Ketosis In Dairy Cows Research Articles

Investigation on the Relationship of Insulin Resistance and Ketosis in Dairy Cows

Ketosis is an important metabolic disease of dairy cows during the transition period, but it is fully unclear about its endocrine etiology. Our study is to clarify the relationship between oxidative stress, liver function, insulin resistance and ketosis in dairy cows. Sixteen ketotic Holstein cows (T) and twenty-four non-ketotic Holstein cows (C) were used as the experimental animals from an intensive dairy farm in Heilongjiang province, China. Blood samples from all experimental cows were collected at 14 days postpartum during morning fasting. Fifteen parameters for energy balance, liver function, oxidative stress, insulin sensitivity and glucose tolerance test between T and C were measured using commercial kits. Results showed that the concentration of plasma glucose (P<0.01) was lower in T compared with C cows, whereas there were marked increases in the concentration of plasma non-esterified fatty acids and beta-hydroxybutyric acid (P<0.01). The level of plasma AST (P<0.01), TBIL (P<0.05), and DBIL (P<0.01) increased significantly in T cows compared with C cows, but plasma CHE (P<0.01) and TP (P<0.05) decreased significantly, and no significant change in plasma ALT, IBIL, ALB, and GLO. Level of plasma malondialdehyde (MDA) and superoxide dismutase (SOD) was significantly higher in ketotic cows than that of non-ketotic cows (P<0.05), but value of plasma revised quantitative insulin sensitivity index (RQUICKI) was lower significantly in T cows than that of C cows (P<0.05). Concentration of plasma Glc increased significantly in T cows compared with C cows during glucose tolerance test (P<0.05). Therefore, the ketosic cows were in condition of negative energy balance, suffered to certain extent from liver function abnormality, and experienced oxidative stress and low insulin sensitivity. Therefore, a closed relationship between ketosis and insulin resistance should be related to liver function and oxidative stress that can cause insulin resistance.

Subclinical ketosis in dairy cows: prevalence and risk factors in grazing production system

The purpose of this study was to estimate the prevalence of Subclinical ketosis (SCK) between 4 and 19days in milk (DIM) in a grazing production system and investigate the importance of potential risk factors for SCK. This cross-sectional study was conducted in dairy cows (n=107), which had more of two parities. The concentration of β-hydroxybutyric (BHB) in blood was quantified through a hand-held meter. Potential risk factors evaluated were calving interval (CI), milk yield in previous lactation, metritis, dystocia, calf sex (male), parity (≤3 vs. ≥4) and pre-partum body condition score (BCS≤3.5 vs. ≥3.75). Prevalence of SCK was 10.3% (95% CI 4.7-15) between 4 and 19 DIM. Risk factors identified were the occurrence of both metritis and pre-partum BCS≥3.75. Cows with metritis had 4.9 (95% CI 1.17-20.98) times more risk of developing SCK than cows without metritis. And the cows with pre-partum BCS≥3.75 had 5.25 (95% CI 1.32-21.11) times more risk of developing SCK than cows with pre-partum BCS≤3.5. Metritis could induce a lower feed intake and promote the development of SCK. High pre-partum BCS could induce a greater mobilization of body reserves altering liver function and aggravating post-partum NEB. The results are indicative of the expected prevalence of SCK in grazing production system. Factors associated could help to identify cattle at risk of SCK and improve the management of strategies to limit the effects.

Comparison of 2 electronic cowside tests to detect subclinical ketosis in dairy cows and the influence of the temperature and type of blood sample on the test results

The objective of this study was to determine the suitability of 2 electronic hand-held devices [FreeStyle Precision (FSP), Abbott GmbH & Co. KG, Wiesbaden, Germany and GlucoMen LX Plus (GLX), A. Menarini GmbH, Vienna, Austria] for measuring β-hydroxybutyrate (BHBA) in dairy cows. Three experiments were conducted to evaluate (1) the diagnostic performance of the devices, (2) the effect of the type of blood sample, and (3) the influence of the ambient temperature on the determined results. A total of 415 blood samples from lactating Holstein and Simmental cows were collected and analyzed with both devices (whole blood) and in a laboratory (serum). Correlation coefficients between whole-blood and serum BHBA concentrations were highly significant, with 94% for the FSP and 80% for the GLX device. Based on thresholds for subclinical ketosis of 1.2 and 1.4 mmol of BHBA/L, results obtained with the hand-held devices were evaluated by receiver operating characteristics analyses. This resulted in adjusted thresholds of 1.2 and 1.4mmol/L for the FSP and 1.1 and 1.3mmol/L for the GLX device. Applying these thresholds, sensitivities were 98 and 100% for the FSP and 80 and 86% for the GLX device, respectively. Corresponding specificities were 90 and 97% for the FSP and 87 and 96% for the GLX device, respectively. Additionally, concentrations of BHBA were tested with both devices in whole blood, EDTA-added whole blood, and in their resulting serum and plasma, collected from 65 animals. Determined BHBA concentrations were similar within each device for whole and EDTA-added blood, and in serum and plasma, but differed between whole blood and serum and between EDTA-added blood and plasma. Blood samples with low (0.4mmol/L), medium (1.1mmol/L), and high (1.6mmol/L) BHBA concentrations were stored between +5 to +32°C and analyzed repeatedly at temperature levels differing by 4°C. Additionally, devices and test strips were stored at equal conditions and used for measurement procedures. Storage temperature of the devices and test strips did not influence the differences between the results of the laboratory and the devices, whereas the temperature of the blood samples caused significant differences. Although the level of agreement between the laboratory and the GLX device was lower than for the laboratory and the FSP device, both devices are useful tools for monitoring subclinical ketosis in dairy cows. Due to their effects on the determined results, the type and temperature of the tested sample should be considered.

Effects of Dexamethasone‐21‐Isonicotinate on Peripheral Insulin Action in Dairy Cows 5 days after Surgical Correction of Abomasal Displacement

Dexamethasone frequently is used for treatment of ketosis in dairy cows, but its effects are not fully understood. Dexamethasone treatment affects whole body insulin sensitivity. Twelve German Holstein cows, 2-4 weeks postpartum, 5 days after omentopexy to correct left abomasal displacement. Randomized, blinded, case-control study. Treatment with dexamethasone-21-isonicotinate (DG; 40 μg/kg IM; n = 6) or saline (control group [CG], 15 mL IM, n = 6) on day 0 (d0). Blood samples were obtained before (d0) and after treatment (d1 and d2), and analyzed for glucose, insulin, and nonesterified fatty acid (NEFA) concentrations. Hepatic triglycerides (TAG) were measured in liver samples taken on d0 and d2. Five consecutive hyperinsulinemic-euglycemic clamps (HEC-I-V; insulin dosages: 0.1, 0.5, 2, 5, 10 mU/kg/min, respectively) were performed on d1 and steady state glucose infusion rate (SSGIR), insulin concentration (SSIC), insulin sensitivity index (ISI = SSGIR/SSIC), and plasma NEFA concentration (SSNEFA) were assessed. Compared with CG-cows, DG-cows on d1 had higher plasma glucose (P = .004) and insulin (P < .001) concentrations, decreased SSGIR (HEC-II, P = .002; HEC-IV, P = .033), ISI (HEC-I, P < .015; HEC-II, P = .004), and insulin-stimulated decrease in SSNEFA (HEC-II, P = .006; HEC-III, P = .01; HEC-IV, P = .003; HEC-V, P = .011). Decrease in hepatic TAG content in DG-cows was higher compared with CG-cows (P < .001). Dexamethasone decreases whole body insulin sensitivity and affects glucose and lipid metabolism in early lactating dairy cows.

Evaluation of the use of nonesterified fatty acids and β-hydroxybutyrate concentrations in pooled serum samples for herd-based detection of subclinical ketosis in dairy cows during the first week after parturition

To evaluate the use of nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA) concentrations in pooled serum samples for herd-based detection of subclinical ketosis (SCK) in dairy cows after calving. Cross-sectional study. 1,100 dairy cows from 110 herds. Blood samples were collected from 10 healthy cows/herd in the first week after parturition. Aliquots of serum were mixed to create a pooled sample. Concentrations of NEFA and BHBA were measured to estimate prevalence of SCK. Pooled sample test results were compared with those obtained for individual samples. Linear regression and receiver-operating characteristic curve analysis were performed; Bland-Altman plots were used to evaluate agreement between methods. Overall prevalence of SCK was 30.7%, 19.3%, and 13.6%, as determined by use of BHBA threshold concentrations of 1,000, 1,200, and 1,400 μmol/L, respectively. Pooled sample concentrations of NEFA and BHBA were significantly correlated (r = 0.98 and 0.97, respectively) with individual sample means and with the number of cows that had NEFA (R(2) range, 0.81 to 0.84) or BHBA (R(2) range, 0.65 to 0.76) concentrations above predefined thresholds. Pooled sample concentrations of NEFA and BHBA were very accurate to highly accurate for herd-based detection of SCK. Analysis of NEFA and BHBA concentrations in pooled serum samples was useful for herd-based detection of SCK. A sample size of 10 cows/herd was deemed adequate for monitoring dairy herds for SCK. Reference criteria specific to pooled samples should be used for this type of herd-based testing.

Prevalence and Clinico-Pathology of Ketosis in Dairy Cows in Tigray Region of Ethiopia

An investigation to study the prevalence and clinico-pathology of ketosis in dairy cows was undertaken from November 2007 to May 2008 at Kalamino, Agazi and Mekelle University dairy farms in and around Mekelle town of Tigray region of Ethiopia. Recently- calved cows were screened for ketosis by subjecting urine and milk sample to strip (URS-10) and Rothera’s tests. An overall prevalence of 12.29% was recorded with highest prevalence during January and February. Age-wise, the highest prevalence was noticed at 8-9 years of age (73.34%). Cows in their 4th lactation (46.67%) and those in 1-2 months (53.35%) of lactation had significantly higher prevalence (p< 0.005). The clinical observations in ketotic cows were anorexia, refusal to take concentrate and decrease in milk yield. There was 30-100% decrease in milk yield in most of the cases. The body temperature, pulse and respiration rates were within normal range with decreased rumen motility. Feces were scanty, mucoid and dry; and urine, breath and fresh milk had characteristic smell of acetone. Ketotic animals were treated with dextrose and insulin. Keywords : Dairy Cows, Ketosis, Prevalence, Mekelle, Ethiopia.

Correlation between Composition of the Bacterial Community and Concentration of Volatile Fatty Acids in the Rumen during the Transition Period and Ketosis in Dairy Cows

The transition period is a severe challenge to dairy cows. Glucose supply cannot meet demand and body fat is mobilized, potentially leading to negative energy balance (NEB), ketosis, or fatty liver. Propionate produces glucose by gluconeogenesis, which depends heavily on the number and species of microbes. In the present study, we analyzed the rumen microbiome composition of cows in the transition period, cows with ketosis, and nonperinatal cows by terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes and quantitative PCR. TRFLP analysis indicated that the quantity of Veillonellaceae organisms was reduced and that of Streptococcaceae organisms was increased in rumen samples from the transition period and ketosis groups, with the number of Lactobacillaceae organisms increased after calving. Quantitative PCR data suggested that the numbers of the main propionate-producing microbes, Megasphaera elsdenii and Selenomonas ruminantium, were decreased, while numbers of the main lactate-producing bacterium, Streptococcus bovis, were increased in the rumen of cows from the transition period and ketosis groups, with the number of Lactobacillus sp. organisms increased after calving. Volatile fatty acid (VFA) and glucose concentrations were decreased, but the lactic acid concentration was increased, in rumen samples from the transition period and ketosis groups. Our results indicate that the VFA concentration is significantly related to the numbers of Selenomonas ruminantium and Megasphaera elsdenii organisms in the rumen.

Effect of insulin-like growth factor-1 (IGF-1) on the gluconeogenesis in calf hepatocytes cultured in vitro

The major role of insulin-like growth factor-1 (IGF-1) in the liver is to mediate glucose uptake in hepatocytes to synthesize glycogen and maintain blood glucose homeostasis. In this study, to evaluate the role of IGF-1 on gluconeogenesis and nutrient metabolism in dairy cattle, pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) expression and enzyme activity were evaluated in primary cultures of bovine hepatocytes treated with different concentrations of IGF-1 by quantitative polymerase chain reaction and spectrophotometry, respectively. The results showed that expression of PC and PEPCK were significantly lower in bovine hepatocytes by IGF-1 treatment in test group compare to the control group (P < 0.01). As IGF-1 concentration increased, PC and PEPCK enzyme activity in bovine hepatocytes decreased. Evaluating PC and PEPCK mRNA levels and enzyme activity may thus be useful to monitor subclinical ketosis in dairy cows.

Latent class evaluation of a milk test, a urine test, and the fat-to-protein percentage ratio in milk to diagnose ketosis in dairy cows

In this study, 3 commonly used tests to diagnose ketosis were evaluated with a latent class model to avoid the assumption of an available perfect test. The 3 tests were the KetoLac BHB (Sanwa Kagaku Kenkyusho Co. Ltd., Nagoya, Japan) test strip that tests milk for β-hydroxybutyrate, the KetoStix (Bayer Diagnostics Europe Ltd., Dublin, Ireland) test strip that tests urine for acetoacetate, and the fat-to-protein percentage ratio (FPR) in milk. A total of 8,902 cows were included in the analysis. The cows were considered to be a random sample from the population of Danish dairy cattle under intensive management, thus representing a natural spectrum of ketosis as a disease. All cows had a recorded FPR between 7 and 21 d postpartum. The KetoLac BHB recordings were available from 2,257 cows and 6,645 cows had a KetoStix recording. The recordings were analyzed with a modified Hui-Walter model, in a Bayesian framework. The specificity of the KetoLac BHB test and the KetoStix test were both high [0.99 (0.97–0.99)], whereas the specificity of FPR was somewhat lower [0.79 (0.77–0.81)]. The best sensitivity was for the KetoStix test [0.78 (0.55–0.98)], followed by the FPR [0.63 (0.58–0.71)] and KetoLac BHB test [0.58 (0.35–0.93)].

Incidence of Subclinical Ketosis in Dairy Cows in Fars Province of Iran and Reproductive Performance in Early Lactetion Period

Incidence of Subclinical Ketosis in Dairy Cows in Fars Province of Iran and Reproductive Performance in Early Lactetion Period

Effect of NEFA and Glucose Levels on CPT-I mRNA Expression and Translation in Cultured Bovine Hepatocytes

The objective of this study was to determine the effects of NEFA and glucose on carnitine palmitoyltransferase-I (CPT-I) mRNA expression in cultured bovine hepatocytes using real-time reverse transcription polymerase chain reaction and ELISA methods. The results indicated that CPT-I transcription increased gradually, but that CPT-I translation was not significantly changed, with glucose concentrations ranging from 0 to 3.0 mmol/L (P<0.01). Furthermore CPT-I transcription and translation were enhanced significantly when the NEFA concentrations increased from 0 to 1.2 mmol/L and decreased significantly when the NEFA concentrations increased from 1.2 to 4.8 mmol/L (P<0.01). A high concentration NEFA was found to reduce fatty acid oxidation, potentially explaining the development from NEB to ketosis in dairy cows.

Use of a hand-held meter for detecting subclinical ketosis in dairy cows

The Optium Xceed is a new hand-held meter for determining blood β-hydroxybutyrate (BHBA) and glucose in human medicine. The objective of this study was to compare BHBA and glucose results obtained using the hand-held meter with those results made with a laboratory method and to evaluate its usefulness as a cowside test in the diagnosis of subclinical ketosis (SCK) in dairy cows. Seventy-eight blood samples from clinically healthy Holstein cows between 5 and 60 days post-calving were analysed. BHBA and glucose values were significantly higher with the hand-held meter versus laboratory methods. Correlation coefficients ( r) for BHBA and glucose with the Optium Xceed versus laboratory methods were 0.97 and 0.63, respectively. Based on Bland–Altman plot and Passing–Bablok regression, agreement between two methods was good for BHBA but the agreement for glucose was only fair. When SCK was defined as plasma BHBA levels ⩾1200 μmol/L, the sensitivity and specificity of the hand-held meter ketone testing in determining SCK were 85% and 94%, respectively. Raising the threshold of the laboratory method to ⩾1400 μmol/L, the sensitivity and specificity incremented to 0.90 and 0.98, respectively. In conclusion, the blood ketone-monitoring device can be used as a rapid and reliable diagnostic test to detect SCK under field conditions.

Magnitude and Duration of Effects of Two Corticosteroid Formulations (Dexamethasone Sodium Phosphate and Phenyl Propionate; Prednisolone Acetate) on Blood Glucose, Leukocyte Values, and Milk Yield in Dairy Cows

The magnitude and duration of the effects of two corticosteroid formulations were determined on blood glucose and leukocyte values and milk yield in normal, lactating dairy cows. One formulation contained a combination of dexamethasone sodium phosphate and dexamethasone phenyl propionate (DEX). The other contained prednisolone acetate (PRED). Blood samples were obtained prior to and at 6, 24, 48, 72, 96, and 144 hours following administration of a single dose of DEX or PRED. Milk yield was determined for two days prior to drug administration and for seven days afterwards. Both corticosteroids caused significant increases in blood glucose values, although DEX caused significantly larger and longer lasting increases. DEX also caused significant leukocytosis and neutrophilia. PRED caused significant, very short lasting neutrophilia, but had no significant effect on total blood leukocyte values. Both drugs caused significant reductions in blood eosinophil and lymphocyte values, and significant increases in monocyte values. DEX also caused a significant, marked drop in milk production on days 1, 2, and 6, post-administration. PRED did not significantly affect milk production. Because DEX produced more dramatic and persistent changes in blood glucose values and milk production than did PRED, the authors believe that DEX is likely to be more efficacious than PRED for treating ketosis in dairy cows. Because DEX produced more dramatic and persistent effects on blood neutrophil values than PRED, it is also likely to be a better option for use as an anti-inflammatory drug.

Evaluation of the Change of Serum Copper and Zinc Concentrations of Dairy Cows with Subclinical Ketosis

Ketosis in dairy cows can lead to poor reproductive success and decreased milk production. Since the serum concentrations of copper (Cu) and zinc (Zn) are closely associated with the health status of cows, we investigated whether serum concentrations of Cu and Zn differed in dairy cows with subclinical ketosis and healthy dairy cows. Blood samples of 19 healthy dairy cows and 15 subclinically ketotic dairy cows were collected from three farms, and the concentrations of β-hydroxybutyrate (BHBA), glucose, non-esterified fatty acids (NEFA), Cu, and Zn were determined. Subclinically ketotic dairy cows had significantly higher BHBA and NEFA levels (p < 0.01) and lower glucose (p < 0.01) than healthy dairy cows. Likewise, serum concentrations of Zn were significantly decreased (p < 0.05) in dairy cows with subclinical ketosis. There was no significant difference observed for serum Cu concentration between healthy and subclinically ketotic dairy cows. This study suggests that a decreased serum Zn concentration could be a cause of decreased reproductive performance in subclinically ketotic dairy cows.

Evaluation of an electronic cowside test to detect subclinical ketosis in dairy cows

The objective of this study was to determine the diagnostic performance of an electronic β-hydroxybutyrate (BHBA) hand-held meter (Precision Xtra) for use in dairy cattle. Specific objectives were to compare the electronic BHBA meter with serum BHBA concentrations determined photometrically and 2 commonly used chemical cowside tests (Ketostix, Ketolac) and to evaluate accuracy in a field study employing 35 investigators. Of the 196 blood samples collected in experiment 1, 17 (8.7%) contained ≥1,200μmol of BHBA/L of blood and 10 (5.1%) contained ≥1,400μmol of BHBA/L of blood. Pearson correlation coefficients were highly significant for all tests. The highest correlation coefficient (0.95) was found between measurements of whole blood BHBA determined with the Precision Xtra test and the serum BHBA concentrations determined photometrically. Correlation coefficients between serum BHBA and BHBA in urine using Precision Xtra and Ketostix, and milk using Ketolac were lower. The Precision Xtra test was both 100% sensitive and specific at ≥1,400μmol of BHBA/L of whole blood. Using milk and urine, positive and negative predictive values were considerably lower for both chemical tests as well as for the electronic meter. In the second study undertaken with 35 bovine veterinary practices, 926 blood samples were collected. In this study, the Precision Xtra test had sensitivities of 88 and 96% at 1,200 and 1,400μmol of BHBA/L of whole blood, respectively. Specificities were 96 and 97%, respectively. Level of agreement was lower in the second study employing multiple investigators. Considerable differences in variance occurred among investigators. We conclude that the electronic hand-held BHBA measuring system using whole blood is a useful and practical tool to diagnose subclinical ketosis. Sensitivity and specificity are excellent for a cowside test and higher than 2 commonly used chemical dipsticks (Ketostix and Ketolac).

Effects of feeding dry propylene glycol to early postpartum Holstein dairy cows on production and blood parameters

In all, 18 multiparous and 19 primiparous Holstein dairy cows were used in a completely randomized design with restrictions to evaluate the effects of feeding propylene glycol (PG) as a dry product, via two delivery methods, on production and blood parameters. PG treatments were administered from parturition through 21 days postpartum. Treatments were: (i) control, no PG; (ii) top dress, 162.5 g PG/day by top dressing onto the total mixed ration (TMR) and; (iii) mixing, 162.5 g PG/day as a part of the TMR by incorporating it into the TMR. PG used was a dry product which contained 65% pure PG and 35% silicon dioxide as the dry carrier. Coccygeal blood was sampled on 4, 7, 14 and 21 days in milk (±1.50 pooled s.d.). Supplementation of dry PG by top dressing onto, or incorporating into, the TMR had no effects on average dry matter intake, milk yield and composition, serum insulin, serum and plasma metabolites and milk ketones. Concentrations of urine ketones tended (P = 0.10) to be reduced by PG supplementation from 41.5 to 15.2 mg/dl. Supplementation of PG tended (P = 0.07) to decrease the incidence for subclinical ketosis from 39% to 24% and 13% for cows fed a TMR supplemented with no dry PG, with dry PG as a top dress and dry PG as a part of the TMR, respectively. It is concluded that supplementing PG as a dry product via incorporating into the TMR is as effective as when used as a top dress, based on the efficacies of both delivery methods to numerically reduce urine ketones concentrations and, therefore, the incidence for subclinical ketosis during the first 21 days of lactation. However, it should be noted that the number of cows used in the current study was minimal, and more cows are needed to confirm the efficacy of supplementing PG as a dry product on reducing the prevalence of subclinical ketosis in dairy cows during the first month of lactation.

Test Comparison of Precision Xtra® and Ketostix® for Ketosis in Dairy Cows

Ketosis is a common disease of periparturient dairy cows. Ketosis is defined as an increased concentration of beta-hydroxybutyric acid (BHBA) in the serum. There is strong evidence that cows with mild ketonemia (above approximately 1.1-1.4mmol/l) are at an increased risk of other disease (e.g. displaced abomasum), decreased milk production and infertility. Diagnosing ketosis is important because it has a financial cost and at the herd level, reflects feeding and management. The objective of this study was to assess the accuracy of a newly available BHBA assay (Precision Xtra®), marketed for human diabetic patients, by comparison to the gold standard test. This new device has potential to be a quality cows-side test for monitoring subclinical ketosis in dairy cattle. An additional objective was to assess the accuracy of the Ketostix® test.

Role of adrenocortical system in occurrence of ketosis in high-yield dairy cows

From the very onset of lactation, the requirements of the mammary gland have an advantage over the requirements of other organic systems, even in the case of clinically exhibited ketosis. In hypoglycemic, ketotic cows, the mammary gland utilizes glucosis approximately in the same degree as the mammary gland of cows with normal glycemia. This indicates that the regulatory role of hormones can have primary importance in the earliest phase of lactation, when metabolic processes are on the very brink of a ketotic state. That is why it is believed that, in conditions of a great burdening of the metabolism, inadequate activity by the adrenocortical system presents one of the primary factors in the etiopathogenesis of ketosis in dairy cows. It is still an open issue whether hypof unction of the adrenal cortex is a direct cause of this disorder, or whether its activity is a consequence of insufficient stimulation by ACTH. In ketotic cows, average concentrations of cortisol have been established in ketotic cows, from 23.98 nmol/l in blood serum, and it is approximately the same as in healthy cows in the corresponding phase of lactation. However, the vast range of individual values largely makes it difficult to make a correct evaluation of the functional state of the adrenal cortex of ketotic cows. On the grounds of individual figures, in 26% diseased cows cortisol concentration in blood serum is from 1.38 to 16.55 nmol/l, in 37% it is from 16.55 to 27.59 nmol/l, and in 37 percent it is over 27.59 nmol/l. This indicates that cows with clinical symptoms of ketosis can be divided into those with low, medium, or high values of cortisol concentration in blood serum. Following the stimulation of the adrenal cortex with ACTH, the individual differences in serum cortisol concentration are considerably decreased. The ratio between the lowest and the highest values of cortisol concentration before the application of ACTH is 1:6, while it is only 1:1.5 four hours following application. After that, the values again take on the starting characteristics, and 24 hours after the application of ACTH they return to the starting values, and the ratio between the individual values is 1:8. It seems that the function of the adrenal cortex has been preserved in cows with clinical symptoms of ketosis and it is capable of reacting fully to stimulation with corticotropin. The cortisolemia values indicate, primarily, that there are big individual differences regarding the regulation of the degree of activity of the adrenal cortex, so that it is possible that, in the ketotic state, it is rather a case of uncoordinated activities of the adrenal cortex with the organism requirements imposed by the mammary gland, than that it is a matter of its hypofunction. .

DETERMINAÇÃO DE CORPOS CETÔNICOS NA URINA COMO FERRAMENTA PARA O DIAGNÓSTICO RÁPIDO DE CETOSE SUBCLÍNICA BOVINA E RELAÇÃO COM A COMPOSIÇÃO DO LEITE

Nas primeiras semanas de lactação as vacas de alta produção apresentam severas mudanças metabólicas, em virtude do déficit energético derivado do baixo consumo de matéria seca e da alta produção, constituindo fator predisponente para a cetose. As perdas econômicas ocasionadas pela cetose subclínica não têm sido adequadamente avaliadas. O presente trabalho teve por objetivo relacionar a presença de corpos cetônicos na urina com os níveis plasmáticos de beta-hidroxibutirato (BHB) e o conteúdo de sólidos totais no leite. Foram utilizadas 140 vacas multíparas da raça Holandesa de cinco rebanhos com produção intensiva nas condições do Sul do Brasil. Os animais foram amostrados nas semanas 2, 5, 8 e 11 de lactação. Em cada período foram coletadas amostras de urina, amostras de sangue para a quantificação de BHB e amostras de leite para a determinação de sólidos totais. Na urina foram aplicadas quatro tiras reativas para a determinação de corpos cetônicos pelo método do nitroprussiato de sódio e foi determinado o pH. A proporção de vacas positivas a cetonúria foi de 11,2%. Valores de BHB acima de 1,2 mmol/L (ponto de corte para cetose) estiveram presentes em 12,4% das vacas. Concluísse que a cetose subclínica pode ser monitorada através tiras reagentes de corpos cetônicos na urina. Não foi encontrada correlação entre os sólidos totais no leite e o estado de cetose do animal.

Predicting Risk of Ketosis in Dairy Cows Using In-Line Measurements of β-Hydroxybutyrate: A Biological Model

Automated monitoring of individual cows to determine health status is a potentially valuable management tool, especially in large dairy herds. Herein is described the rationale, structure, and functionality of a biological model to predict risk of ketosis in individual cows using in-line measurements of the ketone body β-hydroxybutyrate (BHBA) in milk. The model also uses acceleration in milk yield, body fatness at calving, diseases in current lactation, and incidences of ketosis in earlier lactations as additional risk factors for ketosis. However, the model is designed to function merely on the basis of milk BHBA in the absence of other data. Values of milk BHBA are smoothed using a state space model before these are used in calculations in the biological part of the model. The model is designed to be updated each time a new BHBA measurement or a disease occurrence is available and then uses previous and current data. Outputs of the model are the risk of ketosis (value between 0 and 1, where 0 = no risk and 1 = clinical ketosis) and how many days until the next milk sample should be taken and analyzed for BHBA. At higher risks for ketosis, more frequent milk sampling is the recommended output. Test examples from cows for which BHBA has been measured extensively were used to show the functionality of the model. The model performed equally well when reductions in sampling frequency were applied, and it was also relatively robust to the addition of up to±2 residual SD of random noise in the BHBA values. This model has the potential to provide the basis for a useful disease monitoring and management tool. However, thorough validation awaits a much larger dataset and testing of the model under a variety of on-farm situations.