牛初乳中免疫球蛋白的测定

以单向免疫扩散法测定了牛初乳中的IgG。结果表明,产犊后第1次挤乳,初乳gG平均为67.23mg/mL,之后随泌乳进行迅速下降,24h后降到小于5mg/mL,到第5天已降到常乳水平。     

AOT-异辛烷反胶束萃取技术分离牛初乳IgG的研究

在一个琥珀酸二(2-乙基己基)酯磺酸钠(AOT)-异辛烷反胶束体系中，研究了水相pH值、离子强度和有机相表面活性剂AOT浓度等因素对牛初乳乳清蛋白中IgG分离效果的影响。结果表明，在以下两组优化条件：①pH值为7．668，[Na^ ]浓度为0．270mol／L，[AOT]浓度为0．088mol／L；②pH值为6524，[Na^ ]浓度为0．205mol／L，[AOT]浓度为0．175mol／L，水相IgG的残留率或纯度分别达到最大值，分别为90．23％和98．35％．RID分析表明，反胶束萃取过程对原牛初乳乳清IgG的免疫反应活性基本无影响。     

Effect of heat treatment of bovine colostrum on bacterial counts, viscosity, and immunoglobulin G concentration

A study was conducted to identify the optimal temperature and time at which heat treatment of bovine colostrum would least change viscosity and IgG concentrations yet reduce bacterial count. First-milking colostrum with >50 g of immunoglobulins/L (measured by colostrometer) was collected from 30 Holstein cows. Aliquots of colostrum were heated for 0, 30, 60, or 90 min at 57, 60, or 63°C in a water bath. Samples were examined for viscosity, IgG₁, and IgG₂ concentrations, standard plate count, coagulase-negative staphylococci, environmental streptococci, coliform, gram-negative noncoliform, Streptococcus agalactiae, and Staphylococcus aureus counts. All heat treatments reduced counts of all bacteria groups measured compared with untreated colostrum samples. Heat treatment at ≥60°C denatured IgG₁ compared with untreated colostrum; however, colostral IgG₂ levels were not reduced when temperature was held at 60°C for <60 min. Viscosity was not affected when temperature was held at 60°C for <60 min. In this study, heat treatment of bovine colostrum at 60°C for 30 or 60 min reduced bacterial count, slightly reduced IgG concentration, and did not affect viscosity.     

乳制品中牛IgG含量间接竞争性ELISA检测方法的研究

建立了牛初乳制品和添加了牛初乳成分的乳制品中牛IgG含量间接竞争性酶联免疫吸附测定方法,主要研究步骤包括:制备牛IgG保守区(Fc段),以Fc段为免疫原免疫Balb/C小鼠,取其脾细胞进行细胞融合,制备特异性单克隆抗体及合成适合实际测定用途的ELISA试剂盒。应用本研究建立的方法对标准品和实际样品进行牛IgG含量检测的结果表明,该方法回收率在78.9%～117.5%,批内变异系数小于10%,批间变异系数小于15%,检测结果稳定可靠,可满足目前国内牛初乳制品和添加了牛初乳成分的乳制品品质监控的需要。     

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.     

Evaluation of the effects of ultraviolet light on bacterial contaminants inoculated into whole milk and colostrum,and on colostrum immunoglobulin G

Raw milk and colostrum can harbor dangerous microorganisms that can pose serious health risks for animals and humans. According to the USDA, more than 58% of calves in the United States are fed unpasteurized milk. The aim of this study was to evaluate the effect of UV light on reduction of bacteria in milk and colostrum, and on colostrum IgG. A pilot-scale UV light continuous (UVC) flow-through unit (45 J/cm²) was used to treat milk and colostrum. Colostrum and sterile whole milk were inoculated with Listeria innocua, Mycobacterium smegmatis, Salmonella serovar Typhimurium, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Acinetobacter baumannii before being treated with UVC. During UVC treatment, samples were collected at 5 time points and bacteria were enumerated using selective media. The effect of UVC on IgG was evaluated using raw colostrum from a nearby dairy farm without the addition of bacteria. For each colostrum batch, samples were collected at several different time points and IgG was measured using ELISA. The UVC treatment of milk resulted in a significant final count (log cfu/mL) reduction of Listeria monocytogenes (3.2 ± 0.3 log cfu/mL reduction), Salmonella spp. (3.7 ± 0.2 log cfu/mL reduction), Escherichia coli (2.8 ± 0.2 log cfu/mL reduction), Staph. aureus (3.4 ± 0.3 log cfu/mL reduction), Streptococcus spp. (3.4 ± 0.4 log cfu/mL reduction), and A. baumannii (2.8 ± 0.2 log cfu/mL reduction). The UVC treatment of milk did not result in a significant final count (log cfu/mL) reduction for M. smegmatis (1.8 ± 0.5 log cfu/mL reduction). The UVC treatment of colostrum was significantly associated with a final reduction of bacterial count (log cfu/mL) of Listeria spp. (1.4 ± 0.3 log cfu/mL reduction), Salmonella spp. (1.0 ± 0.2 log cfu/mL reduction), and Acinetobacter spp. (1.1 ± 0.3 log cfu/mL reduction), but not of E. coli (0.5 ± 0.3 log cfu/mL reduction), Strep. agalactiae (0.8 ± 0.2 log cfu/mL reduction), and Staph. aureus (0.4 ± 0.2 log cfu/mL reduction). The UVC treatment of colostrum significantly decreased the IgG concentration, with an observed final mean IgG reduction of approximately 50%. Development of new methods to reduce bacterial contaminants in colostrum must take into consideration the barriers imposed by its opacity and organic components, and account for the incidental damage to IgG caused by manipulating colostrum.     

Short communication: Fractional milking distribution of immunoglobulin G and other constituents in colostrum

The provision of quality colostrum with a high concentration of immunoglobulins is critical for newborn calf health. Because first colostrum may be low in overall concentration to effectively reduce the risk of newborn infections, we tested equivalent milking fractions of colostrum for possible IgG differences. The objective of this study was to determine if the fractional composition of colostrum changes during the course of milking with a focus on immunoglobulins. Twenty-four Holstein and Simmental cows were milked (first colostrum) within 4 h after calving. The colostrum of 1 gland per animal was assembled into 4 percentage fractions over the course of milking: 0 to 25%, 25 to 50%, 50 to 75%, and 75 to 100%. The IgG concentration among the various fractions did not change in any significant pattern. Concentration of protein, casein, lactose and somatic cell count remained the same or exhibited only minor changes during the course of fractional milking colostrum. We determined that no benefit exists in feeding any particular fraction of colostrum to the newborn.     

Effect of heat and high-pressure treatments on microbiological quality and immunoglobulin G stability of caprine colostrum

Caprine colostrums (6 batches) were subjected to heat (56°C for 60 min and 63°C for 30 min) and high-pressure (400 and 500 MPa for 10 min at 20°C) treatments at laboratory scale, and analyses of the main microbial groups and the extent of IgG denaturation (determined by immunodiffusion) were performed. Overall mean microbial values in raw colostrums were: total count, 5.55 log cfu/mL; Enterobacteriaceae, 2.64 log cfu/mL; lactococci, 5.41 log cfu/mL; lactobacilli, 2.34 log cfu/mL; and enterococci, 4.06 log cfu/mL. Neither Salmonella spp. nor Listeria monocytogenes were detected, whereas coagulase-positive staphylococci were found in various colostrum samples with an overall mean of 1.02 log cfu/mL. Heat and high-pressure treatments significantly reduced total count (1.47 log), lactococci (1.45 log), enterococci (2.47 log), and Enterobacteriaceae, whereas lactobacilli and coagulase-positive staphylococci counts were reduced to undetectable levels, but differences between technological treatments were not statistically significant. High-pressure treatments were as efficient in reducing the bacterial population as were heat pasteurization treatments: 95.50 and 96.93% for pressure treatments of 400 and 500 MPa, and 91.61 and 97.59% for heat treatments of 56°C for 60 min and 63°C for 30 min, respectively. All treatments assayed produced a reduction in colostrum IgG concentration (27.53, 23.58, 23.33, 22.09, and 17.06 mg/mL for raw, heat-treated at 56°C for 60 min or 63°C for 30 min, and pressure-treated at 400 and 500 MPa, respectively), but differences were only observed between raw colostrums and those pressure-treated at 500 MPa. This laboratory-scale study indicated that 20- to 30-mL volumes of goat colostrum could be heated and pressure-treated (400 MPa) to produce hygienic colostrum without affecting IgG concentration.     

Short communication: evaluation of a color method for testing immunoglobulin G concentration in goat colostrum

Colostrum samples (n = 1084) of first and second milking from Majorera goats were taken. The immunoglobulin (Ig) G concentrations estimated by measurement of the color of goat colostrum and by the radial immunodiffusion technique were compared. Least squares analysis of the relationship between the color measurement method and IgG concentration resulted in a significant linear relationship. Using 20 mg of IgG/ mL of colostrum as the cut-off point for colostrum selection, the sensitivity, specificity, and negative predictive value of the color method as a test of IgG concentration in goat colostrum were 93.03, 71.43, and 78.12%, respectively.     

食品添加剂对牛初乳免疫球蛋白(IgG)稳定性的影响

探讨了几种常用食品添加剂对牛初乳免疫球蛋白稳定性的影响,根据食品添加剂对IgG的变性率的影响,选择了几种在食品加工中常用的添加剂进行正交试验,考察其相互综合作用。结果表明:随着柠檬酸、乳酸和磷酸二氢钠浓度的增大,免疫球蛋白的稳定性逐渐降低,变性率逐渐增大;山梨酸钾对免疫球蛋白的稳定性影响较小;磷酸氢二钠、乳酸钙、增稠剂和甜味剂对免疫球蛋白有一定的保护作用。添加剂最佳用量为:乳酸用量为0.3%,乳酸钙用量为0.015%,黄原胶用量为0.5%,蔗糖用量为8%,此时IgG的变性率为14.7%,在4℃的贮藏条件下最佳保存期为30天。     

Effect of different heating times of high-, medium-, and low-quality colostrum on immunoglobulin G absorption in dairy calves

The objective of this study was to determine the effect of different durations of heat treatment on passive transfer of IgG from high-, medium- and low-quality colostrum. Colostrum was collected from The Pennsylvania State University dairy herd and divided by quality (high, medium, or low) based on colostrometer measurements. Colostrum was pooled by quality to create 3 unique batches. Each batch was further divided in thirds as follows: frozen to be fed without heat treatment, heated at 60°C for 30 min, or heated at 60°C for 60 min. Colostrum samples from each treatment were collected and analyzed for standard plate count, gram-negative noncoliforms, coliforms, and total IgG concentration. Serum samples were collected from 108 Holstein calves before feeding colostrum and 24 h after birth. Blood samples were analyzed for total protein, total IgG, and hematocrit. Colostrum quality (high, medium, or low), heat treatment (unheated, 60°C for 30 min or, 60°C for 60 min), and their interaction were analyzed as fixed effects, with calf sex included as a random block effect. Colostrum IgG was different between quality groups (92.5, 59.4, and 48.1 mg/mL of IgG). Heating colostrum reduced IgG concentration compared with the control by 9% when heated for 30 min and by 12% when heated for 60 min. Colostrum heated for 60 min had a lower standard plate count than colostrum heated for 30 min or not heated (1.8, 2.0, and 3.6 log cfu/mL, respectively). Serum IgG concentration at 24 h increased as colostrum quality increased (18.0, 22.2, and 24.8 mg/mL) and tended to increase as heat treatment time increased (19.7, 20.3, and 25.0 mg/mL of IgG). Apparent efficiency of IgG absorption was greater in calves that received medium-quality colostrum compared with calves fed high-quality colostrum (38.1 and 25.0%, respectively). These results suggest an upper limit may exist to the amount of IgG absorption in a given time period and that medium- or high-quality colostrum yields similar blood IgG concentration given the same volume of intake.     

Heat treatment of bovine colostrum. I: effects of temperature on viscosity and immunoglobulin G level

The objective of this study was to identify the critical temperature, at or below which heat-treatment of bovine colostrum would produce no significant changes in viscosity, IgG concentration, or Ig activity. Results of preliminary work, using a Rapid Visco Analyzer (RVA) to heat 50-mL aliquots from 6 unique batches of bovine colostrum at 59, 60, 61, 62, and 63°C, suggested that colostrum could be heated to 60°C for up to 120 min without changing viscosity or IgG concentration. This finding was confirmed by heating 50-mL aliquots from 30 unique batches of colostrum in an RVA for 120 min at 60 and 63°C. Heating colostrum to 63°C resulted in an estimated 34% decrease in IgG concentration and 33% increase in viscosity. However, there was no difference in IgG concentration between preheat-treated (73.4 ± 26.5 mg/mL) and post-heat-treated (74.5 ± 24.3 mg/mL) samples after heating colostrum to 60°C in an RVA for 120 min. Similarly, viscosity was unaffected after heating colostrum to 60°C in an RVA for 120 min. High quality colostrum (≥73.0 mg/mL) suffered greater losses of IgG and greater viscosity changes when heated to 63°C than did moderate quality colostrum (<73.0 mg/mL). However, the effects of colostrum quality were minor if high quality colostrum was only heated to 60°C. The results of a bovine viral diarrhea serum neutralization assay suggested that antibody activity was unchanged after heating colostrum to either 60 or 63°C. However, these results were interpreted as being inconclusive due to a high proportion of missing results because of the congealing of many samples after heat treatment. The results of this study indicate that 50-mL volumes of bovine colostrum can be heat treated at 60°C for up to 120 min in an RVA without affecting IgG concentration or viscosity.     

Heat-treatment of bovine colostrum. II: effects of heating duration on pathogen viability and immunoglobulin G

Batches (30-L) of first-milking bovine colostrum, inoculated with Mycoplasma bovis (10⁸ cfu/mL), Listeria monocytogenes (10⁶ cfu/mL), Escherichia coli O157:H7 (10⁶ cfu/mL), Salmonella enteritidis (10⁶ cfu/mL), and Mycobacterium avium subsp. paratuberculosis (Map; 10³ cfu/mL), were heat-treated at 60°C for 120 min in a commercial on-farm batch pasteurizer system. Duplicate 50-mL subsamples of colostrum were collected at 15-min intervals throughout the heat-treatment process for the purpose of bacterial culture and for measurement of IgG concentration (mg/mL) and antibody activity [log₂(bovine viral diarrhea virus type 1 serum neutralization titer)]. Four replicate batches of colostrum were run for each of the 5 pathogens studied. There was no effect of heating moderate- to high-quality colostrum at 60°C for at least 120 min on mean IgG concentration (pre = 60.5 mg/mL; post = 59.1 mg/mL). Similarly, there was no effect of heat-treatment on the mean log₂ bovine viral diarrhea virus type 1 serum neutralization titer (pre = 12.3; post = 12.0). Viable M. bovis, L. monocytogenes, E. coli O157:H7, and S. enteritidis added to colostrum could not be detected after the colostrum was heat-treated at 60°C for 30 min. Average bacteria counts showed that Map was not detected when batches were heated at 60°C for 60 min. Although the authors believe that heat-treating colostrum at 60°C for 60 min should be sufficient to eliminate Map from colostrum in most situations, further research is needed to determine whether these findings may be replicated, given that variability was observed in Map culture results.     

Peripartal progesterone and prolactin have little effect on the rapid transport of immunoglobulin G into colostrum of dairy cows

Colostrum formation and lactogenesis in the mammary gland and the timing of parturition are regulated by endocrine signals. Changes in progesterone (P4) and prolactin (PRL) are considered key events that inhibit colostrum formation, trigger parturition, and signal the onset of lactation. The goal of our study was to determine if colostrum yield and composition and immunoglobulin transfer are affected by prepartum milking relative to the decrease in P4, peak of PRL, or occurrence of parturition. Twenty-three multiparous cows were randomly assigned to 1 of 2 groups: (1) control with first milking at 4 h postcalving (CON, n = 11), and (2) treatment group with first milking approximately 1 d before calving and second milking at 4 h after parturition (APM, n = 12). Colostrum yields were recorded and proportional samples were analyzed for immunoglobulin G (IgG) concentration. Blood plasma samples for the analyses of P4 and PRL were collected 3 times daily at 8-h intervals for 4 d prepartum and again taken at 4 h after parturition. Total colostrum mass of APM cows was higher than that of CON cows. Immunoglobulin G concentration and protein content did not differ between antepartum milking in APM cows and postpartum milking in CON cows. Colostrum IgG concentration and protein content in APM cows at the postpartum milking were lower compared with the IgG concentration established at the prepartum (APM) and postpartum milkings of CON cows. Immunoglobulin G mass did not differ in first and second colostrum collection in APM cows but was lower compared with that of CON cows. The sum of IgG mass in APM cows (prepartum + postpartum collections) did not differ from that of CON cows. Lactose and fat in milk (concentration and mass) increased from first to second milking in APM cows. Total mass of lactose and fat in APM cows (prepartum + postpartum collections) was greater compared with that of CON cows. The finding that the time of milking relative to parturition, P4 decrease, and PRL peak slightly affected yield and quality of colostrum emphasizes the complex interactions of numerous endocrine and morphological changes occurring during colostrogenesis and lactogenesis in dairy cows. The considerably rapid transfer of immunoglobulins into colostrum of prepartum-milked cows within a few hours leads to the hypothesis that the transfer of IgG can be very fast and—contrary to earlier findings—persist at least until parturition.     

牛初乳IgG对酸奶双菌混合发酵过程的抑制效应

研究了牛初乳IgG免疫强化对酸奶发酵前熟过程的影响。结果发现，添加外源牛乳IgG（0．85－2．125g/L）对嗜热链球菌和保加利亚乳杆菌双菌混合发酵产酸过程具有明显抑制效应，部分样品前熟产酸过程滞后约1h，采用琼脂单向免疫扩散法（RID）和聚丙烯酰胺凝胶电泳（SDS－PAGE）技术分别定量，定性分析了最终免疫强化凝固型酸奶制品中的IgG，证实普通的酸奶发酵条件（42℃，4－6h）不会导致IgG分子免疫活性的丧失.本研究推测，天然牛初乳内存在抗嗜热链球菌的IgG抗体，但仍可开发出与普通酸奶形态，风味具有可比性的牛初乳IgG免疫强化凝固型酸奶。     

The effect of colostrum storage conditions on dairy heifer calf serum immunoglobulin G concentration and preweaning health and growth rate

The objective of the present study was to compare serum IgG concentration, weight gain, and health characteristics in Irish spring-born dairy calves fed colostrum stored using a range of conditions. Immediately after birth, 75 dairy heifer calves were assigned to 1 of 5 experimental colostrum treatments: (1) fresh pasteurized colostrum, fed immediately after pasteurization; (2) fresh colostrum, fed immediately after collection but not pasteurized; (3) colostrum stored unpasteurized at 4°C in a temperature-controlled unit for 2 d before being fed to calves; (4) colostrum stored unpasteurized at 13°C in a temperature-controlled unit for 2 d before being fed to calves; and (5) colostrum stored unpasteurized at 22°C in a temperature-controlled unit for 2 d before being fed to calves. All colostrum had IgG concentrations >50 g/L and was fed to calves promptly after birth. Blood samples were obtained from calves via the jugular vein at 0 h (before colostrum feeding) and at 24 h of age to determine the rate of passive transfer of IgG; individual calf live-weights were recorded to monitor weight gain (kg/d) from birth to weaning. Colostrum stored in warmer conditions (i.e., 22°C) had >42 times more bacteria present and a pH that was 0.85 units lower and resulted in a serum IgG concentration that was almost 2 times lower compared with colostrum that was pasteurized, untreated, or stored at 4°C for 2 d. Colostrum stored at 4°C for 2 d had more bacteria present than pasteurized and fresh colostrum but did not result in reduced calf serum IgG concentrations. Average daily weight gain from birth to weaning did not differ among treatments. Even if colostrum has sufficient IgG (>50 g/L) but cannot be fed to calves when freshly collected, storage at ≤4°C for 2 d is advisable to ensure adequate passive transfer when it is consumed by the calf.     

Impact of irradiation and immunoglobulin G concentration on absorption of protein and immunoglobulin G in calves fed colostrum replacer

The objective of this study was first to evaluate whether irradiation treatment of a commercial colostrum replacer (CR) affected acquisition of passive immunity. If the irradiation treatment negatively affected the acquisition of passive immunity, the second objective was to evaluate whether an increased total IgG mass, in a single feeding of CR derived from bovine serum fractions, could compensate for this effect. Acquisition of passive immunity was assessed by 24-h serum IgG levels, serum protein levels, apparent efficiency of absorption (AEA) of IgG, and the ability to prevent failure of passive transfer (FPT) in day-old dairy calves fed a single feeding of CR. Single-dose packs of CR were sent to a commercial irradiation facility for electron-beam irradiation at 3 to 7 kGy (low irradiation) or 15 to 20 kGy (high irradiation). Fifty-six Holstein, Jersey, or crossbred calves were randomly assigned to 1 of 5 treatments: 1) 130 g of IgG (460 g of CR), no irradiation; 2) 130 g of IgG (460 g of CR), low irradiation; 3) 160 g of IgG (518 g of CR), low irradiation; 4) 190 g of IgG (575.4 g of CR), low irradiation; and 5) 130 g of IgG (460 g of CR), high irradiation. All CR were reconstituted in water and mixed in a household blender to a constant solids concentration of 18.7%. Increasing doses of irradiation (130 g of Ig with no, low, or high irradiation) resulted in a linear decrease in 24-h serum IgG and AEA of IgG, and increased the percentage of calves with FPT. Increasing the IgG mass in the CR (130, 160, and 190 g of Ig with low irradiation) resulted in a linear increase in 24-h serum IgG and serum total protein levels, and a linear decrease in AEA of IgG. There was no effect of increasing the mass of IgG fed on the percentage of calves with FPT. The correlation between serum IgG and serum total protein at 24 h was positive; however, at 24 h the irradiation treatments reduced the serum IgG-to-serum total protein ratio. In this study, CR isolated from bovine serum, providing 130 g of IgG in the first feeding and receiving either no irradiation or a low irradiation treatment, was sufficient to prevent FPT in calves.     

Effects of lyophilized colostrum and different colostrum feeding regimens on passive transfer of immunoglobulin g in Majorera goat kids

Three experiments were conducted including 180 Majorera kids. In the first experiment, the effect of use of lyophilized colostrum vs. frozen colostrum on immunoglobulin G (IgG) blood serum concentration was evaluated. Kids (n = 40) received the same management and IgG mass [3368 mg/kg of body weight (BW)] during the colostrum feeding period. The IgG in blood serum of kids from the lyophilized colostrum group was greater than that for kids that received frozen colostrum. The second experiment evaluated the effect of total IgG ingested by kids (n = 60) on IgG in blood serum during the colostrum feeding period. Three groups of animals received 3368, 1684, and 842 mg of IgG/kg of BW in 4 feedings for 2 d [high IgG concentration (H-IgG), medium IgG concentration (M-IgG), and low-IgG concentration (L-IgG), respectively]. The IgG blood serum in the kids that received H-IgG was greater than in the other 2 treatment groups, and no statistical differences were found for IgG in blood serum of kids that received either M-IgG or L-IgG. The third experiment evaluated the effect of timing of lyophilized colostrum meals on IgG blood serum concentration. Four groups of kids (n = 80) were used. Two groups received 1684 mg of IgG/kg of BW (higher level-1 d and higher level-2 d) and the other 2 groups received 842 mg of IgG/kg of BW (lower level-1 d and lower level-2 d). Two groups received 2 feedings in 1 d, and the other 2 groups received 4 feedings over a 2-d period, as denoted. Higher level-1 d kids had greater IgG blood serum concentration than the higher level-2 d kids, and no statistical differences were found between lower level-1 d and lower level-2 d kids.     

Effect of feeding colostrum at different volumes and subsequent number of transition milk feeds on the serum immunoglobulin G concentration and health status of dairy calves

Transfer of sufficient IgG to the newborn calf via colostrum is vital to provide it with adequate immunological protection and resistance to disease. The objectives of the present study were to compare serum IgG concentration and health parameters of calves (1) fed different volumes of colostrum [7, 8.5, or 10% of body weight (BW)] within 2 h of birth and (2) given 0, 2, or 4 subsequent feedings of transition milk (i.e., milkings 2 to 6 postcalving). Ninety-nine dairy calves were fed 7, 8.5, or 10% of BW in colostrum within 2 h of birth and given 0, 2, or 4 subsequent feedings of transition milk. The concentration of IgG in the serum of calves was measured at 24, 48, 72, and 642 h of age by an ELISA. The apparent efficiency of absorption for IgG was determined. Health scores were assigned to calves twice per week and all episodes of disease were recorded. The effect of experimental treatment on calf serum IgG concentration differed by the age of the calf. Calves fed 8.5% of BW in colostrum had a greater mean serum IgG concentration than calves fed 7 or 10% of BW at 24, 48, and 72 h of age. At 642 h of age, serum IgG concentrations of calves fed 8.5% of BW (24.2 g/L) and calves fed 10% of BW (21.6 g/L) did not differ, although the serum IgG concentration of calves fed 8.5% of BW was still greater than that of calves fed 7% of BW (20.7 g/L). No difference in serum IgG concentration existed between calves fed 7% of BW and those fed 10% of BW at any age. No significant effect of number of subsequent feedings of transition milk on calf serum IgG concentration was detected. The apparent efficiency of absorption of calves fed 8.5% of BW in colostrum (38%) was greater than calves fed 7% of BW in colostrum (26%) and tended to be greater than in calves fed 10% of BW (29%). Calves fed further feedings of transition milk after the initial feeding of colostrum had a lower odds (0.62; 95% confidence interval: 0.41 to 0.93) of being assigned a worse eye/ear score (i.e., a more copious ocular discharge or pronounced ear droop) and a lower odds (0.5; 95% confidence interval: 0.32 to 0.79) of being assigned a worse nasal score (i.e., a more copious and purulent nasal discharge) during the study period relative to calves that received no further feedings of transition milk. In conclusion, calves fed 8.5% of BW in colostrum within 2 h of birth achieved a greater concentration of IgG in serum in the first 3 d of life than calves fed either 7 or 10% of BW. Feeding calves transition milk subsequently reduced their odds of being assigned a worse eye/ear and nasal score.     

Heat treatment of colostrum increases immunoglobulin G absorption efficiency in high-, medium-, and low-quality colostrum

Previous studies with heat-treated colostrum fed to neonatal calves have consistently used average-quality colostrum. Studies have not compared colostrum across a range of immunoglobulin levels. This study was conducted to investigate IgG absorption in neonatal dairy calves using colostrum of various qualities. Colostrum from the Pennsylvania State University dairy was collected over 2 yr and sorted into high, medium, and low quality based on colostrometer measurement. Colostrum within each category was pooled to create 3 unique, uniform batches. Half of each batch was frozen to be fed without heat treatment. The second half of each batch was heat treated at 60°C for 30 min. This process was conducted in September 2011, and repeated in June 2012. Colostrum treatments were analyzed for standard plate count, coliforms, noncoliform gram-negative bacteria, and total IgG concentration. Plasma samples were collected from 145 calves 48 h after birth and analyzed for IgG₁, IgG₂, total protein, and hematocrit. Colostrum quality (high, medium, or low), treatment (unheated or heat treated), and their interactions were analyzed as fixed effects, with year included as a random effect. Heat treatment significantly reduced all types of bacteria and IgG concentration. Plasma IgG concentration at 48 h increased linearly with the concentration of IgG in the colostrum that was consumed. Heat treatment of colostrum increased plasma IgG concentration by 18.4% and apparent efficiency of absorption by 21.0%. Results of this study suggest that heat treatment of colostrum containing approximately 50 to 100 mg IgG/mL increases absorption of IgG from colostrum.