Chitotriosidase activity in goat blood and colostrum

Chitotriosidase (ChT) activity has not been investigated in ruminants, and therefore, we studied this activity in blood and colostrum of 25 pregnant goats and 60 goat kids. Blood samples were taken from pregnant goats at 3, 2, and 1 d prepartum; at partum; and at 1, 2, 3, and 4 d postpartum. Colostrum samples were obtained by machine-milking at partum and 1, 2, 3, and 4 d postpartum. Goat kid blood was collected at birth and every 7 d thereafter until goats kids were 56 d old. The ChT activity ranged from 2,368 to 3,350 nmol/ mL per hour in goat blood serum, and no statistical differences were detected through time. However, activity tended to decrease from 3 d prepartum to 2 d post-partum. Colostrum ChT activity was 3,912 nmol/mL per hour and 465 nmol/mL per hour on the day of delivery and 4 d postpartum, respectively. Colostrum ChT activity was significantly higher at partum than at any other time. The ChT activity in colostrum was significantly greater at 1 d postpartum than at 2, 3, and 4 d postpartum. Chitotriosidase activity did not differ in colostrum collected on d 2, 3, and 4 postpartum. Chitotriosidase activity in goat kid blood serum ranged from 2,664 to 9,231 nmol/mL per hour at birth and 49 d of life, respectively. Chitotriosidase activity in the blood serum increased with age: at birth, activity was significantly less than at 28, 35, 42, 49, and 56 d postpartum. The maximum ChT activity in blood serum was observed at 49 d postpartum. Activity in 49-d-old kids was significantly greater than that observed in kids at 0, 7, and 14 d postpartum.     

Feed restriction around parturition does not affect colostrum immunoglobulin G concentration in dairy fat-tailed sheep but does affect performance and blood metabolites in newborn lambs

This study aimed to investigate the effect of prepartum and postpartum feed restriction of fat-tailed dairy sheep on colostrum IgG concentration, and performance and blood metabolites of newborn fat-tailed lambs. Twenty fat-tailed dairy sheep were randomly allocated into control (Ctrl; n = 10) and feed restriction (FR; n = 10) groups. The Ctrl group received a diet that met 100% of energy requirements, both prepartum (from wk −5 to parturition) and postpartum (from parturition to wk 5). The FR group received a diet equivalent to 100, 50, 65, 80, and 100% of the energy requirements in wk −5, −4, −3, −2, and −1 relative to parturition, respectively. After parturition, the FR group received a diet equivalent to the 100, 50, 65, 80, and 100% of the energy requirements in wk 1, 2, 3, 4, and 5, respectively. At birth, lambs were assigned to their dam's experimental group. Both the Ctrl lambs (n = 10) and the FR lambs (n = 10) were allowed to suck colostrum and milk from the dams. Colostrum samples (50 mL) were collected at parturition (0 h) and then at 1, 12, 24, 36, 48, and 72 h postpartum. Blood samples were collected from all lambs before suckling colostrum (0 h) and then at 1, 12, 24, 36, 48, and 72 h after birth and weekly until the end of the experimental period (i.e., wk 5 relative to birth). The data were evaluated using the MIXED procedure of SAS (SAS Institute Inc.). The model included feed restriction, time, and the interaction feed restriction × time as fixed effects. The individual lamb was set as a repeated subject. Variables measured in colostrum and plasma were considered dependent variables, and significance was set at P < 0.05. Prepartum and postpartum feed restriction in fat-tailed dairy sheep did not affect colostrum IgG concentration. Consequently, no differences in blood IgG concentrations were observed in the lambs. In addition, the prepartum and postpartum feed restriction experienced by fat-tailed dairy sheep caused decreased body weight and milk intake in lambs from the FR group compared with the Ctrl group. Feed restriction also promoted increased concentration of blood metabolites such as triglycerides and urea in FR lambs compared with control lambs. In conclusion, prepartum and postpartum feed restriction in fat-tailed dairy sheep did not affect either colostrum IgG concentration or blood IgG concentration of the lambs. However, prepartum and postpartum feed restriction decreased lamb milk intake and, therefore, lamb body weight gain during the first 5 wk after birth.     

Immunoglobulin G content and colostrum composition of different goat and sheep breeds in Switzerland and Germany

Colostrum represents the sole source to acquire humoral immunity and is an important energy source for newborn lambs and goat kids. However, colostrum composition (i.e., the contents of IgG, fat, protein, and lactose) is affected by various factors such as parity and litter size and, potentially, by breed. In the present study, we examined the colostrum composition of different goat and sheep breeds raised for milk and meat production in Switzerland and Germany. Ten goat breeds (Anglo-Nubian, Appenzell, Boer, Bunte Deutsche Edelziege, Chamois-colored, Grisons Striped, Peacock, Saanen, Toggenburg, and Valais Blackneck) and 10 sheep breeds (Brown-Headed Meat, East Friesian Milk, German Blackheaded Mutton, Gray Horned Heath, Lacaune Dairy, Merino Land, Swiss Black-Brown Mountain, Swiss Charollais, Swiss White Alpine, and Valais Blacknose) were involved in this study. First colostrum samples were obtained from ewes (n = 100) and goats (n = 116) between 10 and 390 min after parturition and analyzed for total IgG, fat, protein, and lactose contents. Colostral IgG concentrations varied between 4.8 and 75.0 mg/mL in goats, and between 6.2 and 65.4 mg/mL in ewes, and the time interval between milking and parturition did not affect colostral IgG concentrations. In goats, the highest IgG concentrations were found in Boer (meat-type; 61.0 ± 10.3 mg/mL; mean ± SD) and the lowest concentrations were observed in Bunte Deutsche Edelziege (milk-type; 26.5 ± 12.5 mg/mL). In sheep, East Friesian Milk and Lacaune Dairy showed the lowest colostral IgG concentrations (17.9 ± 7.3 and 20.2 ± 8.0 mg/mL, respectively), and the highest values were observed in the Merino Land breed (44.2 ± 15.7 mg/mL). The lowest fat and protein concentrations and concomitantly highest lactose concentrations were observed in colostrum of East Friesian Milk and Lacaune Dairy sheep. Parity number did not affect colostrum composition in sheep or goats. In contrast, colostral fat content was higher in ewes bearing twins and triplets than in those carrying singletons. Increasing litter size tended to be associated with higher protein and lower lactose concentrations in ovine (i.e., singletons vs. twins vs. triplets) and caprine colostrum (i.e., singletons vs. twins), whereas colostral IgG concentrations were not affected by litter size. In conclusion, IgG and concentrations of other colostrum constituents showed a wide range in goats and ewes and were mainly affected by the type of breed.     

山羊初乳成分及其免疫球蛋白构成变化的研究

动物初乳对其后代健康的作用已经得到了广泛的证实,其对人类健康的影响也受到了越来越多的重视.本研究探讨了阿尔卑斯山羊产后一周内乳成分和其中免疫球蛋白(Ig)含量的变化.结果表明:产后48h内山羊奶的蛋白质、总固形物和免疫球蛋白含量均快速下降;脂肪含量在前三次的初乳中逐渐升高,随后又缓慢下降;乳糖含量保持相对稳定于4%～5%;经产山羊前三次初乳的蛋白含量分别达到了16.5%、10.7%和6.8%,显著地高于初产山羊前三次初乳的蛋白含量(7.0%、4.8%和4.1%);经产山羊前两次初乳的IgG含量达到了59.9mg/ml和34.7mg/ml,IgM含量达到了6.14mg/ml和2.37mg/ml,显著地高于初产山羊前两次初乳的IgG含量(18.1mg/ml和13.9mg/ml)和IgM含量(1.95mg/ml和0.98mg/m1);经产和初产山羊初乳的IgA含量无显著差异.     

Effect of colostrum immunoglobulin concentration on immunity in Majorera goat kids

The aim of the research was to evaluate the effects of immunoglobulin G (IgG) colostrum concentration on goat kid immune status when the total amount of IgG fed was constant. Majorera goat kids (n = 56) were randomly assigned to 1 of 4 groups, and kids received 4 g of IgG per kg of body weight of atomized colostrum at 4 different IgG concentrations: 20 (AC-20), 40 (AC-40), 60 (AC-60), and 80 (AC-80) mg/mL. Blood samples were obtained on d 0, 1, 2, 3, 4, and 5 postpartum. Immunoglobulin G, IgA, and IgM plasma concentrations, apparent efficiency of absorption of IgG, plasma chitotriosidase activity, plasma complement activity, and plasma proteinogram were measured. Plasma IgG and IgM concentrations were highest on d 1 in AC-80 animals, and IgA plasma concentration was lower in AC-20 than in AC-80. The apparent efficiency of absorption was higher in AC-80 (24.4%) than in the other treatment groups (by an average of 13.8%). Chitotriosidase plasma activity on d 5 (1,488 nmol/mL per hour) was higher than on d 0 and 1 (average of 1,183 nmol/mL per hour). There were no effects of colostrum IgG concentration on complement activity and plasma protein distribution, but γ-globulin and α-globulin were lower on d 0 than on d 1, 2, 3, 4, and 5. Increasing the immunoglobulin concentration in colostrum using atomized colostrum improves the immunoglobulin absorption at the same amount of immunoglobulin fed.     

Validation of a handheld refractometer to assess Merino ewe colostrum and transition milk quality

Colostrum quality is generally defined by the IgG concentration in colostrum, and many methods have been used to assess it. Methods to measure colostrum quality both in the laboratory and in the field have been validated in cattle; however, this is only a recent topic of interest for sheep colostrum. Laboratory-based methods are often time consuming and require trained personnel compared with new handheld evaluation tools such as the digital Brix refractometer, which gives real-time results. The aims of this study were to (1) evaluate the relationship between the digital Brix refractometer and constituents indicative of quality (IgG, protein, fat, and lactose) in colostrum and transition milk, and (2) determine an appropriate Brix % cut-off value for the Brix refractometer in sheep colostrum and transition milk. The study used 50 colostrum samples (collected at 0 h postpartum, before lambs' sucking) and 169 transitional milk samples (collected at 4 and 24 h postpartum, after lambs had sucked) collected over 6 lambing trials in 2 years (2019 and 2020). We concluded that the Brix refractometer results correlated weakly with IgG concentration determined by radial immunodiffusion assay in colostrum collected at 0 h postpartum (r = 0.11) and in transition milk collected at 4 h postpartum (r = 0.12); however, a moderate to strong correlation was shown in transition milk samples collected at 24 h (r = 0.66). Brix % was significantly correlated with fat %, lactose %, and protein % at all timepoints. To determine an appropriate Brix % cut-off value indicating an IgG concentration of 20 mg/mL, we analyzed sensitivity and specificity of the Brix refractometer at 0, 4, and 24 h. In samples collected at 0 and 4 h, the highest combination of sensitivity, specificity, and accuracy was achieved at a Brix % cut-off value of 29%; in samples collected at 24 h postpartum, a Brix % cut-off value of 27% gave the highest sensitivity, specificity, and accuracy. Overall, the Brix refractometer has potential as a useful in-field tool for researchers and producers in both extensively and intensively managed flocks to measure and determine the quality of sheep colostrum and transition milk.     

Influence of anionic salts on bone metabolism in periparturient dairy goats and sheep

The purpose of the present study was to investigate the influence of diets supplemented with anionic salts on bone metabolism of dairy goats and sheep. Twelve Saanen goats and 12 Ostfrisean milk sheep (fourth lactation) were divided into 2 groups each [sheep control (SC), goat control (GC); sheep anionic salts (SA), goat anionic salts (GA)]. Each group was fed a different diet in the last 10 d of gestation. Groups SC and GC received a normal diet according to the requirements of goats and sheep in this stage of gestation. Groups SA and GA received supplemental anionic salts. The dietary cation-anion difference (DCAD) was +524 (SC) and +515 (GC) vs. −163 (SA) and −164 (GA) mEq/kg of dry matter. Blood and urine samples were collected daily until parturition. Serum Ca, P, Mg, serum crosslaps (CTX), osteocalcin, 1,25-dihydroxy-vitamin D (VITD), urinary pH, and urinary Ca concentrations were analyzed. Bone mineral density and bone mineral content were measured with peripheral quantitative computer tomography. The bone resorption marker CTX showed significant differences between the animals supplemented with anionic salts and the control animals in goats, but not in sheep. The goats receiving anionic salts had greater CTX concentrations throughout the administration of the salts. In sheep, a difference was only observed on the day of parturition. Similar observations were made in VITD concentrations, although a significant difference between the goat groups was only observed 3 d prepartum. The bone formation marker osteocalcin was lower prepartum in the animals supplemented with anionic salts. The urinary pH was lower in the SA and GA animals, whereas urinary Ca concentrations were greater. Bone mineral content and bone mineral density decreased in all groups around parturition. In conclusion, this experiment showed that the addition of anionic salts in goats led to greater bone resorption rates while on this feeding regimen. It can be concluded that the anionic salts induced a mild metabolic acidosis with all its effects on calcium metabolism. These effects were not evident in milk sheep.     

Changes occurring in immune responsiveness of single- and twin-bearing Comisana ewes during the transition period

Changes induced by twin and single lambing in the immune response of 16 periparturient Comisana ewes were studied. Cell-mediated immune responses were evaluated by means of skin tests performed from 3 wk before and up to d 35 after parturition. At d 21 and 7 before lambing, the sheep received an intramuscular injection of the antigen keyhole limpet hemocyanin (KLH), to which the animals had not been previously exposed, to determine their humoral immune response. Starting 3 wk before lambing and up to d 35 postlambing, the ewes were sampled to determine the plasma concentrations of anti-KLH antibody (IgG), IL-6, and IL-1 β. From parturition through d 35 postpartum, individual milk samples were collected for determination of anti-KLH IgG titers and IL-6 and IL-1β concentrations by means of a capture ELISA. The number of lambs born affected IL-6 concentrations in ewe plasma; IL-6 secretion always was higher in ewes birthing twins than in single-lambing ewes. Apart from the number of lambs born, the concentrations of plasma IL-6 in ewes were higher at lambing than at d 21 antepartum and at d 35 postpartum. An interaction of number of lambs born × time of sampling was observed for plasma antibody titers to KLH. The IgG concentrations were significantly higher in single-bearing ewes than in twin-bearing ewes before parturition and were very similar across groups after parturition. A time effect was found for the cell-mediated immune response and for anti-KLH IgG concentrations in milk, such that at parturition, cellular responses were lowest, and the anti-KLH IgG concentration was highest. A significant correlation was found for IgG titers to KLH in plasma and milk. Results indicate that IL-6 concentrations in blood can be considered a reliable indicator of stress connected to lambing and that the mammary gland is a microenvironment unrelated to blood stream with respect to interleukins expression. In contrast, a relationship was found for the IgG secretions in milk and blood, which suggests that the assessment of humoral immune status may be combined with milking routine in dairy animals.     

Increased serum serotonin improves parturient calcium homeostasis in dairy cows

Hypocalcemia in dairy cows is caused by the sudden increase in calcium demand by the mammary gland for milk production at the onset of lactation. Serotonin (5-HT) is a key factor for calcium homeostasis, modulating calcium concentration in blood. Therefore, it is hypothesized that administration of 5-hydroxy-l-tryptophan (5-HTP), a 5-HT precursor, can increase 5-HT concentrations in blood and, in turn, induce an increase in blood calcium concentration. In this study, 20 Holstein dairy cows were randomly assigned to 2 experimental groups. Both groups received a daily i.v. infusion of 1 L of either 0.9% NaCl (C group; n = 10) or 0.9% NaCl containing 1 mg of 5-HTP/kg of BW (5-HTP group, n = 10). Infusions started d 10 before the estimated parturition and ceased the day of parturition, resulting in at least 4 d of infusion (8.37 ± 0.74 d of infusion). Until parturition, blood samples were collected every morning before the infusions, after parturition samples were taken daily until d 7, and a final sample was collected on d 30. Milk yield was recorded during this period. No differences between groups were observed for blood glucose, magnesium, and β-hydroxybutyrate. Cows receiving the 5-HTP infusion showed an increase in fatty acid concentrations from d ?3 to ?1 before parturition. Serum 5-HT concentrations were increased at d ?4 related to parturition until d 5 postpartum in the 5-HTP group compared with the C group. In addition, cows from the 5-HTP group had increased 5-HT concentrations in colostrum, but not in mature milk, on d 7 postpartum. Serum calcium concentrations decreased in both groups around parturition; however, calcium remained higher in the 5-HTP group than in controls, with a significant difference between groups on d 1 (1.62 ± 0.08 vs. 1.93 ± 0.09 mmol/L in control and 5-HTP groups, respectively) and d 2 (1.83 ± 0.06 vs. 2.07 ± 0.07 mmol/L in control and 5-HTP groups, respectively). Additionally, colostrum yield (first milking) was lower in the 5-HTP group compared with the C group, but without consequences on colostrum IgG concentrations. Milk yield did not differ between groups during the rest of the experiment. The study data were consistent with the concept that infusion of 5-HTP to dairy cows increases blood 5-HT concentrations, which in turn is a significant regulatory component in the chain of effectors that affect calcium status around parturition, hence the occurrence of clinical or subclinical hypocalcemia.     

Short communication: Mammary gland tight junction permeability after parturition is greater in dairy cows with elevated circulating serotonin concentrations

After parturition, the start of copious milk production in dairy cows requires the closure of tight junctions (TJ) to form the blood–milk barrier and prevent paracellular transfer of blood constituents into milk [e.g., lactate dehydrogenase (LDH) and serum albumin (SA)] and vice versa [e.g., appearance of α-lactalbumin (α-LA) in blood]. Serotonin (5-HT) has been demonstrated to alter tight junction permeability in the mammary gland. The present study investigated individual differences of TJ permeability of mammary epithelium at the beginning of lactation in relation to circulating 5-HT in dairy cows. Blood and milk samples were obtained from 11 multiparous Holstein dairy cows for the first time at 4 h after parturition, at the following 5 milkings, and at the evening milkings on d 5, 8, 10, and 14 of lactation. Retrospectively, cows were split into 2 groups according to their calculated areas under the curve of serum 5-HT during the entire experimental period: a high-serum 5-HT (HSS) group (5 cows) and a low-serum 5-HT (LSS) group (6 cows). The areas under the curve of serum 5-HT concentrations over the 324-h experimental period were 62 ± 2 × 10³ ng/mL in HSS and 25 ± 5 × 10³ ng/mL in LSS. Plasma α-LA concentration was greater in LSS than in HSS cows at the first milking, but no difference between groups was found from the second to sixth milking. Yield of α-LA in milk was lower in HSS than in LSS during the first 6 milkings postpartum, especially in colostrum. Concentrations of α-LA, IgG₁, and IgG₂ in milk did not differ between groups during the entire experiment except for higher IgG observed in LSS than in HSS at the second milking and for higher IgG₂ found in HSS compared with LSS on d 5. In contrast, SA concentrations and LDH activity in milk were lower in LSS compared with HSS cows during the first 6 milkings postpartum, particularly in colostrum. Milk somatic cell count was higher in HSS than in LSS throughout the study. Higher circulating 5-HT concentrations were associated with an increased transfer of the paracellularly transported SA, LDH, and somatic cell count, especially at the first milking, suggesting that 5-HT affects TJ permeability during closure of the blood–milk barrier at the onset of lactation. Furthermore, higher serum 5-HT concentrations were associated with a lower α-LA yield in milk. A consistent relationship with serum 5-HT concentrations was neither observed for the transfer of IgG₂ nor the primarily transcellular transport of IgG₁ during the first milkings after parturition.     

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.     

Concentrations of sialyloligosaccharides in bovine colostrum and milk during the prepartum and early lactation

Sialyloligosaccharides and sialylglycoconjugates in colostrum and milk are regarded to be important biological components with respect to be source of brain gangliosides in infant and to be antiinfectional components for the attack by the pathogenic bacteria and virus. Several acidic oligosaccharides have been characterised in both bovine and human milk or colostrum. The sialyloligosaccharide content of human colostrum and milk has been extensively studied, whereas that of cows milk and colostrum has received less attention. In this study, the concentrations of three sialyloligosaccharides of bovine colostrum and milk were determined at various stages during the prepartum and the first 7 d postpartum. The concentration of 3'SL (Neu5Ac(alpha2-3)Gal(beta1-4)Glc) reached a maximum value of 0.85 mg/ml immediately following parturition while the concentrations of 6'SL (Neu5Ac(alpha2-6)Gal(beta1-4)Glc) and 6'SLN (Neu5Ac(alpha2-6)Gal(beta1-4)GlcNAc) of 0.14 and 0.12 mg/ml, respectively, were much lower at this initial stage, although these concentration were maximum immediately following parturition. Bovine colostrum, especially that collected immediately after parturition, may be suitable as a source of 3'SL and other sialyloligosaccharides for use as additives by the food or pharmaceutical industries.     

Influence of bovine antiserum (Bo-Bac 2X) injection on colostral immunoglobulin G absorption in neonatal dairy calves

On the background of positive survival data from farms in Mississippi, treating calves with antiserum injection in addition to normal colostrum administration, the objective of the present study was to evaluate the influence of a single subcutaneously administered bovine antiserum injection (0.031 g of IgG/kg of body weight) and pooled colostrum administration on efficiency of Ig absorption and on 24-h plasma IgG concentration in neonatal bull calves. Twenty-nine male dairy calves (21 Holsteins and 8 Jerseys) were assigned randomly at parturition to receive one of four treatments: 1) colostrum (n = 9), 2) colostrum and bovine antiserum injection (n = 7), 3) milk replacer (n = 5), or 4) milk replacer and bovine antiserum injection (n = 8). At birth, calves either did or did not receive an injection of bovine antiserum and were fed pooled colostrum or milk replacer (Holsteins, 3.8 L; Jerseys, 1.9 L) via an esophageal feeder. Blood was collected immediately before administration of the colostrum or milk replacer, then again at 24 and 48 h postpartum. Immunoglobulin G concentrations of colostrum, milk replacer, antiserum, and plasma were monitored by single radial immunodiffusion. Colostrum administration and injection of bovine antiserum each increased plasma Ig concentration at 24 h posttreatment. In addition, antiserum injection increased the apparent efficiency of absorption of colostral Ig by 42% over that for calves fed colostrum alone. The increase in plasma IgG for antiserum-treated calves exceeded the total amount of IgG administered in the antiserum injection; hence, this increase appeared to be the result of an increase in total absorption of colostral IgG, or possibly antiserum injection somehow triggered active synthesis of IgG. Injection of antiserum might possibly serve as a beneficial adjunct to a colostrum management program by enhancing the acquisition of passive immunity from colostral sources.     

Lactoferrin and immunoglobulin contents in camel's milk (Camelus bactrianus, Camelus dromedarius, and Hybrids) from Kazakhstan

Lactoferrin (Lf) and IgG were estimated in camel's milk from Kazakhstan, where 2 species of camels (Camelus bactrianus, Camelus dromedarius) and their hybrids cohabit. The concentrations of Lf and IgG were determined according to 3 variation factors: region (n = 4), season (n = 4), and species (n = 5; sample 4 was mixed milk and sample 5 was of unknown origin). The mean values in raw camel's milk were 0.229 ± 0.135 mg/mL for Lf concentration and 0.718 ± 0.330 mg/mL for IgG concentration. The seasonal effect was the only significant variation factor observed, with the highest values in the spring for Lf and in the winter for IgG. The Lf concentration varied in 1-wk postpartum milk from 1.422 to 0.586 mg/mL. The range in IgG concentration was wide and decreased from 132 to 4.75 mg/mL throughout the 7 d postpartum, with an important drop after parturition. In fermented milk, the lactoproteins are generally hydrolyzed. For milk samples from undefined species, discriminant analyses did not allow the origin of the species to be determined. A slight correlation between Lf and IgG concentrations was observed in raw milk. The values were slightly higher than those reported in cow's milk, but this difference was insufficient to attribute medicinal virtues to camel's milk.     

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.     

Effect of composition of colostrum and transition milk from Holstein heifers on specificity rates of antibiotic residue tests

The objective of this study was to evaluate the effects of colostrum and transition milk composition on specificity rates of antibiotic residue screening tests. Milk from 25 primigravid Holstein heifers was collected from either first, second, or third milking (colostrum) and from either fifth, sixth, or seventh milking (transition milk) following parturition. Milk sampled was visibly normal and heifers were not treated with an antibiotic within 30 d before parturition. Quarter foremilk samples were collected aseptically and analyzed for mastitis pathogens. A sample from the total composite milk was analyzed for somatic cell counts (SCC), milk protein and fat, immunoglobulin concentrations and for antibiotics using four antibiotic residue screening tests. Mastitis pathogens were present in colostrum from 36% of heifers (n = 9) and from 16% of heifers (n = 4) in the subsequent transition milk. Mean SCC were 2,458,000 and 866,000 counts/ml and IgG1 concentrations were 22.7 and 3.07 mg/ml for colostrum and transition milk, respectively. Specificity rates of the screening tests ranged from 0.16 to 0.88 for colostrum and 0.60 to 1.0 for transition milk. Increased milk protein and IgG1 concentrations in milk were associated with an increase in the probability of a false positive outcome for the Charm Cowside (Charm Sciences, Inc., Malden, MA), CITE Snap (IDEXX Laboratories, Westbrook, ME), and Penzyme (Cultor Food Science, Milwaukee, WI) tests. Fat content of milk was positively related to an increase in false positive rates for the CITE Snap test. Milk should not be tested for antibiotic residues before the sixth milking after parturition to avoid high rates of false positive outcomes.     

Bioefficacy of hydroxy-selenomethionine as a selenium supplement in pregnant dairy heifers and on the selenium status of their calves

This study aimed to determine the effects of supplementing pregnant heifers with the organic selenium (Se) source 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) during the last 8 wk of pregnancy on dam and calf Se status. A total of 42 in-calf heifers were recruited to the study and randomly allocated to 1 of 3 treatments; a negative control (Con), sodium selenite (NaSe), or HMSeBA. Animals were blocked by body weight, body condition score, and expected calving date before treatment allocation. Following enrollment, all animals underwent a 7-wk wash-out period, after which they received their respective supplements, top-dressed daily onto a basal diet for the last 8 wk of pregnancy. Heifer blood samples were taken at weekly intervals from enrollment until 2 wk before expected calving date and as soon as possible after calving for determination of whole-blood glutathione peroxidase activity (GSH-Px) and plasma Se and malondialdehyde (MDA) concentrations. Selenized AA were determined in plasma samples taken at 3 wk precalving. A colostrum sample was taken as close to parturition as possible for determination of colostrum total Se, selenized AA, and IgG concentration. Calves were blood sampled as close to birth as possible for determination of whole-blood GSH-Px activity and plasma Se and MDA concentrations. Differences in whole-blood GSH-Px activity did not become apparent until calving; GSH-Px activity was lowest in Con heifers but similar between NaSe and HMSeBA heifers. Plasma Se was lowest in unsupplemented heifers and greatest in those supplemented with HMSeBA; this was attributable to greater selenomethionine concentrations in the plasma of HMSeBA heifers. Colostrum Se was lowest in Con heifers and greatest in HMSeBA heifers. The greater Se concentration of HMSeBA heifers was attributable to a greater proportion of total Se comprising selenocysteine; the reason for this is not known. There was no effect of supplementation on colostrum IgG concentration. Plasma Se was lowest in calves born to Con heifers and greatest in those born to HMSeBA heifers. There were no effects of treatment on calf whole-blood GSH-Px activity or plasma MDA concentration. The enhanced Se status associated with HMSeBA supplementation is likely a consequence of selenomethionine supply and may confer benefits to both the dam and her calf postpartum.     

Granulocyte colony-stimulating factor effects on lymphocytes and immunoglobulin concentrations in periparturient cows.

Immunomodulatory effects of recombinant bovine granulocyte colony-stimulating factor were evaluated in periparturient dairy cows. Eleven of 21 cows were experimentally infected with Staphylococcus aureus in one mammary quarter prior to the study. Cows were assigned to four groups in a randomized complete block design to evaluate the effects of recombinant bovine granulocyte colony-stimulating factor (5 micrograms/kg of body weight or placebo injected subcutaneously once daily beginning 14 d prepartum through 10 d postpartum) on infected and uninfected cows during the periparturient period. Blood lymphocytes were isolated and evaluated from 5 wk before expected parturition through 7 wk postpartum. Lymphocyte function was evaluated using a blastogenesis assay, a mitochondrial methylthiazoltetrazolium cleavage activity assay, and an in vitro assay of IgM production. Serum concentrations of IgM, IgG1, conglutinin, and hemolytic complement were also determined. Injections of cows with recombinant bovine granulocyte colony-stimulating factor resulted in enhanced lymphocyte blastogenesis and mitochondrial methylthiazoltetrazolium cleavage activity in unstimulated cultures, higher serum IgM, and increased in vitro IgM production by B lymphocytes. These data provide support for the use of recombinant bovine granulocyte colony-stimulating factor to alleviate immunosuppression in periparturient cows.     

Evaluation of a colostrum supplement, with or without trypsin inhibitor, and an egg protein milk replacer for dairy calves

Forty-eight Holstein bull calves were assigned to a 2 x 2 x 2 factorial arrangement in a completely randomized block design. Main effects were colostrum versus a serum-derived colostrum supplement, 0 versus 1 g of trypsin inhibitor added at the initial 2 feedings, and milk replacer containing 0 or 50% CP from whole egg. Calves were bled at 0, 6, 12, 18, and 24 h after birth for determination of serum immunoglobulin (Ig). G. Serum IgG concentrations were lower in calves consuming the colostrum supplement compared with calves consuming colostrum. Apparent efficiency of absorption of IgG was similar. Trypsin inhibitor did not affect IgG concentrations or absorption of IgG. Calves were fed either milk replacer for 28 to 35 d (preweaning phase) and weaned when they consumed 0.7 kg of starter grain for 2 consecutive days. The postweaning phase was from weaning to d 56. Feeding colostrum supplement resulted in higher fecal scores postweaning (1.90 vs. 1.58) and overall (1.85 vs. 1.65) and fewer days medicated preweaning (5.1 vs. 2.2 d) and postweaning (3.9 vs. 1.9 d) and overall (9.0 vs. 4.2 d). Calves were treated for upper respiratory tract infections and diarrhea. Dry matter intake and weaning age were not affected by treatment. Postweaning (1.69 vs. 1.2 kg) and overall (1.22 vs. 1.0 kg), calves that received colostrum and egg milk replacer consumed more dry matter and starter. Postweaning, calves fed colostrum and egg milk replacer had similar or greater body weight and gains compared with calves fed colostrum and milk protein milk replacer. Preweaning, feed efficiency was greater for calves fed colostrum (0.44 vs. 0.34), trypsin inhibitor (0.42 vs. 0.36), and milk protein milk replacer (0.48 vs. 0.30) compared with calves fed colostrum supplement, no trypsin inhibitor, and egg milk replacer, respectively. Trypsin inhibitor increased feed efficiency postweaning. Calves fed trypsin inhibitor and milk protein milk replacer were more efficient preweaning and overall than calves fed trypsin inhibitor and egg milk replacer. Results indicate that the blood derived colostrum supplement did not provide as much IgG as colostrum (4.55 g/L vs. 14.6 g/L, respectively), that feeding 1.0 g of trypsin inhibitor did not enhance serum IgG concentrations, and that the egg milk replacer-fed calves fed colostrum performed nearly as well as calves fed colostrum and the milk protein milk replacer.     

Leukocytes,microRNA, and complement activity in raw,heat-treated,and frozen colostrum and their dynamics as colostrum transitions to mature milk in dairy cows

The objectives of this study were to evaluate the abundance and viability of leukocytes, the abundance of microRNA, and the activity of the complement pathway in (1) colostrum following heat-treatment or freezing, and (2) colostrum, transition milk, and mature milk. In experiment 1, composite colostrum samples were harvested from individual cows (n = 14) on a commercial dairy farm in NY and split into 3 aliquots using single-use colostrum bags. One aliquot was immediately cooled on ice following harvest (RAW) and stored at 4°C overnight, one was heat-treated for 60 min at 60°C (HT) before being cooled on ice and stored at 4°C overnight, and one was frozen at −20°C overnight (FR). The following morning, all samples were warmed to 40°C before further processing. In experiment 2, cows were sampled in a longitudinal study where composite samples were collected from colostrum (first milking, n = 23), transition milk (3 to 4 d postpartum, n = 13), and mature milk (6 to 7 d postpartum, n = 13). In both experiments colostrum was harvested from the first milking within 8 h of calving and samples were processed within 14 h of collection. Colostral leukocytes were isolated before viability was determined by trypan blue exclusion and manual differential cell counts were performed. Extracellular vesicles were isolated from whey by ultracentrifugation to isolate and quantify microRNA. Activity of the alternative complement pathway was determined in casein-depleted whey by semi-solid phase hemolysis assay. Somatic cell counts were determined for all raw samples. Macrophages and neutrophils made up the greatest proportion of leukocytes in colostrum followed by lymphocytes. Lymphocyte proportion increased as colostrum transitioned to mature milk, but overall somatic cell numbers declined concurrently. Viable cells were not isolated from HT or FR samples. Abundance of microRNA isolated from transition and mature milk was decreased compared with colostrum, did not differ between HT and RAW, but was increased in FR compared with RAW. Alternative complement pathway activity was decreased in HT, but not FR compared with RAW, and was not measurable in transition or mature milk. Postharvest heat-treatment and freezing of colostrum eliminated viable colostral leukocytes and affected microRNA abundance and complement activity. Leukocyte proportions, microRNA abundance, and complement activity changed as colostrum transitioned to mature milk. Although there were clear changes in the colostral components under study in relation to treatment and transition to mature milk, the biological significance of the described treatment effects and temporal changes were not investigated here.