A 2-year study reveals implications of feeding management and exposure to mycotoxins on udder health, performance, and fertility in dairy herds.

We recently reported the ubiquitous occurrence of mycotoxins and their secondary metabolites in dairy rations and a substantial variation in the feeding management among Austrian dairy farms. The present study aimed to characterize to which extent these factors contribute to the fertility, udder health traits, and performance of dairy herds. During 2019 and 2020, we surveyed 100 dairy farms, visiting each farm 2 times and collecting data and feed samples. Data collection involved information on the main feed ingredients, nutrient composition, and the levels of mycotoxin and other metabolites in the diet. The annual fertility and milk data of the herds were obtained from the national reporting agency. Calving interval was the target criterion for fertility performance, whereas the percentage of primiparous and multiparous cows in the herd with somatic cell counts above 200,000 cells/mL was the criterion for impaired udder health. For each criterion, herds were classified into 3 groups: high/long, mid, and low/short, with the cut-off corresponding to the <25th and >75th percentiles and the rest of the data, respectively. Accordingly, for the calving interval, the cut-offs for the long and short groups were ≥400 and ≤380 d, for the udder health in primiparous cows were ≥20% and ≤8% of the herd, and for the udder health in multiparous cows were ≥35% and ≤20% of the herd, respectively. Quantitative approaches were further performed to define potential risk factors in the herds. The high somatic cell count group had higher dietary exposure to enniatins (2.8 vs. 1.62 mg/cow per d), deoxynivalenol (4.91 vs. 2.3 mg/cow per d), culmorin (9.48 vs. 5.72 mg/cow per d), beauvericin (0.32 vs. 0.18 mg/cow per d), and siccanol (13.3 vs. 5.15 mg/cow per d), and total Fusarium metabolites (42.8 vs. 23.2 mg/cow per d) and used more corn silage in the ration (26.9% vs. 17.3% diet DM) compared with the low counterparts. Beauvericin was the most substantial contributing variable among the Fusarium metabolites, as indicated by logistic regression and modeling analyses. Logistic analysis indicated that herds with high proportions of cows with milk fat-to-protein ratio >1.5 had an increased odds for a longer calving interval, which was found to be significant for primiparous cows (odds ratio = 5.5, 95% confidence interval = 1.65-21.7). As well, herds with high proportions of multiparous cows showing levels of milk urea nitrogen >30 mg/dL had an increased odds for longer calving intervals (odds ratio = 2.96, 95% confidence interval = 1.22-7.87). In conclusion, the present findings suggest that dietary contamination of Fusarium mycotoxins (especially emerging ones), likely due to increased use of corn silage in the diet, seems to be a risk factor for impairing the udder health of primiparous cows. Mismatching dietary energy and protein supply of multiparous cows contributed to reduced herd fertility performance.

[Impact of lameness on milk yield in dairy cows in Austria - results from the Efficient-Cow-project]. / Auswirkung von Lahmheit auf die Milchleistung bei Milchkühen in Österreich ­ Ergebnisse aus dem Efficient- Cow-Projekt.

INTRODUCTION: Introduction The impact of lameness on milk yield in dairy cows has been investigated already in many countries by several authors, taking into consideration almost exclusively locomotion scores ≥ 3. The aim of this study was to evaluate the impact of lameness and of the various lameness scores (2-5) on milk yield and milk solids in cows of the three most important dairy cattle breeds (Fleckvieh, Braunvieh, Holstein-Friesian) in Austria within one lactation period. Material and methods Locomotion scoring of dairy cows was performed by trained personnel every 30-40 days in 2014 during the course of routine performance testing. From the recorded locomotion scores (1-5) and the number of lameness episodes, the cows were classified into five lactation-locomotion-score-groups (LLS-G1-5). In total, data sets of 4005 cows from 144 dairy farms across Austria could be evaluated. Using two statistical models the fixed effects on LLS group, breed (evaluation across all breeds in model 1), farm, year and season of calving, parity and the «continuous effect¼ number of milking days were included in the analyses of milk, fat and protein yield. Results The mean, cumulative lameness prevalence during the observation period was 51.0%, and 8.1% were cows from the LLS-G5 group showing repeated and severe locomotion scores. During the first 100 days in milk 34.7% of all cows were lame. In model 1, all effects considered had a significant impact (P .

INTRODUCTION: Introduction L'impact des boiteries sur le rendement laitier des vaches a déjà été étudié dans de nombreux pays par plusieurs auteurs, en prenant en compte presque exclusivement des scores de locomotion ≥ 3. Le but de cette étude était d'évaluer l'impact de la boiterie et des différents scores de boiterie (2­5) sur le rendement laitier et la matière sèche du lait chez les vaches des trois races bovines laitières les plus importantes (Fleckvieh, Braunvieh, Holstein-Friesian) en Autriche au cours d'une période de lactation. Matériel et méthode Le scoring de locomotion des vaches laitières a été effectué par du personnel formé tous les 30 à 40 jours en 2014 au cours des tests de performance de routine. À partir des scores de locomotion enregistrés (1­5) et du nombre d'épisodes de boiterie, les vaches ont été classées en cinq groupes de score de lactation-locomotion (LLS-G1­5). Au total les données de 4 005 vaches provenant de 144 exploitations laitières de toute l'Autriche ont pu être évaluées. À l'aide de deux modèles statistiques, les effets fixes sur le groupe LLS, la race (évaluation pour toutes les races dans le modèle 1), l'exploitation, l'année et la saison de vêlage, le nombre de lactations et le nombre de jours de traite par rapport aux analyses des quantités de lait, des matières grasses et des protéines ont été pris en compte. Résultats La prévalence moyenne cumulative de boiteries pendant la période d'observation était de 51,0% et 8,1% étaient des vaches du groupe LLS-G5 présentant des boiteries répétées et sévères. Au cours des 100 premiers jours de lactation, 34,7% de toutes les vaches étaient boiteuses. Dans le modèle 1, tous les effets considérés de manière significative (P .

Short communication: Use of lameness scoring to genetically improve claw health in Austrian Fleckvieh, Brown Swiss, and Holstein cattle.

The specific objective of this study was to evaluate the use of lameness scoring to genetically improve claw health in Austrian Fleckvieh, Brown Swiss, and Holstein cows based on data from the "Efficient Cow" project. In 2014, a 1-yr data collection was carried out. Data from 6,519 cows kept on 161 farms were recorded. At each time of milk recording, lameness scores were assessed by trained staff of the milk recording organizations. Hoof trimming on these farms was documented and recorded as well. Veterinarian diagnoses and culling due to foot and leg problems from these farms were available from the routine recording system. As repeated lameness records per cow and lactation were available, an overall lactation lameness score was calculated. Estimated heritabilities for lameness were 0.11, 0.05, and 0.09 for Fleckvieh, Brown Swiss, and Holstein, respectively; however, only heritability estimates for Fleckvieh were significantly different from zero. Breeding values for lameness were obtained, reversed in sign, and cows were ranked according to their breeding value. A low breeding value for lameness resistance (the bottom 10% of the cows) was associated with a significantly higher frequency of trimmed cows, which indicates that the cows selected by the farmer to be trimmed are not completely random. Additionally, a high breeding value for lameness resistance (the top 10% of the cows) was associated with lower frequencies of claw diseases recorded at trimming, claw and leg diagnoses, and culling due to foot and leg problems, which highlights the usefulness of lameness scoring for genetic improvement of claw health. Overall, selecting for a better lameness score has the potential to reduce claw diseases, especially the frequency of severe claw diseases that lead to culling.

Genetic analysis of efficiency traits in Austrian dairy cattle and their relationships with body condition score and lameness.

This study is part of a larger project whose overall objective was to evaluate the possibilities for genetic improvement of efficiency in Austrian dairy cattle. In 2014, a 1-yr data collection was carried out. Data from 6,519 cows kept on 161 farms were recorded. In addition to routinely recorded data (e.g., milk yield, fertility, disease data), data of novel traits [e.g., body weight (BW), body condition score (BCS), lameness score, body measurements] and individual feeding information and feed quality were recorded on each test-day. The specific objective of this study was to estimate genetic parameters for efficiency (related) traits and to investigate their relationships with BCS and lameness in Austrian Fleckvieh, Brown Swiss, and Holstein cows. The following efficiency (related) traits were considered: energy-corrected milk (ECM), BW, dry matter intake (DMI), energy intake (INEL), ratio of milk output to metabolic BW (ECM/BW0.75), ratio of milk output to DMI (ECM/DMI), and ratio of milk energy output to total energy intake (LE/INEL, LE = energy in milk). For Fleckvieh, the heritability estimates of the efficiency (related) traits ranged from 0.11 for LE/INEL to 0.44 for BW. Heritabilities for BCS and lameness were 0.19 and 0.07, respectively. Repeatabilities were high and ranged from 0.30 for LE/INEL to 0.83 for BW. Heritability estimates were generally lower for Brown Swiss and Holstein, but repeatabilities were in the same range as for Fleckvieh. In all 3 breeds, more-efficient cows were found to have a higher milk yield, lower BW, slightly higher DMI, and lower BCS. Higher efficiency was associated with slightly fewer lameness problems, most likely due to the lower BW (especially in Fleckvieh) and higher DMI of the more-efficient cows. Body weight and BCS were positively correlated. Therefore, when selecting for a lower BW, BCS is required as additional information because, otherwise, no distinction between large animals with low BCS and smaller animals with normal BCS would be possible.