Predicting colostrum quality from performance in the previous lactation and environmental changes

Efficacy of an herbal formula Guixiong Yimu San in preventing retained placenta and improving reproductive performance in cows

Retained placenta is a common health issue, and appropriate prevention strategies are effective in postpartum health management. This study aimed to evaluate whether early intervention using GYS can prevent retained placenta and puerperal metritis, as well as enhance reproductive outcomes in cows. Each bovine in the GYS group (n = 591) received a single prophylactic dose of GYS (0.5 g/kg body weight) orally within 2 h after parturition, while those in the control group (n = 598) received no intervention. GYS treatment was associated with a decreased incidence of retained placenta (4.6% vs. 12.0%, P < 0.01, OR = 0.335), a lower puerperal metritis risk (8.8% vs. 20.1%, P < 0.01, OR = 0.369), and a reduced need for additional therapeutic antibiotics (11.2% vs. 26.1%, P < 0.01, OR = 0.342). We observed increases in the first service conception rate (59.7% vs. 49.1%, P < 0.01) and conception rate within 305 days postpartum (93.2% vs. 85.5%, P < 0.01) in the GYS group than in the control group. A significant decrease was observed in the number of services per conception (1.8 ± 1.1 vs. 2.1 ± 1.4, P < 0.01) and the calving-to-conception interval (83.6 ± 39.6 vs. 96.6 ± 52.5 days, P < 0.01) between the two groups. Additionally, GYS treatment increased milk yield on days 7, 14, and 28 postpartum without affecting milk fat, milk protein, somatic cell count (SCC), or milk urea nitrogen (MUN) on days 7 and 28 postpartum. Accordingly, the GYS was effective and safe in preventing retained placenta and to improve reproductive performance in cows. Therefore, it could be a prophylactic intervention for superior postpartum fertility in cows.

Creating models for the prediction of colostrum quantity, quality, and Immunoglobulin G yield in multiparous Jersey Cows from performance in the previous lactation and environmental changes

With multiparous Jersey cows, colostrum production seems to be variable. Due to this, we aimed to identify specific variables involved in colostrum production and quality. From 2021 to 2023, data from 28 US farms (415 multiparous Jersey cows) were used to investigate if colostrum yield, immunoglobulin G concentration (IgG, g/L), and IgG yield (g) could be predicted by farm variables and transmitting abilities. With the data collected, multiple regression equations were developed to aid in predicting colostrum yield, IgG concentration, and IgG yield. Colostrum was weighed and sampled for IgG analysis. Dairy Herd Information (DHI), calving, diet, and management information data were compiled. Days below 5°C (D <), d above 23°C (D >), and d between 5 and 23°C (D) were recorded. Transmitting abilities for milk, fat, protein, and dollars; previous lactation milk yield, fat percent, fat yield, protein percent, protein yield, previous lactation somatic cell score, previous lactation d open, previous lactation d dry, previous lactation d in milk, and previous parity; current lactation parity, d dry, and calving information, birth ordinal d, and latitude were evaluated. Colostrum yield, IgG yield, and concentration had 1 added to correct for values = 0. After addition, values >0 were transformed to ln or log10. Non-transformed variables were also used to develop the model. Variance inflation factor analysis was conducted, followed by backward elimination. The log10 colostrum yield model (r2 = 0.55; β in parentheses) included herd size (-0.0001), ordinal d (-0.001), Ln ordinal d (0.07), latitude (-0.02), dry period length (0.004), D < (-0.005), D (-0.003), time to harvest (0.05), Ln time to harvest (-0.35), IgG (-0.004), log10 IgG (0.46), feedings/d (0.06), Ln pasture access (-0.13), and Ln previous lactation d open (0.14). The model showed that previous lactation d open contributed the most toward increasing and latitude contributed the most toward decreasing colostrum yield. The IgG model (r2 = 0.21) included herd size (0.02), D > (0.38), Ln time to harvest (-19.42), colostrum yield (-4.29), Ln diet type (18.00), Ln previous lactation fat percent (74.43), and previous parity (5.72). The model showed that previous lactation milkfat percent contributed the most toward increasing and time from parturition to colostrum harvest contributed the most toward decreasing colostrum IgG concentration. The log10 IgG yield model (r2 = 0.79) included Ln ordinal d (0.03), time to harvest (-0.01), colostrum yield (-0.11), Ln colostrum yield (1.20), Ln pasture access (-0.09), Ln previous lactation fat percent (0.53), and previous parity (0.02). The model showed that colostrum yield contributed the most toward increasing IgG yield, followed by previous lactation milkfat percent. Pasture access contributed the most toward decreasing IgG yield, though the contribution is very small. These models were validated using 39 samples from 22 farms. Actual minus predicted colostrum yield and IgG concentration and yield were 0.89 kg, -21.10 g/L, and -65.15 g respectively. These models indicate that dry period management and cow information can predict colostrum yield, and IgG concentration and yield.

INVITED REVIEW: Nutritional and management factors that influence colostrum production and composition in dairy cows

Colostrum is a rich source of nutritional and non-nutritional components and is recognized as essential to transfer passive immunity to newborn calves. Because of the individual and seasonal variability in colostrum yield and composition, maintaining an adequate supply of high-quality colostrum year-round remains a challenge for commercial dairy producers. In this narrative review, we described the individual, seasonal, and herd-level variability of colostrum production and summarized the association between individual animal factors such as parity, sex of the calf, calf birth weight, as well as indicators of the cow's metabolic status and the yield and composition of colostrum. Further, we reviewed the current knowledge on the influence of prepartum nutrition and management strategies on colostrum production. Research on the metabolizable energy and protein supplied in the prepartum diet as well as into the inclusion and source of vitamins, minerals, and feed additives suggests prepartum nutrition influences the yield, quality, and composition of colostrum. Furthermore, the prepartum environment and dry period length remain influential factors in the production of colostrum. However, additional research is needed to understand the mechanisms by which prepartum nutrition and management affects colostrum production. Lastly, time to colostrum harvest and oxytocin administration as well as the current knowledge on the effect of heat-treatment and colostrum storage strategies on colostral components were discussed. To conclude, we identify critical gaps in knowledge for future focus of investigation in colostrum research.

Efficacy of oral administration of specific immunoglobulins in preventing neonatal calf diarrhoea in dairy herds

BACKGROUND

The aim of this study was to evaluate the efficacy of bovine concentrated lactoserum (BCL) containing specific immunoglobulin G against Escherichia coli, rotavirus and coronavirus in preventing neonatal calf diarrhoea (NCD).

METHODS

A total of 489 newborn calves from 35 herds were orally given either BCL or a placebo before the first feeding of colostrum and clinically supervised by the farmers for the first 14 days of life. The diarrhoea score was defined according to the following criteria: 0 = no diarrhoea; 1 = light diarrhoea without medical treatment; 2 = diarrhoea requiring oral treatment (rehydration and/or antibiotic therapy); and 3 = severe diarrhoea requiring parenteral rehydration or resulting in death.

RESULTS

A total of 138 calves suffered from diarrhoea (28%), and 65 (13%) showed signs of diarrhoea requiring treatment. The odds of getting NCD were reduced (odds ratio = 0.326; p < 0.001) in the BCL group. There was a tendency towards a reduction in the duration of NCD in the BCL group (2.25 (±1.7) days vs. 2.88 (±2.7) days in the placebo group) (p = 0.052). Furthermore, no calves died in the BCL group, whereas four calves died in the placebo group.

LIMITATIONS

Because of the design of the study using animals in practice, the mechanisms explaining the clinical findings remain as hypotheses. Diarrhoea scoring performed by farmers has to be analysed and interpreted with caution.

CONCLUSIONS

This study demonstrates that BCL as a single preventive treatment is effective in reducing the incidence of NCD even in a region with good general management of dairy calves and overall good colostrum quality.

Minerals and essential amino acids of bovine colostrum: Phenotypic variability and predictive ability of mid- and near-infrared spectroscopy

Colostrum quality and volume are fundamental for calves because it is the primary supplier of antibodies and the first source of energy, carbohydrates, lipids, proteins, minerals, and vitamins for the newborn. Assessing the detailed composition (i.e., AA and mineral content) of bovine colostrum (BC) on-line and at a reasonable cost would help dairy stakeholders such as farmers or veterinarians for precision feeding purposes and industries producing preparations containing BC such as foodstuff, supplements, and medicaments. In the present study we evaluated mid- (MIRS) and near-infrared spectroscopy (NIRS) prediction ability for AA and mineral composition of individual BC. Second, we the investigated the major factors affecting the phenotypic variability of such traits also evaluating the correlations with the Ig concentration. Results demonstrated that MIRS and NIRS were able to provide sufficiently accurate predictions for all the AA. The coefficient of determination in external validation (R2V) fell, in fact, within the range of 0.70 to 0.86, with the exception of Ile, His, and Met. Only some minerals reached a sufficient accuracy (i.e., Ca, P, S, and Mg; R2V ≥ 0.66) using MIRS, and also S (R2V = 0.87) using NIRS. Phenotypically, both parity and calving season affected the variability of these BC composition traits. Heifers' colostrum was the one with the greatest concentration of Ca and P, the 2 most abundant minerals. These minerals were however very low in cows calving in summer compared with the rest of the year. The pattern of AA across parities and calving season was not linear, likely because their variability was scarcely (or not) affected by these effects. Finally, samples characterized by high IgG concentration were those presenting on average greater concentration of AA. Findings suggest that infrared spectroscopy has the potential to be used to predict certain AA and minerals, outlining the possibility of implementing on-site analyses for the evaluation of the broad-sense BC quality.

Evaluation of laboratory and on-farm tests to estimate colostrum quality for dairy cows

The objectives of this study were to evaluate different analytical methods to determine colostrum quality in dairy cattle, including one laboratory-based method (ELISA) and 4 on-farm tests. We hypothesized that the colostral IgG concentration using different analytical methods, such as ELISA (mg/mL), digital Brix refractometer (% Brix), colostrometer (specific gravity and mg/mL), an outflow funnel (seconds), and a lateral flow assay (mg/mL), were highly correlated with the reference method, radial immunodiffusion (RID; mg/mL) and would generate comparable results. Colostrum samples were collected from 209 Holstein Friesian cows on 2 commercial dairy farms in Germany. Colostrum weight and colostrum temperature were measured. Test characteristics, such as optimum thresholds, sensitivity, specificity, and area under the curve (AUC) were determined using a receiver operating characteristic curve analyses for each test. Out of 209 colostrum samples assessed by RID, 186 (89%) samples had high quality (≥50 mg IgG/mL), while 23 colostrum samples (11%) showed poor quality with IgG concentrations less than 50 mg/mL. The mean IgG concentration (±SD) was 101.3 ± 45.9 mg/mL and the range was 6.0 to 244.3 mg/mL. The Pearson correlation coefficient (r) between RID and ELISA was r = 0.78. In comparison to RID, Pearson correlation coefficients for the on-farm tests were: r = 0.79 (digital Brix refractometry), r = 0.58 (colostrometer: specific gravity), r = 0.61 (colostrometer: temperature corrected), r = 0.26 (outflow funnel) and r = 0.43 (lateral flow assay), respectively. The optimal threshold to identify high-quality colostrum using ELISA was 50.8 mg/mL with sensitivity 91.3%, specificity 92.3%, and AUC of 0.94. For the on-farm tests sensitivity ranged from 95.7% (Brix refractometry) to 60.9% (lateral flow assay). Specificity ranged from 88.6% (lateral flow assay) to 75.9% (colostrometer: temperature corrected). The AUC ranged from 0.93 (Brix refractometry) to 0.73 (outflow funnel). Based on the AUC, ELISA (0.94) and Brix refractometry (0.93) can be considered highly accurate. In conclusion, the ELISA is accurate to assess colostrum quality. Regarding the on-farm tests only the digital Brix refractometer and the colostrometer were adequate to determine colostrum quality.

Invited review: Bovine colostrum, a promising ingredient for humans and animals-Properties, processing technologies, and uses

Mammalian colostrum, known as "liquid gold," is considered a valuable source of essential nutrients, growth factors, probiotics, prebiotics, antibodies, and other bioactive compounds. Precisely for this reason, bovine colostrum (BC) is an emerging ingredient for the feed, food, and pharmaceutical industries, being nowadays commercially available in a variety of forms in several countries. Moreover, quite a large number of functional foods and supplements for athletes, human medicines, pet nutrition plans, and complementary feed for some livestock categories, such as piglets and calves, contain BC. The amount of BC yielded by a cow after calving represents approximately 0.5% of the yearly output in dairy breeds. For its nutritional properties and low availability, BC is characterized by a greater market value and an increasing demand compared with other by-products of the dairy sector. However, information regarding the market size of BC for the food and pharmaceutical industries, as well as future developments and perspectives, is scarcely available in the scientific literature. This lack can be attributed to industrial secrecy as well as to the relatively small scale of the BC business when compared with other dairy products, which makes the BC market limited, specific, and intended for a restricted audience. From a legal perspective, regulations assign BC to the large family of milk-derived powders; thus, collecting specific production data, as well as import-export trend information, is not straightforward and can result in unprecise estimates. Given that the interest in BC is increasing in different fields, it is important to have an overview of the production steps and of pros and cons of this emerging ingredient. The present narrative review discloses why BC has started to be considered a product rather than a by-product of the dairy industry. Moreover, the present document aims to summarize the existing methodologies used to assess BC quality in terms of immunoglobulin concentration, the different applications of BC in the industry, and the BC processing technologies. Finally, a panoramic view of the current international market is provided for the first time for this dairy product.

The Effect of Parity on the Quality of Colostrum of Holstein Dairy Cows in the Organic Production System

A special feature of organic production systems is the cows' significantly lower productivity, which is adapted to environmental conditions. The quantity and quality of colostrum is negatively correlated, high amounts of colostrum are associated with low amounts of immunoglobulins. Cows' parity is also a modulating factor, and studies have shown an increase in colostral IgG corresponds with increasing parity. This study's aim was to determine the effect of cows' parity on colostrum quality, in an organic farm setting. From a basic organic herd of dairy cattle, 40 Polish Holstein-Friesian cows were selected: 10 cows each of primiparous, second lactation, fourth lactation, and fifth lactation. Colostrum and transition milk samples were taken from each cow seven times: twice daily on the 1st and 2nd days after calving (every 12 h), and once daily on the 3rd to 5th days. Multiparous cows' colostrum had higher levels of total proteins, casein, and non-fat dry matter, versus primiparous. Only cows in the second and fourth lactations produced very good quality colostrum (with immunoglobulins over 50 g/L), meeting standards for immunoglobulin concentration. In conclusion, the production of very good quality colostrum is limited during the first lactation, which may suggest the mammary gland is poorly developed, and, thus, immunoglobulin transport is limited. Variability in the colostrum's immunoglobulin content from first and second collections post-calving was higher in multiparous versus primiparous cows. Therefore, it should be good practice to freeze colostrum from multiparous cows in case of poor-quality primiparous colostrum.

Epidemiology of bovine colostrum production in New York Holstein herds: Cow, management, and environmental factors

Adequate supply of high-quality colostrum is essential for calf health. Colostrum production, at first milking, varies between animals and seasons, but herd-level and management associations with colostrum production have not been well described. Our objectives were to (1) describe colostrum production and colostrum handling practices and (2) to identify individual cow, herd management, and environmental factors associated with colostrum production. A convenience sample of 19 New York Holstein dairy farms (620 to 4,600 cows) were enrolled in this observational study to describe colostrum production and to evaluate cow, management, and prepartum environmental factors associated with colostrum yield and Brix %. Herd owners or managers were given a colostrum management questionnaire, and farm personnel recorded individual colostrum yield and Brix % for primiparous (PP; n = 5,978) and multiparous (MPS; n = 13,228) cows between October 2019 and February 2021. Temperature, relative humidity, and light intensity were measured by sensors placed in each farm's close-up dry cow pens for the entire length of the study. Median colostrum yield for each farm ranged from 2.5 to 7.6 kg for PP and 4.0 to 7.7 kg for MPS cows. Mean Brix % from each farm ranged from 22.2 to 27.9% for PP and 22.0 to 28.8% for MPS cows. Lowest colostrum yield from PP animals was associated with calf sex (female) and colostrum Brix % (≤22%). Greatest colostrum yield from MPS cows was associated with colostrum Brix % (≤22%), calf sex (twin), dry period length (>67 d), gestation length (283-293 d), an alive calf, second parity, previous lactation length (>344 d) and previous lactation 305-d mature equivalent milk yield (>13,091 kg), heat and humidity exposure area under the curve (AUC) 7 d before calving (>69.2 average temperature-humidity index per 30-min interval), and light intensity AUC 14 d before calving (>154.2 average lux per 15-min interval). Greatest colostrum Brix % from PP animals was associated with calf sex (male), an alive calf, and light intensity AUC 14 d before calving (≤64.0 average lux per 15-min interval). Greatest colostrum Brix % from MPS cows was associated with dry period length (>67 d), an alive calf, 305-d mature equivalent milk yield of previous lactation (≤15,862 kg), gestation length (274-282 d), colostrum yield (<6 kg), fifth or greater parity, and heat and humidity exposure AUC 7 d before calving (≤50.1 average temperature-humidity index per 30-min interval). Dairy producers can use this information to recognize the variation in colostrum production and alter colostrum management programs in anticipation of periods of low production or quality.

Programming effects of late gestation heat stress in dairy cattle

The final weeks of gestation represent a critical period for dairy cows that can determine the success of the subsequent lactation. Many physiological changes take place and additional exogenous stressors can alter the success of the transition into lactation. Moreover, this phase is pivotal for the final stage of intrauterine development of the fetus, which can have negative long-lasting postnatal effects. Heat stress is widely recognised as a threat to dairy cattle welfare, health, and productivity. Specifically, late gestation heat stress impairs the dam's productivity by undermining mammary gland remodelling during the dry period and altering metabolic and immune responses in early lactation. Heat stress also affects placental development and function, with relevant consequences on fetal development and programming. In utero heat stressed newborns have reduced birth weight, growth, and compromised passive immune transfer. Moreover, the liver and mammary DNA of in utero heat stressed calves show a clear divergence in the pattern of methylation relative to that of in utero cooled calves. These alterations in gene regulation might result in depressed immune function, as well as altered thermoregulation, hepatic metabolism, and mammary development jeopardising their survival in the herd and productivity. Furthermore, late gestation heat stress appears to exert multigenerational effects, influencing milk yield and survival up to the third generation.

Hazelnut Skin in Ewes' Diet: Effects on Colostrum Immunoglobulin G and Passive Transfer of Immunity to the Lambs

Passive immunity transfer has a pivotal role in newborn lambs, where the colostrum represents the primary source of immunoglobulins. This study hypothesized that the high content in polyphenolic compounds, mono- and poly-unsaturated fatty acids, and vitamin E of hazelnut skin affects blood and colostrum immunoglobulin G (IgG) concentration and related gamma-glutamyl-transferase (GGT) and lactate dehydrogenase (LDH) levels in sheep and their lambs. In the last 45 days of pregnancy, ewes were divided into a control (CTR) and a hazelnut skin supplemented group (HZN). Blood and colostrum were collected from ewes and lambs before the first suckling, at 24 and 48 h after birth, then IgG concentration, GGT and LDH activity levels were measured. IgG concentration in the colostrum and in lamb's serum were significantly greater in HZN than CTR. No significant difference was detected for ewe's blood. A significant positive correlation was found between IgG and GGT in lambs' serum and colostrum, between IgG and LDH, as well as between GGT and LDH in lambs' serum and colostrum. Our results suggest that hazelnut skin supplementation influences IgG colostrum concentration, with improved immune passive transfer to the suckling lambs. The transfer of maternal derived immune factors is confirmed by the GGT and LDH enzyme activity levels.

Changes in the Lactoferrin Concentration in the Bovine Colostrum During Postpartum Period

The health condition of the mammary gland is highly crucial for obtaining good quality colostrum. The lactoferrin (LF), as an iron-binding protein, plays a key role in the defense mechanisms of the mammary gland due to its’ bacteriostatic properties. The study aimed to investigate the factors affecting the LF concentration in the bovine colostrum milk during the postpartum period, and the effect of somatic cell count (SCC) on the LF concentration and milk composition. The cows were randomly selected at a dairy farm in Pelagonia region. Colostrum samples from 12 cows were collected. Samples were taken at different time intervals after parturition, 1, 6, 12, 24, 48, 72, 96, and 120 h after parturition. Cows in their second parity were found to have higher levels of LF compared to cows in the third and higher parity (p>0.05). Time had a significant effect on the LF concentration (p<0.01), with the highest value recorded 1 h after parturition remaining stable for one hour. LF concentration and SCC in the colostrum showed a weak positive correlation (r=0.40; p<0.01). The highest LF concentration was noticed when SCC was above 800,000 cells/mL. In conclusion, the colostrum LF concentration was significantly affected by the interactions of the two factors, i.e., time after parturition and SCC (p<0.05). Milk composition was affected by elevated SCC. Parity showed no association with LF. The SCC can be used as a reliable means of assessing colostrum quality.

Delayed First Milking in Unassisted Overnight Calving Did Not Affect the Quality of Colostrum but Influenced Serum Brix Refractometry in Holstein Calves at Two Days of Life

Timely administration of good-quality colostrum represents the first farm strategy to avoid the failure of passive transfer (FPT). However, calves born during the night are likely to be fed later than recommended. Our aim was to evaluate whether night-occurring calving and delayed first milking affected colostrum quality and immune passive transfer. The dataset included 463 calvings. Four liters of colostrum were administered by an esophageal tube feeder. The mean Brix% of colostrum was 27.43%, while serum Brix% at two days of life in calves was 10.19%. According to the Generalized Linear Model, parity ≥ 4, calving months of March, April, and from September to November positively influenced the quality of colostrum. Dams carrying a male calf produced lower quality colostrum compared with those carrying a female calf (−2.78 ± 1.04 Brix%, p = 0.008); heavier female calves were associated with greater colostrum quality (0.29 ± 0.05 for each kg increase, p < 0.001). Night- or day-calving had no effect on the quality of colostrum. The only factor influencing the serum Brix% of female Holstein calves at two days of life was the day- or night-occurring birth (−0.386 ± 0.188 Brix% in calves born during the night, p = 0.04). Our results showed that calves born overnight and fed the day after had decreased serum Total Protein concentrations as indicated by reduced Brix refractometer readings, compared with calves born during the day and fed quickly after birth. However, the administration of 4 L of high-quality colostrum likely improved their serum Brix% at two days of life. Alternatively, where the prevalence of good-quality colostrum is lower, improving calving supervision and ensuring timely feeding are important to reduce the risk of FPT.

Associations between putative risk factors and poor colostrum yield in Holstein Friesian cattle

When dairy cows produce little or no colostrum, calves are likely to suffer from failure of passive transfer (FPT). Volume of colostrum produced by the dam may be affected by: nutrition; environmental conditions; time from calving to milking; parity; dry period length; calving difficulty; calf weight; calf sex; calf viability; cow BCS / body weight; milk production in previous lactation and dam health. While risk factors for poor IgG concentration in colostrum have been extensively studied, there is little published literature on low colostrum yields and associated risk factors. The aim of this observational study was to identify risk factors for poor colostrum yield in dairy cows and to quantify the effect of variation in those variables that the farmer can directly control (length of dry period, and close-up transition period nutrition) using inverse probability modelling. 439 animals from a single Scottish dairy farm were used as a convenience sample. First milking colostrum yield was measured by farmers using a graduated bucket. For each animal, risk factor data and meteorological data from the nearest weather were obtained. Decreased colostrum yield was associated with increasing daily temperature range, while increasing UV index, lactation number and number of days dry increased colostrum yield. Marginal effect models revealed that for each additional day of dry period, colostrum yield increased. Higher UV indices the month before calving were positively associated with colostrum yield, particularly in primiparous cows, and higher temperatures in the months before calving were positively associated with colostrum yield in all cows.

Colostrum Management: Keys to Optimizing Output and Uptake of Immunoglobulin G

Colostrum is essential for the health and wellbeing of dairy cattle. This review provides insight into different means of augmenting or enhancing colostrum quality including colostrum feeding, dry cow management, prepartum cow diets, freezing, pasteurization, colostrum additives, and colostrum replacers. Other components in colostrum such as maternal cells and their importance are discussed. New research is needed regarding the components in colostrum (bioactive peptides and growth factors) and their effects on the neonate. Colostrum replacers and a prediction equation to estimate colostrum quality are reviewed.

Effectiveness of visible - Near infrared spectroscopy coupled with simulated annealing partial least squares analysis to predict immunoglobulins G, A, and M concentration in bovine colostrum

Visible - near infrared spectroscopy coupled with variable selection using simulated annealing PLS regression was tested to predict immunoglobulin fractions (g/L) of bovine colostrum, namely IgG, IgA and IgM. Immunoglobulins were quantified in 678 samples using the gold standard radial immunodiffusion. Samples were divided in calibration (50%) and validation (50%) datasets. Maximum number of selected variables were limited to 200 and root mean squared error in cross validation (RMSE_CV) was used as loss function. Performance of the final model developed using the calibration dataset was assessed on the validation dataset. Overall, simulated annealing PLS improved validation RMSE_CV compared to ordinary PLS regression by 3% to 17%. The present study demonstrated the effectiveness of the calibration model for accurate quantification of IgG, the most abundant immunoglobulin of bovine colostrum (RMSE_CV = 13.28 g/L; R² = 0.83). These outcomes could be useful to assess colostrum quality intended for animal and human usage.

Heat treatment of colostrum at 60°C decreases colostrum immunoglobulins but increases serum immunoglobulins and serum total protein: A meta-analysis

Calves are born hypogammaglobulinemic; thus, the newborn calf's immune defense relies on the ingestion and absorption of colostrum, which provides energy, immunoglobulins, immune cells, and cytokines to the newborn calf. A heat treatment applied to colostrum for 60 min at 60°C has been found to be effective at reducing the total bacterial count while preserving the colostrum IgG levels. The objective of this work was to perform a meta-analysis on the association between the characteristics of heat-treated colostrum and the concentration of colostrum IgG, serum IgG concentration, and serum total protein (STP). A meta-analysis was carried out based on existing peer-reviewed literature. Publications comparing colostrum IgG, serum IgG, and STP for heat-treated or raw frozen colostrum were included. The different heating temperatures applied to the colostrum were divided into 2 subgroups: high temperature (HT; > 60°C) and low temperature (LT; ≤ 60°C). Twelve studies, including 21 trials, met the inclusion criteria for colostrum IgG concentration. The results indicated decreases in colostrum IgG by 20.6 g/L [95% confidence interval (CI) = 11.8-29.4] for HT and 5.38 g/L (95% CI = 2.9-7.8) for LT when colostrum was heat-treated compared with raw or frozen colostrum. Heterogeneity was high to moderate (I² = 82% for HT and 65% for LT). The heat treatment of colostrum was also associated with a nonsignificant decrease in serum IgG by 3.40 g/L for HT (95% CI = 7.54-0.74) but a significant increase in serum IgG by 2.65 g/L for LT (95% CI = 1.51-3.79). The regression model indicated that heterogeneity was not explained by any moderators. The heat treatment of colostrum was also associated with a significant increase in STP by 0.21 g/dL for LT (95% CI = 0.07-0.35). In conclusion, the present work demonstrated that the heat treatment of colostrum ≤60°C decreased colostrum IgG by 5.38 g/L for LT and increased serum IgG by 2.65 g/L and STP by 0.21 g/dL. When compared with the range of values observed in the field for serum IgG, the present results are of high interest for the cattle industry. Because immune colostrum benefits also include cytokines and immune cells, further work is required to evaluate the effect of colostrum heat treatment on these 2 immune components of colostrum.

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.

The concentrations of immunoglobulins in bovine colostrum determined by the gold standard method are genetically correlated with their near-infrared prediction

Background

The quality of colostrum administered to calves is based on its concentration in immunoglobulins G (IgG, g/L). Immunoglobulins A (IgA) and M (IgM) are also present but at a lower level. The gold standard reference analysis for these traits, radial immunodiffusion, is time-consuming and expensive. In order to define breeding strategies that are aimed at improving colostrum quality in dairy cattle, a large amount of data is needed, and the use of indicator traits would be beneficial. In the study presented here, we explored the heritabilities of reference (radial immunodiffusion) and near infrared-predicted IgG, IgA, and IgM concentrations and estimated their genetic correlations. First, the colostrum of 765 Holstein cows from nine herds was sampled to perform a reference analysis and the near-infrared spectra (400–2500 nm) were stored. We used a calibration set (28% of the initial samples) that was representative of the herds and cow parity orders to develop prediction equations for IgG, IgA, and IgM concentrations. Finally, these traits were predicted in the validation set (72% of the initial samples) to estimate genetic parameters for the predictions. Genetic correlations between reference and predicted values of each trait were estimated through bivariate linear animal models.

Results

The three near-infrared-predicted immunoglobulin fractions were genetically correlated with their reference value. In particular, the reference and predicted IgG concentrations were strongly correlated at both the genetic (0.854 ± 0.314) and phenotypic level (0.767 ± 0.019). Weaker associations were observed for IgA and IgM concentrations, which were predicted with lower accuracy compared to IgG. Simulation analyses suggested that improving colostrum quality by selective breeding in Holstein cattle based on near-infrared predicted colostrum immunoglobulins concentrations is feasible. In addition, less than 10 mL of colostrum are needed for spectra acquisition and thus implementation of such analyses is possible in the near future.

Conclusions

The concentrations of colostrum immunoglobulins can be predicted from near-infrared spectra and the genetic correlation between the reference and the predicted traits is positive and favourable, in spite of the large standard errors of the estimates. Near-infrared spectroscopy can be exploited in selective breeding of dairy cattle to improve colostral immunoglobulins concentration.

A Scoping Review of On-Farm Colostrum Management Practices for Optimal Transfer of Immunity in Dairy Calves

Newborn calves are agammaglobulinemic and rely for their first immune protection almost completely on the transfer of immune constituents via colostrum. Inadequate colostrum management practices such as on-farm colostrum storage practices and colostrum feeding methods could affect immune components in colostrum and subsequently immune status of the newborn calf. We conducted a scoping review to identify all literature on the interactions between several colostrum management factors and immunological colostrum quality and passive transfer of immunity. Three major stages were defined: milking methods, colostrum treatment and storage, and administration procedures. Separate CAB Abstracts searches were performed for each of the subjects of interest. The search process was completed on November 9, 2020. Colostrum should be milked as soon as possible, as IgG concentration diminishes over time, probably due to dilution. To minimize bacterial contamination, it is advised to pasteurize colostrum in small batches at maximal 60°C for 30 or 60 min. Freeze/thawing of colostrum does not or only slightly affect IgG concentrations, as long as thawing is done au bain-marie and temperature does not exceed 40°C. In on-farm situations, it is difficult to determine the volume that should be fed as the variables contributing to the absorption of IgG by the newborn calf are many and include the quality of the colostrum, the bacterial contamination, the time interval between birth and first moment of feeding and the weight of the calf. Despite all knowledge regarding optimal colostrum management strategies, it remains challenging to predict the effects of certain colostrum management choices in field conditions. Therefore, we recommend measuring the colostral quality, weighing the newborn calf, adjusting the feeding volume accordingly to ensure optimal colostrum intake for each calf.

Variation of immunoglobulins G, A, and M and bovine serum albumin concentration in Holstein cow colostrum

Immunoglobulins G (IgG), A (IgA), and M (IgM) represent 70-80% of total proteins in cattle colostrum and are essential for the passive transfer of antibodies from the dam to the calf. Considering the practical difficulties of colostrum sample collection and the high cost of analysis, non-genetic sources of variation of the three immunoglobulins fractions have been scarcely studied together on a large scale in dairy cows. In the present study, IgG, IgA, IgM, and bovine serum albumin (BSA) were determined in colostrum samples of Holstein cows through bovine-specific radial immunodiffusion kits; such phenotypes allowed to investigate the effects of parity, herd, and calving season, and interactions. Only the first colostrum was considered in the present study, as the calf was separated from the dam immediately after birth and was not allowed to suckle. The average of IgG (n = 676), IgA (n = 573), IgM (n = 658), total immunoglobulins (n = 525), and BSA (n = 614) was 91.31, 4.20, 105.99, 5.05, and 2.47 g/L, respectively, and all traits positively correlated to each other. Overall, the immunoglobulins were less concentrated in colostrum of first- and second-parity cows than later-parity cows. These findings suggest that colostrum quality, based on Ig, is overall greater in cows that experienced more than two lactations, likely due to a greater experience of the immune system and to a wider immune heritage compared to younger cows. As regards the effect of calving season, the concentration of all Ig tended to be generally greater in colostrum sampled from August to November. Moreover, there were differences in IgG, IgA, and IgM concentration among the nine herds involved. Future studies will investigate the relationships of these traits with yield, and gross and detailed composition of bovine colostrum and will consider their genetic background to evaluate potential selection strategies to improve colostrum quality.

Predicting colostrum and calf blood components based on refractometry

Provision of good quality colostrum is essential for the passive immunity and nutrition of newborn calves. In order to better predict the quality of colostrum and the transfer of passive immunity, the relationships between colostrum components and between calf serum components were examined in this study. Samples of bulk tank milk, colostrum pooled from several cows 0-4 d postpartum, and colostrum collected from individual cows twice daily for 3 d post-partum were compared. With the exception of fat percentage, there were strong correlations between the levels of the components in the pooled colostrum and in the individual cow colostrum collected 0-1 d postpartum. The correlations between total solids as measured by Brix refractometry and total protein, immunoglobulin G (IgG), lactose % and protein % in colostrum within 1 d postpartum and pooled colostrum were 0.92, 0.90, -0.88 and 0.98, respectively. These high correlations enabled these colostrum components to be accurately predicted from Brix % and therefore, the volume of colostrum required to feed neonate calves can be optimised based on Brix refractometry to avoid failure of passive immunity transfer. To assess whether the components obtained from colostrum were correlated in calf blood, newborn calves were separated from their dams before suckling and blood sampled before feeding (day 0), and on days 1 and 7, after receiving colostrum or milk twice a day. The correlations between glucose, total protein, IgG, and gamma-glutamyl transferase (GGT) levels in the calf blood were lower than the correlations observed between the colostrum components. The highest correlation was between serum protein measured by refractometer and serum IgG within one week postpartum. GGT activity was not a good indicator of serum IgG levels. However, serum protein refractometer measurements predicted serum IgG level with high accuracy, providing an on-farm test to determine that calves have received sufficient passive immunity and colostrum components.

The impact of elective caesarean section on colostrum characteristics in double-muscled Belgian Blue cows

Identification of factors associated with the quality and quantity of colostrum production has always been a major challenge in cattle industry. In purebred double-muscled Belgian Blue (BB) cows, parturition is mainly performed by elective caesarean section (CS; >90%). However, the CS itself may influence colostrum production characteristics. The present study aimed to evaluate the impact of maternal and newborn calf factors and the duration of the procedure of CS on the quality and quantity of colostrum production in BB cows. The dataset includes 551 records of cow-calf pairs that were presented for an elective CS at the Ghent University veterinary clinic between 2017 and 2019. The quality (measured via a colostrum densimeter) and the quantity (measured via a standard volume scale) of colostrum were measured within 30 min after the end of the CS. Fixed effects were fitted in mixed linear regression models to test for their potential association with colostrum quality (specific gravity; SG) and quantity (liters), and generalized mixed-effects models were constructed to test the associations of fixed effects with the optimal colostrum production index (yes vs no) based on an adequate supply of both colostrum quality and quantity. The fixed effects tested were parity, the gender of the calf, birth weight, duration of CS (min), and season of birth. Our results show that parity (primiparity), duration of CS (longer CS), and calving season (summer) had a significantly negative impact on colostrum production. Concluding, both colostrum quality and quantity can be influenced by intrinsic and extrinsic factors (including duration of CS), which should be considered while feeding newborn calves delivered via CS.

Effects of Melatonin on Dairy Herd Improvement (DHI) of Holstein Cow with High SCS

Mastitis is a common disease in cows breeding. The milk quality will be significantly reduced with increased milk somatic cells, which often occurs in cows with mastitis. In this study, the influence of seasonal changes, age and lactation stages in the Dairy Herd Improvement (DHI) of cows was investigated. Then, the Dairy Herd Improvement (DHI) of cows with high somatic cell score (SCS) after melatonin treatment was systemically investigated. The results showed that melatonin significantly suppressed the milk somatic cell score under all of the tested conditions. The melatonin treatment also improved the milk nutritional value by reducing its fat but increasing its lactose and protein contents. The application of melatonin significantly improved the DHI. The beneficial effects of melatonin on DHI are likely attributed to the antioxidant and anti-inflammatory activities of melatonin.

Colostrum composition and immunoglobulin G content in dairy and dual-purpose cattle breeds

Immunoglobulins (Ig) are essential components in the colostrum of bovine species that enable passive immunization of newborn calves. Concentrations of fat and protein are greater in colostrum compared with mature milk and represent a vital source of energy and nutrients. Colostral IgG was shown to vary between individual dairy cows, but comparative data on different breeds and performance levels are scarce. The objective of the present field study was to investigate the contents of total IgG, fat, protein, and lactose in colostrum in different Swiss and German dairy and dual-purpose breeds. We collected colostrum samples of 458 cows of 13 different breeds (dairy breeds: Brown Swiss, Swiss and German Holstein Friesian, and New Zealand Holstein; dual-purpose breeds: German Fleckvieh, Holstein Friesian × Montbéliarde, Montbéliarde, Murnau-Werdenfels, Original Braunvieh, Pinzgauer, Rhetic Gray, and Simmental; and beef-type crossbred: Charolais × Holstein Friesian). Colostrum samples were obtained between 5 and 900 min after calving and analyzed for total IgG, fat protein, and lactose contents. Immunoglobulin G concentrations varied between 12.7 and 204.0 mg/mL. No effect of breeding purpose (i.e., dairy or dual-purpose) nor of previous lactation yield on IgG content was observed. However, milking of cows for the first time later than 12 h after parturition resulted in lower colostrum IgG concentrations compared with colostrum harvest within 9 h after calving (P < 0.05). Multiparous cows had a higher colostral IgG concentration than primiparous cows (P < 0.0001). Overall, concentrations of IgG and other constituents in colostrum varied widely in the different cattle breeds. High-yielding dairy cows did not have poorer colostrum quality compared with lower-yielding animals or beef and dual-purpose breeds, which suggests an individually different transfer of circulating IgG into colostrum.

Short communication: Comparative estimation of colostrum quality by Brix refractometry in bovine, caprine, and ovine colostrum

Newborn ungulates depend on the timely supply of colostrum containing sufficient immunoglobulins to obtain passive immunity against disease. Brix refractometry enables a rapid on-farm estimation of colostrum quality and has been intensively studied in bovines. However, the suitability of Brix refractometers for assessing colostrum quality in goats and ewes has been scarcely evaluated. The present study compared bovine, caprine, and ovine colostrum quality estimation using an optical Brix refractometer. In addition, between-species variations in the relationships between Brix values and colostrum constituents (IgG, fat, protein, and lactose) and the accuracy of Brix refractometry at different cutoff values were evaluated by a receiver operating characteristic curve analysis. We measured the Brix value and contents of IgG, fat, protein, and lactose in 324 colostrum samples (108 cows, 116 does, and 100 ewes). Thresholds for classification of good colostrum quality (as determined by ELISA) were set at 50 mg IgG/mL in cows and 20 mg/mL in does and ewes. Bovine colostrum showed the greatest IgG concentrations compared with caprine and ovine colostrum. Fat and protein content was higher in sheep colostrum compared with the other species, whereas the highest lactose concentrations were detected in goat colostrum. Brix values ranged from 11.4 to 34.6% (22.1 ± 4.2%; mean ± standard deviation), 15.4 to 40.0% (28.5 ± 6.8%), and 8.8 to 39.8% (21.6 ± 5.3%) in bovine, ovine, and caprine colostrum, respectively. In all 3 species, Brix was highly correlated with IgG and protein concentrations (cows, r = 0.83 and 0.98; goats, r = 0.83 and 0.89; sheep, r = 0.75 and 0.87). Optimal cutoff points for greatest accuracy of Brix measurements were 19.3% Brix in cows [with 87.1% sensitivity (Se) and 100% specificity (Sp)], 20.7% Brix in does (with 53.5% Se and 100% Sp), and 26.5% Brix in ewes (with 75% Se and 91.3% Sp). In conclusion, Brix refractometry is an acceptable tool for on-farm estimations of colostrum quality in does and ewes despite distinct between-species variations in colostrum composition.

Use of somatic cell count as an indicator of colostrum quality

The impact of cow mammary gland diseases on the quality of colostrum is not conclusively defined; research results are conflicting. However, it is widely believed that mastitis lowers the level of immunoglobulins and the quality of the colostrum produced. Therefore, the aim of this study was to determine the influence of somatic cell counts (SCC) on the colostrum immunostimulating and chemical components. The experiment was conducted on an experimental organic dairy farm in which a herd of approximately 250 cows was kept in a freestall housing system, with the average performance exceeding 6,000 kg of milk per lactation. Colostrum and milk samples were taken individually from each cow seven times during the experiment: from the first to second day after calving–twice per day, and from the third to fifth day after calving–once per day. Therefore, after preliminary analyses, the cows were divided into two groups based on the cytological quality of their colostrum at the first collection: 1. SCC ≤400,000 cells/ml (good quality colostrum; GCC– 18 cows), 2. SCC ≥ 400,000 cells/ml (low quality colostrum; LCC– 22 cows). The study found almost double the concentration of immunoglobulins and essential fatty acids in first milking colostrum in the GCC group than in colostrum from the LCC group. In addition, an increase in the concentration of lysozyme in first milking colostrum was associated with a decrease in the concentration of immunoglobulins. In addition, the increase in the level of lysozyme was associated with a decrease in the concentration of immunoglobulins. In conclusion, the SCC of first milking colostrum can be used as an indicator of colostrum quality.

Nutrition and feeding of dairy cattle

Feeding dairy cattle utilize the sciences of nutrition, biochemistry, and microbiology and combine them with animal husbandry. In this chapter, we will discuss the nutrients and how they are integral for dairy cattle performance (growth and milk production). We will evaluate the feeding of calves and heifers along with some brief practical feeding recommendations for dry and prepartum cows.

Symposium review: Colostrum management and calf nutrition for profitable and sustainable dairy farms

Multistate dairy management research project NC-2042, which is part of the National Institute of Food and Agriculture, has devoted an ongoing objective to calf and heifer nutrition and management. Within this objective, colostrum research has been a priority due to continued opportunities to improve this area on US dairy farms. Research has focused on heating colostrum to reduce bacterial populations and pathogens while increasing IgG absorption. Research also identified other proteins that are reduced when heating colostrum. Studies indicated an apparent upper limit to IgG absorption from colostrum fed to calves. Additional studies have shed light on absorption of IgG from colostrum replacers and evaluated the use of lactoferrin and sodium bicarbonate in both maternal colostrum and colostrum replacers. Milk replacer formulation, feeding strategies, and the effect of calfhood nutrition on future performance have also been researched. Finally, water quality and its effect on calves and heifers have been studied. This review focuses on research done by multistate research project NC-2042 member states in the area of colostrum and calf nutrition and management.

Pattern of milk yield and immunoglobulin concentration and factors associated with colostrum quality at the quarter level in dairy cows after parturition

First colostrum yield and constituents as well as milk yield during established lactation vary considerably among mammary quarters in dairy cows. However, data on the development of milk yield, IgG concentration, and their distribution per quarter within cows during the first milkings after calving are scarce. We analyzed milk production and IgG concentration at the individual quarter level in 29 multiparous Holstein cows during the first 5 milkings after calving. Cow- and calf-related factors (time interval between calving and first milking, parity number, previous lactation yield, gestation length, dry period length, sex, and birth weight of the calf) potentially affecting first colostrum quality and quantity were assessed. Milking of first colostrum was carried out between 30 and 180 min after parturition. Further milkings were performed twice daily. Quarter milk yield varied between 0.1 and 5.5 kg at the first milking and between 1.4 and 5.1 kg at the fifth milking relative to parturition. Quarter IgG concentration ranged between 18.8 and 106.0 mg/mL at the first milking and between 0.8 and 46.1 mg/mL at the fifth milking. Distribution of milk yield and IgG concentration among quarters was not entirely repeatable during the first 5 successive milkings after parturition; that is, the ranking of quarters changed (intraclass correlation coefficients for quarter milk yield and IgG concentration: 0.64 and 0.79, respectively). The average hourly milk production increased in all quarters, ranging from 0.02 to 0.26 kg/h between the first 2 milkings up to 0.11 to 0.45 kg/h between the fourth and fifth milkings. First colostrum yield was not affected by any of the evaluated cow- and calf-related factors. Quarter colostrum IgG concentration was higher in cows with a higher previous lactation yield, whereas a lower colostrum IgG content was observed in cows with a longer gestation period and consequently heavier calves. In conclusion, milk yield and IgG concentration of individual quarters varied considerably, and their distribution among quarters within cows was moderately repeatable in consecutive milkings and changed partially over time. The decline of IgG concentration was independent of the concomitant increase in milk secretion, with changes occurring at different rates in individual quarters. Our results confirm the independence of the single mammary quarters at the onset of lactation despite an identical exposure to endocrine stimuli.

Changes in the content of immunostimulating components of colostrum obtained from dairy cows at different levels of production

BACKGROUND

Recent data indicate that almost 60% of colostrum samples do not have enough antibodies to provide adequate protection for the calf. Thus, the aim of this study was to determine the influence of the level of production of cows on the content of immunostimulating components of protein fraction of colostrum. The observations were conducted on two farms that keep dairy cows. One of the farms was selected to represent a typical performance level for the mass population of dairy cows in Poland, about 5500 kg of milk per cow per year (LI) and the second one was characterized by a higher level of production, about 8000 kg (HI).

RESULTS

Based on the data obtained, 100% of the samples collected from LI had an immunoglobulin G (IgG) content >50 gL^-1 , in the first collection. In the case of HI, 63% of the samples had an IgG content >50 gL^-1 , with a distribution in the range of 10.7 to 72.7 gL^-1 . The colostrum of LI cows was characterized by a higher content of lactoferrin, lysozyme, α-lactalbumin, and β-lactoglobulin compared to the milk of HI cows.

CONCLUSIONS

The immunostimulating components of colostrum declined rapidly in subsequent milkings or with the increased productivity of the cows. The concentration of IgG was negatively correlated with the performance level of cows, which means that high-producing cows had colostrum with a low concentration of IgG. © 2018 Society of Chemical Industry.

Preweaned heifer management on US dairy operations: Part II. Factors associated with colostrum quality and passive transfer status of dairy heifer calves

Passive transfer of immunity is essential for the short- and long-term health of dairy calves. The objective of this study was to evaluate factors associated with colostrum quality and passive transfer status of US heifer calves. This study included 104 operations in 13 states that participated in the calf component of the National Animal Health Monitoring System's Dairy 2014 study. This 18-mo longitudinal study included 1,972 Holstein heifer calves from birth to weaning. Multivariable mixed linear regression models were selected using backward elimination model selection after univariate screening to determine which factors were associated with colostrum IgG and serum IgG concentrations. The mean colostrum IgG concentration was 74.4 g/L with 77.4% of colostrum samples having IgG concentrations >50 g/L. The final model for colostrum IgG included colostrum source and a categorized temperature-humidity index value (cTHI) for the month before calving. Mean colostrum IgG concentrations were highest for dams in third and higher lactations (84.7 g/L) and lowest for commercial colostrum replacers (40.3 g/L). Colostrum IgG concentrations were highest for cTHI ≥70 (72.6 g/L) and lowest for cTHI <40 (64.2 g/L). The mean serum IgG concentration was 21.6 g/L, with 73.3% of calves having serum IgG concentrations >15 g/L. The final model for serum IgG concentration included region, heat treatment of colostrum, colostrum source, timing to first feeding, volume of colostrum fed in the first 24 h, age of the calf at blood sampling, and colostrum IgG concentration. Mean serum IgG concentrations were highest for calves that received colostrum from first-lactation dams (25.7 g/L) and lowest for calves fed commercial colostrum replacer (16.6 g/L). Serum IgG concentrations were higher for calves fed heat-treated colostrum (24.4 g/L) than for calves fed untreated colostrum (20.5 g/L). Serum IgG concentration was positively associated with the volume of colostrum fed in the first 24 h and colostrum IgG concentration, and negatively associated with the number of hours from birth to colostrum feeding and age (days) at blood collection. Dairy producers should be encouraged to measure the quality of colostrum before administering it to calves and to measure serum IgG or a proxy such as serum total protein or Brix to evaluate passive immunity and colostrum management programs.

Evaluation of factors associated with immunoglobulin G, fat, protein, and lactose concentrations in bovine colostrum and colostrum management practices in grassland-based dairy systems in Northern Ireland

The objectives of this study were to investigate colostrum feeding practices and colostrum quality on commercial grassland-based dairy farms, and to identify factors associated with colostrum quality that could help inform the development of colostrum management protocols. Over 1 yr, background information associated with dairy calvings and colostrum management practices were recorded on 21 commercial dairy farms. Colostrum samples (n = 1,239) were analyzed for fat, protein, lactose, and IgG concentration. A subset was analyzed for somatic cell count and total viable bacteria count. Factors associated with nutritional and IgG concentrations were determined using both univariate and multivariate models. This study found that 51% of calves were administered their first feed of colostrum via esophageal tube, and the majority of calves (80%) were fed >2 L of colostrum at their first feed (mean = 2.9 L, SD = 0.79), at a mean time of 3.2 h (SD 4.36) after birth, but this ranged across farms. The mean colostral fat, protein, and lactose percentages and IgG concentrations were 6.4%, 14%, 2.7%, and 55 mg/mL, respectively. The mean somatic cell count and total viable count were 6.3 log₁₀ and 6.1 log₁₀, respectively. Overall, 44% of colostrum samples contained <50 mg/mL IgG, and almost 81% were in excess of industry guidelines (<100,000 cfu/mL) for bacterial contamination. In the multivariate model, IgG concentration was associated with parity and time from parturition to colostrum collection. The nutritional properties of colostrum were associated with parity, prepartum vaccination, season of calving, and dry cow nutrition. The large variation in colostrum quality found in the current study highlights the importance of routine colostrum testing, and now that factors associated with lower-quality colostrum on grassland-based dairy farms have been identified, producers and advisers are better informed and able to develop risk-based colostrum management protocols.