Influence of the coincubation of post-thawed bull semen with elevated ß-hydroxybutyrate concentrations on sperm characteristics.

In this study, the relationships between post-thaw bull sperm characteristics and hyperketonemic conditions after coincubation with cow plasma or media were determined to investigate if such a condition could affect bull sperm characteristics. Two experiments were conducted. In experiment 1, blood samples were collected from 31 cows to prepare plasma. Cows were independently categorized into two groups according to plasma ß-hydroxybutyrate (BHB) concentrations (above or below 1.2 mM). Thawed bull semen was diluted and incubated with diluted plasma; motility parameters were evaluated using Computer Assisted Semen Analysis (CASA). In experiment 2, a pooled sample of thawed semen was diluted and divided into three aliquots: without BHB (control) and treated with either 1.2 mM (1.2) or 3 mM (3) BHB. In addition to motility, flow cytometric analyses were carried out. In experiment 1, the overall motility decreased significantly in plasma containing high (≥1.2 mM) BHB compared to plasma containing low (<1.2 mM) BHB. In experiment 2, the overall motility tended to be lower in BHB (3 mM)-supplemented samples. The supplementation of 3 mM BHB increased the proportion of live superoxide-positive sperm and sperm with high mitochondrial potential, while the DNA fragmentation index decreased.

Non-steroidal anti-inflammatory drugs at embryo transfer on pregnancy rates in cows: A meta-analysis.

Non-steroidal anti-inflammatory drugs (NSAIDs) at the time of embryo transfer (ET) are commonly used to improve pregnancy rates in cows. A meta-analysis was conducted on 16 trials from 9 publications involving control (n = 2335) and NSAID-treated (n = 2849) cows. The meta-analysis explained the relative risk (RR) with its 95% confidence interval (CI) for pregnancy per embryo transfer (P/ET) after NSAID treatment under various circumstances. NSAID treatment with was associated on average with a 15% higher P/ET compared to no treatment (RR = 1.15, 95% CI = 1.07 to 1.2). The results also highlight that the use of NSAIDs at the time of ET was particularly effective in cows with difficulty in passing the catheter from the cervix during ET, with 71% more likely P/ET (RR = 1.71, 95% CI = 1.07 to 2.74) with the use of NSAIDs for these cows compared to other cows. The data were too limited to analyse the influence of NSAID molecules (flunixin meglumine [FM] and meloxicam), cyclooxygenase (COX) inhibitor type (non-selective COX inhibitor [both COX-1 and COX-2] and selective COX inhibitor [only COX-2]), embryo processing (embryo production, embryo conservation and embryo quality), stress, synchronization, breed and parity on the relationship between NSAIDs and P/ET.

Association of pregnancy per artificial insemination with gonadotropin-releasing hormone and human chorionic gonadotropin administered during the luteal phase after artificial insemination in dairy cows: A meta-analysis.

One strategy for improving fertility in cattle is administration of GnRH or human chorionic gonadotropin (hCG) during the luteal phase, which increases progesterone (P4) secretion and delays luteolysis. To provide an overview of how GnRH or hCG treatment between 4 and 15 d after artificial insemination (AI) improves pregnancy per AI (P/AI) in cows, a meta-analysis was performed on 107 different trials from 52 publications. Data from 18,082 treated cows and 18,385 untreated controls were meta-analyzed. The meta-analysis explained the relative risk for P/AI with GnRH or hCG treatment under various circumstances. The results did not show any difference in P/AI between cows treated with hCG and cows treated with GnRH. Compared with no treatment, treatment with GnRH or hCG improved the chances of P/AI in cows with very poor (<30%) and poor (30.1 to 45%) fertility, whereas treatment did not benefit cows with very good fertility (>60.1%). Moreover, treatment with GnRH and hCG improved the chances of P/AI in primiparous cows. The improvement was much better in primiparous cows with very low fertility. Treatment with buserelin at a dose above 10 µg and with hCG at a dose above 2,500 IU was associated with increased chances of P/AI compared with lower doses. Treatment with GnRH 10 d after AI was also associated with increased chances of P/AI compared with earlier treatment. The present meta-analysis showed that the use of GnRH and hCG after AI should be focused on cows expected to have low or moderate fertility. Day and dose of treatment have to be considered as well.

Hyperketolactia occurrence before or after artificial insemination is associated with a decreased pregnancy per artificial insemination in dairy cows.

The reproductive parameters of dairy cattle have continuously declined worldwide over the last 50 years. Nutritional imbalances are identified as risk factors for this decrease of reproductive performance. The present paper aims to quantify the decrease in the pregnancy per artificial insemination (P/AI) in the case of high milk ketones before and after AI. A total of 388,731 test-day from the Brittany Milk Recording Program in France from 226,429 cow-lactations were provided for this trial. For each test-day, information about lactation characteristics, date of AI, date of the following calving, and acetone and ß-hydroxybutyrate (BHB) values were included. Ketones were predicted by Fourier transform mid-infrared spectroscopy using MilkoScan Foss analyzers (Foss, Hillerød, Denmark). Many thresholds were evaluated to define cows with hyperketolactia. Hyperketolactia statuses were then categorized into 1 of 4 possible classes according to the milk ketone dynamics for each AI and each threshold of acetone or BHB values (low-low, high-low, low-high, and high-high) within 20 d before and after AI. Similarly, the dynamics of udder health were characterized by changes in somatic cell counts measured at the same test day as ketone bodies. A logistic regression with a Poisson correction was performed to explain the relationship of P/AI with milk ketones and somatic cell count dynamics. Predicted acetone and BHB ranged from -0.51 to 4.92 mM (mean = 0.08 mM, SD = 0.10 mM) and -0.62 to 5.85 mM (mean = 0.07 mM, SD = 0.1 mM), respectively. Hyperketolactia defined by high acetone levels before AI was not associated with decreased P/AI, but high acetone levels after AI were associated with a >10% reduction in P/AI for all thresholds >0.10 mM. Hyperketolactia, defined by high BHB values before, after, or before and after AI, was associated with a 6 to 14% reduction in P/AI compared with cows with low BHB values. These associations are lower than those reported in previous trials in which blood ketones were used. High ketones in advanced lactation are likely to be the result of various primary disorders (secondary ketosis). Because the present work demonstrated that this situation is considered a risk factor for deteriorated reproductive performance, we suggest that high ketones in early and advanced lactation should be of interest to farm advisors.

Economic assessment of an emerging disease: the case of Schmallenberg virus in France.

Schmallenberg virus (SBV) was first detected in 2011 in Germany and then in France in 2012. This study simulates the production of different ruminant systems in France and estimates, through partial budget analyses, the economic cost of SBV at the farm level, under two disease scenarios (a high-impact and low-impact scenario). A partial budget is used to evaluate the financial effect of incremental changes, and includes only resources or production that will be changed. In the high-impact scenario, the estimated impact of SBV ranged from €23 to €43 per cow per year and €19 to €37 per ewe per year. In the low-impact scenario, it was approximately half (for cows) or one-third (for ewes) of this amount. These financial impacts represent 0.6% to 63% of the gross margin, depending on the chosen scenario and the livestock system being considered. The impacts of SBV come mainly from: the extra costs from purchasing and raising replacement heifers and losses in milk production (dairy cows); the losses in calf or lamb production (beef systems and meat sheep); and the losses in milk production and from unsold replacement lambs (dairy sheep). The use of integrated production and economic models enabled the authors to estimate the cost of SBV and to tackle the problem of scarce data, which is a difficulty for most emerging diseases, by their very nature. It also allowed the authors to develop an accurate disease impact assessment for several production systems, over a short time span. Extrapolating from this economic assessment to predict the scenario in coming years depends on the immunity period of the disease and the length of the production cycles.

Le virus de Schmallenberg a été détecté pour la première fois en 2011 en Allemagne, puis en France en 2012. Les auteurs présentent une étude de simulation de plusieurs systèmes de production de ruminants en France, dont l'objectif était d'estimer, à partir d'analyses budgétaires partielles, les coûts économiques du virus de Schmallenberg à l'échelle des exploitations, sous deux scénarios différents (hypothèses d'un fort impact et d'un faible impact de la maladie, respectivement). Une analyse budgétaire partielle sert à évaluer les conséquences financières d'un changement graduel et ne prend en compte que les modifications effectives en termes de ressources et de production. Dans l'hypothèse d'un impact fort de la maladie, l'impact annuel estimé du virus de Schmallenberg variait de 23 à 43 euros par vache et de 19 à 37 euros par brebis. Dans l'hypothèse d'un impact faible, l'impact annuel était deux fois moindre chez les vaches et trois fois moindre chez les brebis que dans la première hypothèse. Ces impacts financiers représentent 0,6 % à 63 % de la marge brute en fonction du scénario choisi et du système de production. Les impacts du virus de Schmallenberg découlent principalement des coûts supplémentaires induits par l'achat et le maintien de génisses de remplacement et d'une baisse de la production de lait (vaches laitières), des pertes de veaux ou d'agneaux (bovins et ovins de boucherie), d'une baisse de la production de lait et du coût des agnelles de remplacement invendues (brebis laitières). L'utilisation de modèles intégrant les aspects économiques et les données de production a permis aux auteurs d'estimer le coût du virus de Schmallenberg malgré la pénurie de données, s'attaquant ainsi à une difficulté inhérente à la plupart des maladies émergentes. Cela leur a également permis d'effectuer une évaluation précise de l'impact sanitaire dans plusieurs systèmes de production, sur une durée courte. La possibilité d'extrapoler à partir de cette évaluation économique un scénario pour les années à venir dépend de la période d'immunité vis-à-vis de la maladie et de la durée des cycles de production.

El virus de Schmallenberg fue detectado por primera vez en 2011 en Alemania y ulteriormente en 2012 en Francia. Los autores describen un estudio en el que se simularon distintos sistemas de producción de rumiantes en Francia y se estimó, con análisis presupuestarios parciales, el coste económico que entrañaría para una explotación el virus de Schmallenberg en dos hipotéticas situaciones sanitarias (una situación con efectos profundos y otra con efectos leves). El análisis presupuestario parcial sirve para evaluar los efectos económicos de cambios graduales, e incluye únicamente aquellos recursos y aspectos de la producción que experimentarán cambios. En la hipótesis de efectos profundos, el impacto estimado de la infección por el virus de Schmallenberg oscilaba entre 23 y 43 euros anuales por vaca y entre 19 y 37 euros anuales por oveja hembra. La hipótesis de efectos leves deparaba importes de aproximadamente la mitad (en el caso de las vacas) o un tercio (en el de las ovejas). Este impacto económico representa del 0,6% al 63% del margen bruto, dependiendo de la hipótesis elegida y del sistema productivo de que se trate. Los efectos de la infección por el virus de Schmallenberg se concretan básicamente en: los costos suplementarios derivados de adquirir y criar vaquillas de sustitución y de obtener una menor producción de leche (vacas lecheras); las pérdidas de terneros o corderos (sistemas de bovino u ovino cárnicos); y los costos derivados de la menor producción de leche y de no vender las corderas de sustitución (ovejas lecheras). El uso de modelos que integran los factores productivos y económicos sirvió a los autores para estimar el costo del virus de Schmallenberg a pesar de la escasez de datos, que, por la propia naturaleza de las enfermedades emergentes, es una dificultad común a la mayoría de ellas. También les permitió evaluar con exactitud el impacto de la enfermedad en distintos sistemas productivos en un breve lapso de tiempo. La realización de extrapolaciones a partir de esta evaluación económica para pronosticar la situación en años venideros depende del periodo de inmunidad respecto de la enfermedad y de la duración de los ciclos productivos.

High urea and pregnancy or conception in dairy cows: A meta-analysis to define the appropriate urea threshold.

Dietary proteins play an important role in reproduction, and increased dietary crude proteins, increased degradability of dietary proteins, and elevated blood or milk urea have been associated with decreased conception and pregnancy in many studies. The aim of this work was to provide a meta-analysis on the relationship between high milk or blood urea and pregnancy or conception, with a focus on defining the appropriate urea threshold associated with this issue. The meta-analysis included 61 different models from 21 papers. The thresholds of urea tested in the various models were built by steps of 1 mM urea. This constructed variable reduced heterogeneity by 61% in the meta-regression. The meta-analysis showed 43% lower odds of pregnancy or conception (odds ratio = 0.57; 95% confidence interval = 0.45-0.73) in cases where urea was ≥7.0 mM in the blood (plasma urea nitrogen = 19.3 mg/dL) or where urea was ≥420 mg/L in the milk compared with where urea values were lower. This threshold is the most suitable with regard to pregnancy or conception success, even if a threshold of 6.5 mM cannot be excluded with certainty. The results also highlighted the possibility of a stronger association between high urea concentrations and pregnancy or conception when high nitrogen exposure occurs before artificial insemination compared with after artificial insemination, but this possibility needs to be further studied. Whether the present results also apply to extensively pasture-based countries remains to be determined.

Changes in milk urea around insemination are negatively associated with conception success in dairy cows.

Dietary protein levels are a risk factor for poor reproductive performance. Conception is particularly impaired in cases of high blood or milk urea. The objective of this study was to investigate the association between conception and low milk urea or changes in milk urea around artificial insemination (AI). Data were obtained from the French Milk Control Program for a 4-yr period (2009-2012). Milk urea values between 250 and 450 mg/kg (4.3 and 7.7 mM) were considered intermediate (I), and values ≤150 mg/kg (2.6 mM) were considered low (L). Milk urea values before and after each AI were allocated into 4 classes representing the dynamics of milk urea (before-after; I-I, I-L, L-I, and L-L). Subclinical ketosis was defined using milk fat and protein contents before AI as proxies. A logistic regression with a Poisson correction and herd as a random variable was then performed on data from Holstein or all breeds of cows. The success of conception was decreased [relative risk (95% confidence interval) = 0.96 (0.94-0.99)] in low-urea cows compared with intermediate-urea cows after AI; no significant association was found for urea levels before AI. When combining data on urea before and after AI, I-L urea cows exhibited a 5 to 9% decrease in conception compared with I-I urea cows, and L-I urea cows showed no difference in conception success compared with I-I urea cows. A decreased conception success for L-L urea cows compared with I-I urea cows was observed for the analysis with cows of all breeds. This work revealed that a decrease in urea from intermediate (before AI) to low (after AI) is a risk factor for conception failure. Surveys of variation in milk urea in dairy cows close to breeding are highly recommended.

The economic impact of subclinical ketosis at the farm level: Tackling the challenge of over-estimation due to multiple interactions.

Subclinical ketosis (SCK) is a major metabolic disorder that affects dairy cows, and its lactational prevalence in Europe is estimated to be at 25%. Nonetheless, few data are available on the economics of SCK, although its management clearly must be improved. With this in mind, this study develops a double-step stochastic approach to evaluate the total cost of SCK to dairy farming. First, all the production and reproduction changes and all the health disorders associated with SCK were quantified using the meta-analysis from a previous study. Second, the total cost of SCK was determined with a stochastic model using distribution laws as input parameters. The mean total cost of SCK was estimated to be Є257 per calving cow with SCK (95% prediction interval (PI): Є72-442). The margin over feeding costs slightly influenced the results. When the parameters of the model are not modified to account for the conclusions from the meta-analysis and for the prevalence of health disorders in the population without SCK, the mean cost of SCK was overestimated by 68%, reaching Є434 per calving cow (95%PI: Є192-676). This result indicates that the total cost of complex health disorders is likely to be substantially overestimated when calculations use raw results from the literature or-even worse-punctual data. Excluding labour costs in the estimation reduced the SCK total cost by 12%, whereas excluding contributors with scarce data and imprecise calibrations (for lameness and udder health) reduced costs by another 18-20% (Є210, 95%PI=30-390). The proposed method accounted for uncertainty and variability in inputs by using distributions instead of point estimates. The mean value and associated prediction intervals (PIs) yielded good insight into the economic consequences of this complex disease and can be easily and practically used by decision makers in the field while simultaneously accounting for biological variability. Moreover, PIs can help prevent the blind use of economic results in the field when only the mean value is considered.

Diseases, reproductive performance, and changes in milk production associated with subclinical ketosis in dairy cows: a meta-analysis and review.

Many studies have shown that subclinical ketosis (SCK) is associated with an increased risk of developing various diseases, reproductive disorders, and changes in milk production. The present work aims at producing an overview between this disorder and theses outcomes. A meta-analysis of the literature, including 131 different models from 23 papers, or a review when the literature was scarce was conducted. For each outcome, the odds ratio (OR), relative risk, or hazard ratio was presented for various moderators to reduce heterogeneity among the studies. The raw change in milk production associated with SCK was estimated and adjusted, taking into consideration the outcomes known to interact with milk production during the peripartum period. The results showed that 2 main categories of moderators had a significant effect on the adjusted risk. First, the adjustment made by defining SCK as (1) ß-hydroxybutyrate concentration >1.4 mM, (2) nonesterified fatty acid (NEFA) concentration >0.4 mM prepartum, or (3) NEFA concentration >1.0 mM postpartum corrected the underestimated risk (despite low significance). This is because several trials reported the relevant risks using lower thresholds for the ß-hydroxybutyrate or NEFA values. Using a low threshold leads to lower risk of disease compared with using a high threshold. Second, the correction produced using the polyfactorial terms corrected the overestimation of risk because many trials reported only univariable models. The relative risk or OR (95% confidence interval) related to abomasal displacement, clinical ketosis, early culling and death, metritis, placental retention, clinical mastitis, lameness, and a doubling of the SCC in cases with SCK were 3.33 (2.60-4.25), 5.38 (3.27-8.83), 1.92 (1.60-2.30), 1.75 (1.54-2.01), 1.52 (1.20-1.93), 1.61 (1.24-2.09), 2.01(1.64-2.44), and 1.42 (1.26-1.60), respectively. The precision level of the estimate depended on the outcome. The direct mean ± standard deviation of the 305-d milk losses associated with SCK were 251 ± 73 kg after adjusting for abomasal displacement, clinical ketosis, metritis, and placental retention. The OR (95% confidence interval) for first service calving risk in cases of SCK was 0.67 (0.53-0.83). The calving-to-first-service interval was 8 d longer and the calving-to-conception interval was 16 to 22 d longer in cows with SCK. The relationships among the different reproductive indicators were quantified in only 1 or 2 trials. The present work highlights the need to conduct further studies on the associations between SCK and the risks of diseases, changes in milk production, and reproductive parameters.

Effect of acute and chronic excesses of dietary nitrogen on blood neutrophil functions in cattle.

Excess dietary nitrogen (EDN) is commonly expected in dairy herds, but no data are available regarding its consequences on cattle immunity. In this study neutrophil functions were assessed during EDN in steers. In experiment 1, 4 one-month periods, 4 diets [16% crude protein (CP; DM basis), 20% CP based on soybean meal, 20% CP based on urea, and 24% CP based on urea and soybean meal], and 4 steers were included in a crossover design to determine the effects of a chronic excess. In experiment 2, the repercussions of an acute excess were assessed with 2 periods of 10 d, the same 4 steers, and 2 diets containing 14 and 20% CP. Sampling was done during the fourth week of each period in experiment 1, and on d 0, 1, 2, 3, 7, and 9 of each period in experiment 2. Individual blood biochemistry parameters were measured and neutrophil factors, such as counts, recovery after isolation, surface expression of CD11b and CD62L, phagocytosis, diapedesis, reactive oxygen species (ROS) production, and bacteria killing, were determined. Data were analyzed by general linear models of R, with period, diet or biochemical component, and animal as explanatory variables. The outcome variables were biochemical or immune variables. The variables diet, period, and animal were forced as fixed effects. Data collected over the entire period of experiment 2 were pooled. Several multiples linear regressions or ANOVA were performed and a Bonferroni correction was applied. In experiment 2 (acute EDN), neutrophil counts were negatively associated with nitrogen intake, conversely to CD62L expression. The observed relative neutropenia may be due to neutrophil margination because CD62L-expressing neutrophils are more likely to stick to endothelium. Interestingly, ROS production was changed by EDN: chronic EDN (experiment 1) was negatively associated with opsonized zymozan (OZ)-induced ROS production and acute EDN (experiment 2) with spontaneous ROS production. For chronic EDN, ROS production upon phorbol 12-myristate 13-acetate was not modified, in contrast to OZ stimulation. Decreased ROS production during chronic EDN probably involves the early events leading to ROS production, as OZ acts through membrane receptors and phorbol 12-myristate 13-acetate directly activates protein kinase C. This is the first study to provide evidence that the modifications of neutrophil functions produced by excess nitrogen depend on the intensity and duration of the excess. Further studies, including epidemiological studies during risk periods, are needed to resolve the issues linked to EDN.

Factors influencing dairy calf and replacement heifer mortality in France.

Herd-level risk factors for dairy calf and heifer mortality in France were identified by calculating herd-level variables (including mortality risk or rate) using the National Bovine Identification Database (2005 and 2006). Eleven dairy production areas representing different livestock systems were also included. Statistical analyses were based on a probit model (mortality risk or rate=0 or >0) and a linear model (mortality risk or rate >0) corrected by the sample bias Heckman method. The same associations were reported for 2005 and 2006. The mortality risks or rates for calves and heifers were positively associated with the proportion of purchased cows or being a Milk Control Program member and negatively associated with adhering to the Good Breeding Practices charter and having an autumn calving peak. The associations between mortality and the breeds or the production areas were positive or negative, depending on the classes of animal. Mortality and having a beef herd in addition to the dairy herd were negatively associated for noncrossed birth to 2-d-old calves, noncrossed 3-d- to 1-mo-old calves, and 3-d- to 1-mo-old heifers. Having a beef herd probably provides specific know-how related to newborn and young calf management that makes it easier to attain low mortality in pure-breed dairy calves. The proportion of males born was positively associated with mortality for the birth to 2-d-old calves (all classes) and for the 3-d- to 1-mo-old beef-crossed calves, but negatively for all classes of heifers. This indicates that heifer management was improved when the availability of newborn heifers decreased, resulting in low mortality. This lower mortality is apparent for all classes of heifers present on the farm during the year when the proportion of males was low, and demonstrates an anticipatory effect. In conclusion, this study shows that the presence of a beef herd in addition to the dairy herd within a farm is associated with decreased dairy calf mortality. It also shows that heifer mortality decreases when the proportion of heifers born decreased. These determinants of dairy calf and heifer mortality are of great importance for farmer advisors, the dairy industry, and the political decision makers.

Perinatal, neonatal, and rearing period mortality of dairy calves and replacement heifers in France.

Dairy calf and replacement heifer mortality in France was assessed by calculating mortality rates at 0 to 2d (calves), 3d to 1 mo (calves and heifers), 1 to 6 mo of age, and 6 mo of age to first calving (heifers) using the national identification database. Between birth and 2-d-old, 261,000 and 251,000 of the 3.56 and 3.43 million calves born in 2005 and 2006, respectively, died. The overall 0- to 2-d-old calf mortality rate was around 6.7%, which is similar to the low range of values reported in the literature. Among the 2.38 and 2.39 million calf-month, 139,000 and 133,000 died between 3d and 1 mo of age in 2005 and 2006, respectively. Among the 3d to 1 m of age group, dairy calf mortality rate was around 5.7%. Such a rate has not been reported previously because of the great differences in age classes between studies. For the 0- to 2-d-old and 3-d- to 1-mo-old calves, annual mortality was zero on 26 and 44% of the farms, respectively. Calf mortality during the first month of life increased in winter (to 12-17%) and decreased in summer (to 8-12%), with a small peak in June or July. Mortality during the first month of life is higher in males than in females, with a mortality odds ratio of 1.20 (and 95% confidence interval of 1.19-1.21). Such a difference is also found within the noncrossed or beef-crossed calf subpopulations. Disregarding the sex, the mortality of beef-crossed calves is slightly less than that of noncrossed dairy calves, with a mortality odds ratio of 0.98 (and 95% confidence interval of 0.98-0.99) before 1 mo of age. In heifers, around 51,000, 35,000, and 40,900 out of the 1.2 million 3-d- to 1-mo-old, 1.1 million 1- to 6-mo-old, and 950,000 6-mo-old to first calving heifers died, respectively. The respective mortality rates were 4.5, 3.1, and 4.1%; these rates are similar to the low range of values previously published. The proportions of farms with no heifer mortality during a year were higher than for calves, between 60 and 70%. The mortality probability for heifers was very high for the first day of life (95% survival between 2-30 d of age), then decreased during the first year of life and became constant up to around 3 yr of age (88% survival at 36 mo of age). The risk of mortality is higher in Montbéliarde and Normande heifers compared with Holstein. In conclusion, and beyond the average mortality rates, farmers and farm advisors should keep in mind the broad range of mortality values, which shows that very low mortality (1-2%) can be achieved, even in animals with a known high risk of mortality, such as beef-crossed dairy calves.

Experimental soybean meal intoxication in cattle.

BACKGROUND: Cattle are commonly fed soybean meal (SBM) and accidental intoxication sometimes occurs. OBJECTIVES: To describe the biologic and clinical features of SBM intoxication. ANIMALS: Four steers with ruminal cannula. METHODS: Controlled experimental trial. SBM was administered once at 1 and 2% of body weight (BW) via cannula at 2-month intervals. RESULTS: This study showed a 2-phase pathogenic course for 2% BW SBM intoxication. The 1st phase (until 10 hours post-administration) is restricted to ruminal modification with volatile fatty acid overproduction and moderate ruminal ammonia concentration. In the 2nd phase (12-22 hours post-administration), ruminal pH returned to initial values and marked ammonia accumulation occurred in blood, inducing severe metabolic alkalosis with hyperglycemia, hyperinsulinemia, and delayed aciduria (30-40 hours post-administration). Among the clinical signs, nervous signs were only observed during the period with increased plasma ammonia concentration. At 1% BW, ruminal and blood modifications were less pronounced than at 2% BW, and clinical signs were not observed. CONCLUSIONS AND CLINICAL RELEVANCE: Ammonia accumulation in blood during the second phase is the consequence of continued ammonia production, decreased carbohydrate fermentation, and overwhelming of hepatic detoxifying capacity. Because ammonia accumulation is associated with the clinical signs, treatment of SBM intoxication could be similar to treatment of urea intoxication, including rumenotomy, oral administration of cold water and vinegar, and measurement of ruminal pH.

Herd-level and contextual factors influencing dairy cow mortality in France in 2005 and 2006.

Dairy cow mortality causes financial loss and is increasing over time; it indicates suboptimal herd health or welfare. To describe the herd-level and contextual factors affecting cow mortality, the French National Bovine Dataset Identification was used to create dairy, beef, or fattening units within farms, for 2005 and 2006. Mortality rate (MO-RA, outcome variable) and most variables were calculated at the unit level, whereas contextual variables were defined at the municipality level [cattle density, inhabitant density, agricultural land always with grass on overall agricultural land (ALWG/OAL)]. The localization (11 dairy production areas, representative of the farming systems) was also included. The statistical analysis was performed with a probit regression model (MO-RA=0 or>0) and with a linear model corrected by the Heckman method for bias sample selection. For 2005 and 2006, 3.8 and 3.7 million dairy cow-years, 101,445 and 96,954 dairy units, and 141,677 and 143,424 deaths were recorded, respectively. Over one-third of the units had no dairy cow mortality in 2005 or 2006. Overall MO-RA was 3.7 and 3.8% for 2005 and 2006, respectively. Restricted MO-RA (farms without death excluded) was 5.8% for 2005 and 2006. The correlation of MO-RA among units between the 2 yr was 0.25. The same effects and close estimate values were reported for 2005 and 2006 with both models. Mortality rate was positively associated with the number of cow-years, having a beef unit in addition to a dairy unit, the proportion of purchased cows, the proportion of first-calving cows, the average calving interval, being a Milk Control Program member, inhabitant density, not being in dairy production area Grand-Ouest, and ALWG/OAL. Negative associations were reported for breed other than Holstein, being a Good Breeding Practices member, having a calving peak in autumn, culling rate, and municipal cattle density. This study reports an average mortality rate for the French dairy cows. It suggests that the farmer's management style highly influences mortality. In addition, farming system has an effect on the mortality. A possible association between municipal intensification of production and decreased mortality was also reported.

Detection of bacteriuria and bacteremia in newborn calves by a catalase-based urine test.

BACKGROUND: Bacteremia occurs frequently in newborn calves. The predictive value of clinical signs is low, suggesting the use of calf-side diagnostic tests. OBJECTIVES: To investigate testing of urine catalase activity (Uriscreen test) for bacteriuria and bacteremia detection. ANIMALS: Five colostrum-free calves and 3 colostrum-fed control calves. METHODS: Controlled experimental trial. Colostrum-free calves were inoculated PO with Escherichia coli O78+. A clinical score was established to define the onset of the illness. Blood and urine (cystocentesis) samplings and cultures, and Uriscreen tests, were performed 4-6 times from inoculation to death. Three control calves received the same management as 3 inoculated calves, but with colostrum and without inoculation. RESULTS: Bacteremia was demonstrated in all of the inoculated colostrum-free calves and in none of the control calves. The E. coli O78+ strain, E. coli, and Klebsiella spp. were recovered from 4/5, 5/5, and 2/5 inoculated colostrum-free calves, respectively. Urine cultures were negative for the 2 groups at the start of the experiment; 5/5 colostrum-deprived inoculated calves were positive for E. coli thereafter whereas 3/3 controls remained negative. Concordance of Uriscreen tests with bacteremia and bacteriuria was 0.86 and 0.88, respectively. Kappa value of agreement between Uriscreen and bacteremia and bacteriuria was 0.73 and 0.76, respectively. Sensitivity of Uriscreen for bacteremia and bacteriuria was 80.0 and 86.6%, respectively, and specificity was 92.8 and 88.8%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The results suggest that Uriscreen can be used for detection of bacteremia in neonatal calves in connection with a constant bacteriuria.