V.S. Suthar

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.

Validity of prepartum changes in vaginal and rectal temperature to predict calving in dairy cows

The prevalence of dystocia is high in many dairy herds and is associated with stillbirth and negative effects for the cow. An accurate predictor of calving would enable supervision of cows more precisely to a relevant time interval so that obstetrical assistance can be provided in a timely manner. This might help to decrease calf mortality rate. Evidence exists that cows exhibit a decrease in body temperature before the onset of calving. The performance of a decrease in body temperature as a test to predict the onset of calving in dairy cows has not been investigated. The objective was to investigate test criteria of a decrease in vaginal and rectal temperature as predictors of calving in dairy cows. In 3 experiments, temperature loggers (Minilog 8, Vemco Ltd., Halifax, Canada) were inserted into the vagina of cows before calving (n = 85), and rectal temperatures were measured twice daily in 55 of these cows. Vaginal temperatures were 0.2 to 0.3 °C and 0.6 to 0.7 °C lower on the day of calving compared with 24 and 48 h before calving, respectively. Rectal temperatures were 0.3 to 0.5 °C and 0.4 to 0.6 °C lower on the day of calving compared with 24 and 48 h before calving, respectively. Vaginal temperatures exhibited a diurnal rhythm during the 120 h before calving, which continued on a lower level during the 48 h preceding parturition. In the 3 experiments, a decrease in vaginal temperature of ≥ 0.3 °C over 24h could predict calving within 24h, with sensitivity ranging from 62 to 71% and specificity ranging from 81 to 87%. Similarly, a decrease in rectal temperature measured at 0730 h of ≥ 0.3 °C could predict calving within 24h, with sensitivity from 44 to 69% and specificity from 86 to 88%. Although dairy cows exhibit a distinctive decrease in vaginal and rectal temperatures commencing approximately 48 h before calving, detecting this decrease does not determine the onset of calving precisely. Nevertheless, it can provide valuable information in addition to the traditional signs (i.e., relaxation of the sacrosciatic ligament) that calving is imminent.

Technical note: Evaluation of data loggers for measuring lying behavior in dairy calves

Lying behavior might indicate how the animal interacts with its environment and is an important indicator of cow and calf comfort. Measuring behavior can be time consuming; therefore, behavioral recording with the help of loggers has become common. Recently, the Hobo Pendant G data logger (Onset Computer Corp., Bourne, MA) was validated for measuring lying behavior in cows but no work to date has validated this logger for measuring lying behavior in calves. The objective of this study was to test the accuracy of the Hobo Pendant G data logger for measuring total lying time and frequency of lying bouts in dairy calves. In 2 experiments (experiment 1: thirty-seven 2-h observation periods; experiment 2: nineteen 24-h observation periods), we tested the effect of 2 different recording intervals, the effect of attachment to different legs, and the effect of removing short, potentially erroneous readings. We found an excellent relationship when comparing the 30-s and 60-s recording intervals. For total lying time and bout frequency, the highest correlation was found when the logger was attached to the hind legs and recording was conducted with a 60-s sampling interval. In experiment 2, average total lying time was 1,077 ± 54 min/24 h (18.0 ± 0.9h/24h), with an average frequency of 19.4 ± 4.5 bouts per day. Predictability, sensitivity, and specificity for experiment 2 were >97% using the 60-s recording interval and removing single readings of lying or standing from the data set compared with direct observation as reference. The data logger accurately measured total lying time and bout frequency when the sampling interval was ≤ 60 s and short readings of lying and standing up to 1 min were converted into the preceding behavior. The best results were achieved by attaching the logger to the right hind leg.

Body temperature around induced estrus in dairy cows

The overall objective of this study was to study the influence of induced estrus on body temperature, comparing 5 distinct intervals around induced estrus and to determine the diurnal pattern from 4 ± 1 d before to 4 ± 1 d after induced estrus. Sixteen estrous cycles of 9 postpartum dairy cows were synchronized with 2 injections of PGF(2α), 10 d apart. After the second PGF(2α) injection on d 10, temperature loggers were inserted into the vaginal cavity for a 12 ± 1-d period. Two days later, a third dose of PGF(2α) was injected to induce estrus. After confirmation of a corpus luteum, loggers were removed on d 5 ± 1. Observation of estrus, rectal palpation, and ultrasound scanning to determine ovulation were carried out every 4 ± 1h, beginning at 12h after the third PGF(2α) injection. Blood samples from the vena coccygea mediana were collected twice daily from d 11 to 12 and every 4 ± 1h after the third PGF(2α) injection until ovulation. Vaginal temperature was recorded every 5 min and averaged to hourly means for the following 5 periods: 1) 48 h preceding the third PGF(2α) injection, 2) from the third PGF(2α) injection to first signs of estrus, 3) estrus to ovulation, 4) a 4-h interval in which ovulation occurred, and 5) a 96-h post-ovulation period. High body temperatures (39.0 ± 0.5 °C) and low progesterone (P4) concentrations (<0.5 ng/mL) were observed during estrus, whereas low body temperatures were observed from PGF(2α) injection to estrus (38.6 ± 0.3 °C) and around ovulation (38.5 ± 0.2 °C), respectively. An association between body temperature and serum P4 concentrations did not exist. However, P4 concentrations on d 11 and 12 were high (5.0 ± 1.5 ng/mL) and decreased (0.9 ± 0.2 ng/mL) after ovulation. Diurnal temperature rhythms were similar before and after estrus. Vaginal temperature before estrus (d 11 and 12) was slightly (0.1 °C) higher compared with the post-ovulation period.

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.

Effect of heat stress on body temperature in healthy early postpartum dairy cows

Measurement of body temperature is the most common method for an early diagnosis of sick cows in fresh cow protocols currently used on dairy farms. Thresholds for fever range from 39.4 °C to 39.7 °C. Several studies attempted to describe normal temperature ranges for healthy dairy cows in the early puerperium. However, the definition of a healthy cow is variable within these studies. It is challenging to determine normal temperature ranges for healthy cows because body temperature is usually included in the definition. Therefore, the objectives of this study were to identify factors that influence body temperature in healthy dairy cows early postpartum and to determine normal temperature ranges for healthy cows that calved in a moderate (temperature humidity index: 59.8 ± 3.8) and a hot period (temperature humidity index: 74.1 ± 4.4), respectively, excluding body temperature from the definition of the health status. Furthermore, the prevalence of fever was calculated for both periods separately. A subset of 17 (moderate period) and 15 cows (hot period) were used for analysis. To ensure their uterine health only cows with a serum haptoglobin concentration ≤ 1.1 g/L were included in the analysis. Therefore, body temperature could be excluded from the definition. A vaginal temperature logger that measured vaginal temperature every 10 min was inserted from Day 2 to 10 after parturition. Additionally rectal temperature was measured twice daily. Day in milk (2 to 10), period (moderate and hot), and time of day had an effect on rectal and vaginal temperature. The prevalence of fever (≥ 39.5 °C) was 7.4% and 28.1% for rectal temperature in the moderate and hot period, respectively. For vaginal temperature (07.00 to 11.00 h) it was 10% and 33%, respectively, considering the same threshold and period. This study demonstrates that body temperature in the early puerperium is influenced by several factors (day in milk, climate, time of day). Therefore, these factors have to be considered when interpreting body temperature measures to identify sick cows. Furthermore, the prevalence of fever considering different thresholds is higher during hot than moderate periods. However, even in a moderate period healthy cows can exhibit a body temperature that is considered as fever. This fact clearly illustrates that fever alone should not be considered the decision criterion whether a cow is allocated to an antibiotic treatment, although it is the most important one that is objectively measurable.

Relationship between bacteriological findings in the second and fourth weeks postpartum and uterine infection in dairy cows considering bacteriological results

The uterine lumen in early postpartum dairy cows is contaminated with different bacteria. The most relevant uterine pathogens are Escherichia coli and Trueperella pyogenes. Prevalence of α-hemolytic streptococci and coagulase-negative staphylococci (CNS) is also high; however, these pathogens are considered opportunistic. The overall objective of this study was to investigate effects of the intrauterine presence of E. coli, T. pyogenes, α-hemolytic streptococci, or CNS at 10±1 d in milk (DIM) on the type of bacteria 2 wk later and their influence on uterine infections and subsequent reproductive performance. Furthermore, we set out to quantify 2 relevant methodological factors (i.e., laboratory and sampling instrument). Bacteriological samples were collected at 10±1 and 24±1 DIM from the uterine lumen using a cytobrush (CB). Vaginal mucus was classified by vaginoscopy. In a subsample, bacteriological results of 3 different laboratories and of CB and cotton swabs (CS) were compared. Samples of uterine discharge were collected at 10±1 DIM and bacteriological samples were taken using CB and CS. Bacteria were identified and bacterial growth quantified on a 4-point scale. Animals infected with E. coli or T. pyogenes at 10±1 DIM had a higher risk for an infection with the same bacterial species at 24±1 DIM [E. coli relative risk (RR)=3.7 and T. pyogenes RR=2.9]. Moreover, the risk of being diagnosed with abnormal vaginal discharge at 24±1 DIM increased in cows with E. coli (RR=1.7) or T. pyogenes (RR=1.7) at 10±1 DIM. Uterine infection with α-hemolytic streptococci or CNS did not increase the risk of an infection with T. pyogenes or E. coli or abnormal vaginal discharge 2 wk later. Cows with E. coli at 10±1 DIM or T. pyogenes at 24±1 DIM had greater days to first artificial insemination than cows positive for the 3 remaining bacterial species. Cows with T. pyogenes at 10±1 DIM had more days to pregnancy and more cows were culled when positive for E. coli at 10±1 DIM. Agreement of bacteriological results of 3 different laboratories were significant for laboratory A + B and A + C for the CB and CS. The highest agreement considering the bacterial species was for E. coli. All results for laboratory A + B and A + C for the CB and CS were significant. The results generated from samples collected with CB agreed nicely with those from CS from each laboratory (laboratory A: 250/272; laboratory B: 264/272; laboratory C: 253/272).

Agreement between rectal and vaginal temperature measured with temperature loggers in dairy cows

The overall objective of this study was to evaluate agreement between rectal (RT) and vaginal temperature (VT) measured with the same temperature loggers in dairy cows. Three experiments were conducted. The study began with a validation in vitro of 24 temperature loggers comparing them to a calibrated liquid-in-glass thermometer as a reference method. The association and agreement between the 24 temperature loggers with the reference method was r=0.996 (P<0.001) with a negligible coefficient of variance (0.005) between the loggers. In-vivo temperature loggers were tested in 11 healthy post-partum cows (Experiment 2) and 12 early post-partum cows with greater body temperature (Experiment 3). Temperature loggers were set to record VT and RT at 1-min intervals. To prevent rectal and vaginal straining and potential expulsion of temperature logger an epidural injection of 2.5 ml of 2% Procain was administered. Association between RT and VT was r=0.92 (P<0.001; Experiment 2) and r=0.94 (P<0.001; Experiment 3) with a negligible difference of -0.1 and 0.01 °C. Bland-Altman plots demonstrated agreement between RT and VT for healthy and early post-partum cows with greater body temperature in Experiments 2 and 3, respectively. Furthermore the intra-class correlation coefficient between RT and VT measured with identical loggers within cows of Experiments 2 and 3 also demonstrated greater agreements (P<0.001). Therefore, continuous VT monitoring with temperature loggers can be used as a measure of body temperature in dairy cows.

Endogenous and exogenous progesterone influence body temperature in dairy cows

Three experiments were conducted to determine the effect of endogenous progesterone (P4) on body temperature comparing lactating, pregnant with lactating, nonpregnant cows, and to study the effect of exogenous P4 administered via a controlled internal drug release (CIDR) insert on body temperature in lactating dairy cows. Body temperature was measured vaginally and rectally using temperature loggers and a digital thermometer, respectively. In experiment 1, 10 cyclic lactating cows (3 primiparous, 7 multiparous) and 10 lactating, pregnant cows (3 primiparous, 7 multiparous) were included. Vaginal temperatures and serum P4 concentrations were greater in pregnant cows (vaginal: 0.3±0.01°C; P4: 5.5±0.4 ng/mL) compared with nonpregnant cows. In experiment 2, estrous cycles of 14 postpartum healthy, cyclic, lactating cows (10 primiparous, 4 multiparous) were synchronized, and cows were assigned randomly to 1 of 2 treatments (CIDR-P4 or CIDR-blank). A temperature logger was inserted 1 d after ovulation using a P4-free CIDR (CIDR-blank) and a CIDR containing 1.38g of P4 (CIDR-P4) in the control (n=7) and the P4-treated group (n=7), respectively. On d 3 after P4 treatment, vaginal temperature was 0.3±0.03°C greater compared with that on d 1 and d 5. In experiment 3, 9 cyclic multiparous lactating cows were enrolled 1±1 d after confirmed ovulation and a temperature logger inserted. Two days later, a CIDR-P4 was inserted on top of the CIDR-blank. On d 5±1 and d 7±1, respectively, the CIDR-P4 and CIDR-blank with the temperature logger were removed. During the CIDR-P4 treatment (48h), vaginal temperature was 0.2±0.05°C and 0.1±0.05°C greater than during the pre- and post-treatment periods (48h), respectively. Serum P4 concentration peaked during CIDR-P4 treatment (2.2±0.8 ng/mL) and was greater than during the pre-treatment period (0.2±0.2 ng/mL) for 48h. An increase in vaginal temperature could be due to endogenous and exogenous P4. However, a correlation between serum P4 concentrations and body temperature did not exist. Further investigations are warranted to better understand the pathways of the thermogenic effect of P4 on body temperature.

Factors associated with body temperature of healthy Holstein dairy cows during the first 10 days in milk

In this prospective observational study rectal and vaginal temperature of 82 (26 primiparous, 56 multiparous) early post-partum healthy dairy cows that calved without intervention within 3 months and did not show clinical signs of infectious and metabolic diseases were continuously measured and evaluated for associations with plausible factors during the first 10 days in milk (DIM). During May, June and July mean (±SD) temperature humidity index (THI) was 60·1±5; 66·8±5·6 and 74·2±4·3, respectively. Environmental conditions had a negligible effect on body temperature (BT) during May (P<0·05). During June and July, however, the ambient temperature and THI influenced BT (P<0·05). Furthermore, plausible factors like parity, DIM, months and time of day had an effect on BT (P<0·05). Overall, primiparous cows demonstrated 0·2°C greater BT during the first 10 DIM than multiparous cows. The effect of parity, however, on BT varied between DIM according to month (P<0·001). During this 3-month study period all cows demonstrated BT rhythms; however, the amplitude of BT increased from May to July (0·3 to 0·7°C). A greater proportion of the vaginal temperature measurements exceeded a threshold tested (≥39·5°C) during July (46·8%) than in June (33·9%) and May (19·3%). Overall the percentage of BT values above a threshold of ≥39·5°C was lower during the period 6.00-10.00 compared with the remaining 20 h (P<0·05). Therefore this study concluded that the BT of healthy post-partum dairy cows during the period 1-10 DIM post partum is greater compared with the reference range of 38·6 to 39·5°C reported by others and is influenced by parity, DIM, time of day and THI. When the association between BT and THI increased the reliability of threshold levels of BT (≥39·5°C) decreased.