Comparative evaluation of mineral profiles in different blood specimens of dairy cows at different production phases.

Background: Evaluation of mineral profiles including essential and toxic elements in dairy cows provides fundamental information for bovine practitioners during regular herd supervision and monitoring. The present research was designed to investigate the variations of mineral profiles in different blood specimens of dairy cows at different lactation stages. Methods: This study was divided into two parts: the first included 32 cows, which were classified into four groups according to their lactation stages, and the second involved 10 cows at mid-lactation. The concentrations of copper (Cu), zinc (Zn), selenium (Se), manganese (Mn), barium (Ba), strontium (Sr), calcium (Ca), magnesium (Mg), total phosphorous (P), sulfur (S), cobalt (Co), silicon (Si), lithium (Li), nickel (Ni), thallium (Tl), boron (B), aluminum (Al), uranium (U), and arsenic (As) were measured in serum, ethylene diamine tetraacetic acid (EDTA) plasma, heparin plasma, and EDTA whole blood samples. Results: The concentrations of Cu, Zn, Fe, Mn, Ba, and Sr showed significant variations among the dairy cows of different lactation stages (p < 0.05). Strong regressions were determined between the mineral concentrations in individual and pooled samples (R 2 = 0.991, p = 0.000). In comparison to other blood sample types, the concentration of Cu, Ba, and Sr was higher in EDTA plasma (p < 0.000). In addition, the values of Zn, Se, Fe, and Mn were significantly increased in heparin and EDTA whole blood samples. Concentrations of Ca and Mg, and P were higher in EDTA plasma, and EDTA whole blood samples, respectively. Furthermore, the mean values of Si, Li, Ni, and Tl showed significant increases in EDTA plasma, while S values were higher in EDTA whole blood samples (p < 0.000). Concentrations of Al and U exhibited significant increases in serum samples (p < 0.000). Conclusion: Concentrations of Cu, Zn, Fe, Mn, Ba, and Sr undergo physiological variations among dairy cows at different lactation stages. Therefore, caution should be taken during assessment of these minerals. The concentrations of essential and toxic elements, as well as Ca, P, Mg, and S, varied among the different blood sample specimens, indicating their interpretations should be based on this regard. During dairy herd supervision, the use of pool sample, instead of individual ones, for determination of mineral status may be promising to minimize the costs of individual sample measurements. In general, EDTA plasma may be more suitable for measurements of Ca, Mg, P, and S. It seems that EDTA plasma and heparinized plasma are suited for the estimation of Se and Fe, respectively.

Effects of calcium supplementation, incomplete milking, and vitamin D3 injection on serum total calcium concentration during the first 24 hours after parturition in dairy cows fed an anionic diet during late gestation.

OBJECTIVE: To evaluate various strategies for prevention of subclinical hypocalcemia (SH) during the first 24 hours after parturition in dairy cows. ANIMALS: 165 multiparous German Holstein cows from 1 herd. PROCEDURES: All cows were fed a ration with a moderate dietary cation-anion difference (approx 0 mEq/100 g of dry matter; anionic diet) for the last 2 to 3 weeks of gestation. In the first part of a 2-part study, cows were randomly assigned to 1 of 4 treatment groups (no calcium supplementation [n = 30], oral administration of a calcium bolus alone [34] or in combination with IV administration of 500 mL of a calcium solution [34] or incomplete milking during the first 24 hours after parturition [34]). In part 2, cows in their fifth or greater parity were randomly assigned to receive vitamin D3 (20,000 U/kg, IM; n = 15) 7 days before the predicted calving date or a control group (18). A calcium bolus was orally administered within 30 minutes after parturition to all cows of part 2. Serum total calcium (Cat) concentration was measured immediately after parturition and every 2 hours thereafter for 24 hours and compared among treatment groups. Subclinical hypocalcemia was defined as a Cat concentration < 2.00 mmol/L. RESULTS: In part 1, the mean ± SD Cat concentration during the 24 hours after parturition for the IV-treated group (2.28 ± 0.42 mmol/L) was greater than that for the other 3 groups, each of which had a mean Cat concentration < 2.00 mmol/L. In part 2, the mean Cat concentration for the vitamin D3-treated cows was greater than that for control cows and remained above 2.00 mmol/L for the duration of the observation period. CONCLUSIONS AND CLINICAL RELEVANCE: Intramuscular administration of vitamin D3 or IV administration of a calcium solution in combination with oral administration of a calcium bolus might alleviate SH during the first 24 hours after parturition in dairy cows fed an anionic diet during late gestation.

[Chronic oversupply with copper as a potential herd health problem on a German dairy farm - Diagnostic value of different sample types for assessment of copper supply in dairy cows]. / Chronische Kupferüberversorgung als mögliches Bestandsproblem in einer deutschen Milchviehherde.

In contrast to sheep, chronic copper oversupply or toxicity represent infrequent events in cattle. This case report describes a chronically elevated exposure to copper arising from excessive supplementation of mineral feedstuff leading to a herd health problem in a German Holstein dairy herd. For diagnosis on herd level, 10 cows of both the close-up (VB) and high-yielding (HL) groups were selected and blood as well as urine samples were collected. Clinical chemistry investigation of these samples only revealed slightly raised activities of liver enzymes in cows of the HL group. Analysis of the total mixed ration (TMR) of both groups revealed a significant oversupply with copper, zinc, cobalt, and selenium. On the basis of these findings, the copper content of urine, feces, pigmented hair as well as plasma ceruloplasmin activity were measured additionally. Liver biopsies were performed in cows of the HL group and in heifers, the latter of which had received a mineral feed for young cattle according to the manufacturer's instructions. Results indicated increased fecal copper in both HL and VB groups as well as above normal or high-normal values of hepatic copper and cobalt resp. selenium, zinc, and manganese in the HL cows. In contrast, heifers had physiological amounts of trace elements in their liver tissues. This report demonstrates the suitability of fecal analysis and TMR for a reliable assessment of copper supply, while blood, urine, and hair failed to represent appropriate sample types. In order to attain a dependable diagnosis of potential copper oversupply, a liver biopsy - which may also be performed in buiatric practice - is deemed necessary.

Evaluation of different acute-phase proteins for herd health diagnostics in early postpartum Holstein Friesian dairy cows.

This research communication describes (1) the comparison of acute-phase protein (APP) concentrations in transition dairy cows on different farms using both pooled and individual blood samples, and (2) the association among different APP and clinical health parameters. The first hypothesis was that early postpartum dairy cows from different farms differ in the level of inflammation, which might be determined using APP assays in both pooled and individual blood samples. The second hypothesis was that the APP haptoglobin (Hp) might be the most sensitive parameter to detect cows at risk of excessive postpartum inflammation concomitant with systemic disease. Serum concentrations of Hp, serum amyloid-A (SAA), total protein (TP), albumin (Alb), coeruloplasmin (Cp) and C-reactive protein (CRP) in 100 fresh lactating cows (within 0-8 d postpartum) from 10 farms were compared and associated to clinical health parameters (rectal body temperature, vaginal discharge (Metricheck™ score), rumen fill, vulvovaginal laceration) using both pooled and individual blood samples. Mean serum concentrations of Hp, SAA and TP revealed significant differences among farms. Pooled serum samples of farms showed high correlations with the mean of individual samples. Only Hp was significantly positively correlated to both body temperature and Metricheck™ score. In conclusion, Hp differentiates dairy farms regarding the inflammatory state of transition cows using individual and pooled serum samples within the first week postpartum. It also mirrors the individual degree of inflammation, thus proving to be a diagnostic parameter of high interest during the periparturient period.

24-h variations of blood serum metabolites in high yielding dairy cows and calves.

BACKGROUND: Blood profile testing is commonly used to monitor herd health status, diagnose disorders, and predict the risk of diseases in cows and calves, with subsequent optimization the production of dairy herds. By understanding the physiological ranges of serum metabolites relative to age, lactation stage, and the sampling time in healthy cows and calves, the dairy practitioners can accurately diagnose abnormalities with a blood test. The effect of sampling time on the variation of serum metabolites within 24 h were evaluated in 83 cattle. All animals were originated from a dairy herd, where the animals, based on their ages and lactation stages, were classified into eight groups. The blood samples were collected from each animal every 4 h within a day. RESULTS: The time of sampling within the day showed significant influences on the serum concentrations of glucose, ß-hydroxybutyric acid (BHBA) and urea. BHBA was the most metabolite that showed day variation among cows' groups. Furthermore, the concentrations of total cholesterol were the most stable metabolite in all groups. The mean values of albumin, total proteins, glucose, non-esterified fatty acids (NEFA), BHBA, total cholesterol, total bilirubin, urea, and creatinine revealed significant variations among the different studied groups. CONCLUSIONS: A certain suitable time of blood sample collection cannot be recommended. However, care shall be taken for the time of sampling for measurements of glucose, NEFA, BHBA and urea, otherwise the comparative values of these metabolites at different sampling time points may differ significantly from each other's, without a disease cause. It may be recommended, for metabolic assessment of dairy herds, classification the subjects into different groups based on lactation stages and ages of animals.

[Bovine trace mineral concentrations in different sample media with emphasis on fecal analysis]. / Konzentration von Spurenelementen beim Rind in verschiedenen Probenmedien unter besonderer Berücksichtigung von Kotproben.

OBJECTIVE: The objective of this study was to evaluate the suitability of feces as sample material for the evaluation of trace mineral supply in cattle. Fecal trace element concentrations of iron, copper, zinc, selenium, manganese and molybdenum were compared with those in feed. Furthermore, fecal trace element-concentrations were compared with those in various additional sample media (serum, plasma, whole blood, urine and hair). MATERIALS AND METHODS: Samples (feces, blood, urine, hair) from up to 10 cows in the close-up (3-0 weeks a. p.) and high-yielding (6-20 weeks p. p.) group each were collected during 73 farm visits on 63 dairy farms. Pooled samples of each lactation group were formed and the concentrations of trace elements were determined with ICP-OES or ICP-MS. Furthermore, TMR was analyzed. Additionally, feces from cattle in cow-calf herds during grazing and housing period were evaluated. RESULTS: Nutritional trace mineral requirements were exceeded by the majority of feeds. Trace mineral concentrations were 2- to 3-fold higher in feces than in feed. In this study, the strongest significant correlation existed between feed and fecal concentrations for all elements. Seasonal variations were detected for iron, copper and manganese. Furthermore, iron concentration differed depending on lactation stage. CONCLUSION AND CLINICAL RELEVANCE: Feed intake of the trace minerals analyzed is most optimally reflected by the fecal concentration in comparison to other substrates. Fecal analysis of these minerals may therefore be employed as an alternative to feed analysis with regards to the evaluation of nutritional trace mineral supply. Analyzing fecal trace mineral concentrations possesses practical significance wherever feed or TMR cannot be analyzed. In particular, this concerns grazing animals, heifers, mother cows and cattle in barns without TMR. Assessment of the complete metabolic status only on the basis of fecal contents is insufficient. However, subnormal fecal copper-, zinc- and manganese concentrations may be suggestive of an inadequate metabolic situation and represent an indication for further diagnostics.

[Course of the energy balance in the early lactation of Holstein-Friesian cows calculated according to 3 different models]. / Verlauf der nach 3 unterschiedlichen Formeln berechneten Energiebilanz bei Holstein-Friesian-Kühen in der Frühlaktation.

OBJECTIVE: The aim of this study was to compare the results of the energy balance of dairy cows calculated with 3 different formulas. The course of the energy balance up to the 100th lactation day in Holstein-Friesian dairy cows from a herd with a mean 305-day milk yield of 11 761 kg was to be described. MATERIALS AND METHODS: Data from a total of 193 dairy cows were available within 2 study periods. Body weight measurements were taken at fixed time points. The feed intake was determined by means of transponder-supported feeding troughs. Milk data was obtained from the corresponding milking recordings. Energy balance was determined by calculation according to the society for nutritional physiology (GfE), Jans and Kessler and National Research Council (NRC) modified according to Collard. RESULTS: The 3 models yielded very similar results. The calculation modified by Collard, however, generally led to lower values. Minimum values for energy balance were calculated in the colostrum phase. The transition from the negative to the positive energy balance occurred in the mean 53 days postpartum. CONCLUSION AND CLINICAL RELEVANCE: All 3 calculation methods were equally suitable to assess energy balance of dairy cows conveying similar results. Over 50 % of the examined cows reach a positive energy balance before the 60th day of lactation. According to the literature, the course of the energy balance with a low point around the 60th day postpartum is not to be assumed in principle for each herd. Strategies to improve negative energy balance with regard to time point, extent, and duration in the early lactation must be developed individually for each herd and still require research.

Validation of an automated assay for measurement of bovine plasma ceruloplasmin.

Ceruloplasmin (Cp) plays an important role in copper transport and iron metabolism, as well as Cp is also an indicator for the health status of dairy cows. The present study reports the validation of an automated assay to assess the plasma Cp in dairy cows. Plasma Cp levels were determined in 40 Holstein cows and intra- and inter-assay precision, accuracy, detection limit, and clinical validation of the assay were determined. Intra- and inter-assay coefficients of variation were < 2% and < 7%, respectively. The results were linear when serial sample dilutions were tested (r = 0.999, P < 0.001). The detection limit was lower than what could be measured in plasma from healthy cows. Increased plasma Cp levels were found in cows with inflammatory diseases. The method validated in this study is precise, simple, and fast and can be easily adapted to biochemical automated analysers. Furthermore, the promising results obtained with this protein will contribute to a wider use of Cp determination in bovine practice.

[Assessment of rumen fill in dairy cows for evaluation of the individual feed intake in herd management]. / Bewertung der Pansenfüllung von Milchkühen zur Beurteilung der individuellen Futteraufnahme in der Bestandsbetreuung.

OBJECTIVE: Postpartal disease complexes of dairy cows are frequently related to an insufficient feed intake around calving. The study examined the relationship between the rumen fill (RF) score and the feed intake. A further aim was to evaluate whether the RF score can be used in practice to estimate the cow's individual feed intake (in kg dry mass intake or fresh-mass intake per cow). MATERIAL AND METHODS: In pluriparous cows (n = 109), the RF was scored daily according to the schema of Zaaijer and Noordhuizen (2003) modified by half-points between day 24 (±â€…4 days) ante partum (a. p.) and day 9 post partum (p. p.) as well as on days 28 (±â€…2 days) and 60 (±â€…2 days) p. p. The individual feed intake per cow was recorded. Additionally, measurements of the feed intake were performed every 4 hours over 24 hours (24-hour daily profiles) in 21 cows a. p. and in 10 cows p. p. RESULTS: There was a significant relationship between the RF score and the feed intake both a. p. and p. p. The number of days in milk greatly influenced this relationship. Immediately p. p., there was a response in the RF score of half a score with an additional intake of 3.5 kg dry matter, while a. p., a change of the PF score only occurred when the feed uptake was reduced by 18 kg dry matter. CONCLUSION: During the first week p. p., the RF score proved to be a sensitive measuring instrument for the individual feed intake. Because of its low response a. p., it was only suitable for the detection of animals at risk with a considerably reduced feed intake over several days. CLINICAL RELEVANCE: The RF score provides the most informative value during the first week p. p. to assess the increase in feed intake in the individual cow after calving. It is recommended to score the RF daily during the first 7-9 days p. p. and to evaluate it individually to detect risk animals with a reduced feed intake. During the dry period, only cows with a significantly reduced feed intake over several days can be detected and consequently treated early to prevent disorders p. p. During lactation (evaluated on days 28 and 60 p. p.), the RF score appears to be of very limited informative value regarding the individual feed intake.

Short communication: Repeatability of intravenous glucose tolerance test traits in young Holstein-Friesian cattle.

Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices.

Effects of auditory and visual stimuli on glucose metabolism in Holstein dairy cattle.

BACKGROUND: Standardization of the intravenous glucose tolerance test (ivGTT) in cattle has received little attention despite its widespread use to monitor glucose metabolism. The impact of management practices including several sensorial stimuli on test responses has not yet been described in young cattle. The objective of this study was to analyze the effects of noise exposure, and visual food stimuli in combination with physical restraint on ivGTT and insulin traits in Holstein cattle. A total of 108 ivGTT (6 tests per animal) were performed in bulls (n = 6), steers (n = 6), and heifers (n = 6) aged 312 to 344 days. The main parameters analyzed for glucose and insulin included: basal concentration (G0, Ins0), maximum concentration (GMAX, InsMAX), and final concentration at 63 min (G63, Ins63), glucose and insulin area under the curve (GAUC, InsAUC), and glucose half-life time (GHLT). Noise stimuli were induced by playing rock music at approximately 90 dB either before (NI) or immediately after glucose injection (NII). Visual food stimuli were induced by feeding the neighboring animals while the tested animal was restrained in a headlock. RESULTS: Almost all glucose and insulin traits were affected by gender (P< 0.05) whereas the factor with least impact on ivGTT was NI. InsMAX and InsAUC were affected (P < 0.002) by all factors analyzed. GHLT and G63 were affected by gender and noise with higher values in bulls when compared to steers and heifers. Furthermore, InsAUC and InsMAX values derived from NII significantly differed in bulls when compared to steers and heifers. Significantly higher values for G0 (P < 0.001), InsMAX (P < 0.001) and InsAUC (P = 0.001) were observed when exposed to the visual food stimulus whereas GMAX (P = 0.02) and GAUC (P = 0.04) decreased. Higher Ins63 values were observed in bulls exposed to the visual food stimulus when compared to heifers. CONCLUSIONS: Short-term exposure to noise and visual food stimuli might lead to variations in glucose metabolism and insulin secretion which emphasizes the necessity to avoid practices involving auditory or visual stimuli prior to or during the conduction of an ivGTT.

Comparative evaluation of ultrasonography with clinical respiratory score in diagnosis and prognosis of respiratory diseases in weaned dairy buffalo and cattle calves.

BACKGROUND: Respiratory troubles have economic impacts in countries where livestock industry is an important segment of the agricultural sector, as well as these problems may cause significant economic losses for bovine producers. Various practical methods are used to assess diseases that affect the bovine respiratory system. Ultrasonography is a noninvasive tool that has been used frequently in diagnosis of various animal diseases. The present study was designed to establish whether thoracic ultrasonography is a diagnostic tool for detection of respiratory troubles in weaned buffalo and cattle calves, as well as to assess its prognostic value in comparison with clinical respiratory scores. Thirty five (15 buffalo and 20 cattle) calves were included. Twelve (6 buffalo and 6 cattle) clinically healthy calves were enrolled as controls. RESULTS: Based on physical examinations, clinical respiratory scores (CRS), ultrasound lung scores (ULS) and postmortem findings, animals were classified into 4 groups as pulmonary emphysema (n = 8), interstitial pulmonary syndrome (n = 7), bronchopneumonia (n = 12), and pleurisy (n = 8). The mean values of CRS and ULS were significantly higher in diseased calves (P < 0.01). In calves with pulmonary emphysema and interstitial syndrome, thoracic ultrasonography revealed numerous comet-tail artifacts, which varied in numbers and imaging features. Furthermore, variable degrees of pulmonary consolidation with alveolograms and bronchograms were noticed in bronchopneumonic calves. In addition, thick irregular or fragmented pleura with pleural effusions and fibrin shreds were imaged in calves with pleurisy. A weak correlation was calculated between CRS and ULS (r = 0.55, P < 0.01). Hematologically, the counts of white blood cells, activities of aspartate aminotransferase and partial tensions of carbon dioxide were significantly increased in all diseased groups. Serum concentrations of total globulins were higher in claves with bronchopneumonia (P < 0.05). The partial tension of oxygen was decreased in all diseased calves (P < 0.05). CONCLUSIONS: Thoracic ultrasonography is a diagnostic tool for various lung troubles and assessment the grade and severity of pulmonary diseases, as well as it can be used as a follow-up tool for evaluating the prognosis of respiratory troubles and monitoring the efficacy of therapies.

[Mineral concentrations in cattle in different sample media with emphasis on fecal analysis]. / Konzentrationen an Mengenelementen beim Rind in verschiedenen Probenmedien unter besonderer Berücksichtigung von Kotproben.

OBJECTIVE: The objective of this study was to evaluate whether the concentrations of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na) and sulfur (S) in the feces reflect the content in feeds and whether analysis of the feces provides information on the nutritional supply of the body with these elements. MATERIALS AND METHODS: For this purpose, element concentrations in feed and in serum, plasma, whole blood, urine and hair were compared. During 73 farm visits on 63 dairy farms, samples were collected from up to 10 cows in both the close-up (3-0 weeks a. p.) and high-yielding (6th-20th week p. p.) groups. Concentrations of Ca, P, Mg, K, Na and S were determined in pooled samples of each lactation group and in a sample of the total mixed ration (TMR) by ICP-OES. Additionally, feces from beef cows during the grazing and housing periods were analyzed. RESULTS: Mineral concentrations in feed samples were sufficiently high to meet the nutritional requirements. Mineral concentrations were higher in feces than in feed, with the exception of Na and K. There were significant correlations between feed and fecal concentrations for all elements, whereby the correlations between the TMR and urine concentrations were higher for K, Na and S. Seasonal variations were detected in all elements, with the exception of Ca. Furthermore, Ca, P, Mg and S concentrations differed depending on the stage of lactation. CONCLUSION: The fecal concentration of Ca, P and Mg best reflect the intake with the feed in comparison to other substrates. Fecal analysis of these elements can, therefore, be applied as an alternative to feed analysis regarding the evaluation of the nutritional mineral supply. Assessment of the metabolic status only on the basis of the fecal contents is insufficient. The urine Mg concentration provides information regarding Mg metabolic status. Furthermore, urine is the substrate of choice for the evaluation of the K and Na metabolic status. The most useful information about S nutritional and metabolic status is provided by combining the results of fecal and urinary examinations.

Evaluation of glucose dose on intravenous glucose tolerance test traits in Holstein-Friesian heifers.

Glucose metabolism in dairy and beef cattle has received considerable attention because balanced blood glucose is essential for numerous processes, such as milk production and general health. The glucose tolerance test measures the ability of an organism to regulate blood glucose levels. Glucose half-life time (GHLT) has high heritability and could serve as a potential parameter to breed for metabolic resistance. However, studies focusing on identification of an adequate glucose dose have not yet been conducted in cattle. The objective of this study was to analyze the effect of 5 different glucose doses (0.5, 1, 1.5, 2, and 3 g/kg of body weight0.75) on intravenous glucose tolerance test (ivGTT) traits and insulin responses in nongestating heifers. A total of 150 tests were performed in 30 Holstein-Friesian heifers aged 13 to 15 mo. Blood samples were obtained every 7 min after glucose injection until min 63. Glucose traits and insulin parameters included blood serum glucose and insulin concentration at min 0 (basal concentration), min 7 to 21 (peak glucose and insulin concentration), and min 63 (last sampling) relative to glucose administration, glucose and insulin area under the curve (GAUC and IAUC), and GHLT estimated between min 14 and 42. Serum glucose and insulin concentrations were measured according to the hexokinase colorimetric method and radioimmunoassay, respectively. Generalized linear mixed model was used to test for significant differences in ivGTT traits, insulin responses, and glucose elimination rates (k) over time at different glucose doses. Maximum glucose and insulin concentrations at min 63 increased with higher glucose doses. Significantly lower GHLT were obtained at increasing glucose doses, whereas GAUC and IAUC were significantly higher at increasing doses. The k values were affected by glucose dose and by time interval. Glucose dose greatly affected most ivGTT traits, insulin responses, and glucose elimination rates. Therefore, researchers should standardize their methods to achieve repeatable results and use the same time points for GHLT calculation. Higher glucose doses (≥1.5 g/kg of body weight0.75) triggered glucose concentrations above the glucose renal threshold during the initial 42 min, whereas the lowest glucose concentration failed to induce a maximum insulin response. Further research is necessary to determine an adequate dose inducing maximum insulin responses with minimum renal glucose losses.

[Factors influencing the quality of the first colostrum in Holstein Friesian cows and their relationship to postpartum calcium concentrations in the blood and colostrum]. / Einflussfaktoren auf die Immunglobulinkonzentration im Erstkolostrum bei Holstein-Friesian-Milchkühen und deren Beziehung zur postpartalen Kalziumkonzentration im Blut und Kolostrum.

OBJECTIVE: To investigate the factors that affect the quality (immunoglobulin concentration) of the first colostrum in Holstein Friesian cows and their relationship to the calcium concentrations in the blood and colostrum, with particular attention to the lactation number. MATERIAL AND METHODS: An observational study was conducted at a commercial dairy farm (2278 Holstein Friesian cows). The analysis comprised the following variables: colostrum content of immunoglobulins and calcium, colostrum yield; blood serum concentrations of calcium, phosphate, non-esterified fatty acids, and ß-hydroxybutyrate; back-fat thickness; daily milk production; calving data; lactation number; male parent of the cow; length of gestation; age at first calving; duration of the dry period; fertility parameters of prelactation; diseases during the dry period and up to 3 days postpartum. A stepwise analysis of the data for correlations and influencing factors was conducted by means of variance, correlation and multiple linear-regression analyses. RESULTS: The mean colostral immunoglobulin concentration was 65.6 g/l with a standard deviation of 10.67 g/l. The most influential factor was the genetic background (male parent), followed by colostrum quantity and duration of the dry period. Together, these factors explained 47% of the variation of the colostral immunoglobulin content. A dominant effect of the lactation number was not confirmed. Additionally, the calcium concentrations of the blood and colostrum had no influence on colostrum quality. CONCLUSION AND CLINICAL RELEVANCE: By selecting bulls, whose daughters give colostrum with a high immunoglobulin concentration, the colostrum quality of the herd can be increased. A high amount of colostrum and a short or a lack of a dry period can cause a lower immunoglobulin concentration. On well-managed dairy farms, a very high colostrum quality can be expected. There is only a limited possibility for improvement of the immunoglobulin concentration with respect to the indicated factors.

Analytical validation of bovine plasma ceruloplasmin measurement by p-phenylenediamine oxidation and effect of storage time and freezing temperature.

BACKGROUND: Determination of ceruloplasmin (Cp) activity in plasma can provide an objective measure of the health of dairy cows as well as it can be used for various diagnostic purposes. The current study was designed to perform an analytical validation of a method for the determination of plasma Cp activity in dairy cows and to evaluate the influences of plasma storage times and temperatures as well as freeze-thaw cycles on the activity of this enzyme. This cohort was carried out on ten cows. For each cow, 24 aliquots of plasma, which were stored at different temperature regimes, were prepared. Both intra- and interassay coefficients of variation (CVs) were determined. The linearity was evaluated using bovine plasma Cp standard. RESULTS: The mean values of intra- and interassay CVs were 1.08 and 2.12%, respectively. Results of linearity testing showed a high correlation coefficient (r = 0.998, P < 0.001). After 3 days of storage at room temperature and refrigeration, the plasma activity of Cp was significantly lowered (P < 0.05). Plasma samples kept at freezing for 3 months revealed insignificant changes in the activity of Cp. Repeated freeze-thaw cycles for three times had no significant influence on the activity of Cp. CONCLUSIONS: The method is easy and may be valid at values of Cp ranging from 100 to 1000 mg/L. It seems that keeping of plasma samples at room temperature and refrigeration longer than 3 days is unsuitable for Cp measurement. In addition, Cp remains stable in plasma samples stored at freezing as well as repeat freeze-thaw cycles.

[Factors influencing first-colostrum calcium concentration in Holstein-Friesian cows and the relationship to postpartum calcium concentration]. / Einflussfaktoren auf die Kalziumkonzentration im Erstkolostrum bei Holstein-Friesian-Kühen und deren Beziehung zur postpartalen Kalziumkonzentration im Blut.

OBJECTIVE: To investigate the factors that affect the calcium content of the first colostrum (milk exclusively of the first withdrawal) and the relationship to the blood calcium concentration. We tested the hypotheses that the lactation number is the main influence factor and that there is a relationship to the postpartum serum calcium concentration. MATERIAL AND METHODS: An observational study was conducted from April 2012 to March 2013 at a commercial dairy farm (2278 Holstein-Friesian cows). The analysis comprised the following variables: blood serum concentrations of calcium, phosphate, non-esterified fatty acids, and ß-hydroxybutyrate; back-fat thickness; daily milk production; calving data; lactation number; male parent of the cow; length of gestation; age at first calving; dry-period duration; fertility parameters of prelactation; diseases during the dry period and up to 3 days postpartum. A stepwise analysis of the data for correlations and influencing factors was conducted by means of variance, correlation, and multiple linear regression analyses. RESULTS: The mean calcium concentration of the colostrum was 2386 mg/l (standard deviation 550 mg/l), with heifers having a higher value by 148.5 mg/l than pluriparous cows. Factors influencing the colostrum calcium content were the mean milk production during the first week of lactation and the back-fat thickness at drying off. The correlation to the milk production was negative, which may be a dilution effect. An increase in back-fat thickness caused an increase in the colostrum calcium concentration. Together, these two factors explained 25% of the colostrum calcium variation. The lactation number and the blood calcium concentration were not significant influence factors on the colostrum calcium content. CONCLUSION AND CLINICAL RELEVANCE: The hypotheses could not be confirmed in that there was neither a relationship of to the blood calcium concentration nor of the lactation number with the colostrum calcium content. The colostrum calcium content displayed a wide individual variation. However, there was a possible influence through milk production and back-fat thickness, but this would not be beneficial with regard to prophylaxis of parturient paresis.

Influence of food deprivation on intravenous glucose tolerance test traits in Holstein Friesian heifers.

Glucose is essential for numerous cellular functions due to its involvement in energy supply from early development to adulthood. In the lactating cow, glucose demands by the mammary gland significantly increase to support milk production when compared with other tissues. Thus, insufficient blood glucose levels might predispose dairy cows to metabolic disturbances. The intravenous glucose tolerance test (ivGTT) is a suitable tool to characterize glucose metabolism and insulin responses, but results must be reliable and repeatable. One factor influencing ivGTT is food deprivation period, which has been considered as an obligatory requirement before conduction of glucose tolerance studies in monogastric species, whereas it has been permissive in ruminants. The objective of this study was to determine the influence of 5 fasting periods (0, 12, 24, 36, and 48 h) on ivGTT traits and insulin responses in German Holstein heifers. A total of 140 tests were conducted in 28 females aged 12 to 19 mo. Blood samples were collected every 7 min within 1 h. Assessed glucose and insulin parameters included basal serum glucose and insulin concentration, maximum glucose and insulin concentration obtained between min 7 to 21, and concentrations at min 63 (last sampling) relative to glucose administration, glucose area equivalent (GA), glucose area under the curve (GAUC), insulin area equivalent (InsA), insulin area under the curve (InsAUC), and blood glucose half-life time (GHLT). Serum glucose and insulin concentration were measured according to the hexokinase colorimetric method and solid phase radio immunoassay, respectively. The generalized linear mixed model was used to test for significant differences in all glucose traits and insulin responses at different fasting periods. The model used season and weight as confounding variables. Glucose and insulin concentrations at 0, 7 to 21 (maximum concentration), and 63 min were affected by the duration of food deprivation. The GA, InsA, GAUC, InsAUC, and especially GHLT were also affected by fasting period. A positive linear relationship between GHLT and length of food deprivation was found. Significantly higher GA, GAUC, GHLT values, and glucose and insulin concentration at min 63 were obtained at increasing fasting periods. High intraclass correlation coefficient (0.48) was found for GHLT. The results demonstrate that GHLT might be used to reliably characterize an individual's glucose metabolism and the importance of standardizing food deprivation schedules when performing an ivGTT in nongestating Holstein heifers.

[Zinc concentrations in different sample media from dairy cows and establishment of reference values]. / Untersuchungen zur Zinkkonzentration in unterschiedlichen Probenmedien von Milchkühen und Ableitung von Referenzwerten.

OBJECTIVE: Zinc plays an important role in many body functions, including health and fertility. The assessment of the zinc supply can be performed using blood, urine and hair. The objective of this study was to establish reference values for herd analysis for the different sample media and stages of lactation in German dairy herds. MATERIALS AND METHODS: The data of 1515 herds, which had been visited by the Clinic for Ruminant and Swine, Free University of Berlin, Germany, between 1995 and 2012 were analyzed. Serum, plasma, whole-blood, hair and urine zinc concentrations of pooled samples with 7 to 10 cows per group were determined. In herds with more than 200 cows, five groups were sampled (8-3 weeks ante partum [a. p.], 3-0 weeks a. p., 0-1 week post partum [p. p.], 3-5 weeks p. p. and 15-18 weeks p. p.). In herds with fewer than 200 cows, only four groups were sampled (8-3 weeks a. p., 3-0 weeks a. p., 0-5 weeks p. p. and 6-20 weeks p. p.). RESULTS: Correlations among zinc concentrations in different sample media varied between r = 0.001 (whole blood and urine) and r = 0.75 (serum and plasma). Serum and plasma zinc concentrations changed rapidly and followed a lactation dynamic, with the lowest values around parturition. Whole-blood and hair zinc concentrations changed slowly but displayed a similar decrease a few weeks after parturition. Reference values for pooled samples for the different sample media and stages of lactation are proposed. CONCLUSION AND CLINICAL RELEVANCE: When assessing the zinc supply, different reference values have to be applied for the different sample media and stages of lactation. For repeated analysis to evaluate changes in zinc nutritional status, the same sample medium and stage of lactation should be used.

Randomized, blinded, controlled clinical trial shows no benefit of homeopathic mastitis treatment in dairy cows.

Mastitis is one of the most common diseases in dairy production, and homeopathic remedies have been used increasingly in recent years to treat it. Clinical trials evaluating homeopathy have often been criticized for their inadequate scientific approach. The objective of this triple-blind, randomized controlled trial was to assess the efficacy of homeopathic treatment in bovine clinical mastitis. The study was conducted on a conventionally managed dairy farm between June 2013 and May 2014. Dairy cows with acute mastitis were randomly allocated to homeopathy (n = 70) or placebo (n = 92), for a total of 162 animals. The homeopathic treatment was selected based on clinical symptoms but most commonly consisted of a combination of nosodes with Streptococcinum, Staphylococcinum, Pyrogenium, and Escherichia coli at a potency of 200c. Treatment was administered to cows in the homeopathy group at least once per day for an average of 5 d. The cows in the placebo group were treated similarly, using a placebo preparation instead (lactose globules without active ingredients). If necessary, we also used allopathic drugs (e.g., antibiotics, udder creams, and anti-inflammatory drugs) in both groups. We recorded data relating to the clinical signs of mastitis, treatment, time to recovery, milk yield, somatic cell count at first milk recording after mastitis, and culling. We observed cows for up to 200 d after clinical recovery. Base-level data did not differ between the homeopathy and placebo groups. Mastitis lasted for an average of 6 d in both groups. We observed no significant differences in time to recovery, somatic cell count, risk of clinical cure within 14 d after disease occurrence, mastitis recurrence risk, or culling risk. The results indicated no additional effect of homeopathic treatment compared with placebo. The advantages or disadvantages of homeopathy should be carefully assessed for individual farms.