Blood Blood Β-hydroxybutyrate Research Articles

Predicting blood β-hydroxybutyrate using milk Fourier transform infrared spectrum, milk composition, and producer-reported variables with multiple linear regression, partial least squares regression, and artificial neural network

Prediction of postpartum hyperketonemia (HYK) using Fourier transform infrared (FTIR) spectrometry analysis could be a practical diagnostic option for farms because these data are now available from routine milk analysis during Dairy Herd Improvement testing. The objectives of this study were to (1) develop and evaluate blood β-hydroxybutyrate (BHB) prediction models using multivariate linear regression (MLR), partial least squares regression (PLS), and artificial neural network (ANN) methods and (2) evaluate whether milk FTIR spectrum (mFTIR)-based models are improved with the inclusion of test-day variables (mTest; milk composition and producer-reported data). Paired blood and milk samples were collected from multiparous cows 5 to 18 d postpartum at 3 Wisconsin farms (3,629 observations from 1,013 cows). Blood BHB concentration was determined by a Precision Xtra meter (Abbot Diabetes Care, Alameda, CA), and milk samples were analyzed by a privately owned laboratory (AgSource, Menomonie, WI) for components and FTIR spectrum absorbance. Producer-recorded variables were extracted from farm management software. A blood BHB ≥1.2 mmol/L was considered HYK. The data set was divided into a training set (n = 3,020) and an external testing set (n = 609). Model fitting was implemented with JMP 12 (SAS Institute, Cary, NC). A 5-fold cross-validation was performed on the training data set for the MLR, PLS, and ANN prediction methods, with square root of blood BHB as the dependent variable. Each method was fitted using 3 combinations of variables: mFTIR, mTest, or mTest + mFTIR variables. Models were evaluated based on coefficient of determination, root mean squared error, and area under the receiver operating characteristic curve. Four models (PLS-mTest + mFTIR, ANN-mFTIR, ANN-mTest, and ANN-mTest + mFTIR) were chosen for further evaluation in the testing set after fitting to the full training set. In the cross-validation analysis, model fit was greatest for ANN, followed by PLS and MLR. Diagnostic strength after cross-validation was poorest for MLR and was similar for ANN and PLS. Models that used mTest + mFTIR variables performed marginally better than models that used only mFTIR or mTest variables. These results suggest that blood BHB prediction models that use mFTIR + mTest variables may be useful additions to existing HYK diagnostic and management programs.

Technical note: Validation of the BHBCheck blood β-hydroxybutyrate meter as a diagnostic tool for hyperketonemia in dairy cows

Accurate cow-side blood β-hydroxybutyrate (BHB) detection meters are valuable tools for rapid diagnosis of hyperketonemia. The main objective of this study was to compare the blood BHB measured in whole blood by the BHBCheck meter (PortaCheck, Moorestown, NJ) to a previously validated meter, Precision Xtra meter (Abbott Laboratories, Abbott Park, IL) and a colorimetric laboratory assay. Samples (n = 426) were collected from postpartum primiparous and multiparous Holstein cows (n = 79 cows) enrolled in 1 of 2 experiments (Exp) with different sampling schedules (Exp 1: n = 39 cows, 58 samples; Exp 2: n = 40 cows, 368 samples). In both Exp, whole-blood samples were collected from the coccygeal vessels after morning milking, before morning feeding. Blood samples were used immediately for BHB quantification via the BHBCheck meter and the Precision Xtra meter. Blood was also collected into evacuated tubes containing no additive (Exp 1) or potassium oxalate/sodium fluoride (Exp 2), which were centrifuged for serum or plasma separation and stored at -20°C for subsequent analysis. Laboratory quantification of BHB concentration was done by the BHB LiquiColor Assay (EKF Diagnostics-Stanbio, Boerne, TX; certified for serum and plasma). Data were analyzed by UNIVARIATE, CORR, FREQ, REG, and LOGISTIC procedures of SAS 9.4 (SAS Institute Inc., Cary, NC). Within this sample set, average parity was 3.3 lactations and DIM was 14 d. The proportion of samples classified as hyperketonemia (BHB ≥1.2 mmol/L) was 25, 28, and 31% as determined by the colorimetric assay, BHBCheck meter, and Precision Xtra meter, respectively. The correlation for BHBCheck meter BHB concentration compared with the colorimetric assay concentrations was r = 0.96, with a sensitivity of 91% and specificity of 93%. Correlation, sensitivity, and specificity of the Precision Xtra meter concentrations were 0.97, 98%, and 92%, respectively. Bland-Altman plots demonstrated minimal bias for both meters. Area under the receiver operator characteristic curve suggests adequate diagnostic accuracy of both meters. Overall, accuracy, sensitivity, and specificity of the BHBCheck meter was similar to the Precision Xtra meter and laboratory assay, indicating the BHBCheck meter is appropriate for use as a cow-side diagnostic test for hyperketonemia in dairy cows.

Effect of two treatment protocols for ketosis on the resolution, postpartum health, milk yield, and reproductive outcomes of dairy cows

We determined the effect of ketosis treatment with propylene glycol (PG) or PG plus l-carnitine and methionine (Metabolase®, Fatro, Bologna, Italy) on the resolution, postpartum health, milk yield, and reproductive performances of dairy cows. Blood from 475 Holstein cows was collected weekly until 4 weeks after calving to measure blood β-hydroxybutyrate (BHBA) concentrations. Cows with blood BHBA concentration ≥1.2 mmol/L were diagnosed with ketosis and were enrolled. One hundred and fifty cows diagnosed with ketosis were randomly assigned to three treatment groups (Day 0): (1) PG (300 g, PO) for 3 days (PG group, n = 50), (2) PG (300 g, PO) plus l-carnitine (1.25 g) plus methionine (5 g, IV) for 3 days (PG + CM group, n = 50), and (3) no treatment (control group, n = 50). On Day 3, blood was collected to evaluate whether the ketosis had resolved. Cows in the PG and PG + CM groups with blood BHBA ≥1.2 mmol/L were retreated for an additional 2 days, and then blood BHBA concentration was evaluated on Days 5 and 10. Blood glucose and haptoglobin concentrations, rumen fill score (RFS), and body condition score (BCS) were measured on Days 0, 3, 5, and 10. Postpartum complications, milk yield during the first 2 months, and reproductive outcomes were evaluated. The probability of resolution from ketosis was higher (P < 0.05) in the PG + CM group than in the control group on Days 3, 5, and 10 (odds ratio: 2.6–6.3). Blood BHBA in the PG + CM group was lower (P < 0.05) than that of the control group on Days 3 and 5, whereas blood glucose in the PG + CM group was higher (P < 0.05) than that of the control group on Days 3 and 5. RFS in the PG and PG + CM groups was higher than that of the control group on Day 10 (P < 0.01), while BCS loss from Day 0–10 in the control group was higher than those of the PG and PG + CM groups (P < 0.05). Milk yields on the 30th and 60th days postpartum were higher in the PG + CM group than the control and PG groups (P < 0.05). Postpartum complications and intervals between calving and first postpartum insemination or pregnancy did not differ among the groups (P > 0.05). In conclusion, treatment of dairy cows with PG plus l-carnitine and methionine improved the chances of resolution of ketosis and increased milk yield, while affecting neither the incidence of postpartum complications nor reproductive performance.

Accuracy of a cow-side test for the diagnosis of hyperketonemia and hypoglycemia in lactating dairy cows

The objective of this study was to evaluate the use of a cow-side device (FreeStyle Precision Neo™) to diagnose ketosis and hypoglycemia based on measures of blood β-hydroxybutyrate (BHBA) and glucose. Eleven commercial dairy farms were visited and blood samples were taken from Holstein cows between 2 and 14days in milk, yielding 441 samples for BHBA analysis and 308 samples for glucose analysis. Concentrations of BHBA and glucose were measured in two ways, 1) using the cow-side device with whole blood immediately after sampling and 2) serum samples analyzed with a standard laboratory assay (Animal Health Laboratory, University of Guelph, Canada). The accuracy of the device was determined by comparing the results to the laboratory method as well as the ability to diagnose ketosis (BHBA ≥1.2mmol/L) and hypoglycemia (glucose <2.5mmol/L). The concordance correlation coefficient (CCC), Bland-Altman plot and Kappa coefficient were calculated to evaluate agreement between the 2 methods using SAS (version 9.3). The CCC was 0.92 for BHBA and 0.56 for glucose measurements. The 95% confidence intervals of the Bland-Altman plot encompassed 97% and 95% of the mean difference between methods for BHBA and glucose measurements, respectively. The Kappa coefficients were 0.78 for BHBA and 0.23 for glucose measurements. These results indicate that the cow-side device is accurate for rapid measurement of blood BHBA and diagnosis of ketosis on farms but is not accurate for measurement of blood glucose concentrations and diagnosis of hypoglycemia.

Genetic parameters of blood β-hydroxybutyrate predicted from milk infrared spectra and clinical ketosis, and their associations with milk production traits in Norwegian Red cows

The aim of this study was to estimate genetic parameters for blood β-hydroxybutyrate (BHB) predicted from milk spectra and for clinical ketosis (KET), and to examine genetic association of blood BHB with KET and milk production traits (milk, fat, protein, and lactose yields, and milk fat, protein, and lactose contents). Data on milk traits, KET, and milk spectra were obtained from the Norwegian Dairy Herd Recording System with legal permission from TINE SA (Ås, Norway), the Norwegian Dairy Association that manages the central database. Data recorded up to 120 d after calving were considered. Blood BHB was predicted from milk spectra using a calibration model developed based on milk spectra and blood BHB measured in Polish dairy cows. The predicted blood BHB was grouped based on days in milk into 4 groups and each group was considered as a trait. The milk components for test-day milk samples were obtained by Fourier transform mid-infrared spectrometer with previously developed calibration equations from Foss (Hillerød, Denmark). Veterinarian-recorded KET data within 15 d before calving to 120 d after calving were used. Data were analyzed using univariate or bivariate linear animal models. Heritability estimates for predicted blood BHB at different stages of lactation were moderate, ranging from 0.250 to 0.365. Heritability estimate for KET from univariate analysis was 0.078, and the corresponding average estimate from bivariate analysis with BHB or milk production traits was 0.002. Genetic correlations between BHB traits were higher for adjacent lactation intervals and decreased as intervals were further apart. Predicted blood BHB at first test day was moderately genetically correlated with KET (0.469) and milk traits (ranged from -0.367 with protein content to 0.277 with milk yield), except for milk fat content from across lactation stages that had near zero genetic correlation with BHB (0.033). These genetic correlations indicate that a lower BHB is genetically associated with higher milk protein and lactose contents, but with lower yields of milk, fat, protein, and lactose, and with lower frequency of KET. Estimates of genetic correlation of KET with milk production traits were from -0.333 (with protein content) to 0.178 (with milk yield). Blood BHB can routinely be predicted from milk spectra analyzed from test-day milk samples, and thereby provides a practical alternative for selecting cows with lower susceptibility to ketosis, even though the correlations are moderate.

An attempt at predicting blood β-hydroxybutyrate from Fourier-transform mid-infrared spectra of milk using multivariate mixed models in Polish dairy cattle.

Fourier transform mid-infrared (FT-MIR) spectra of milk are commonly used for phenotyping of traits of interest through links developed between the traits and milk FT-MIR spectra. Predicted traits are then used in genetic analysis for ultimate phenotypic prediction using a single-trait mixed model that account for cows' circumstances at a given test day. Here, this approach is referred to as indirect prediction (IP). Alternatively, FT-MIR spectral variable can be kept multivariate in the form of factor scores in REML and BLUP analyses. These BLUP predictions, including phenotype (predicted factor scores), were converted to single-trait through calibration outputs; this method is referred to as direct prediction (DP). The main aim of this study was to verify whether mixed modeling of milk spectra in the form of factors scores (DP) gives better prediction of blood β-hydroxybutyrate (BHB) than the univariate approach (IP). Models to predict blood BHB from milk spectra were also developed. Two data sets that contained milk FT-MIR spectra and other information on Polish dairy cattle were used in this study. Data set 1 (n = 826) also contained BHB measured in blood samples, whereas data set 2 (n = 158,028) did not contain measured blood values. Part of data set 1 was used to calibrate a prediction model (n = 496) and the remaining part of data set 1 (n = 330) was used to validate the calibration models, as well as to evaluate the DP and IP approaches. Dimensions of FT-MIR spectra in data set 2 were reduced either into 5 or 10 factor scores (DP) or into a single trait (IP) with calibration outputs. The REML estimates for these factor scores were found using WOMBAT. The BLUP values and predicted BHB for observations in the validation set were computed using the REML estimates. Blood BHB predicted from milk FT-MIR spectra by both approaches were regressed on reference blood BHB that had not been used in the model development. Coefficients of determination in cross-validation for untransformed blood BHB were from 0.21 to 0.32, whereas that for the log-transformed BHB were from 0.31 to 0.38. The corresponding estimates in validation were from 0.29 to 0.37 and 0.21 to 0.43, respectively, for untransformed and logarithmic BHB. Contrary to expectation, slightly better predictions of BHB were found when univariate variance structure was used (IP) than when multivariate covariance structures were used (DP). Conclusive remarks on the importance of keeping spectral data in multivariate form for prediction of phenotypes may be found in data sets where the trait of interest has strong relationships with spectral variables.

The effect of different treatments for early-lactation hyperketonemia on blood β-hydroxybutyrate, plasma nonesterified fatty acids, glucose, insulin, and glucagon in dairy cattle.

Despite increased efforts in preventing the occurrence of metabolic disorders in transition cows, hyperketonemia remains a frequent early-lactation metabolic disease affecting an average of 40% of cows in herds in the United States. Despite the demonstrated economic effect of this disorder, controlled clinical trials comparing different treatment strategies in affected cows are lacking. The objective of our study was to investigate the effect of treatment with intravenous glucose, oral propylene glycol, or a combination of both on the reduction in blood β-hydroxybutyrate (BHB) concentrations of early-lactation hyperketonemic dairy cows. Multiparous Holstein cows between 3 to 9 d in milk were screened for hyperketonemia using a handheld meter 3 times per week, and enrolled at whole blood BHB concentration ≥1.2 mmol/L to 1 of 4 treatment groups: (1) 500 mL of a 50% dextrose solution i.v. once daily for 3 d (GLU, n = 9), (2) 300 mL of propylene glycol as a drench once daily for 3 d (PG, n = 9), (3) a combination treatment of a 500 mL of 50% dextrose solution i.v. and 300 mL of propylene glycol orally once daily for 3 d (GLU+PG, n = 8), or (4) an untreated control group (CTRL, n = 8). Blood samples were collected immediately before as well as at 1, 2, 4, 8, 12, 24, 36, 48, 60, and 72 h after administration of the first treatment through a jugular catheter and 3 times per week thereafter from coccygeal vessels. Concentrations of BHB were measured in whole blood, and plasma samples were analyzed for glucose, fatty acid (NEFA), insulin, glucagon, and electrolyte concentrations. The EDTA-anticoagulated blood samples were assessed for red blood cell indices, and smears were made for evaluation of red blood cell morphology. Outcomes were analyzed using repeated measures analysis. Overall least squares means (95% CI) of whole blood BHB concentrations between 1 h and d 11 relative to first treatment were 1.11 (0.95 to 1.30), 1.26 (1.07 to 1.47), 0.96 (0.81 to 1.13), and 1.53 (1.30 to 1.80) mmol/L for the GLU, PG, GLU+PG, and CTRL groups, respectively. Treatment with both glucose and propylene glycol led to a greater magnitude and more prolonged decrease in BHB concentrations compared with individual treatments. The NEFA and glucagon concentrations were lower immediately after treatment in GLU and GLU+PG groups compared with CTRL, and treatment with both glucose and propylene glycol was associated with a greater increase in glucose and insulin concentrations immediately after treatment compared with CTRL and GLU treatment alone. Treatments did not lead to differences in plasma mineral concentrations. We conclude that treatments varied in the magnitude of decreasing blood BHB concentrations in hyperketonemic postpartum cows, with the greatest decline after treatment with a combination of intravenous glucose and oral propylene glycol.

Randomized clinical field trial on the effects of butaphosphan-cyanocobalamin and propylene glycol on ketosis resolution and milk production

The purpose of this study was to determine the effects of a butaphosphan-cyanocobalamin combination product (B+C) and 2 durations of propylene glycol treatment (PG; 3 versus 5 d) on ketosis resolution and early lactation milk yield. Cows from 9 freestall herds (8 in Ontario and 1 in Michigan) were tested at weekly intervals between 3 and 16 d in milk. Ketosis was defined as blood β-hydroxybutyrate (BHB) ≥1.2 mmol/L. Ketotic cows were randomly assigned to treatment with 25 mL of B+C or 25 mL of saline placebo for 3 d and 3 or 5 d of 300 g of PG orally in a 2 × 2 factorial arrangement. Outcomes evaluated for all farms included ketosis cure (blood BHB <1.2 mmol/L at 1 wk after enrollment), maintenance of ketosis cure (blood BHB <1.2 mmol/L 1 and 2 wk after enrollment), and blood BHB concentrations at 1 and 2 wk after enrollment. Daily milk weights were collected in 3 herds. Poisson regression was used to evaluate cure and maintenance of cure, whereas repeated-measures ANOVA was used to evaluate blood BHB concentrations in the 2 wk after enrollment and average daily milk production in the 30 d after treatment. A total of 594 animals were enrolled in the study with 124 treated with B+C and 5 d of PG, 176 treated with B+C and 3 d of PG, 128 treated with saline and 5 d of PG, and 166 treated with saline and 3 d of PG. Animals with blood BHB >2.4 mmol/L at the time of enrollment were 1.7 times more likely [95% confidence interval (CI): 1.4 to 2.2] to cure and had a decrease of 0.25 ± 0.11 mmol/L blood BHB at 1 wk after enrollment if treated with 5 d of PG compared with 3 d, though this response was not seen in animals with BHB of 1.2 to 2.4 mmol/L at enrollment. Cows with blood glucose concentrations <2.2 mmol/L at enrollment produced 3.1 kg/d (95% CI: 1.3 to 5.0) more milk if treated with B+C and 3.4 kg/d (95% CI: 1.7 to 5.1) more milk if treated with 5 d of PG compared with their respective controls. This response was not seen in animals with blood glucose ≥2.2 mmol/L at enrollment and there was no interaction between treatments. These results indicate that extended PG treatment is beneficial in decreasing blood BHB concentrations in more severely affected animals. Additionally, both B+C treatment and extended PG treatment improved milk yield in animals with low blood glucose at the time of ketosis diagnosis.

Effects of a combination butaphosphan and cyanocobalamin product and insulin on ketosis resolution and milk production

The objective of this study was to determine the effects of butaphosphan-cyanocobalamin (B+C), glargine insulin, and propylene glycol on resolution of ketosis and average daily milk yield after treatment. Cows from 16 herds in Ontario, Canada, and 1 herd in Michigan were tested at weekly intervals between 3 and 16 DIM. Ketosis was defined as blood β-hydroxybutyrate (BHB) ≥1.2 mmol/L. All ketotic cows were given a baseline treatment of 3 d of 300 g of propylene glycol orally. Animals were then randomly assigned to treatment with 3 doses of either 25 mL of B+C or 25 mL of saline placebo and 1 dose of either 2 mL (200 IU) of glargine insulin or 2 mL of saline placebo in a 2 × 2 factorial arrangement. Outcomes of interest on all farms were ketosis cure (blood BHB <1.2 mmol/L 1 wk postenrollment), maintenance of ketosis cure (blood BHB <1.2 mmol/L 1 and 2 wk postenrollment), and blood BHB concentrations at 1 and 2 wk postenrollment. Milk weights were collected daily in 1 large freestall herd. Repeated measures ANOVA was used to evaluate blood BHB concentrations 2 wk after treatment and milk production for 30 d after treatment. Poisson regression was used to examine the effect of treatment on cure and maintenance of cure. Due to a regulatory delay causing temporary unavailability of B+C in Canada, data were analyzed in 2 sets of models: one for insulin and the corresponding placebo (n = 620) and one for the full trial (n = 380). Animals with blood glucose concentrations ≤2.2 mmol/L at the time of ketosis diagnosis were 2.1 times more likely (95% CI = 1.2 to 3.7) to be cured if treated with B+C. Animals in lactation 3 or higher that had blood glucose concentrations <2.2 mmol/L at enrollment produced 4.2 kg/d (95% CI = 1.4 to 7.1) more milk if treated with insulin versus placebo and 2.8 kg/d (95% CI = 0.9 to 4.7) more milk if treated with B+C versus placebo. Animals in lactation 3 or higher with blood glucose ≥2.2 mmol/L that were treated with insulin produced 2.3 kg/d (95% CI = 0.3 to 4.4) less milk than untreated controls. No interaction was observed between treatments. This evidence suggests that B+C and insulin may be beneficial for ketosis treatment in animals with blood glucose <2.2 mmol/L at ketosis diagnosis. It also suggests that blood glucose concentration may be an important predictor of success of ketosis treatment.

β-Hydroxybutyrate (BHB) and glucose concentrations in the blood of dairy calves as influenced by age, vaccination stress, weaning, and starter intake including evaluation of BHB and glucose markers of starter intake

The objective of this research was to determine how blood β-hydroxybutyrate (BHB) and glucose are affected by age, time of day, stress, weaning, forced intake restriction, and voluntary starter intake in calves between 1 and 9 wk of age, and to evaluate if either is an acceptable proxy for starter intake. Holstein calves were fed a 27% crude protein, 17% fat milk replacer at 660 g of dry matter daily along with free-choice starter and water. Calves were weaned on d 42. Jugular blood was sampled at 0800, 1200, and 1600 h, and within 5 min of sampling BHB, and glucose concentrations were estimated using test strips (Nova Max Plus meter, Nova Biomedical Corporation, Waltham, MA). Age effects and time of day were estimated by sampling blood weekly (d 6, 13, 20, 27, 34, 41, and 48). To determine vaccination stress, a Pasteurella vaccine was administered after blood sampling at 0800 h on d 36. Effect of voluntary starter intake was tested by selecting calves for low and high intakes (d 35 to 39) and sampling on d 40, 41, 43, and 44. Starter intake restriction was tested by restricting intake in half of the calves and sampling on d 60 and 61. Data were analyzed with repeated measurements in a mixed model procedure with either within-calf effect (day or week) or within-calf effects (hour, and day or week) included in the model. Time of day did not affect blood BHB and glucose in the first 6 wk. Blood BHB was greater in wk 7 versus wk 1 to 6. Blood glucose was greater in the first 5 wk compared with wk 6 and 7. Blood BHB increased and glucose decreased with increasing starter intake. Blood BHB declined due to vaccination, but glucose was unaffected. Starter intake restriction reduced BHB for 3 d and glucose for 2 d after restriction. Both were affected by time of day. Around weaning (d 40 to 44), BHB and glucose increased with increasing starter intake. In this research, neither blood BHB nor glucose was a good proxy for starter intake. Blood BHB was positively and glucose negatively related to starter intake; however, relationships were weak, variable, and affected by time of day, stress, and intake restriction. Over 30% of calves tested ≤0.2 mmol/L BHB when consuming >1,250 g/d of starter, and test strip increments were 0.1 mmol/L, which represented >25% of the mean blood BHB concentration. In this study, neither blood BHB nor glucose was an acceptable proxy for estimating starter intake.

0438 β-hydroxybutyrate and glucose concentrations in the blood of dairy calves

This research was conducted to determine how blood β-hydroxybutyrate (BHBA) and glucose are impacted by age, time of day, voluntary starter intake, stress, weaning, and intake restriction in 1- to 9-wk-old calves and to see if either is an acceptable proxy for starter intake. Male Holstein calves were fed a 27% CP, 17% fat milk replacer at 660 g DM daily to weaning on d 42, along with free-choice starter (20% CP, 41% starch) and water. Jugular blood was sampled at 0800, 1200, and 1600 h and within 5 min of sampling BHBA and glucose concentrations were estimated using test strips (Nova Max® Plus meter, Nova Biomedical). Age effects were estimated by sampling blood weekly (d 6, 13, 20, 27, 34, 41, and 48). To determine vaccination stress, a Pasteurella vaccine was administered after blood sampling at 0800 h on d 36. Effect of voluntary starter intake was tested by selecting calves for low and high intakes (d 35 to 39) and sampling on d 40, 41, 43, and 44. Starter intake restriction was tested by restricting intake in 6 of 12 calves and sampling on d 60 and 61. Data were analyzed using several mixed model procedures (repeated measures, regression, etc.) in SAS. Time of day did not impact blood BHBA or glucose to wk 6, but did in wk 7 (P < 0.05). Blood glucose was greater (P < 0.05) in the first 5 wk compared with wk 6 and 7. Blood BHBA increased (P < 0.02; R2 = 0.28) and glucose decreased (P < 0.02; R2 = 0.23) with increasing starter intake. Blood BHBA declined (P < 0.05) due to vaccination but glucose was unaffected. Starter intake restriction reduced BHBA for 3 d (P < 0.05) and glucose for 2 d (P < 0.05) after intake restriction. Around weaning (d 40 to 44), BHBA and glucose increased (P < 0.05) with increasing starter intake. Blood BHBA was positively and glucose negatively related with starter intake; however, relationships were weak, variable, and impacted by time of day, stress, and intake restriction. Over 30% of calves tested ≤ 0.2 mmol/L BHBA when consuming > 1250 g/d of starter, and test strip increments were 0.1 mmol/L which represented > 25% of the mean blood BHBA concentration. In this study, neither blood BHBA nor glucose were an acceptable proxy for estimating starter intake.

A randomized controlled trial of dexamethasone as an adjunctive therapy to propylene glycol for treatment of hyperketonemia in postpartum dairy cattle.

Treatment of hyperketonemia with oral propylene glycol has proven efficacy but the cure rate remains moderate. Dexamethasone has long been suggested as a treatment for hyperketonemia, even though evidence of its efficacy is contradictory. The objective of this randomized controlled trial was to evaluate the effect of adding a single intramuscular injection of 20mg of dexamethasone to oral propylene glycol therapy for hyperketonemia [blood β-hydroxybutyrate (BHB) ≥1.2mmol/L]. All cows between 3 and 16d in milk on 4 dairy farms in New York State were tested once weekly for hyperketonemia using a handheld ketone meter. All enrolled animals received 312g (300mL) of propylene glycol orally once daily for 4d and either a single injection of dexamethasone or an equivalent volume of sterile saline. A total of 509 animals were enrolled, with 254 and 255 in the placebo and dexamethasone groups, respectively. Treatment with dexamethasone decreased the odds of being hyperketonemic in the second week posttreatment; however, the odds of hyperketonemia in the first week posttreatment only decreased in those animals that were treated at a BHB blood concentration between 1.2 and 1.5mmol/L. For the 8% of cows with blood BHB >3.2mmol/L at enrollment, receiving dexamethasone increased the odds of being hyperketonemic the following week. We detected no difference between treatment groups in the odds of postpartum disease or in milk production. For cows with initial BHB of 1.2 to 1.5mmol/L, treatment with dexamethasone tended to reduce the odds of pregnancy at first insemination. Based on the small and conditional benefits of dexamethasone and a lack of difference in milk yield or disease incidence, we do not recommend the use of dexamethasone to treat hyperketonemia.

Effect of different alfalfa hay levels on growth performance, rumen fermentation, and structural growth of Holstein dairy calves.

Introducing forage in dairy calf diets during the preweaning period stimulates development of rumen capacity and function and gut wall integrity. It was hypothesized that calves fed alfalfa hay (AH) at greater levels (up to 25% of DM) would result in an increase in starter diet intake and growth performance. The objective of this study was to determine the effects of increasing levels of supplemental AH on growth performance, rumen fermentation, blood metabolites, and feeding behavior in intact male dairy calves. For this purpose, 45 Holstein male calves (3 d of age and 41 ± 2.5 kg of BW) were randomly assigned to 1 of the following 3 starter diets differing in their forage level: 1) diet without AH (control), 2) diet with 12.5% AH on a DM basis, and 3) diet with 25% AH on a DM basis. Supplementation of AH in the starter diets linearly increased total DMI and ADG during the postweaning ( < 0.01) and overall ( = 0.02) periods. Alfalfa hay supplementation linearly increased ( < 0.01) ruminal pH on d 35 and 70 of the study. The concentrations of total VFA ( = 0.85), acetate ( = 0.74), propionate ( = 0.93), and butyrate ( = 0.91) were not affected by treatments. Furthermore, forage supplementation tended (linearly, = 0.08) to increase the acetate to propionate ratio compared with the control calves. Blood β-hydroxybutyrate (BHBA) concentrations in the control calves were less ( = 0.03) than in the AH-fed calves on d 70 of the study. Among all the measured variables of skeletal growth, supplementation of AH in the starter diets linearly increased heart girth ( = 0.05) and abdominal girth ( < 0.01) on d 70 of the study. These results indicate that the feed intake, feeding behavior, rumen fermentation parameters, and blood BHBA concentration may be affected by rations differing in AH level so that providing calves with 25% AH can improve calf performance.

Comparative Clinical and Haematological Investigations in Lactating Cows with Subclinical and Clinical Ketosis

Abstract Ketosis of lactating cows is among the most common metabolic diseases in modern dairy farms. The economic importance of the disease is caused by the reduced milk yield and body weight loss, poor feed conversion, lower conception rates, culling and increased mortality of affected animals. In the present study, a total of 47 high-yielding dairy cows up to 45 days in milk (DIM) are included. All animals were submitted to physical examination wich included checking the rectal body temperature, heart rate, respiratory and rumen contraction rates, and inspection of visible mucous coats. The body condition was scored, and blood β-hydroxybutyrate (BHBA) concentrations were assayed. The cows were divided into 3 groups: first group (control) (n=24) with blood β-hydroxybutyrate level &lt;1.2 mmol/l, second group (n=15) with blood β-hydroxybutyrate between 1.2-2.6 mmol/l (subclinical ketosis) and third group (n=8) with blood β-hydroxybutyrate &gt;2.6 mmol/l (clinical ketosis). Whole blood samples were obtained and analyzed for Red Blood Cell (RBC, 1012/l), Hemoglobin (HGB, g/l), Hematocrit (HCT, %), Mean Corpuscular Volume (MCV, fl), Mean Corpuscular Hemoglobin (MCH, pg), Mean Corpuscular Hemoglobin Concentration (MCHC, g/l), White Blood Cell (WBC, 109/l), Lymphocytes (LYM, 109/l), Monocytes (MON, 109/l), Granulocytes (GRA, 109/l), Red Blood Distribution Width (RDW, %), Red Blood Cell Distribution Width Absolute (RDWa, fl), Platelets (PLT, 109/l) and Mean Platelet Volume (MPV, fl). In this study, deviations in the clinical parameters in the control group and in those with subclinical ketosis were not identified. The cows from the third group (clinical ketosis) exhibited hypotonia, anorexia and body weight loss vs. control group. Hematological analysis showed leukocytosis and lymphocytosis in cows with subclinical ketosis vs. control group. In cows with clinical ketosis WBC counts decreased (leukopenia), while hemoglobin content and hematocrit values are higher vs. control group. Blood BHBA values are higher in both groups of ketotic cows vs. the control group. The other analyzed parameters (RBC, MCH, MCHC, MCV, RDW, RDWa, MON, GRA, PLT and MPV) were close to control values.

Association between β-hydroxybutyrate concentration at surgery for correction of left-displaced abomasum in dairy cows and removal from the herd after surgery

To estimate the sensitivity, specificity, likelihood ratios, and predictive values of blood β-hydroxybutyrate (BHB) concentrations in dairy cows immediately prior to surgical correction of left-displaced abomasum (LDA) for determining associations between BHB concentration and removal from the herd ≤ 30 days after surgery and to evaluate postsurgical risk of removal for cows with the BHB concentration that had highest sensitivity and specificity for predicting this outcome. Prospective cohort study. 136 dairy cows with LDA diagnosed between 5 and 30 days in lactation (ie, days in milk). Blood BHB concentration was measured immediately prior to surgery. All cows underwent surgical correction of LDA while standing. Follow-up information was obtained ≥ 30 days after surgery. Receiver operating characteristic curves were used to estimate a critical threshold value for BHB concentration that was associated with removal from the herd, and this value was used in Poisson regression to estimate risk ratio for the same outcome. While controlling for parity in the model, cows with a BHB concentration < 1.2 mmol/L at the time of LDA surgery were 2.5 times as likely (95% confidence interval, 1.3 to 5.0) to be removed from the herd ≤ 30 days after surgery, compared with cows that had a BHB concentration ≥ 1.2 mmol/L. Results indicated that blood BHB concentration in dairy cows undergoing surgical correction of LDA may potentially be a useful prognostic indicator for the likelihood of removal from the herd ≤ 30 days after surgery. Further research is needed to evaluate other risk factors that may be associated with this outcome.

Short communication: Evaluation of the accuracy of an electronic on-farm test to quantify blood β-hydroxybutyrate concentration in dairy goats

The objective of this cross-sectional study was to validate the accuracy of a hand-held electronic on-farm test (Precision Xtra) for quantifying the blood β-hydroxybutyrate (BHBA) concentration in dairy goats. A total of 114 dairy goats from 3 commercial herds were sampled once for blood in the jugular vein between 1mo before and 2mo after parturition. Blood samples were centrifuged to harvest serum and sera were sent to the Animal Health Laboratory of the Université de Montréal for quantification of BHBA concentration (gold standard). Laboratory BHBA values were between 0.1 and 3.7mmol/L. Precision Xtra values were compared with gold standard values; Pearson correlation coefficient was 0.98 and coefficient of determination was 0.95. Overall, these results suggested that Precision Xtra provides excellent accuracy for measuring blood BHBA concentration in dairy goats compared with the gold standard test.

Effects of type and treatment of grain and protein source on dairy cow performance

AbstractThe effects of different types of energy or protein supplementation on performance of cows given grass silage-based diets were studied. The possibility of maintaining high energy intakes by using different grain sources, barley or maize, or by the use of the physical processing of the barley was investigated. In addition, the relative quality of rapeseed meal as a protein supplement compared with alternative protein supplements was examined. In experiment 1 16 Finnish Holstein-Friesian cows were used in a cyclic change-over design experiment with eight diets and four 21- day periods. The concentrate supplements comprised a 2 ✕ 2 ✕ 2 factorial arrangement of two grain sources (barley (B) and maize (M)) given either ground (T–) or steam-rolled (T+), each supplemented with either rapeseed expeller (R) or a mixture of maize gluten and soya-bean meal (GS). Grass silage was givenad libitumand concentrates at a rate of 11·2 kg DM per day. M supplements increased milk, milk protein and lactose output (P&lt; 0·05) and decreased milk urea concentration (P&lt; 0·01) compared with B supplements. Blood β-hydroxy-butyrate (BHB) and plasma urea concentrations were higher (P&lt; 0·01) for B than M diets. R supplements increased silage intake, energy-corrected milk yield and milk protein output and concentration (P&lt; 0·05) compared with GS supplements. Steam-rolled grain decreased food intake, blood BHB (P&lt; 0·05) and plasma and milk urea concentrations (P&lt; 0·001). Steam rolling improved organic matter digestibility (grain ✕ processing interaction,P&lt; 0·05) with M but not with B supplements.In experiment 2 four Finnish Holstein-Friesian cows fitted with rumen cannula were used in a balanced complete change-over design to evaluate ground or steam-rolled barley (T– v. T+) and two protein treatments (rapeseed expeller, R or a mixture of maize gluten/soya-bean meal/sugar beet solubles, GSS). Cows were given concentrates at 11·2 kg dry matter (DM) per day and offered grass silagead libitum. There were no differences (P&gt; 0·05) in food intake, digestibility or milk production and composition between treatments. Plasma urea concentrations (P&lt; 0·01) and molar proportion of butyrate (P&lt; 0·05) in rumen fluid were decreased with R compared with GSS supplements. The results showed that replacing B with M grain resulted in minor increases in milk production. Steam rolling of grain did not influence animal performance. Among the protein supplements R increased animal performance compared with GS supplement.