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ABSTRACT: A dysregulated inflammatory response contributes to the occurrence of disorders in cows during the transition period from pregnancy to lactation. However, a detailed characterization of clinically healthy cows that exhibit an enhanced inflammatory response during this critical period remains incomplete. In this experiment, a total of 99 individual transition dairy cows and 109 observations (18 cows monitored in 2 consecutive lactations), submitted to similar transition management were involved to evaluate the relationship between elevated an inflammatory response and metabolic and oxidative status, as well as transition outcomes. Blood was taken at −7, 3, 6, 9, and 21 DIM, and concentrations of metabolic parameters (glucose, β-hydroxybutyric acid, nonesterified fatty acids [NEFA], insulin, IGF-1, and fructosamine) were analyzed. Additionally, oxidative parameters (proportion of oxidized glutathione to total glutathione in red blood cells, the activity of glutathione peroxidase [GPx] and superoxide dismutase, concentrations of malondialdehyde, and oxygen radical absorbance capacity) and acute phase proteins (APP) including haptoglobin (Hp), serum amyloid A (SAA) and albumin-to-globulin ratio (A:G) were determined in the blood at 21 DIM. The 3 APP parameters were used to group clinically healthy cows into 2 categories through k-medoids clustering (i.e., a group showing an acute phase response, APR; n = 39) and a group not showing such a response (i.e., non-APR; n = 50). Diseased cases (n = 20) were handled in a separate group. Lower SAA and Hp concentrations as well as higher A:G were observed in the non-APR group, although for Hp, differences were observed from the APR group and not from the diseased group. Only 1 of the 5 oxidative parameters differed between the groups, with the non-APR group exhibiting lower GPx activity compared with the diseased group. The non-APR group showed the highest IGF-1 levels among the 3 groups and and lower NEFA concentrations compared with the diseased groups. Cows in the diseased group also showed reduced dry matter intake and milk yield compared with clinically healthy cows, regardless of their inflammatory status. Moreover, the APR group exhibited temporarily lower activity levels compared with the non-APR group. These findings highlight that cows with a lower inflammatory status after 21 DIM exhibited better metabolic health characteristics and productive performance, as well as activity levels. Nevertheless, the detrimental effects of a higher inflammatory status in the absence of clinical symptoms are still relatively limited.

ABSTRACT: Lowering dietary protein content is a promising strategy to reduce N excretions in cattle but it requires improved N utilization by the animal. Feed enzymes (e.g., exogenous α-amylase) and plant extracts (e.g., essential oils [EO]) are 2 additives that may enhance rumen function and possibly also microbial protein yield. This may increase fat- and protein-corrected milk yield (MY) and milk nitrogen efficiency and thus lower N losses from dairy cows. Both types of additives were studied in an experiment including 39 Holstein cows that had (average ± SD) 40.7 ± 7.95 kg/d MY, 89 ± 43 DIM, 2.7 ± 1.5 lactations, and 677 ± 68.6 kg of BW, consisting of a covariate (4 wk) and treatment period (5 wk). During the whole experiment cows were fed a typical Benelux diet (CTRL), supplemented with concentrates to meet individual requirements for energy and MP, which were fulfilled for 100% and 101%, respectively. The total diet was low in CP (15.5%) and relatively high in starch (22.6% and 6.6% rumen bypass starch). Cows were balanced for parity, DIM, MY, and roughage intake and randomly assigned to one of 3 groups, which received the following treatments in the treatment period: (1) CTRL (n = 13); (2) CTRL + 14 g/cow per day Ronozyme RumiStar α-amylase enzyme (AMEZ, n = 13; DSM); and (3) CTRL + 2.5 g/cow per day Crina Protect, a blend of EO components (ESOL, n = 13; DSM). Animal performance, ruminal pH, and enteric gas emissions were monitored throughout the experiment. During the last week of the covariate and treatment periods, nitrogen balances were conducted, total-tract nutrient digestibility was determined, and urinary allantoin and uric acid were determined as indicators for microbial N production. The statistical model applied to these variables contained group and DIM during treatment period as fixed effects and the values from the covariate period as covariate. Post hoc Dunnet-corrected comparisons between each treatment group and the control group were explored. The α-amylase enzyme tended to increase apparent total-tract starch digestibility and increased milk lactose concentration. The EO blend tended to increase MY and increased milk N output, milk nitrogen efficiency, and feed efficiency. Therefore, when feeding reduced dietary protein levels, EO have potential to improve the N-use efficiency in cattle, whereas the α-amylase enzyme might increase starch digestibility and milk lactose. However, additional research is necessary to substantiate our findings.

ABSTRACT: The transition period is one of the most challenging periods in the lactation cycle of high-yielding dairy cows. It is commonly known to be associated with diminished animal welfare and economic performance of dairy farms. The development of data-driven health monitoring tools based on on-farm available milk yield development has shown potential in identifying health-perturbing events. As proof of principle, we explored the association of these milk yield residuals with the metabolic status of cows during the transition period. Over 2 yr, 117 transition periods from 99 multiparous Holstein-Friesian cows were monitored intensively. Pre- and postpartum dry matter intake was measured and blood samples were taken at regular intervals to determine β-hydroxybutyrate, nonesterified fatty acids (NEFA), insulin, glucose, fructosamine, and IGF1 concentrations. The expected milk yield in the current transition period was predicted with 2 previously developed models (nextMILK and SLMYP) using low-frequency test-day (TD) data and high-frequency milk meter (MM) data from the animal's previous lactation, respectively. The expected milk yield was subtracted from the actual production to calculate the milk yield residuals in the transition period (MRT) for both TD and MM data, yielding MRTTD and MRTMM. When the MRT is negative, the realized milk yield is lower than the predicted milk yield, in contrast, when positive, the realized milk yield exceeded the predicted milk yield. First, blood plasma analytes, dry matter intake, and MRT were compared between clinically diseased and nonclinically diseased transitions. MRTTD and MRTMM, postpartum dry matter intake and IGF1 were significantly lower for clinically diseased versus nonclinically diseased transitions, whereas β-hydroxybutyrate and NEFA concentrations were significantly higher. Next, linear models were used to link the MRTTD and MRTMM of the nonclinically diseased cows with the dry matter intake measurements and blood plasma analytes. After variable selection, a final model was constructed for MRTTD and MRTMM, resulting in an adjusted R2 of 0.47 and 0.73, respectively. While both final models were not identical the retained variables were similar and yielded comparable importance and direction. In summary, the most informative variables in these linear models were the dry matter intake postpartum and the lactation number. Moreover, in both models, lower and thus also more negative MRT were linked with lower dry matter intake and increasing lactation number. In the case of an increasing dry matter intake, MRTTD was positively associated with NEFA concentrations. Furthermore, IGF1, glucose, and insulin explained a significant part of the MRT. Results of the present study suggest that milk yield residuals at the start of a new lactation are indicative of the health and metabolic status of transitioning dairy cows in support of the development of a health monitoring tool. Future field studies including a higher number of cows from multiple herds are needed to validate these findings.

ABSTRACT: Milk composition, particularly milk fatty acids, has been extensively studied as an indicator of the metabolic status of dairy cows during early lactation. In addition to milk biomarkers, on-farm sensor data also hold potential in providing insights into the metabolic health status of cows. While numerous studies have explored the collection of a wide range of sensor data from cows, the combination of milk biomarkers and on-farm sensor data remains relatively underexplored. Therefore, this study aims to identify associations between metabolic blood variables, milk variables, and various on-farm sensor data. Second, it seeks to examine the supplementary or substitutive potential of these data sources. Therefore, data from 85 lactations on metabolic status and on-farm data were collected during 3 wk before calving up to 5 wk after calving. Blood samples were taken on d 3, 6, 9, and 21 after calving for determination of β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), glucose, insulin-like growth factor-1 (IGF-1), insulin, and fructosamine. Milk samples were taken during the first 3 wk in lactation and analyzed by mid-infrared for fat, protein, lactose, urea, milk fatty acids, and BHB. Walking activity, feed intake, and body condition score (BCS) were monitored throughout the study. Linear mixed effect models were used to study the association between blood variables and (1) milk variables (i.e., milk models); (2) on-farm data (i.e., on-farm models) consisting of activity and dry matter intake analyzed during the dry period ([D]) and lactation ([L]) and BCS only analyzed during the dry period ([D]); and (3) the combination of both. In addition, to assess whether milk variables can clarify unexplained variation from the on-farm model and vice versa, Pearson marginal residuals from the milk and on-farm models were extracted and related to the on-farm and milk variables, respectively. The milk models had higher coefficient of determination (R2) than the on-farm models, except for IGF-1 and fructosamine. The highest marginal R2 values were found for BHB, glucose, and NEFA (0.508, 0.427, and 0.303 vs. 0.468, 0.358, and 0.225 for the milk models and on-farm models, respectively). Combining milk and on-farm data particularly increased R2 values of models assessing blood BHB, glucose, and NEFA concentrations with the fixed effects of the milk and on-farm variables mutually having marginal R2 values of 0.608, 0.566, and 0.327, respectively. Milk C18:1 was confirmed as an important milk variable in all models, but particularly for blood NEFA prediction. On-farm data were considerably more capable of describing the IGF-1 concentration than milk data (marginal R2 of 0.192 vs. 0.086), mainly due to dry matter intake before calving. The BCS [D] was the most important on-farm variable in relation to blood BHB and NEFA and could explain additional variation in blood BHB concentration compared with models solely based on milk variables. This study has shown that on-farm data combined with milk data can provide additional information concerning the metabolic health status of dairy cows. On-farm data are of interest to be further studied in predictive modeling, particularly because early warning predictions using milk data are highly challenging or even missing.

ABSTRACT: The objective of this study was to analyze if maternal supply of rumen-protected protein during the dry period can affect the IgG concentration and microbial composition of colostrum and the IgG absorption and fecal microbial composition in the calf. Seventy-four multiparous Holstein Friesian (HF) dairy cows were stratified per parity and randomly assigned to one of 2 different dry period diets, a diet with a low crude protein (CP) level (LP) and a diet with a high CP level (HP) by addition of rumen-undegraded protein (RUP; formaldehyde-treated soybean meal, Mervobest, Nuscience, Drongen, Belgium). Colostrum was collected within 1 h after calving and IgG concentration was quantified by radial immunodiffusion analysis. Forty-nine calves (23 female and 26 male) were enrolled in the trial with a 2 × 2 factorial design, with prenatal and postnatal treatment as the 2 independent variables. This led to 4 experimental groups: LPLP, LPHP, HPLP, and HPHP, in which the first 2 letters refer to the prenatal treatment (diet of the dam) and the last 2 refer to the postnatal treatment (diet of the colostrum-producing cow). Calves received 3× 2 L of colostrum within 2, 6, and 24 h after birth. Meconium and feces were collected solely from female calves (n = 18) by digital palpation of the rectum, immediately after birth and before colostrum administration and at d 3 of age. Microbial DNA was extracted from meconium (n = 9), feces (n = 15), and colostrum (n = 49). Amplicon sequencing of the bacterial V3-V4 region of the 16S rRNA gene was performed for characterization of the bacterial communities. Colostrum IgG concentration was higher in cows that were supplemented with RUP, especially in cows entering their second lactation (LSM ± SEM 61.3 ± 2.3 vs. 55.2 ± 2.8 g of IgG/L). Calves born out of LP cows that received colostrum from HP cows (LPHP) had a lower serum IgG level compared with HPHP and LPLP calves (LSM ± SEM 14.2 ± 1.3 vs. 18.8 ± 1.2 and 20.9 ± 1.3 g of IgG/L in HPHP and LPLP, respectively). The most abundant phyla in colostrum were Proteobacteria (48.2%), Firmicutes (24.8%), Bacteroidetes (9.5%), and Actinobacteria (5.0%). The most abundant phyla in calf meconium and feces were Firmicutes (42.5 and 47.5%), Proteobacteria (21.7% and 33.7%), Bacteroidetes (16.8% and 15.7%), and Actinobacteria (2.9% and 3.1%). There was no difference in the overall microbial communities between colostrum from HP and LP cows. However, 2 genera (both members of the family Lachnospiraceae) were more abundant in colostrum from HP cows compared with LP cows. The microbial composition of meconium, feces and colostrum differed from each other. Fecal samples were more similar to each other and are characterized by a lower intersample diversity compared with colostrum and meconium samples. To conclude, increasing the CP level by addition of RUP in the dry period diet affected the colostrum IgG concentration and the transfer of passive immunity, but did not change the overall microbial composition of colostrum nor of meconium and feces in the calf.

ABSTRACT: Metabolic and oxidative stress have been characterized as risk factors during the transition period from pregnancy to lactation. Although mutual relations between both types of stress have been suggested, they rarely have been studied concomitantly. For this, a total of 99 individual transition dairy cows (117 cases, 18 cows sampled during 2 consecutive lactations) were included in this experiment. Blood samples were taken at −7, 3, 6, 9, and 21 d relative to calving and concentrations of metabolic parameters (glucose, β-hydroxybutyric acid (BHBA), nonesterified fatty acids, insulin, insulin-like growth factor 1, and fructosamine) were determined. In the blood samples of d 21, biochemical profiles related to liver function and parameters related to oxidative status were determined. First, cases were allocated to 2 different BHBA groups (ketotic vs. nonketotic, N:n = 20:33) consisting of animals with an average postpartum BHBA concentration and at least 2 out of 4 postpartum sampling points exceeding 1.2 mmol/L or remaining below 0.8 mmol/L, respectively. Second, oxidative parameters [proportion of oxidized glutathione to total glutathione in red blood cells (%)], activity of glutathione peroxidase, and of superoxide dismutase, concentrations of malondialdehyde and oxygen radical absorbance capacity were used to perform a fuzzy C-means clustering. From this, 2 groups were obtained [i.e., lower antioxidant ability (LAA80%, n = 31) and higher antioxidant ability (HAA80%, n = 19)], with 80% referring to the cutoff value for cluster membership. Increased concentrations of malondialdehyde, decreased superoxide dismutase activity, and impaired oxygen radical absorbance capacity were observed in the ketotic group compared with the nonketotic group, and inversely, the LAA80% group showed increased concentrations of BHBA. In addition, the concentration of aspartate transaminase was higher in the LAA80% group compared with the HAA80% group. Both the ketotic and LAA80% groups showed lower dry matter intake. However, a lower milk yield was observed in the LAA80% group but not in the ketotic group. Only 1 out of 19 (5.3%) and 3 out of 31 (9.7%) cases from the HAA80% and LAA80% clusters belong to the ketotic and nonketotic group, respectively. These findings suggested that dairy cows vary in oxidative status at the beginning of the lactation, and fuzzy C-means clustering allows to classify observations with distinctive oxidative status. Dairy cows with higher antioxidant capacity in early lactation rarely develop ketosis.

ABSTRACT: Early lactation metabolic imbalance is an important physiological change affecting the health, production, and reproduction of dairy cows. The aims of this study were (1) to evaluate the potential of test-day (TD) variables with or without milk fatty acids (FA) content to classify metabolically imbalanced cows and (2) to evaluate the robustness of the metabolic classification with external data. A data set was compiled from 3 experiments containing plasma β-hydroxybutyrate, nonesterified FA, glucose, insulin-like growth factor-I, FA proportions in milk fat, and TD variables collected from 244 lactations in wk 2 after calving. Based on the plasma metabolites, 3 metabolic clusters were identified using fuzzy c-means clustering and the probabilistic membership value of each cow to the 3 clusters was determined. Comparing the mean concentration of the plasma metabolites, the clusters were differentiated into metabolically imbalanced, moderately impacted, and balanced. Following this, the 2 metabolic status groups identified were imbalanced cows (n = 42), which were separated from what we refer to as “others” (n = 202) based on the membership value of each cow for the imbalanced cluster using a threshold of 0.5. The following 2 FA data sets were composed: (1) FA (groups) having high prediction accuracy by Fourier-transform infrared spectroscopy and, thus, have practical significance, and (2) FA (groups) formerly identified as associated with metabolic changes in early lactation. Metabolic status prediction models were built using FA alone or combined with TD variables as predictors of metabolic groups. Comparison was made among models and external evaluations were performed using an independent data set of 115 lactations. The area under the receiver operating characteristics curve of the models was between 75 and 91%, indicating their moderate to high accuracy as a diagnostic test for metabolic imbalance. The addition of FA groups to the TD models enhanced the accuracy of the models. Models with FA and TD variables showed high sensitivities (80–88%). Specificities of these models (73–79%) were also moderate and acceptable. The accuracy of the FA models on the external data set was high (area under the receiver operating characteristics curve between 76 and 84). The persistently good performance of models with Fourier-transform infrared spectroscopy-quantifiable FA on the external data set showed their robustness and potential for routine screening of metabolically imbalanced cows in early lactation.

ABSTRACT: Lowering the dietary protein content can reduce N excretions and NH3 emissions from manure and increase milk N efficiency of dairy cows. However, milk yield (MY) and composition can be compromised due to AA deficiency. Methionine and Lys are known as first limiting EAA for dairy cows, and recently His is also mentioned as limiting, especially in grass-based or low-protein diets. To examine this, a trial was conducted with a 3-wk pre-experimental adaptation period (diet 16.5% crude protein), followed by a depletion period of 4 wk, in which 39 cows (average ± standard deviation: 116 ± 29.3 d in milk, 1.8 ± 1.2 lactations, 638 ± 73.2 kg of body weight, and 32.7 ± 5.75 kg MY/d) received a low-protein diet (CTRL) (14.5% crude protein). Then, taking into account parity, His plasma concentration, and MY, cows were randomly assigned to 1 of 3 treatment groups during the rumen-protected (RP) AA period of 7 wk; (1) CTRL; (2) CTRL + RP-Met + RP-Lys (MetLys); (3) CTRL + RP-Met + RP-Lys + RP-His (MetLysHis). Products were dosed, assuming requirements for digestible (d) Met, dLys, and dHis being, respectively, 2.4%, 7.0%, and 2.4% of intestinal digestible protein. In the cross-back period of 5 wk, all cows received the CTRL diet. During the last week of each period, a N balance was conducted by collecting total urine and spot samples of feces. Total feces production was calculated using the inert marker TiO2. Statistical analysis was performed with a linear mixed model with cow as random effect and data of the last week of the pre-experimental period used as covariate for the animal performance variables. No effect of supplementing RP-Met and RP-Lys nor RP-Met, RP-Lys, and RP-His on feed intake, milk performance, or milk N efficiency was observed. However, the plasma AA profile indicated additional supply of dMet, dLys, and dHis. Nevertheless, evaluation of the AA uptake relative to the cow's requirements showed that most EAA (exclusive Arg and Thr) were limiting over the whole experiment. Only dHis was sufficiently supplemented during the RP-AA period due to an overestimation of the diet's dMet and dLys supply in the beginning of the trial. The numerically increased milk urea N and urinary N excretion when RP-Met, RP-Lys, and RP-His were added to the low-protein diet suggest an increased catabolism of the excess His.

ABSTRACT: Data on metabolic profiles of blood sampled at d 3, 6, 9, and 21 in lactation from 117 lactations (99 cows) were used for unsupervised k-means clustering. Blood metabolic parameters included β-hydroxybutyrate (BHB), nonesterified fatty acids, glucose, insulin-like growth factor-1 (IGF-1) and insulin. Clustering relied on the average and range of the 5 blood parameters of all 4 sampling days. The clusters were labeled as imbalanced (n = 42) and balanced (n = 72) metabolic status based on the values of the blood parameters. Various random forest models were built to predict the metabolic cluster of cows during early lactation from the milk composition. All the models were evaluated using a leave-group-out cross-validation, meaning data from a single cow were always present in either train or test data to avoid any data leakage. Features were either milk fatty acids (MFA) determined by gas chromatography (MFA [GC]) or features that could be determined during a routine dairy herd improvement (DHI) analysis, such as concentration of fat, protein, lactose, fat/protein ratio, urea, and somatic cell count (determined and reported routinely in DHI registrations), either or not in combination with MFA and BHB determined by mid-infrared (MIR), denoted as MFA [MIR] and BHB [MIR], respectively, which are routinely analyzed but not routinely reported in DHI registrations yet. Models solely based on fat, protein, lactose, fat/protein ratio, urea and somatic cell count (i.e., DHI model) were characterized by the lowest predictive performance [area under the receiver operating characteristic curve (AUCROC) = 0.69]. The combination of the features of the DHI model with BHB [MIR] and MFA [MIR] powerfully increased the predictive performance (AUCROC = 0.81). The model based on the detailed MFA profile determined by GC analysis did not outperform (AUCROC = 0.81) the model using the DHI-features in combination with BHB [MIR] and MFA [MIR]. Predictions solely based on samples at d 3 were characterized by lower performance (AUCROC DHI + BHB [MIR] + MFA [MIR] model at d 3: 0.75; AUCROC MFA [GC] model at d 3: 0.73). High predictive performance was found using samples from d 9 and 21. To conclude, overall, the DHI + BHB [MIR] + MFA [MIR] model allowed to predict metabolic status during early lactation. Accordingly, these parameters show potential for routine prediction of metabolic status.

ABSTRACT: The measurement of pH in the reticulorumen in combination with a time–pH threshold has been widely applied in research to diagnose subacute ruminal acidosis. However, other pH metrics also have biological value. In this study, 44 animals were monitored during the transition period using reticuloruminal pH boluses. Traditional and more complex pH characteristics were calculated to characterize the reticuloruminal pH profile: time pH

ABSTRACT: Both ruminal microbial structure and functionality might play a role in inter-individual variation in susceptibility for subacute rumen acidosis (SARA) observed in dairy cows. The aims of this study were to determine whether differences between cows with distinct SARA susceptibility were reflected in distinct (1) ruminal microbial communities, (2) salivary bacterial communities, and (3) fermentative capacity of ruminal microbiota assessed in vitro. To test this hypothesis, rumen samples were collected via an esophageal tube on 21 d postpartum from 38 multiparous Holstein cows, which were classified into 4 groups differing in median and mean time of reticular pH below 6 as well as area under the curve of pH below 6.0. During the 21 d postpartum, all cows within a group fulfilled following criteria: susceptible (S, n = 10; mean or median ≥180 min/d), moderately susceptible (MS, n = 7; 60 min/d < mean time of pH below 6 < 180 min/d, and median time of pH below 6

Cattle behaviour is fundamentally linked to the cows’ health, (re)production, and welfare. The aim of this study was to present an efficient method to incorporate Ultra-Wideband (UWB) indoor location and accelerometer data for improved cattle behaviour monitoring systems. In total, 30 dairy cows were fitted with UWB Pozyx wearable tracking tags (Pozyx, Ghent, Belgium) on the upper (dorsal) side of the cow’s neck. In addition to the location data, the Pozyx tag reports accelerometer data as well. The combination of both sensor data was performed in two steps. In the first step, the actual time spent in the different barn areas was calculated using location data. In the second step, accelerometer data were used to classify cow behaviour using the location information of step 1 (e.g., a cow located in the cubicles cannot be classified as feeding, or drinking). A total of 156 hours of video recordings were used for the validation. For each hour of data, the total time each cow spent in each area and performing which behaviours (feeding, drinking, ruminating, resting, and eating concentrates) were computed using the sensors and compared against annotated video recordings. Bland-Altman plots for the correlation and difference between the sensors and the video recording were then computed for the performance analysis. The overall performance of locating the animals into the correct functional areas was very high. The R2 was 0.99 (P

The aim of the present research was to assess factors associated with first-lactation milk yield in dairy heifers, including maternal and environmental factors, factors related to the development of the heifer and factors related to its offspring such as gender of the calf. In addition, the potential underlying mechanism, in particular metabolic adaptations, was further explored. Data on body growth, reproduction and milk yield of 74 Holstein Friesian heifers on three herds in Flanders (Belgium) were collected. At birth, body measurements of the heifers were recorded and blood samples were taken (in order) to determine basal glucose and insulin concentrations. Body measurements were assessed every 3 months until first calving, and gender and weight of their first calf were recorded. Information on fertility and milk yield of the heifer and its dam were collected from the herd databases. Daily temperature and photoperiod were recorded from the database of the Belgian Royal Meteorological Institute. Linear mixed models were run with herd as a random factor, to account for differences in herd management. Heifers grew 867±80.7 g/day during their first year of life and were inseminated at 14.8±1.34 months. First calving took place at 24.5±1.93 months, at a weight of 642±61.5 kg and heifers produced 8506±1064 kg energy corrected milk during their first 305-day lactation. Regression models revealed that none of the maternal factors such as milk yield and parity, nor the growth of the heifer during the 1st year of life were associated with milk yield during first lactation. Age, and to a lesser extent BW at first parturition were positively associated with first-lactation milk yield. In addition, the season of birth, but not calving, had a significant influence on milk yield, with winter-born heifers producing less than heifers born in any other season. The lower yielding winter-born heifers had higher insulin concentrations at birth, whereas glucose concentrations were similar, the latter being suggestive for lower insulin sensitivity of the peripheral tissues. Furthermore, environmental temperature at the end of gestation was negatively correlated with neonatal insulin concentrations. In conclusion, results of the present study suggest heifers born during the hotter months are born with a higher peripheral insulin sensitivity, finally leading to a higher first-lactation milk yield.

Prenatal development is known to be extremely sensitive to maternal and environmental challenges. In this study, we hypothesize that body growth and lactation during gestation in cattle reduce nutrient availability for the pregnant uterus, with consequences for placental development. Fetal membranes of 16 growing heifers and 27 fully grown cows of the Belgian Blue (BB) breed were compared to determine the effect of body growth on placental development. Furthermore, the fetal membranes of 49 lactating Holstein Friesian (HF) cows and 27 HF heifers were compared to study the impact of dam lactation compared to dam body growth. After parturition, calf birth weight and body measurements of dam and calf were recorded, as well as weight of total fetal membranes, cotyledons and intercotyledonary membranes. All cotyledons were individually measured to calculate both the surface of each individual cotyledon and the total cotyledonary surface per placenta. Total cotyledonary surface was unaffected by breed or the breed×parity interaction. Besides a 0.3 kg lower cotyledonary weight (P=0.007), heifer placentas had a smaller total cotyledonary surface compared with placentas of cows (0.48±0.017 v. 0.54±0.014 m2, respectively, P

For dairy cattle on pasture in temperate regions, it is largely unknown to what degree hot summer conditions impact energy metabolism, milk yield and milk composition and how effective shade is in reducing these negative effects. During the summer of 2012, a herd of Holstein cows was kept on pasture without access to shade (treatment NS). During the summers of 2011 and 2013, the herd was divided into a group with (treatment S) and a group without (treatment NS) access to shade. Shade was provided by young trees combined with shade cloths (80% reduction in solar radiation). A weather station registered the local climatic conditions on open pasture, from which we calculated daily average Heat Load Index (HLI) values. The effects of HLI and shade on rectal temperature (RT), blood plasma indicators of hyperventilation and metabolic changes due to heat stress, milk yield and milk composition were investigated. RT increased with increasing HLI, but was less for S cows than for NS cows (by 0.02°C and 0.03°C increase per unit increase of HLI, respectively). Hyperchloraemia (an increased blood plasma concentration of Cl−), a sign of hyperventilation, increased for NS cows but not for S cows. The plasma concentration of alkaline phosphatase, a regulator of energy metabolism in the liver, decreased with increasing HLI for NS cows only. Access to shade, thus, reduced the effect of HLI on RT, hyperchloraemia and the regulation of metabolism by the liver. As HLI increased, the plasma concentration of cholesterol decreased (indicating increased lipolysis) and the plasma concentration of creatinine increased (indicating increased protein catabolism). These effects did not differ between S and NS cows. For NS cows, after a lag-time of 2 days, the milk yield decreased with increasing HLI. For S cows, the milk yield was unaffected by HLI and its quadratic factor. The milk concentrations of lactose, protein and fat decreased as HLI increased, but only the effect on milk protein content was remediated by shade. In conclusion, access to shade tempered the negative effects of high HLI on RT, hyperchloraemia and a blood plasma indicator of changing energy metabolism (generally) as well as prevented the decrease in milk yield observed in cows without access to shade.

Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾30°C), >50% of the animals under shade retained normal PS and RR (PS

The objective of the present retrospective cohort study was to evaluate potential associations between environmental factors and dam characteristics, including level of milk production during gestation, and insulin traits in newborn Holstein calves. Birth weight and gestational age of the calves at delivery were determined. On the next day, heart girth, wither height and diagonal length of both the calves and their dams were measured. Parity, body condition score and age at calving were recorded for all dams. For the cows, days open before last gestation, lactation length (LL), length of dry period (DP) and calving interval were also calculated. The magnitude and shape of the lactation curve both quantified using the MilkBot model based on monthly milk weights, were used to calculate the amount of milk produced during gestation. Using the same procedure, cumulative milk production from conception to drying off (MGEST) was calculated. A blood sample was collected from all calves (n=481; 169 born to heifers and 312 born to cows) at least 5 h after a milk meal on day 3 of life to measure basal glucose and insulin levels. In addition, an intravenous glucose-stimulated insulin secretion test was performed in a subset of the calves (n=316). After descriptive analysis, generalized linear mixed models were used to identify factors that were significantly associated with the major insulin traits (Insb, basal insulin level; QUICKI, quantitative insulin sensitivity check index; AIR, acute insulin response; DI, disposition index) of the newborn calves. The overall average birth weight of the calves was 42.7±5.92 kg. The insulin traits were significantly associated with gender and season of birth when data of all calves were analyzed. In addition, the insulin traits in calves born to cows were significantly associated with MGEST, DP and LL. The Insb was estimated to be higher in calves born to the cows having passed a higher MGEST (P=0.076) and longer DP (P=0.034). The QUICKI was estimated to be lower in calves born to the cows having passed a higher MGEST (P=0.030) and longer DP (P=0.058). Moreover, the AIR (P=0.009) and DI (P=0.049) were estimated to be lower in male compared with female calves. Furthermore, the AIR (P=0.036) and DI (P=0.039) were estimated to be lower in calves born to cows having passed a longer LL. The decisive effects of MGEST, DP and LL in cows on the insulin traits of their calves may provide a basis for developing managerial interventions to improve metabolic health of the offspring.

Telomere length (TL) is a recognized biomarker for ageing in multiple species. In dairy cattle, the transition period is considered a very stressful period. We hypothesized that TL shortens during this period. Holstein cows (n = 61) were followed during the transition period. Blood and milk samples were collected at - 7, 3, 6, 9, 21d relative to calving to determine concentrations of oxidative, energetic metabolic, and inflammatory markers. Average relative leukocyte TL was measured by a modified qPCR protocol 7d before and 21d after parturition. We confirmed TL attrition during the transition period (P = 0.02), as TL was 1.05 ± 0.229 (mean ± SD) before, and 0.97 ± 0.191 (mean ± SD) after parturition. Univariable analyses assessed associations between blood markers and TL shortening. Greater plasma oxidative parameters, including oxidized glutathione and glutathione peroxidase, were positively and negatively (respectively) associated with TL attrition. Higher blood α- and β-globulin were all positively associated, while IGF-1, albumin-globulin ratio and albumin were negatively associated with TL attrition. Greater serum amyloid A and haptoglobin were linked with greater TL shortening. This study reveals significant TL shortening during the transition period in dairy cows and identifies significant associations with oxidative stress, metabolic stress, and inflammation. While these associations are observed, no causality can be established. Our findings suggest the need for further research to explore the effects of transition-related stress on TL dynamics., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

High-yielding dairy cows encounter metabolic challenges in early lactation. Typically, BHB, measured at a specific time point, is employed to diagnose the metabolic status of cows based on a predetermined threshold. However, in early lactation, BHB is highly dynamic, with high interindividual variability in its time profile. This could limit the effectiveness of the single measurement and threshold-based diagnosis and could contribute to the disparities in reports linking metabolic status with productive and reproductive outcomes. This research examines the trajectories of BHB to unveil intercow variations and identify latent metabolic groups. We compiled a dataset from 2 observational studies involving a total of 195 lactations from multiparous Holstein Friesian cows. The dataset encompasses measurements of BHB, nonesterified fatty acids (NEFA), and insulin from blood samples collected at 3, 6, 9, and 21 DIM, along with weekly determinations of milk composition and fatty acids (FA) proportions in milk fat. In both experiments, milk yield (MY) and feed intake were recorded daily during the first month of lactation. We explored interindividual and intraindividual variations in metabolic responses using the trajectories of blood BHB and evaluated the presence of distinct metabolic groups based on such variations. For this purpose, we employed the growth mixture model, a trajectory clustering technique. Our findings unveil novel insights into the diverse metabolic responses among cows, encompassing both trajectory patterns and the magnitude of blood BHB concentrations. Specifically, we identified 3 latent metabolic groups: the quickly increasing BHB (QuiBHB) cluster (≈10%) exhibited a higher initial BHB concentration than other clusters, peaked on d 9 (average maximum BHB of 2.4 mM) and then declined by d 21; the slowly increasing BHB (SloBHB) cluster (≈23%) started with a lower BHB concentration, gradually increased until d 9, and reached the highest BHB concentration at d 21 (1.6 mM serum BHB at the end of the experimental period); and the low BHB (LoBHB) cluster (≈67%) began with the lowest serum BHB concentration (serum BHB <0.75 mM) and remained relatively stable throughout the sampling period. Notably, the 3 metabolic groups exhibited significant physiological disparities, which were evident in blood NEFA and insulin concentrations. The QuiBHB and SloBHB cows exhibited higher NEFA and lower insulin concentrations as compared with the LoBHB cows. Interestingly, these metabolic differences extended to MY and DMI during the first month of lactation. The elevated BHB concentrations observed in QuiBHB cows were linked with lower DMI and MY as compared with SloBHB and LoBHB cows. Accordingly, these animals were considered metabolically impaired. Conversely, SloBHB cows displayed higher MY along with increased DMI, and thus the elevated BHB might be indicative of an adaptive response for these cows. The QuiBHB cows also displayed higher proportions of UFA, MUFA, and total C18:1 FA in milk during the first week of lactation. Prediction of the QuiBHB cows using these FA and test day variables resulted in moderate predictive accuracy (area under the receiver operating characteristic curve >0.7). Given the limited sample size for the development of prediction models and the variation in DIM among samples in the same week, the result is indicative of the predictive potential of the model and room for model optimization. In summary, distinct metabolic groups of cows could be identified based on the trajectories of blood BHB in early lactation., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Hydrolysable tannins (HT) show potential as silage additive for autumn herbage silages, high in (rumen degradable) protein, as they may reduce proteolysis. Additionally, they have abilities to form pH-reversible tannin-protein complexes, non-degradable in the rumen but degradable in the abomasum and intestines of ruminants. Therefore they can improve milk N efficiency and shift N excretions from urine to faeces, possibly mitigating the environmental impact of ruminants. In this study, two small bunker silos were filled with autumn grass. One was treated with 20 g/kg DM HT extract (TAN) (TannoSan-L), the other with 8 mg/kg DM inoculant containing lactic acid bacteria (INO) (Bonsilage Fit G). Secondly, micro-silos (2.75 L) were filled with four treatments; (1) grass without additive (CON) (n = 5); (2) TAN (n = 5); (3) INO (n = 5); and (4) TAN + INO (n = 5). The bunker silos were used in a cross-over feeding experiment with periods of 4 weeks involving 22 lactating Holstein cows (average ± SD: 183 ± 36.3 days in milk, 665 ± 71.0 kg body weight, and 33.8 ± 3.91 kg/day milk yield). The HT dose was insufficient to reduce proteolysis or alter chemical composition and nutritional value in the micro- and bunker silages. Including grass silage added with TAN (3.2 g HT/kg DM) in the diet, did not affect feed intake nor fat and protein corrected milk yield in comparison to feeding the grass silage added with INO in a similar diet. The TAN-fed cows had an increased faecal N excretion and decreased apparent total-tract N and organic matter digestibility, but no improvement in the cows' N utilization could be confirmed in milk and blood urea levels. Overall, feeding an autumn grass silage treated with 20 g/kg chestnut HT extract did not affect the performance of dairy cows in comparison to feeding an autumn grass silage treated with a lactic acid bacteria inoculant., (© 2023 The Authors. Journal of Animal Physiology and Animal Nutrition published by Wiley-VCH GmbH.)

Aims: Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI)., Methods and Results: In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (-35%, P < 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P < 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. -4.5 cm2, P < 0.001) and LA activation time prolonged (+8.0 vs. -9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005)., Conclusion: Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Gender-related differences have been reported in patients who underwent pulmonary vein isolation (PVI). Atrial substrate plays a role in the outcomes after ablation but gender-related differences in atrial substrate have never been described in detail. We sought to analyze gender-related differences in atrial remodeling (spontaneous low-voltage zones [LVZs]) and their clinical relevance after PVI. We conducted a prospective multicenter study, including consecutive patients who underwent first PVI-only atrial fibrillation (AF) ablation. LVZs were analyzed on high-density electroanatomical maps collected with multipolar catheter, before PVI. In total, 262 patients (61 ± 11 years, 31% female, 50% persistent AF) were followed for 28 months. In women, LVZs were larger (10% vs 4% of left atrial surface [p <0.001]) and female gender was independently associated with fourfold higher risk of having advanced (LVZ > 15%) atrial remodeling (odds ratio 4.56, p <0.001). AF recurrence-free survival was not different between men and women (log-rank p = 0.2). Although LVZs were independently associated higher AF recurrences at multivariate analysis (hazard ratio [HR] 1.2, p = 0.038), female gender was not (HR 1.4, p = 0.211). Specifically, the LVZ cutoff to predict outcomes was different in men and women: >5% in men (HR 3.0, p <0.001), >15% in women (HR 2.7, p = 0.02). In conclusion, women have more widespread LVZ in all left atrial regions. Despite more extensive atrial remodeling, the AF recurrence rate is similar in men and women, and LVZs become prognostic in women only at high burden (>15%). LVZs seem to have a different prognostic role in men and women., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The benefit of an anterior mitral line (AML) in patients with persistent atrial fibrillation (AF) and anterior atrial scar undergoing ablation has never been investigated., Objective: The purpose of this study was to evaluate the outcomes of AML in addition to standard treatment compared to standard treatment alone (no AML) in this subset of patients., Methods: Patients with persistent AF and anterior low-voltage zone (LVZ) treated with AML in 3 centers were retrospectively enrolled. The patients were matched in 1:1 fashion with patients having persistent AF and anterior LVZ who underwent conventional ablation in the same centers. Matching parameters were age, LVZ burden, and repeated ablation. Primary endpoint was AF/atrial tachycardia (AT) recurrence., Results: One hundred eight-six patients (age 66 ± 9 years; 34% women) were selected and divided into 2 matched groups. Bidirectional conduction block was achieved in 95% of AML. After median follow-up of 2 years, AF/AT recurrence occurred in 29% of the patients in the AML group vs 48% in the no AML group (log-rank P = .024). On Cox regression multivariate analysis, left atrial volume (hazard ratio [HR] 1.03; P = .006) and AML (HR 0.46; P = .003) were significantly associated with the primary endpoint. On univariate logistic regression, lower body mass index, older age, extensive anterior LVZ, and position of the left atrial activation breakthrough away from the AML were associated with first-pass AML block., Conclusion: In this retrospective matched analysis of patients with persistent AF and anterior scar, AML in addition to standard treatment was associated with improved AF/AT-free survival compared to standard treatment alone., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

We aimed to compare the viability of circulating polymorphonuclear leukocyte (cPMN) and endometrial PMN (ePMN) and their function dynamics in postpartum dairy cows with subclinical (SCE) or clinical endometritis (CE). To do so, blood samples from 38 Holstein cows were collected at -7, 9, 21, and 36 d relative to calving, and endometrial cytology samples from 32 Holstein cows were harvested at 9, 21, and 36 d postpartum. Uterine health status was assessed at 36 d postpartum, and cows were classified as healthy (absence of abnormal vaginal discharge and ≤5% ePMN), SCE (absence of abnormal vaginal discharge and >5% ePMN), or CE (mucopurulent or purulent vaginal discharge and >5% ePMN). Viability (viable, apoptotic, and necrotic) and function parameters phagocytosis (PC), oxidative burst, and intracellular proteolytic degradation were evaluated for cPMN via flow cytometry. For ePMN, only viability and PC were evaluated. The association of cPMN and ePMN viability and functional parameters with reproductive tract health classification were fitted in mixed linear regression models, accounting for repeated measures, sampling day, and interactions of reproductive tract status and day. Cows with CE had a lower proportion of cPMN viability (84.5 ± 2.1%; least squares means ± standard error) and a higher proportion of apoptosis (14.4 ± 2.0%) than healthy (92.4 ± 1.3 and 6.7 ± 1.3%, respectively) or SCE (95.3 ± 2.4 and 3.8 ± 2.3%, respectively) at 9 d postpartum. Interestingly, cPMN intracellular proteolytic degradation was lower [6.2 ± 0.1 median fluorescence intensity (MFI)] in SCE compared with healthy (6.7 ± 0.08 MFI) or CE (6.8 ± 0.1 MFI) at d 9 postpartum. No other differences in cPMN function were found among experimental groups. The proportion of necrotic ePMN was higher for healthy (49.6 ± 5.1%) than SCE (27.4 ± 7.3%) and CE (27.7 ± 7.3%) cows at 36 d postpartum. Also, at 36 d postpartum, the proportion of ePMN performing PC was higher in CE (47.0 ± 8.6%) than in healthy (18.4 ± 7.6%) cows, but did not differ from SCE cows (25.9 ± 8.7%). Results of the present study suggest that cPMN viability and function at 9 d postpartum are associated with the development of uterine disease. Furthermore, ePMN at 36 d postpartum are mostly necrotic in healthy cows but viable and functional in cows with CE, probably due to active uterine inflammation. Remarkably, ePMN in cows with SCE at 36 d postpartum are also mostly viable but seem to display a numerically lower proportion of PC compared with ePMN in CE cows., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Background Left atrial substrate may have mechanistic relevance for ablation of atrial fibrillation (AF). We sought to analyze the relationship between low-voltage zones (LVZs), transition zones, and AF recurrence in patients undergoing pulmonary vein isolation. Methods and Results We conducted a prospective multicenter study on consecutive patients undergoing pulmonary vein isolation-only approach. LVZs and transition zones (0.5-1 mV) were analyzed offline on high-density electroanatomical maps collected before pulmonary vein isolation. Overall, 262 patients (61±11 years, 31% female) with paroxysmal (130 pts) or persistent (132 pts) AF were included. After 28 months of follow-up, 73 (28%) patients experienced recurrence. An extension of more than 5% LVZ in paroxysmal AF and more than 15% in persistent AF was associated with recurrence (hazard ratio [HR], 4.4 [95% CI, 2.0-9.8], P <0.001 and HR, 1.9 [95% CI, 1.1-3.7], P =0.04, respectively). Significant association was found between LVZs and transition zones and between LVZs and left atrial volume index (LAVI) (both P <0.001). Thirty percent of patients had significantly increased LAVI without LVZs. Eight percent of patients had LVZs despite normal LAVI. Older age, female sex, oncological history, and increased AF recurrence characterized the latter subgroup. Conclusions In patients undergoing first pulmonary vein isolation, the impact of LVZs on outcomes occurs with lower burden in paroxysmal than persistent AF, suggesting that not all LVZs have equal prognostic implications. A proportional area of moderately decreased voltages accompanies LVZs, suggesting a continuous substrate instead of the dichotomous division of healthy or diseased tissue. LAVI generally correlates with LVZs, but a small subgroup of patients may present with disproportionate atrial remodeling, despite normal LAVI.

Background: The transition period is a challenging period for high-producing dairy cattle. Cows in early lactation are considered as a group at risk of subacute ruminal acidosis (SARA). Variability in SARA susceptibility in early lactation is hypothesized to be reflected in fecal characteristics such as fecal pH, dry matter content, volatile and odd- and branched-chain fatty acids (VFA and OBCFA, respectively), as well as fecal microbiota. This was investigated with 38 periparturient dairy cows, which were classified into four groups differing in median and mean time of reticular pH below 6 as well as area under the curve of pH below 6. Furthermore, we investigated whether fecal differences were already obvious during a period prior to the SARA risk (prepartum)., Results: Variation in reticular pH during a 3-week postpartum period was not associated with differences in fecal pH and VFA concentration. In the postpartum period, the copy number of fecal bacteria and methanogens of unsusceptible (UN) cows was higher than moderately susceptible (MS) or susceptible (SU) cows, while the genera Ruminococcus and Prevotellacea&#95;UCG-001 were proportionally less abundant in UN compared with SU cows. Nevertheless, only a minor reduction was observed in iso-BCFA proportions in fecal fatty acids of SU cows, particularly iso-C15:0 and iso-C16:0, compared with UN cows. Consistent with the bacterial changes postpartum, the lower abundance of Ruminococcus was already observed in the prepartum fecal bacterial communities of UN cows, whereas Lachnospiraceae&#95;UCG-001 was increased. Nevertheless, no differences were observed in the prepartum fecal VFA or OBCFA profiles among the groups. Prepartum fecal bacterial communities of cows were clustered into two distinct clusters with 70% of the SU cows belonging to cluster 1, in which they represented 60% of the animals., Conclusions: Inter-animal variation in postpartum SARA susceptibility was reflected in post- and prepartum fecal bacterial communities. Differences in prepartum fecal bacterial communities could alert for susceptibility to develop SARA postpartum. Our results generated knowledge on the association between fecal bacteria and SARA development which could be further explored in a prevention strategy., (© 2022. The Author(s).)

Introduction: Different methods are used for atrial fibrillation (AF) cycle length (CL) measurement with variable results. Previous studies of pulmonary vein (PV) CL measurement showed contradictory results on predicting PV isolation (PVI) efficacy. A novel simple method of measuring the average of 10 consecutive Fastest Atrial Repetitive Similar morphology signal (FARS 10 )-CL to characterize local atrial activity rate was evaluated prospectively., Methods: The intra-observer reproducibility of FARS 10 -CL and traditional AF-CL measurement of continuously fragmented coronary sinus (CS) signals were tested. We prospectively enrolled 100 consecutive patients (62 ± 10 years, 72% male) undergoing wide antral PVI only ablation for persistent AF, measured PV-FARS 10 -CLs, and evaluated long-term outcome., Results: The Kendall area correlation between repeated traditional AF-CL measurements was -0.006 and between repeated FARS 10 -CL measurements in the right and left atrial appendages, CS and PVs were 0.944, 0.859, 0.882, 0.675-0.955, respectively. Patients with recurrent atrial tachyarrhythmia had significantly longer fastest PV-FARS 10 -CL (172 ± 41 vs. 156 ± 41 ms, p = .047). Patients with high burden of spontaneous low-voltage zone (LVZ) had significantly longer fastest PV-FARS 10 -CL. Freedom from recurrent tachyarrhythmia at 24 months was 85% versus 59% in patients with fastest PV-FARS 10 -CL ≤ 140 versus >140 ms, p = .0018, respectively. In multivariable analysis fastest PV-FARS 10 -CL ≤ 140 ms was the only significant predictor of freedom from recurrent tachyarrhythmia., Conclusions: FARS 10 -CL measurements have a high reproducibility in contrast to traditional AF-CL measurement of continuously fragmented CS signals. Patients with high burden of LVZ have longer fastest PV-FARS 10 -CLs. Fastest PV-FARS 10 -CL ≤ 140 ms is associated with a high success of wide antral PVI-only ablation approach in persistent AF., (© 2022 Wiley Periodicals LLC.)

The aim of the present study was to assess the counts, viability, and functionality of circulating and endometrial polymorphonuclear leukocytes (PMN) isolated from fourteen clinically and metabolically healthy multiparous dairy cows in the peripartum period. For this, blood samples were collected at -5, +9, +21 and + 37 days (d) relative to calving. Cytology samples were collected from the vagina, cervix, and uterus at +9, +21 and + 37 d, using the cytobrush technique. Additional vaginal samples were collected at -5 d. Cytology smears were prepared and the PMN-to-all nucleated cell proportions (PMN%) were calculated. The endometrial cytobrush samples were also used for flow cytometric assessment of endometrial PMN (ePMN) viability and functionality. Functionality tests for circulating PMN (cPMN) included phagocytosis (PC), oxidative burst, and intracellular proteolytic degradation. For ePMN, we evaluated PC only. The effect of day relative to calving on PMN viability and functionality were fitted in linear regression models, accounting for repeated measures. The endometrial PMN% were higher at +9 d (23.5 ± 0.4%; least-squares means ± standard error) and +21 d (8.5 ± 0.3%) than at +37 d (1.4 ± 0.3%). No changes in PMN% were found on either vaginal or cervical cytology along the peripartum period. The cPMN counts were higher pre- (6.2 ± 0.4 x 10 6 /mL) than postpartum (4.9 ± 0.4 x 10 6 /mL). Upon viability analysis, only the percentage of viable cPMN tended to be lower at -5 d (90.1 ± 1.5%) than at +37 d (94.1 ± 1.4%), and no other changes in the percentage of apoptotic and necrotic cPMN, nor in their functionality were found during the peripartum period. Analysis of ePMN viability showed that the percentage of viable ePMN did not change over time. In marked contrast, the percentage of apoptotic ePMN was higher at +9 d (37.8 ± 5.1%) than at +21 d (20.9 ± 5.1%) and +37 d (11.9 ± 5.3%), while the percentage of necrotic ePMN was lower at +9 d (27.0 ± 6.3%) than at +37 d (54.9 ± 6.6%). The percentage of ePMN PC was higher at +9 d (27.5 ± 3.4%) than at +37 d (13.3 ± 4.9%). In conclusion, during the peripartum period ePMN in the healthy postpartum uterus are highly dynamic in terms of counts, viability, and functionality compared to their circulating counterparts., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Transmission of bluetongue (BT) virus serotype 8 (BTV-8) via artificial insemination of contaminated frozen semen from naturally infected bulls was investigated in two independent experiments. Healthy, BT negative heifers were hormonally synchronized and artificially inseminated at oestrus. In total, six groups of three heifers received semen from four batches derived from three bulls naturally infected with BTV-8. Each experiment included one control heifer that was not inseminated and that remained BT negative throughout. BTV viraemia and seroconversion were determined in 8 out of 18 inseminated heifers, and BTV was isolated from five of these animals. These eight heifers only displayed mild clinical signs of BT, if any at all, but six of them experienced pregnancy loss between weeks four and eight of gestation, and five of them became BT PCR and antibody positive. The other two infected heifers gave birth at term to two healthy and BT negative calves. The BT viral load varied among the semen batches used and this had a significant impact on the infection rate, the time of onset of viraemia post artificial insemination, and the gestational stage at which pregnancy loss occurred. These results, which confirm unusual features of BTV-8 infection, should not be extrapolated to infection with other BTV strains without thorough evaluation. This study also adds weight to the hypothesis that the re-emergence of BTV-8 in France in 2015 may be attributable to the use of contaminated bovine semen.