Effects of time and sampling location on concentrations of β-hydroxybutyric acid in dairy cows

Two trials were conducted to examine factors potentially influencing the measurement of blood β-hydroxybutyric acid (BHBA) in dairy cows. The objective of the first trial was to study effects of sampling time on BHBA concentration in continuously fed dairy cows. Furthermore, we determined test characteristics of a single BHBA measurement at a random time of the day to diagnose subclinical ketosis considering commonly used cut-points (1.2 and 1.4 mmol/L). Finally, we set out to evaluate if test characteristics could be enhanced by repeating measurements after different time intervals. During 4 herd visits, a total of 128 cows (8 to 28 d in milk) fed 10 times daily were screened at 0900 h and preselected by BHBA concentration. Blood samples were drawn from the tail vessels and BHBA concentrations were measured using an electronic BHBA meter (Precision Xceed, Abbott Diabetes Care Ltd., Witney, UK). Cows with BHBA concentrations ≥0.8 mmol/L at this time were enrolled in the trial (n=92). Subsequent BHBA measurements took place every 3h for a total of 8 measurements during 24 h. The effect of sampling time on BHBA concentrations was tested in a repeated-measures ANOVA repeating sampling time. Sampling time did not affect BHBA concentrations in continuously fed dairy cows. Defining the average daily BHBA concentration calculated from the 8 measurements as the gold standard, a single measurement at a random time of the day to diagnose subclinical ketosis had a sensitivity of 0.90 or 0.89 at the 2 BHBA cut-points (1.2 and 1.4 mmol/L). Specificity was 0.88 or 0.90 using the same cut-points. Repeating measurements after different time intervals improved test characteristics only slightly. In the second experiment, we compared BHBA concentrations of samples drawn from 3 different blood sampling locations (tail vessels, jugular vein, and mammary vein) of 116 lactating dairy cows. Concentrations of BHBA differed in samples from the 3 sampling locations. Mean BHBA concentration was 0.3 mmol/L lower when measured in the mammary vein compared with the jugular vein and 0.4 mmol/L lower in the mammary vein compared with the tail vessels. We conclude that to measure BHBA, blood samples of continuously fed dairy cows can be drawn at any time of the day. A single measurement provides very good test characteristics for on-farm conditions. Blood samples for BHBA measurement should be drawn from the jugular vein or tail vessels; the mammary vein should not be used for this purpose.

Application of vaginal temperature measurement in bitches

Finding innovative, non-invasive methods for continuously measuring body temperature minimizing human interference is important for accurate data collection. The objective of this study was to assess feasibility and accuracy of continuous body temperature measurements with loggers placed in the vaginal cavity of bitches. First, an in vitro experiment was performed to compare values obtained by temperature loggers (n = 26) to a calibrated liquid-in-glass thermometer. The mean differences between the two methods were low. Next, an in vivo experiment was performed using five healthy bitches, and values obtained by the vaginal loggers were compared to measurements collected rectally with digital thermometers. The results show that rectal and vaginal temperatures were correlated. The mean differences between rectal and vaginal temperatures were negligible. We conclude that the utilized temperature loggers provide accurate and reliable data.

Presence of Escherichia coli, Trueperella pyogenes, α-hemolytic streptococci, and coagulase-negative staphylococci and prevalence of subclinical endometritis

Subclinical endometritis (SCE) has a severe negative effect on reproductive performance of dairy cows. Different studies have shown a wide variety of cut points for the polymorphonuclear neutrophilic leukocyte (PMNL) percentage to define SCE and differing sampling times. Possible risk factors for SCE, such as low body condition score, hyperketonemia, and increased haptoglobin concentrations have been demonstrated. The aim of this study was to determine the relationship between bacterial findings in the uterus and PMNL in the early postpartum period and to compare 2 classification schemes for the diagnosis of SCE. Cytological and bacteriological samples from the uterus were taken from 149 cows at 2 consecutive times postpartum [10 ± 1 and 24 ± 1 d in milk (DIM)] and additionally, 131 cows were sampled at 21 to 27 DIM. For sample collection, the cytobrush technique was used and vaginal discharge was examined by vaginoscopy. Polymorphonuclear neutrophilic leukocyte cut points were set at 5, 10, and 18%. Cows positive with α-hemolytic streptococci at 10 ± 1 DIM had significant higher PMNL percentages at 21 to 27 DIM and greater median days to pregnancy (193.5d) than cows not infected (123.0 d). Cows with Trueperella pyogenes at 10±1 DIM had higher odds (5.2) of having more than 18% PMNL at 21 to 27 DIM compared with cows without infection. Escherichia coli had no effect on the prevalence of SCE regardless of the cut point. Primiparous cows with more than 18% PMNL had greater median days to pregnancy (144.5 d) than cows with less than 5% (80.0 d) or cows between 5 and 18% PMNL (68.0 d). Cows between 5 and 18% PMNL or 10 and 18% PMNL showed the best reproductive performance. The results demonstrate that an early infection with α-hemolytic streptococci increased the PMNL percentage 2 wk later and that 18% PMNL at 21 to 27 DIM was a predictive cut point for primiparous cows to diagnose animals with or without SCE.

Technical note: Evaluation of odor from vaginal discharge of cows in the first 10 days after calving by olfactory cognition and an electronic device

The objective of this study was to determine test characteristics (i.e., intra- and interobserver variability, intraassay variability, sensitivity, and specificity) of an evaluation of odor from vaginal discharge (VD) of cows in the first 10 d postpartum conducted by olfactory cognition and an electronic device, respectively. In experiment 1, 16 investigators (9 veterinary students and 7 licensed veterinarians) evaluated 5 VD samples each on 10 different days. The kappa test revealed an agreement between investigators (interobserver) of κ=0.43 with a Fleiss adjusted standard error of 0.0061. The overall agreement was the same for students (κ=0.28) and veterinarians (κ=0.28). Mean agreement within observers (intraobserver) was κ=0.52 for all observers, and 0.49 and 0.62 for students and veterinarians, respectively. In experiment 2, the repeatability of an electronic device (DiagNose; C-it, Zutphen, the Netherlands) was tested. Therefore, 5 samples of VD from 5 cows were evaluated 10 times each. The repeatability was 0.97, determined by Cronbach's α. In experiment 3, 20 samples collected from healthy cows and 20 of cows with acute puerperal metritis were evaluated by the 16 investigators and the DiagNose using a dichotomous scale (1=cow with acute puerperal metritis; 0=healthy cow). Sensitivity and specificity of olfactory evaluation was 75.0 and 60.1% compared with 92.0 and 100%, respectively, for the electronic nose device. The study revealed a considerable subjectivity of the human nose concerning the classification into healthy and sick animals based on the assessment of vaginal discharge. The repeatability of the electronic nose was higher. In conclusion, the DiagNose system, although imperfect, is a reasonable tool to improve odor assessment of VD. The current system, however, is not suitable as a screening tool in the field. Further research is warranted to adapt such electronic devices to practical on-farm screening tools.

Measurement of fecal glucocorticoid metabolites and evaluation of udder characteristics to estimate stress after sudden dry-off in dairy cows with different milk yields

Sudden dry-off is an established management practice in the dairy industry. But milk yield has been increasing continuously during the last decades. There is no information whether the dry-off procedure, which often results in swollen and firm udders, causes stress, particularly in high-producing dairy cows. Therefore, we evaluated the effect of a sudden dry-off on extramammary udder pressure and the concentration of fecal glucocorticoid metabolites (i.e., 11,17-dioxoandrostane, 11,17-DOA) as an indirect stress parameter. Measurements were carried out within the last week before dry-off and until 9d after dry-off considering 3 groups of milk yield (i.e., low: <15 kg/d, medium: 15-20 kg/d, and high: >20 kg/d). Udder pressure increased in all yield groups after dry-off, peaked at d 2 after dry-off and decreased afterwards. Pressures were highest in high-yielding cows and lowest in low-yielding cows. But only in high-yielding cows was udder pressure after dry-off higher than before dry-off. Baseline 11,17-DOA concentrations depended on milk yield. They were highest in low-yielding (121.7 ± 33.3 ng/g) and lowest in high-yielding cows (71.1 ± 30.0 ng/g). After dry-off, 11,17-DOA increased in all yield groups and peaked at d 3. Whereas in medium- and high-yielding cows 11,17-DOA levels differed significantly from their respective baseline during the whole 9-d measuring period, low-yielding cows showed elevated 11,17-DOA levels only on d 3 after dry-off. However, especially the increase in 11,17-DOA after dry-off between the 3 yield groups was considerably different. Mean 11,17-DOA increase from baseline to d 3 was highest in high-yielding cows (129.1%) and considerably lower in low-yielding cows (40.1%). The highest fecal 11,17-DOA concentrations were measured on d 3 after dry-off, indicating that the stress was most intense on d 2, which is due to an 18-h time lag; at about the same time, udder pressure peaked. Our results showed a negligible effect of a sudden dry-off on low-yielding cows. High-yielding cows, however, faced high extramammary pressures and increased glucocorticoid production. Considering animal welfare aspects, a review of the current dry-off strategies might be warranted.

Prevalence of subclinical ketosis and relationships with postpartum diseases in European dairy cows

Subclinical ketosis (SCK) is defined as concentrations of β-hydroxybutyrate (BHBA) ≥ 1.2 to 1.4 mmol/L and it is considered a gateway condition for other metabolic and infectious disorders such as metritis, mastitis, clinical ketosis, and displaced abomasum. Reported prevalence rates range from 6.9 to 43% in the first 2 mo of lactation. However, there is a dearth of information on prevalence rates considering the diversity of European dairy farms. The objectives of this study were to (1) determine prevalence of SCK, (2) identify thresholds of BHBA, and (3) study their relationships with postpartum metritis, clinical ketosis, displaced abomasum, lameness, and mastitis in European dairy farms. From May to October 2011, a convenience sample of 528 dairy herds from Croatia, Germany, Hungary, Italy, Poland, Portugal, Serbia, Slovenia, Spain, and Turkey was studied. β-Hydroxybutyrate levels were measured in 5,884 cows with a handheld meter within 2 to 15 d in milk (DIM). On average, 11 cows were enrolled per farm and relevant information (e.g., DIM, postpartum diseases, herd size) was recorded. Using receiver operator characteristic curve analyses, blood BHBA thresholds were determined for the occurrence of metritis, mastitis, clinical ketosis, displaced abomasum, and lameness. Multivariate binary logistic regression models were built for each disease, considering cow as the experimental unit and herd as a random effect. Overall prevalence of SCK (i.e., blood BHBA ≥ 1.2 mmol/L) within 10 countries was 21.8%, ranging from 11.2 to 36.6%. Cows with SCK had 1.5, 9.5, and 5.0 times greater odds of developing metritis, clinical ketosis, and displaced abomasum, respectively. Multivariate binary logistic regression models demonstrated that cows with blood BHBA levels of ≥ 1.4, ≥ 1.1 and ≥ 1.7 mmol/L during 2 to 15 DIM had 1.7, 10.5, and 6.9 times greater odds of developing metritis, clinical ketosis, and displaced abomasum, respectively, compared with cows with lower BHBA blood levels. Interestingly, a postpartum blood BHBA threshold ≥ 1.1 mmol/L increased the odds for lameness in dairy cows 1.8 (95% confidence interval: 1.3 to 2.5) times. Overall, prevalence of SCK was high between 2 to 15 DIM and SCK increased the odds of metritis, clinical ketosis, lameness, and displaced abomasum in European dairy herds.

Therapy of bovine endometritis with prostaglandin F2α: a meta-analysis

The objective of the conducted meta-analysis was to assess the efficacy of the treatment of bovine endometritis with PGF(2α) by statistical means. Postpartum uterine infections have a high prevalence and a very negative effect on reproductive performance in dairy cattle. Because of a wide discordance between research results, a meta-analysis of the efficacy of the treatment of bovine endometritis with PGF(2α) was conducted. A comprehensive literature search was performed using online databases to reveal a total of 2,307 references. In addition, 5 articles were retrieved by reviewing citations. After applying specific exclusion criteria and evaluating specific evidence parameters, 5 publications, comprising 6 trials, were eligible for being analyzed by means of meta-analysis. Data for each trial were extracted and analyzed using meta-analysis software Review Manager (version 5.1; The Nordic Cochrane Centre, Copenhagen, Denmark). Estimated effect sizes of PGF(2α) were calculated on calving to first service and calving to conception interval. Prostaglandin F(2α) treatment of cows with chronic endometritis had a negative effect on both reproductive performance parameters. Heterogeneity was substantial for calving to first service and calving to conception interval [I(2) (measure of variation beyond chance)=100 and 87%, respectively]; therefore, random-effects models were used. Sensitivity analysis as well as subgroup analysis showed that the performance of randomization was influential in modifying effect size of PGF(2α) treatment. The funnel plot illustrated a publication bias toward smaller studies that reported a prolonged calving to conception interval after a PGF(2α) treatment. We conclude that the investigation of this subject by means of meta-analysis did not reveal an improvement of reproductive performance of cows with endometritis after treatment with PGF(2α). Furthermore, there is a shortage of comparable high quality studies investigating reproductive performance after PGF(2α) treatment of cows with chronic endometritis.

Does oral administration of the amino acid tyrosine affect oestradiol-17β concentration and sexual behaviour in the bitch?

The oral administration of the amino acid, tyrosine, has been for years recommended in order to improve fertility, especially to improve copulation behaviour in female dogs. However, evidence is comparatively poor. The objective of our study was to determine whether oral administration of tyrosine has an effect on oestradiol-17β concentrations and the oestrous behaviour in the bitch. Fifty bitches were randomly allocated to one of two treatment groups in which each dog received 100mg/kg/day of either tyrosine or milk sugar orally between Day 3 and Day 9 of heat. Every two to three days, a gynaecological examination was performed and blood samples were taken to determine oestradiol-17β and progesterone concentrations. The day of ovulation was estimated by clinical findings, and according to the specifications of the laboratory, once progesterone values exceeded 12.7nmol/l. The observed copulation behaviour was not different between the groups. No differences in volume and visual nature of vaginal discharge were observed. At the day of ovulation, mean oestradiol-17β concentration in the treated group was 163.4pmol/l and 162.2pmol/l in the placebo group, respectively. In conclusion, feeding tyrosine to female dogs between Day 3 and Day 9 of heat did not alter visual signs of heat or copulation behaviour, and did not alter oestradiol-17β concentration.

[Decision making in veterinary practice]

OBJECTIVE

In daily practice, a veterinarian has to judge information and decide whether it can be adequately implemented for a given case. In this context, it is vital to base decisions on the most recent and reliable scientific findings. In Germany, every practitioner must take part in 20 to 40 hours annually of continuing education. To outline the current assessment and employment of evidence-based veterinary medicine (EBVM), we surveyed practitioners concerning continuing education and their skills in obtaining and evaluating scientific information.

MATERIALS AND METHODS

A survey amongst veterinary practitioners was conducted throughout five continuing education courses between May 2010 and November 2011. The questionnaire contained 32 questions concerning demographic data and profession (n = 4), qualification (n = 3), continuing education (n = 5) and skills related to EBVM (n = 20). Besides evaluating the statements of all participants, veterinarians were classified based on the type of practice and their statements compared.

RESULTS

In total, 293 questionnaires were returned. The majority of small animal practitioners (58.3%) and those working with food animals (54.9%) declared being capable of comprehending scientific talks or papers in English without difficulty. 10.4% of all practitioners neglected reading veterinary journals on a regular basis, while 20.8% stated they regularly read English veterinary journals. The majority of the practitioners sought advice from their employer or a colleague. They attributed a high or very high quality to both these information sources. Almost every participant (92.6%) stated that they consulted medical books, and 88.6% certified this information source as being of high or very high quality. 68.6% of the practitioners evaluated their skills in finding suitable literature as high or very high. However, only approximately half (52.1%) of all participants attributed themselves a high ability to evaluate the quality of the literature found.

CONCLUSION AND CLINICAL RELEVANCE

Most practitioners are very limited in their ability to assess the evidence of scientific information. Therefore, courses that introduce EBVM should be taught in both veterinary and postgraduate education to train critical appraisal of information and to support decision-making based on valid, clinically relevant data.

Estrus detection in dairy cattle: changes after the introduction of an automated activity monitoring system?

OBJECTIVE

In context of the study farmers using an automated activity monitoring (AAM) system called Heatime were surveyed on estrus detection practices. The aim of the study was to gain an overview of the usual estrus detection methods and especially to learn about the practical aspects of that system.

MATERIAL AND METHODS

Items addressing farm and animal environment, estrus detection before and after installation of Heatime, reproduction, Heatime management and the farmer's perception of efficiency were asked.

RESULTS

A total of 232 survey forms were returned (58.3% response rate) and 219 surveys could be used for final analysis. Visual observation was the most common practice to detect estrus. After installation of the Heatime system the farmers assessed that the application of hormones for reproduction management decreased. The majority of the responding dairy farmers (93.1%) strongly agreed or agreed that heat detection was higher after the installation of Heatime. Most of them (92.3%) strongly agreed or agreed with the statement that the reproduction management became easier with Heatime.

CONCLUSION

Overall, 94.1% of the responding farm managers were satisfied with the Heatime system and almost all of them (94.5%) would install the system again.

CLINICAL RELEVANCE

The results show that the Heatime system is a well accepted estrus detection aid and has the potential to reduce the time needed for estrus detection and might potentially reduce the use of hormones.

Messung der Körpertemperatur bei Milchkühen – Methoden und Einflussfaktoren

In Monitoring-Programmen für frühpuerperale Milchkühe spielt die Messung der Körpertemperatur eine herausragende Rolle. Eine erhöhte Körpertemperatur ist weiterhin Teil der international anerkannten Definition der puerperalen Metritis, einer klassischen Erkrankung des Frühpuerperiums. In vielen internationalen Untersuchungen dient die Körpertemperatur als wichtiges Entscheidungskriterium für eine antibiotische Behandlung im Puerperium. Ziel dieses Artikels ist, einen Überblick über aktuelle Studien zur Körpertemperatur der Milchkuh zusammenzustellen. Zahlreiche Faktoren beeinflussen sowohl die Temperaturmessung (Art des Thermometers, Eindringtiefe, Erfahrenheit des Untersuchers) als auch die Körpertemperatur der Milchkuh (Laktationsdauer, Laktationsnummer, Tageszeit, Klima zum Zeitpunkt der Abkalbung). Zusätzlich konnte in einigen Studien unabhängig voneinander gezeigt werden, dass ein gewisser Prozentsatz von gesunden Kühen im Frühpuerperium eine erhöhte Körpertemperatur aufweist. Bei unklaren Diagnosen (z. B. kein weiteres Symptom außer einer erhöhten Körpertemperatur) sollten die Messergebnisse hinterfragt werden.

[Measuring body temperature in dairy cows--applications and influencing factors]

Measuring body temperature plays an integral role in early puerperal cow monitoring programs. Furthermore, body temperature is part of the definition of puerperal metritis. Antibiotic treatment decisions are based on body temperature in several international publications on intervention strategies widely adopted in the modern dairy industry. The objective of this article is to provide a brief overview of the most recent publications on this important criterion. Several factors can influence the measurement of the body temperature (type of thermometer, insertion depth, skills of the investigator) as well as the cow's body temperature (days in milk, parity, time of the day, climate at calving). Furthermore, the occurrence of increased body temperature in healthy cows was demonstrated independently by several investigations. In ambiguous cases (e.g. raised body temperature as the only symptom) results should be interpreted with caution.

[Repeatability of measurements of the rectal temperature and comparison of vaginal and rectal temperature in puerperal sows]

OBJECTIVE

Postpartum diseases of sows are economically important in the pig industry. They affect animal health and welfare of sows and piglets. Measuring rectal temperature in sows post partum is a commonly used diagnostic method to early detection of infectious diseases. The study consisted of five parts. The objective of the first four parts was to evaluate the influence of different factors on the measurements of rectal temperature (e.g. investigator, thermometer, penetration depth of the thermometer). The secondary objective of this study was to validate the application of a temperature logger to continuously measure vaginal temperature.

MATERIAL AND METHODS

Thirty sows on the first day postpartum were used in the first four parts of the study. Rectal temperature was measured repeatedly by one investigator, by different investigators, with different thermometers and at different penetration depths. For the fifth part of the study 21 sows on the first day postpartum were used. A temperature logger was inserted in the vagina for a duration of 6 hours. Additionally, rectal temperature was measured.

RESULTS

The data showed that rectal temperature can be measured repeatably (mean ± standard deviation = 38.7 ± 0.1 °C, coefficient of variation = 0.2%). Different investigators or thermometers resulted in low differences (0.0 °C and 0.1 °C). The penetration depth of the thermometer influenced the result (difference of 0.4 °C between 5 and 10 cm). Rectal and vaginal temperatures, measured in 21 sows, were highly correlated (r = 0.80, p < 0.01) with a mean difference of 0.3 °C.

CONCLUSION AND CLINICAL RELEVANCE

Rectal temperature measurement can be regarded as a repeatable diagnostic method. The measurement should be standardized (type of thermometer, penetration depth). The measurement of vaginal temperature with a data logger in early puerperal sows is a possible means for a continuous and non-invasive monitoring of body temperature.

[Results of a survey regarding the publication of scientific results in German-speaking countries]

OBJECTIVE

Veterinarians should conduct diagnostic and therapeutic procedures according to the most recent and scientifically proven methods. Therefore, a rapid and effective transfer of scientific information is crucial. An important link between science and practice are findings published in scientific journals. The productivity of scientists is often measured referring to the number of papers published in reputable journals. Because many of these journals publish in the English language, it is possible that results from German research may never reach German veterinarians or only after a delay.

MATERIAL AND METHODS

Using an online questionnaire, faculty members (professors and scientific assistants) from Germany, Austria and Switzerland were asked how they had published their results during the previous 5 years. Furthermore, they were asked to identify the factors influencing their choice of journal for publication.

RESULTS

A total of 118 respondents completed the questionnaire. Nearly two thirds had published ten or more papers during the previous 5 years. More than half of these were published in the English language. Most participants consider the peer review process suitable for enhancing the quality of publications. The impact factor is seen as a fair indicator for the quality of a paper while considered an important factor for the choice of a journal for publication of the respondents own results.

CONCLUSION AND CLINICAL RELEVANCE

According to the data, respondents prefer to publish their results in the English language and in journals with a high impact factor. Therefore, veterinarians may never receive this information via German journals or only after a delay. One possible solution could be a regularly published practice-oriented compilation of relevant scientific findings.

Short communication: Evaluation of vaginal discharge following treatment with a progesterone insert

Yellowish discharge after application of intravaginal progesterone releasing inserts is frequently observed in cows. The objective of this study was to compare the bacteriological contamination of the vagina and uterus before and after a treatment with a progesterone insert in heifers. Forty-two Holstein heifers received a progesterone releasing insert [Eazi-Breed controlled internal drug release (CIDR) insert; Pfizer Animal Health, Berlin, Germany] for 7d. The protruding tail had been removed from half of the inserts (no tail group: n=21; tail group: n=21). Nine heifers from the tail group lost the insert within the 7-d treatment interval and were excluded. Heifers identified in estrus were artificially inseminated on d 9 or 10. Vaginal discharge was scored on a 4-point scale [vaginal discharge score (VDS) 0 to 3] and vaginal swabs were taken for bacteriological examination on d 0 and 7 and the day of artificial insemination (AI). Furthermore, cytological and bacteriological samples were obtained from the uterus on d 7 and the day of AI. On d 0, coliforms and Streptococcus spp. were found in vaginal swabs of 21 heifers (64%). On d 7, all heifers showed purulent vaginal discharge (VDS 2 to 3). The VDS was higher in the tail group compared with the no tail group. Arcanobacterium pyogenes, coliforms, and Streptococcus spp. were isolated from the vaginal swabs in 32 of 33 (96%) heifers on d 7. On the day of AI, VDS had improved to 0 or 1 in 96% of the heifers. However, A. pyogenes, coliforms, and Streptococcus spp. were still isolated in 17 of 33 (53%) heifers from the vagina and in 32 of 33 (96%) heifers from the endometrium. Endometrial cytology revealed polymorphonuclear neutrophils (PMN) in 11 heifers (6 to 32% PMN). Five samples exceeded the threshold of 5% PMN, and 2 samples exceeded the 10% PMN threshold, indicative of subclinical endometritis. In conclusion, pyogenic bacteria were found in the vagina and uterus on d 7 and the day of AI after intravaginal progesterone treatment. The severity of the discharge was affected by the protruding tail of the insert.