Colour measurement of colostrum for estimation of colostral IgG and colostrum composition in dairy cows

Influence of lactic acid fermentation on the microbiological parameters, biogenic amines, and volatile compounds of bovine colostrum

In this study we hypothesized that the relations between the bovine colostrum (BC) microbiota, biogenic amine (BA) as well as volatile compound (VC) profiles can lead to new deeper insights concerning the BC changes during the biological preservation. To implement such an aim, BC samples were collected from 5 farms located in Lithuania and fermented with Lactiplantibacillus plantarum and Lacticaseibacillus paracasei strains. Nonfermented and fermented BC were subjected to microbiological [lactic acid bacteria (LAB), Escherichia coli, and total bacteria (TBC), total Enterobacteriaceae (TEC) and total mold and yeast (M-Y) viable counts] and physicochemical (pH, color coordinates, BA content and VC profile) parameters evaluation, and the relationship between the tested parameters were also further analyzed. In comparison pH and dry matter (DM) of nonfermented samples, significant differences were not found, and pH of BC was, on average, 6.30, and DM, on average, 27.5%. The pH of fermented samples decreased, on average, until 4.40 in Lp. plantarum fermented group, and, on average, until 4.37 in Lc. paracasei fermented group. Comparing color characteristics among nonfermented BC groups, significant differences between lightness (L*) and yellowness (b*) were not detected, however, the origin (i.e., agricultural company), LAB strain used for fermentation and the interaction between these factors were statistically significant on BC redness (a*) coordinate. The microbial contamination among all the tested BC groups was similar. However, different LAB strains used for BC fermentation showed different effects toward the microbial contamination reduction, and specifically Lc. paracasei was more effective than Lp. plantarum strain. Predominant BA in BC were putrescine and cadaverine. The main VC in nonfermented and fermented BC were decane, 2-ethyl-1-hexanol, dodecane, 1,3-di-tert-butylbenzene, 3,6-dimethyldecane and tetradecane. Moreover, this study showed worrying trends with respect to the frozen colostrum storage, because most of the dominant VC in BC were contaminants from the packaging material. Additionally, significant correlations between separate VC and microbial contamination were obtained. Finally, these experimental results showed that the separate VC in BC can be an important marker for biological as well as chemical contamination of BC. Also, it should be pointed out that despite the fermentation with LAB is usually described as a safe and natural process with many advantages, control of BA in the end product is necessary.

Relation between Color and Chemical Composition of Dromedary Camel Colostrum

Camel milk industrialization faces technological problems related to the presence of colostrum in milk. The determination of color parameters may serve to differentiate between colostrum and milk. This work aimed to study the relationship between the chemical composition of camel colostrum and milk and their colors. Samples of colostrum were collected at 2, 12, 24, 48, 72, 96, 120, 144, 168, and 360 h postpartum (n = 16), and their physicochemical properties (pH, acidity, viscosity, color, dry matter, ash, protein, and fat) were analyzed. The results show that all the components decreased during the first 3 days except fat. The content of this later increased from zero in the three sampling on the first day (2, 12, and 24 h) to 1.92 ± 0.61% at 48 h postpartum. The amount of total dry matter and protein decreased from 20.95 ± 3.63% and 17.43 ± 4.28% to 13.05 ± 0.81% and 3.71 ± 0.46%, respectively, during the first 7 days postpartum. There was a weak correlation between the brightness (L*) of the camel milk and its contents of dry matter, protein, and fat; however, these parameters were strongly correlated with redness (a*) and yellowness (b*). Ash content was poorly correlated with the color parameters. Hence, the measurement of the color parameters of camel colostrum and milk can be a new tool to evaluate their quality.

Qualitative identification of mature milk adulteration in bovine colostrum using noise-reduced dielectric spectra and linear model

BACKGROUND

The rapid and accurate identification of colostrum, a strong non-homogeneous food, remains a challenge. In the present study, the dielectric spectra including the dielectric constant (ε') and loss factor (ε″) of 154 colostrum samples adulterated with 0-50% mature milk were measured from 20 to 4500 MHz.

RESULTS

The results showed that the noise-reducing spectral preprocessing, including Savitzky-Golay (S-G), second derivative (SD), and S-G + SD, was significantly better than scattering-eliminating, including standard normal variate (SNV), multiplicative scatter correction (MSC), and SNV + MSC. The combination of S-G and SD was the best. Principal component analysis results demonstrated that dielectric spectroscopy is less susceptible to the inhomogeneity of colostrum and can be used to identify doped colostrum. The identification performance of linear models was better than that of non-linear models. The established linear discriminant analysis model based on full spectra had the best accuracy rates of 99.14% and 97.37% in the calibration and validation sets, respectively. Confirmatory tests on samples from different sources confirmed the satisfactory robustness of the proposed model.

CONCLUSION

We found that the main unfavorable effect on the identification based on dielectric spectroscopy was noise interference, rather than scattering effect caused by inhomogeneity of colostrum. The satisfactory results undoubtedly cast light on rapid detection of strongly non-homogeneous foods based on dielectric spectroscopy. © 2022 Society of Chemical Industry.

Suitability of Goat Colostrum to Produce a Fermented Yogurt-Type Product

The aim of this study was to investigate the potential use of goat colostrum to produce a yogurt-type product as a novel functional dairy food. Four batches of fermented goat colostrum (GCY) were produced using fermented goat milk (GMY) as a reference. Physicochemical, mechanical, and microbial characteristics of cold storage fermented products were evaluated in a weekly basis for 28 days. Sensory analysis was applied to detect potential differences between products and to evaluate the acceptance of GCY by consumers. Results indicate that colostrum showed higher coagulation times than goat milk (480 vs. 350 min to reach pH 4.6). In general, GCY showed a higher protein and fat content and similar features than GMY for most quality parameters, which were highly stable along time. Sensory evaluation led to significant differences between products related to their color and taste. The consumer acceptance test, using a 5 point-Likert scale, showed an overall acceptance of 3.90 ± 0.79 for GCY, with aroma and consistency being the sensory attributes having highest ratings (4.30 ± 0.80 and 4.20 ± 0.96, respectively). Therefore, fermenting goat colostrum with yogurt specific starters could be an interesting alternative to make use of surplus colostrum on farms, allowing for the diversification of commercial goat milk products with potential health benefits for the consumer.

Effects of prepartum supplementation of β-carotene on colostrum and calves

Little is known about transfer of dietary β-carotene into colostrum, its absorption by the calf, and its effects on retinol and α-tocopherol in the calf when the dam's dietary vitamin A is adequate. Our objective was to assess the effect of β-carotene supplementation during the close-up dry period on the colostrum and calf. The study was conducted on a large commercial dairy farm in Indiana during early summer of 2015. Ninety-four multiparous Holstein cows were blocked by calving data, parity, and previous production, and then randomly assigned to either control or β-carotene (BC) treatments. While locked in headgates each morning, each cow received a topdress of β-carotene (Rovimix, DSM Nutritional Products, 8 g/d; provided 800 mg β-carotene) or carrier from 21 d before expected calving until calving. Colostrum was collected within 2 h of parturition. Calf blood samples were obtained within 2 h of birth before receiving the dam's colostrum, at 24 h after birth, and at 7 d and 60 d of age. Blood serum was analyzed for β-carotene, retinol, α-tocopherol, and other metabolites and enzymes. Colostrum was analyzed for β-carotene, retinol, α-tocopherol, colorimetry profile, and milk components. Data were analyzed using mixed-effects models in SAS (SAS Institute Inc.). Calf serum β-carotene data were analyzed using the FREQ procedure. Colostrum β-carotene was higher for BC cows. Colostrum from BC cows had increased a* [measures red (positive) to green (negative)] and b* [measures yellow (positive) to blue (negative)] colorimeter values, indicating that β-carotene altered colostrum color toward red and yellow. Supplementation did not affect colostral or calf IgG concentrations. Colostrum color indices were correlated with IgG concentrations as well as concentrations of β-carotene, retinol, and α-tocopherol. Before receiving colostrum, the concentration of β-carotene in calf serum was below the detectable threshold of 0.05 μg/mL. At 24 h of age, the number of calves with detectable β-carotene concentrations increased, with more calves from BC cows (52.1%) having detectable concentrations than calves from cows in the control group (6.1%). No differences in concentrations of retinol or α-tocopherol were observed in calf serum. Supplementation of β-carotene to cows decreased activities of gamma-glutamyl transpeptidase and glutamate dehydrogenase in calf serum. In pregnant cows already receiving adequate vitamin A, supplementation of β-carotene increased concentration of β-carotene in colostrum, altered colostrum color, and increased serum β-carotene in calves at birth.

Determining Immunoglobulin Content of Bovine Colostrum and Factors Affecting the Outcome: A Review

The immunoglobulin concentration in bovine colostrum should be measured to ensure feeding with sufficient immunoglobulins (≥50 mg immunoglobulin G mL-1). Adequate feeding prevents diseases, promotes development, and has a positive influence on the adult animal. Indirect and direct measurement methods are available for this purpose. Direct measurement methods cannot be easily used in practice; therefore, farmers use indirect methods such as a colostrometer and a refractometer. Many factors influence the immunoglobulin concentration of colostrum; some of them have already been intensively researched. In particular, lactation and temporal aspects play an essential role. Newer aspects such as dry period, seasonal influences, and genetics are gaining importance, but their impact on immunoglobulin content has not been sufficiently investigated. Developments are still needed, especially in data management. This review analyzes the outcome of different studies on the indirect and direct measurement methods and discusses different factors influencing the immunoglobulin concentration of bovine colostrum.

Temporal kinetics of bovine mammary IgG secretion into colostrum and transition milk

Neonatal calf survival and health is predominantly dependent on sufficient consumption of immunoglobulin G (IgG) and the resulting transfer of passive immunity (TPI). In this study, we investigate the potential for continued IgG secretion and temporal kinetics of mammary IgG output in sequential milkings performed at 0, 4, 16, 28, 40, and 52 hr postcalving in Holstein dairy cows. For colostrum (0 hr), we also scrutinize the relationships between IgG concentration, volume, refractometer readings (˚Bx values, Brix) and concentration of sugars (lactose and glucose). Mammary transcripts postpartum (0 hr) indicated that active IgG secretion continues beyond the first milking (colostrum; n = 4 to 5). IgG measurements at the different timepoints indicated that colostrum represents only 25.1% of the total IgG produced across the 6 sequential milking timepoints, with a substantial 48.9% being secreted into transition milk over the next 3 timepoints (4-, 6-, and 28-hr) combined. The differences on the basis of IgG concentrations across 0-, 4-, and 16-hr milking timepoints were not statistically significant (P = 0.1522; n = 9). For colostrum, volume remained highly variable, even with induced let-down prior to milking (n = 27). Nonetheless, colostrum IgG secretion was significantly co-regulated with volume (R2 = 0.915; P < 0.001; n = 18), an association that was stronger than that measured for lactose (R2 = 0.803; P < 0.001; n = 18) and glucose (R2 = 0.467; P = 0.002; n = 17). Comparing colostrum ˚Bx values to absolute IgG concentrations showed no correlation (R2 = 0.127; P = 0.07; n = 27); biochemical separation of colostrum components indicated that both proteins and nonprotein solutes could affect ˚Bx values (P < 0.0001 for both; n = 5). This suggests that ˚Bx values do not reasonably indicate IgG concentration to serve as a measure of "colostrum quality." Additionally, our finding that early transition milk (4-, 6-, and 28-hr) can contribute substantially more IgG than colostrum forces a rethink of existing feeding paradigms and means to maximize TPI in calves. Collectively, our results reveal the remarkable value of early transition milk and caveats to colostrum assessments that could advance application in enhancing neonatal calf health.

Quantitative assessment of German Holstein dairy cattle colostrum and impact of thermal treatment on quality of colostrum viscosity and immunoglobulins

OBJECTIVE

This study aimed to determine the color, fat, viscosity, IgG concentration, %Brix and refractive index of fresh postpartum colostrum of German Holstein dairy cattle and assess the impact of different thermal treatments on the visual and dynamic viscosity, in association to IgG concentration, of colostrum that can be used for pasteurization process.

RESULTS

Of the total 40 fresh postpartum colostrum, the color of colostrum (ranging from white-pale yellow to yellow and dark-yellowish), fat (1.4-8.2 100 g^-1), IgG (4-116 mg mL^-1), %Brix (8.5-35.4%), refractive index (1.3454-1.3905 nD), visual (ranging from watery to liquid and thick) and dynamic (4.9-219 cp) viscosity, were recorded. Statistical analysis between visual and dynamic viscosity of fresh colostrum showed significant correlation coefficients (r_s = 634). Moreover, a significant correlation between viscosity and three IgG concentrations was also observed. Heat-treated colostrum showed dynamic viscosity ranged from 25 to 3066 cP, where dynamic viscosity of colostrum before- and after heat-treatment showed no significant correlation. Treated colostrum at 60 °C/60 min and 63.5 °C/30 min containing IgG concentration ≤ 80 mg mL^-1 and ≤ 68 mg mL^-1 showed no significant change in the viscosity and can successfully be applied for pasteurization of first postpartum colostrum.

Invited review: Metabolic challenges and adaptation during different functional stages of the mammary gland in dairy cows: Perspectives for sustainable milk production

Milk production of dairy cows has increased markedly during recent decades and continues to increase further. The evolutionarily conserved direction of nutrients to the mammary gland immediately after calving provided the basis for successful selective breeding toward higher performance. Considerable variation in adaptive responses toward energy and nutrient shortages exists; however, this variation in adaptability recently gained interest for identifying more metabolically robust dairy cows. Metabolic challenges during periods of high milk production considerably affect the immune system, reproductive performance, and product quality as well as animal welfare. Moreover, growing consumer concerns need to be taken into consideration because the public perception of industrialized dairy cow farming, the high dependency on feed sources suitable for human nutrition, and the apparently abundant use of antibiotics may affect the sales of dairy products. Breeding for high yield continues, but the metabolic challenges increasingly come close to the adaptational limits of meeting the mammary gland's requirements. The aim of the present review is to elucidate metabolic challenges and adaptational limitations at different functional stages of the mammary gland in dairy cows. From the challenges and adaptational limitations, we derive perspectives for sustainable milk production. Based on previous research, we highlight the importance of metabolic plasticity in adaptation mechanisms at different functional stages of the mammary gland. Metabolic adaptation and plasticity change among developing, nonlactating, remodeling, and lactational stages of the mammary gland. A higher metabolic plasticity in early-lactating dairy cows could be indicative of resilience, and a high performance level without an extraordinary occurrence of health disorders can be achieved.

Prediction efficiency by near-infrared spectroscopy of immunoglobulin G in liquid and dried bovine colostrum samples

The objective of this study was to compare the prediction efficiency of IgG concentration in bovine colostrum by NIRS, using liquid and dried (Dry-Extract Spectroscopy for Infrared Reflectance, DESIR) samples by transflectance and reflectance modes, respectively. Colostrum samples (157), obtained from 2 commercial Holstein dairy farms, were collected within the first hour after calving and kept at -20 °C until analysis. After thawing and homogenisation, a subsample of 500 mg of liquid colostrum was placed in an aluminium mirror transflectance cell (0·1 mm path length), in duplicate, to collect the spectrum. A glass fiber filter disc was infused with another subsample of 500 mg of colostrum, in duplicate, and dried in a forced-air oven at 60 °C for 20 min. The samples were placed in cells for dry samples to collect the spectra. The spectra in the VIS-NIR region (400-2500 nm) were obtained with a NIRSystems 6500 monochromator. Mathematical treatments, scatter correction treatments and number of cross-validation groups were tested to obtain prediction equations for both techniques. Reference analysis for IgG content was performed by radial immunodiffusion. The DESIR technique showed a higher variation in the spectral regions associated with water absorption bands, compared with liquid samples. The best equation for transflectance method (liquid samples) obtained a higher coefficient of determination for calibration (0·95 vs. 0·94, respectively) and cross validation (0·94 vs. 0·91, respectively), and a lower error of cross validation (9·03 vs. 11·5, respectively) than the best equation for reflectance method (DESIR samples). In final, both methods showed excellent capacity for quantitative analysis, with residual predictive deviations above 3. It is concluded that, regarding accuracy of prediction and time for obtaining results of IgG from bovine colostrum, NIRS analysis of liquid samples (transflectance) is recommended over dried samples (DESIR technique by reflectance).

Quarter vs. composite colostrum composition assessed by Brix refractometry, specific gravity and visual color appearance in primiparous and multiparous dairy cows

The control of colostrum quality is essential for successful calf rearing. Instruments for on-farm colostrum quality determination are mostly utilized for testing composite colostrum samples, but do not take potential variation between quarters into account. In cases of low composite colostrum quality, feeding of better quality colostrum from individual quarters might be beneficial. The objective of the present study was to identify relationships between colostrum color, colostrum quality and composition. Besides laboratory methods, a colostrometer and a Brix refractometer were used to assess colostrum quality at quarter levels. Quarter and composite colostrum samples from 17 primiparous and 11 multiparous Holstein cows were analyzed for total IgG, fat, protein and lactose content; color was measured by a spectrophotometer. In the present study, an IgG concentration below 50 g/L as determined by ELISA was found in 14.3% of the analyzed quarter samples. Concentration and mass of IgG in composite colostrum samples were greater in multiparous compared with primiparous cows. Specific gravity (SG) of colostrum of individual and composite samples was lower in primiparous compared with multiparous cows. Milk fat content was greater in quarter and composite colostrum samples of primiparous compared with multiparous dairy cows. No clear relationships between IgG content and SG, Brix, and the color space coordinates L*, a*, and b* were detected. Interestingly, results indicate that despite a similar range of the variables investigated, correlations between those parameters can differ at quarter compared to composite level. Not only for SG and Brix determination, but also for the color space coordinates measured, correlation coefficients with IgG concentration of the respective samples were greater at a composite compared with the individual quarter level. In conclusion, accuracy and limitations of on-farm instruments estimating colostrum quality apply to both quarter colostrum samples and composite evaluations. Identification of quarters with superior colostrum quality would possibly be a way to improve the immunization of newborn calves. However, the potential on-farm methods validated in the present study to estimate quarter colostrum quality are not sufficiently sensitive to distinguish between quarters. This is due to the variation of gross colostrum composition between individual quarters of a cow.

Diagnostic accuracy of refractometry for assessing bovine colostrum quality: A systematic review and meta-analysis

Provision of good quality colostrum [i.e., immunoglobulin G (IgG) concentration ≥50g/L] is the first step toward ensuring proper passive transfer of immunity for young calves. Precise quantification of colostrum IgG levels cannot be easily performed on the farm. Assessment of the refractive index using a Brix scale with a refractometer has been described as being highly correlated with IgG concentration in colostrum. The aim of this study was to perform a systematic review of the diagnostic accuracy of Brix refractometry to diagnose good quality colostrum. From 101 references initially obtain ed, 11 were included in the systematic review meta-analysis representing 4,251 colostrum samples. The prevalence of good colostrum samples with IgG ≥50g/L varied from 67.3 to 92.3% (median 77.9%). Specific estimates of accuracy [sensitivity (Se) and specificity (Sp)] were obtained for different reported cut-points using a hierarchical summary receiver operating characteristic curve model. For the cut-point of 22% (n=8 studies), Se=80.2% (95% CI: 71.1-87.0%) and Sp=82.6% (71.4-90.0%). Decreasing the cut-point to 18% increased Se [96.1% (91.8-98.2%)] and decreased Sp [54.5% (26.9-79.6%)]. Modeling the effect of these Brix accuracy estimates using a stochastic simulation and Bayes theorem showed that a positive result with the 22% Brix cut-point can be used to diagnose good quality colostrum (posttest probability of a good colostrum: 94.3% (90.7-96.9%). The posttest probability of good colostrum with a Brix value <18% was only 22.7% (12.3-39.2%). Based on this study, the 2 cut-points could be alternatively used to select good quality colostrum (sample with Brix ≥22%) or to discard poor quality colostrum (sample with Brix <18%). When sample results are between these 2 values, colostrum supplementation should be considered.

Covariance structures of fat and protein influence the estimation of IgG in bovine colostrum

On-farm instruments for assessing colostrum quality are needed in order to ensure that the calf is supplied with enough IgG to avoid failure of passive transfer. The aim of this study was to evaluate methods for estimating the IgG concentration in cows' colostrum. This research included 126 colostrum samples from 21 Danish farms with different breeds, ensuring a broad variation pattern in IgG, total protein and fat concentration. Approximately one third of the samples did not fulfil the recommendation of >50 g IgG/l colostrum, and the IgG concentration decreased with time from calving to milking. The ratio of IgG to total protein varied from 6 to 61%, however IgG and total protein were correlated with r2 = 0·70. The variation in fat was independent of variations in protein and IgG. The IgG concentration was measured by ELISA and compared to fast measurements by specific gravity by colostrometer, Brix by refractometer and prediction from infrared spectroscopy. The three fast methods were all correlated to the total protein concentration of colostrum; however specific gravity was also influenced by the fat concentration. Furthermore, specific gravity generally overestimated the IgG concentration, and the cut-off level should be raised to 1050 in order to ensure adequate IgG in colostrum. None of the methods estimated IgG concentration better than the correlation of total protein and IgG, meaning that they all depended on the indirect correlation between total protein and IgG. The results suggest that using a refractometer for quality control of colostrum is an easy and feasible method, and a cut-off level of Brix 22 seems sufficient to assure adequate IgG concentration in colostrum fed to the calf.