regarding BoNT gene occurrence could be observed between Case and Control farms or chronically diseased and clinically healthy animals within the particular category. Thus, the postulated form of chronic botulism in cows could not be confirmed. This study supports the general opinion that C. botulinum can occasionally be found in the rumen and intestine of cows without causing disease.

The effect of metritis and subclinical hypocalcemia on uterine involution in dairy cows evaluated by sonomicrometry.

The objective of this study was to examine the effects of metritis and subclinical hypocalcemia on reduction of uterine size in dairy cows using ultrasonography and sonomicrometry. Four piezoelectric crystals were implanted via laparotomy into the myometrium of the pregnant uterine horn of 12 pluriparous Holstein Friesian cows 3 weeks before the calculated calving date. Sonometric measurements were conducted daily from 2 days before parturition (= Day 0) until Day 14 after calving and then every other day until Day 28. Distances between adjacent crystals were expressed in relation to reference values obtained before calving. The diameter of the formerly pregnant uterine horn was measured using transrectal B-Mode sonography starting on Day 10. Cows were retrospectively divided into the following groups: cows without metritis (M-; n = 7), cows with metritis (M+; n = 5), cows with normocalcemia (SH-; Ca > 2.0 mmol/l on Days 1 to 3; n = 5) and cows with subclinical hypocalcemia (SH+; Ca < 2.0 mmol/l in at least one sample between Days 1 and 3; n = 7). Metritis did not affect (P > 0.05) sonometric measurements, but the diameter of the formerly pregnant horn was larger (P ≤ 0.05) between Days 15 and 21 in M+ cows than in M‒ cows. Reduction in uterine length in hypocalcemic cows was delayed (P ≤ 0.05) between Days 8 and 21 compared with normocalcemic cows, but the uterine horn diameter was not related to calcium status. In conclusion, both diseases affected reduction of uterine size until Day 28. Cows with metritis had a larger uterine diameter, possibly attributable to accumulation of lochia, and cows with subclinical hypocalcemia had delayed reduction of uterine length, presumably related to reduction of myometrial contractility.

Which Factors Influence the Consumption of Antibiotics in Q-Fever-Positive Dairy Farms in Northern Germany?

It was the aim of this study to examine whether the usage of the vaccine COXEVAC® (Ceva Santé Animale) could reduce the consumption of antibiotics in Q-fever-positive dairy farms. Additionally, the effects of other herd-level factors on the consumption of antibiotics were investigated. A total of 36 farms with vaccination and 13 farms without vaccination participated in this longitudinal cohort study. In all herds, Coxiella burnetii had been directly or indirectly diagnosed. To compare the treatment frequency of antibiotics between the vaccinated group and the non-vaccinated group, the consumption of antibiotics for each farm was collected using the veterinary documents about the application and delivery of antibiotics. To gather detailed information about herd data, nutrition, milking management, housing, and animal health, the farmers were interviewed with the help of a questionnaire. The results thereof suggest that there might be an association between the vaccination against Q fever and a reduced consumption of antibiotics. Neither herd size nor milk yield level influenced the consumption of antibiotics in the study herds. Type of flooring and udder-cluster disinfection while milking were associated with a lower and higher therapy frequency, respectively. Further studies are necessary to elucidate the cause-effect relationship between vaccination and the consumption of antibiotics.

Application of Epidemiological Methods in a Large-Scale Cross-Sectional Study in 765 German Dairy Herds-Lessons Learned.

From 2016 to 2020, the "PraeRi" study, conducted by three German veterinary universities, was aimed at enhancing animal health and welfare in dairy farms. With 765 dairy farms visited and 101,307 animals examined, this study provided a basis for improving animal health and welfare. The study population comprised three different regions representing a broad variety of characteristics. To ensure representative estimates, a sample size of 250 farms was determined for each region, employing a stratified sampling plan based on farm size. According to the information provided by the farmers, the most commonly occurring disease in their herds was mastitis without general disorder (14.2% to 16.3% of the herd-depending on the region). For most disorders, prevalence data were lowest for the region South compared with the two remaining regions. Multivariable regression analyses were performed to identify risk factors for various target variables, and the results were communicated through individual reports and benchmarking flyers to participating farmers. The authors encountered challenges in management and communication due to the project's size in terms of personnel, data, and farms examined. Harmonizing data management and hypothesis testing across all involved parties added complexity.

The relationship between lameness prevalence and pasture access in 659 dairy herds in Germany.

Lameness in dairy cows is an expression of pain most likely originating from a claw disorder, causing impaired animal wellbeing and substantial economic losses for farmers. The aim of this study was to investigate the effects of access to pasture, time spent on pasture, and season on farm level lameness prevalence. The survey was part of a cross-sectional observational study, in which farms in three regions of Germany (North, East and South) were visited by study veterinarians. On each farm (total: 659, N: 240, E: 247, S: 172), management data were recorded, and cows were scored for locomotion, according to Sprecher. Median farm-level lameness prevalence (Score 3/5 or higher) was 29.4% (IQR: 18.7% - 42.0%), and 8.2% (IQR: 3.7% - 14.0%) for severe lameness (Score 4/5 or higher). Farm-level lameness prevalence continuously decreased with increasing time spent on pasture (up to approximately 10 hours per cow per day). On farms that did not offer their cows access to pasture lameness prevalence did not show a seasonal variation. On farms where cows had pasture access for up to three hours per day lameness prevalence peaked in autumn. In contrast, on farms offering their cows access to pasture beyond three hours per day the peak of lameness was observed in spring. Our results revealed that even short periods of pasture access of at least two hours per cow and day (on average per year) are beneficial for the locomotion of dairy cows.

Perinatal mortality in German dairy cattle: Unveiling the importance of cow-level risk factors and their interactions using a multifaceted modelling approach.

Perinatal mortality (PM) is a common issue on dairy farms, leading to calf losses and increased farming costs. The current knowledge about PM in dairy cattle is, however, limited and previous studies lack comparability. The topic has also primarily been studied in Holstein-Friesian cows and closely related breeds, while other dairy breeds have been largely ignored. Different data collection techniques, definitions of PM, studied variables and statistical approaches further limit the comparability and interpretation of previous studies. This article aims to investigate the factors contributing to PM in two underexplored breeds, Simmental (SIM) and Brown Swiss (BS), while comparing them to German Holstein on German farms, and to employ various modelling techniques to enhance comparability to other studies, and to determine if different statistical methods yield consistent results. A total of 133,942 calving records from 131,657 cows on 721 German farms were analyzed. Amongst these, the proportion of PM (defined as stillbirth or death up to 48 hours of age) was 6.1%. Univariable and multivariable mixed-effects logistic regressions, random forest and multimodel inference via brute-force model selection approaches were used to evaluate risk factors on the individual animal level. Although the balanced random forest did not incorporate the random effect, it yielded results similar to those of the mixed-effect model. The brute-force approach surpassed the widely adopted backwards variable selection method and represented a combination of strengths: it accounted for the random effect similar to mixed-effects regression and generated a variable importance plot similar to random forest. The difficulty of calving, breed and parity of the cow were found to be the most important factors, followed by farm size and season. Additionally, four significant interactions amongst predictors were identified: breed-calving ease, breed-season, parity-season and calving ease-farm size. The combination of factors, such as secondiparous SIM breed on small farms and experiencing easy calving in summer, showed the lowest probability of PM. Conversely, primiparous GH cows on large farms with difficult calving in winter exhibited the highest probability of PM. In order to reduce PM, appropriate management of dystocia, optimal heifer management and a wider use of SIM in dairy production are possible ways forward. It is also important that future studies are conducted to identify farm-specific contributors to higher PM on large farms.

Do Calving-Related Injuries of the Vestibulum Vaginae and the Vagina Affect the Reproductive Performance in Primiparous Dairy Cows?

The aim of this study was to investigate the influence of calving-related injuries of the vestibulum vaginae and the vagina on fertility measures in heifers. German Holstein heifers (n = 236) were checked for vestibulum vaginae and vaginal injuries. These were scored according to localization, depth and length. The healing process was assessed until day 42 post partum. Calving ease and the occurrence of metritis and endometritis were evaluated. In 160 heifers, the following fertility measures were calculated to assess the reproductive performance of heifers: mean interval from calving to first insemination, mean days open, mean interval from first insemination to conception, mean calving interval, mean pregnancy index, percentage of animals pregnant at 200 days p.p., and first service conception rate. On the one hand, dystocia was a risk factor for injuries of the soft birth canal, and, on the other hand, those injuries were a risk factor for metritis and endometritis. In this study, calving-related injuries of the vestibulum vaginae and the vagina had no statistically significant effect on the reproductive performance of heifers. One reason for this outcome was probably the overall good healing tendencies of those injuries in heifers.

Relationship of body condition and milk parameters during lactation in Simmental cows in Bavaria, Germany.

In dairy cows the body condition forms a reflection of the energy reserves of the organism. Health, welfare and productivity of dairy cows are strongly associated with changes in body condition. As lactation puts substantial demands on the metabolism of dairy cows, farm management aims at avoiding either a deficient body condition or a substantial loss of body condition within a short period of time. A body condition higher or lower than recommended (over- and underconditioning in the following) compromises dairy cow productivity. While the body condition of Holstein Friesian cows has been thoroughly explored, few is known about the consequences of deviations from a target body condition for health and productivity of cows from other breeds. This study explores the percentage of over- and underconditioned cows at different days post partum [dpp] and their association with production parameters i.e., milk yield, milk fat and milk protein content of Simmental cows on Bavarian farms, categorized by parity (primi- or multiparous). Our study displays that in Simmental cows, overconditioning is more prevalent than underconditioning. While the middle of lactation (dpp = 100-199) resulted in higher percentage of overconditioning, the dry period (dpp = < 0 & > 299) indicated a higher percentage of underconditioned cows. The dry period and the middle of lactation are therefore the most challenging lactation stages for Simmental cows. We found milk protein content to have the strongest association with over- and underconditioning in Simmental cows. The probability of overconditioning was higher with higher milk protein content for every lactation stage and the probability of underconditioning was lower with higher milk protein content in every lactation stage. This study provides a theoretical basis for potential improvements in stockbreeding, which, if implemented, could improve not only the milk yield of Simmental dairy cows, but also their health and welfare.

Status of udder health performance indicators and implementation of on farm monitoring on German dairy cow farms: results from a large scale cross-sectional study.

Regional benchmarking data enables farmers to compare their animal health situation to that of other herds and identify areas with improvement potential. For the udder health status of German dairy cow farms, such data were incomplete. Therefore, the aim of this study was (1) to describe the incidence of clinical mastitis (CM), (2) to describe cell count based udder health indicators [annual mean test day average of the proportion of animals without indication of mastitis (aWIM), new infection risk during lactation (aNIR), and proportion of cows with low chance of cure (aLCC); heifer mastitis rate (HM)] and their seasonal variation, and (3) to evaluate the level of implementation of selected measures of mastitis monitoring. Herds in three German regions (North: n = 253; East: n = 252, South: n = 260) with different production conditions were visited. Data on CM incidence and measures of mastitis monitoring were collected via structured questionnaire-based interviews. Additionally, dairy herd improvement (DHI) test day data from the 365 days preceding the interview were obtained. The median (Q0.1, Q0.9) farmer reported incidence of mild CM was 14.8% (3.5, 30.8%) in North, 16.2% (1.9, 50.4%) in East, and 11.8% (0.0, 30.7%) in South. For severe CM the reported incidence was 4.0% (0.0, 12.2%), 2.0% (0.0, 10.8%), and 2.6% (0.0, 11.0%) for North, East, and South, respectively. The median aWIM was 60.7% (53.4, 68.1%), 59.0% (49.7, 65.4%), and 60.2% (51.5, 67.8%), whereas the median aNIR was 17.1% (13.6, 21.6%), 19.9% (16.2, 24.9%), and 18.3% (14.4, 22.0%) in North, East, and South, respectively with large seasonal variations. Median aLCC was ≤1.1% (≤ 0.7%, ≤ 1.8%) in all regions and HM was 28.4% (19.7, 37.2%), 35.7% (26.7, 44.2%), and 23.5% (13.1, 35.9%), in North, East and South, respectively. Participation in a DHI testing program (N: 95.7%, E: 98.8%, S: 89.2%) and premilking (N: 91.1%, E: 93.7%, S: 90.2%) were widely used. Several aspects of udder health monitoring, including exact documentation of CM cases, regular microbiological analysis of milk samples and the use of a veterinary herd health consultancy service were not applied on many farms. The results of this study can be used by dairy farmers and their advisors as benchmarks for the assessment of the udder health situation in their herds.

Multinomial logistic regression based on neural networks reveals inherent differences among dairy farms depending on the differential exposure to Fasciola hepatica and Ostertagia ostertagi.

Fasciola hepatica and Ostertagia ostertagi are cattle parasites with worldwide relevance for economic outcome as well as animal health and welfare. The on-farm exposure of cattle to both parasites is a function of host-associated, intrinsic, as well as environmental and farm-specific, extrinsic, factors. Even though knowledge on the biology of both parasites exists, sophisticated and innovative modelling approaches can help to deepen our understanding of key aspects fostering the exposure of dairy cows to these pathogens. In the present study, multiple multinomial logistic regression models were fitted via neural networks to describe the differences among farms where cattle were not exposed to either F. hepatica or O. ostertagi, to one parasite, or to both, respectively. Farm-specific production and management characteristics were used as covariates to portray these differences. This elucidated inherent farm characteristics associated with parasite exposure. In both studied regions, pasture access for cows, farm-level milk yield, and lameness prevalence were identified as relevant factors. In region 'South', adherence to organic farming principles was a further covariate of importance. In region 'North', the prevalence of cows with a low body condition score, herd size, hock lesion prevalence, farm-level somatic cell count, and study year appeared to be of relevance. The present study broadens our understanding of the complex epidemiological scenarios that could predict differential farm-level parasite status. The analyses have revealed the importance of awareness of dissimilarities between farms in regard to the differential exposure to F. hepatica and O. ostertagi. This provides solid evidence that dynamics and relevant factors differ depending on whether or not cows are exposed to F. hepatica, O. ostertagi, or to both.

Associations of production characteristics with the on-farm presence of Fasciola hepatica in dairy cows vary across production levels and indicate differences between breeds.

Fasciola hepatica is one of the economically most important endoparasites in cattle production. The aim of the present work was to evaluate the relevance of production level on the associations of on-farm presence of F. hepatica with farm-level milk yield, milk fat, and milk protein in Holstein cows, a specialised dairy breed, and in Simmental cows, a dual purpose breed. Furthermore, we investigated whether differential associations were present depending on breed. Data from 560 dairy farms across Germany housing 93,672 cows were analysed. The presence of F. hepatica antibodies was determined via ELISA on bulk tank milk samples. Quantile regression was applied to model the median difference in milk yield, milk fat, and milk protein depending on the interaction of breed and fluke occurrence. Whereas a reduction in milk yield (-1,206 kg, p < 0.001), milk fat (-22.9 kg, p = 0.001), and milk protein (-41.6 kg, p <0.001) was evident on F. hepatica positive German Holstein farms, only milk fat (-33.8 kg, p = 0.01) and milk protein (-22.6 kg, p = 0.03) were affected on F. hepatica positive German Simmental farms. Subsequently, production traits were modelled within each of the two breeds for low, medium, and high producing farms in the presence of F. hepatica antibodies and of confounders. On Holstein farms, the presence of F. hepatica seropositivity was associated with lower production, while on German Simmental farms such an association was less evident. This work demonstrates that production level is relevant when assessing the associations between the exposure to F. hepatica with production characteristics. Moreover, both models indicate a breed dependence. This could point towards a differential F. hepatica resilience of specialised dairy breeds in comparison with dual purpose breeds.

Hock Lesions in Dairy Cows in Cubicle Housing Systems in Germany: Prevalence and Risk Factors.

Hock lesions in dairy cows are an important indicator of animal welfare, in particular housing conditions. The aim of this study was to assess the prevalence of hock lesions in dairy cows kept in cubicle housing systems in three structurally different regions of Germany and to derive recommendations from risk factor analyses. Lactating and dry cows kept in cubicle housing systems were assessed for hock lesions (north: 206 farms with 20,792 cows; south: 156 farms with 8050 cows; east: 192 farms with 37,839 cows). Risk factor analyses were conducted using multi-factorial logistic regression models. The median prevalence of hock lesions (hairless patches, wounds, and/or swelling) at farm level was 79.8% (SD: 25.0; north), 66.2% (SD: 31.0; south), and 78.5% (SD: 26.3; east). The mean prevalence of severe hock lesions (wounds and/or swelling) at farm level was 12.5% (SD: 11.3; north), 8.0% (SD: 13.5; south), and 14.4% (SD: 17.9; east). Cows kept in pens with rubber mats or mattresses (with or without a small amount of litter) had a particularly higher chance of hock lesions compared with cows kept in pens with deep-bedded cubicles (OR: north: 3.1 [2.3-4.2]; south: 8.7 [5.9-13.0], east: 2.0 [1.7-2.4]). The study showed that hock lesions are a widespread problem on German dairy farms with cubicle housing systems. Deep-bedded cubicles are likely to reduce hock lesions and increase cows' comfort.