Canine amniotic fluid at birth: From a discarded sample to a potential diagnostic of neonatal maturity.

The definition of new reliable markers for neonatal maturity evaluation is crucial in canine clinical practice. Concerns about the safety of amniotic sampling in pregnant dogs have prevented its collection for diagnostic purposes. Moreover, amniotic fluid had been considered waste material until the latest studies reported amniocentesis as a reliable and safe procedure, even in the canine species. In our study, amniotic fluid (n = 63) collected at birth from ten dogs undergoing elective Caesarean sections at term was analysed to discover new potential indices of canine neonatal maturity. Based on gestational age, mothers and puppies were divided into two groups: the early group (≤65 days from luteinizing hormone (LH) surge, n = 5) and the late group (>65 days from LH surge, n = 5). Amniotic parameters of the lightest and heaviest puppy in individual/each litter, with a birth weight difference of at least 20% among littermates, were also compared. In particular, the content of lecithin, sphingomyelin, surfactant protein A (SP-A), cortisol, and pentraxin 3 (PTX3) in amniotic fluid, which is considered predictive of foetal development in humans, were investigated. Maternal serum SP-A and cortisol were also measured simultaneously. All amniotic parameters were detectable in canine amniotic fluid. Interestingly, the concentrations of different amniotic parameters correlated with each other. Lecithin was positively correlated with sphingomyelin (p < 0.0001), maternal SP-A (p < 0.0005), and the ratio of amniotic and maternal cortisol (p < 0.004). Amniotic SP-A was inversely correlated to maternal SP-A (p < 0.05), lecithin (p < 0.005), and lecithin-sphingomyelin ratio (p < 0.05). A positive correlation was also recorded between amniotic and maternal cortisol (p < 0.008). Considering that all puppies were born alive and mature, these data could provide a potential range of expected amniotic values in full-term new-born dogs. Furthermore, since gestational age was positively correlated with both maternal and amniotic cortisol (p < 0.0001) and amniotic PTX3 (p < 0.05), amniotic fluid seems to be an attractive, innovative, and minimally invasive matrix with potential diagnostic and prognostic utility for the investigation of canine maturity.

Ketogenic Diet: Impact on Cellular Lipids in Hippocampal Murine Neurons.

BACKGROUND: The mechanism of action of the ketogenic diet (KD), an effective treatment for pharmacotherapy refractory epilepsy, is not fully elucidated. The present study examined the effects of two metabolites accumulating under KD-beta-hydroxybutyrate (ßHB) and decanoic acid (C10) in hippocampal murine (HT22) neurons. METHODS: A mouse HT22 hippocampal neuronal cell line was used in the present study. Cellular lipids were analyzed in cell cultures incubated with high (standard) versus low glucose supplemented with ßHB or C10. Cellular cholesterol was analyzed using HPLC, while phospholipids and sphingomyelin (SM) were analyzed using HPTLC. RESULTS: HT22 cells showed higher cholesterol, but lower SM levels in the low glucose group without supplements as compared to the high glucose groups. While cellular cholesterol was reduced in both ßHB- and C10-incubated cells, phospholipids were significantly higher in C10-incubated neurons. Ratios of individual phospholipids to cholesterol were significantly higher in ßHB- and C10-incubated neurons as compared to controls. CONCLUSION: Changes in the ratios of individual phospholipids to cholesterol in HT22 neurons suggest a possible alteration in the composition of the plasma membrane and organelle membranes, which may provide insight into the working mechanism of KD metabolites ßHB and C10.

Comparative Lipidomic Study of Human Milk from Different Lactation Stages and Milk Formulas.

In this report, we present a detailed comparison of the lipid composition of human milk (HM) and formula milk (FM) targeting different lactation stages and infant age range. We studied HM samples collected from 26 Polish mothers from colostrum to 19 months of lactation, along with FM from seven brands available on the Polish market (infant formula, follow-on formula and growing-up formula). Lipid extracts were analysed using liquid chromatography coupled to high-resolution mass spectrometry (LC-Q-TOF-MS). We found that the lipid composition of FM deviates significantly from the HM lipid profile in terms of qualitative and quantitative differences. FM had contrasting lipid profiles mostly across brands and accordingly to the type of fat added but not specific to the target age range. The individual differences were dominant in HM; however, differences according to the lactation stage were also observed, especially between colostrum and HM collected in other lactation stages. Biologically and nutritionally important lipids, such as long-chain polyunsaturated fatty acids (LC-PUFAs) containing lipid species, sphingomyelines or ether analogues of glycerophosphoethanoloamines were detected in HM collected in all studied lactation stages. The observed differences concerned all the major HM lipid classes and highlight the importance of the detailed compositional studies of both HM and FM.

Lipidomic profiling of amniotic fluid and its application in fetal lung maturity prediction.

BACKGROUND: The pulmonary surfactant especially lipids in amniotic fluid can reflect the development stage of fetal lung maturity (FLM). However, the conventional lecithin/sphingomyelin (L/S) ratio method by thin layer chromatography (TLC) is insufficient and inconvenient for FLM prediction in clinical practice. METHODS: The amniotic fluid samples were collected from the pregnant women in labor or undergoing amniocentesis and analyzed for its lipid contents with the liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) method and the lamellar body count (LBC) method. To reveal the lipidomic profiling of different FLM stages, three groups of amniotic fluid samples including 8 from premature group (gestational week (GW) < 37), 10 from mature group (GW < 37), and 10 from mature group (GW > 38) were compared with the control group (n = 6) of 18 GWs separately. RESULTS: In the FLM prediction study, the sensitivity of the LC-HRMS method and LBC method was 91% and 73%, respectively; the specificity was 100% and 95%, respectively. The most significant metabolic pathway was linoleic acid metabolism between the premature group and the control group. Both glycerophospholipid metabolism and glycosylphosphatidylinositol-anchor biosynthesis were enriched in the mature groups. In search of potential FLM prediction markers in amniotic fluid, 8 phosphatidylcholines, 1 sphingomyelin, and 1 phosphatidylethanolamine were significantly increased in the mature groups compared with the premature group. CONCLUSION: An efficient LC-HRMS method for L/S ratio in predicting FLM was established. The linoleic acid metabolism may play an important role in the fetal lung development.

Rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted respiratory distress syndrome with high sensitivity.

AIM: Respiratory distress syndrome (RDS) is a major cause of mortality and morbidity in premature infants. By the time symptoms appear, it may already be too late to prevent a severe course, with bronchopulmonary dysplasia or mortality. We aimed to develop a rapid test of lung maturity for targeting surfactant supplementation. METHODS: Concentrations of the most surface-active lung phospholipid dipalmitoylphosphatidylcholine and sphingomyelin in gastric aspirates from premature infants were measured by mass spectrometry and expressed as the lecithin/sphingomyelin ratio (L/S). The same aspirates were analysed with mid-infrared spectroscopy. Subsequently, L/S was measured in gastric aspirates and oropharyngeal secretions from another group of premature infants using spectroscopy and the results were compared with RDS development. The 10-minute analysis required 10 µL of aspirate. RESULTS: An L/S algorithm was developed based on 89 aspirates. Subsequently, gastric aspirates were sampled in 136 infants of 24-31 weeks of gestation and 61 (45%) developed RDS. The cut-off value of L/S was 2.2, sensitivity was 92%, and specificity was 73%. In 59 cases, the oropharyngeal secretions had less valid L/S than gastric aspirate results. CONCLUSION: Our rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted RDS with high sensitivity.

The influence of the obstetrical condition on canine neonatal pulmonary functional competence.

OBJECTIVE: To compare the influence of the obstetrical condition on neonatal respiratory performance, to estimate surfactant synthesis through lecithin and sphingomyelin ratio (L/S) in amniotic fluid of pregnant bitches and correlate the L/S with the respiratory condition during the first hour of life. DESIGN: Prospective randomized study. SETTING: University veterinary teaching hospital and private referral centers. ANIMALS: In accordance to the condition at birth, puppies from 25 healthy bitches aged 2-6 years were allocated into: Eutocia Group--EUT (n = 19 neonates and 14 bitches); Dystocia Group--DYS (n = 8 neonates and 5 bitches) and Elective Cesarean Section Group--CS (n = 12 neonates and 11 bitches). INTERVENTIONS: Amniotic fluid was drawn from amniotic sac and lecithin (L) and sphingomyelin (S) were measured by high performance liquid chromatography to obtain the L/S ratio. Neonatal physical examination was performed at 1, 5, and 60 minutes after delivery, and included the assessment of respiratory rate (RR) and respiration effort (RE). MEASUREMENTS AND MAIN RESULTS: CS group had significantly lower amniotic L/S ratio when compared to EUT and DYS. There were no significant differences between vaginal groups (EUT versus DYS) in respect to L/S ratios. RE of eutocic neonates improved promptly, while RE of DYS and CS groups improved only 1 hour following birth. Moreover, amniotic L/S ratio positively correlated with RR after 60 minutes. CONCLUSIONS: We identified a possible influence of the delivery method on the final surfactant maturation process. Thus, neonates born by elective CS prior to the onset of expulsive uterine contractions should have their respiratory parameters carefully monitored. Additionally, we propose that assessment of respiratory parameters 1 hour following birth can serve as a practical means to indirectly estimate pulmonary maturation (ie, surfactant synthesis) in puppies.

Composition and microstructure of colostrum and mature bovine milk fat globule membrane.

The microstructures of colostrum and mature bovine milk fat globule membrane (MFGM) were investigated using confocal laser scanning microscopy (CLSM) at different temperatures, and the relationships between microstructure variations and the chemical compositions of the MFGM were also examined. Using a fluorophore-labeled phospholipid probe, we found that non-fluorescent domains on the MFGM were positively correlated with the amount of sphingomyelin at both room (20 °C) and physiological (37 °C) temperatures. However, at the storage temperature (4 °C), there were more non-fluorescent domains on the MFGM. These results indicate that the heterogeneities in the MFGM are most likely to be the result of the lateral segregation of sphingomyelin at the room and physiological temperatures, and at the storage temperature, phospholipids with saturated fatty acids affect the formation of these domains.

Prediction of fetal lung maturity using the lecithin/sphingomyelin (L/S) ratio analysis with a simplified sample preparation, using a commercial microtip-column combined with mass spectrometric analysis.

Fetal lung maturity is estimated using the lecithin/sphingomyelin ratio (L/S ratio) in amniotic fluid and it is commonly measured with thin-layer chromatography (TLC). The TLC method is time consuming and technically difficult; however, it is widely used because there is no alternative. We evaluated a novel method for measuring the L/S ratio, which involves a tip-column with a cation-exchange resin and mass spectrometry. Phospholipids in the amniotic fluid were extracted using methanol and chloroform. Choline-containing phospholipids such as lecithin and sphingomyelin were purified by passing them through the tip-column. LC-MS/MS and MALDI-TOF were used to directly analyze the purified samples. The L/S ratio by mass spectrometry was calculated from the sum peak intensity of the six lecithin, and that of sphingomyelin 34:1. In 20 samples, the L/S ratio determined with TLC was significantly correlated with that obtained by LC-MS/MS and MALDI-TOF. There was a 100% concordance between the L/S ratio by TLC and that by LC-MS/MS (kappa value=1.0). The concordance between the L/S ratio by TLC and that by MALDI-TOF was also 100% (kappa value=1.0). Our method provides a faster, simpler, and more reliable assessment of fetal lung maturity. The L/S ratio measured by LC-MS/MS and MALDI-TOF offers a compelling alternative method to traditional TLC.

High-dose simvastatin exhibits enhanced lipid-lowering effects relative to simvastatin/ezetimibe combination therapy.

Statins are the frontline in cholesterol reduction therapies; however, their use in combination with agents that possess complimentary mechanisms of action may achieve further reductions in low-density lipoprotein cholesterol. Thirty-nine patients were treated with either 80 mg simvastatin (n=20) or 10 mg simvastatin plus 10 mg ezetimibe (n=19) for 6 weeks. Dosing was designed to produce comparable low-density lipoprotein cholesterol reductions, while enabling assessment of potential simvastatin-associated pleiotropic effects. Baseline and post-treatment plasma were analyzed for lipid mediators (eg, eicosanoids and endocannabinoids) and structural lipids by liquid chromatography tandem mass spectrometry. After statistical analysis and orthogonal projections to latent structures multivariate modeling, no changes were observed in lipid mediator levels, whereas global structural lipids were reduced in response to both monotherapy (R(2)Y=0.74; Q(2)=0.66; cross-validated ANOVA P=7.0×10(-8)) and combination therapy (R(2)Y=0.67; Q(2)=0.54; cross-validated ANOVA P=2.6×10(-5)). Orthogonal projections to latent structures modeling identified a subset of 12 lipids that classified the 2 treatment groups after 6 weeks (R(2)Y=0.65; Q(2)=0.61; cross-validated ANOVA P=5.4×10(-8)). Decreases in the lipid species phosphatidylcholine (15:0/18:2) and hexosyl-ceramide (d18:1/24:0) were the strongest discriminators of low-density lipoprotein cholesterol reductions for both treatment groups (q<0.00005), whereas phosphatidylethanolamine (36:3e) contributed most to distinguishing treatment groups (q=0.017). Shifts in lipid composition were similar for high-dose simvastatin and simvastatin/ezetimibe combination therapy, but the magnitude of the reduction was linked to simvastatin dosage. Simvastatin therapy did not affect circulating levels of lipid mediators, suggesting that pleiotropic effects are not associated with eicosanoid production. Only high-dose simvastatin reduced the relative proportion of sphingomyelin and ceramide to phosphatidylcholine (q=0.008), suggesting a pleiotropic effect previously associated with a reduced risk of cardiovascular disease.

Investigation into the dosage of dietary sphingomyelin concentrate in relation to the improvement of epidermal function in hairless mice.

We previously found that dietary sphingomyelin (SPM) concentrate from bovine milk improved epidermal function. In this study, we investigated the dosage of dietary SPM concentrate from bovine milk in relation to the improvement of epidermal function. Thirteen-week-old hairless male mice were separated into four experimental groups, each fed one of four types of experimental diet: the control group, the low SPM group, the medium SPM group and the high SPM group. The mice were each fed the experimental diet for 6 weeks. The stratum corneum hydration and the transepidermal water loss (TEWL) were measured using a Corneometer and a Tewameter at 3 weeks and 6 weeks. After the feeding period, ceramides in the stratum corneum were analyzed. We found that the stratum corneum hydration in all the SPM groups was significantly higher than that in the control group, whereas TEWL in all the SPM groups was significantly lower than that in the control group. Ceramides increased significantly in mice fed the medium SPM diet and statistically tended to increase in mice fed the high SPM diet. Our results indicate that a daily intake of 17 mg SPM concentrate is enough to improve epidermal function in hairless mice.

Performance of lecithin-sphingomyelin ratio as a reflex test for documenting fetal lung maturity in late preterm and term fetuses.

OBJECTIVE: To determine if infants delivered after immature or indeterminate TDx-FLM II testing and a mature reflex test are at increased risk for neonatal respiratory complications. METHODS: The primary analysis compared neonatal respiratory morbidity (RDS or TTN) in 34-39-week fetuses delivered after either (i) mature TDx-FLM II testing, or (ii) indeterminate or immature TDx-FLM II and a positive reflex test (PG or L/S ratio). RESULTS: Fifty patients delivered after mature TDx-FLM II, and 30 after immature or indeterminate TDx-FLM II with an L/S ≥ 2.0. Respiratory morbidity was significantly higher in the group delivered after mature reflex testing compared with mature TDx-FLM II (23% vs. 2%, p < 0.01). When PG was present, there were no cases of RDS or TTN. CONCLUSIONS: Utilizing L/S ratios as a reflex test to confirm lung maturity was associated with a high risk for respiratory morbidity, particularly when PG was not present.

Clinical and laboratory trends in fetal lung maturity testing.

BACKGROUND: The surfactant/albumin ratio is a popular fetal lung maturity (FLM) test that will be unavailable in the near future. We conducted surveys of obstetricians and clinical laboratorians to assess FLM testing trends from the perspectives of both disciplines and to identify how both communities might adapt to the loss of the surfactant/albumin ratio. METHODS: 2067 physicians were surveyed about their familiarity with and clinical utility of various FLM tests. 6137 laboratorians were surveyed about their FLM test menu and volumes. RESULTS: Twenty-five percent of physicians indicated a decrease in FLM test ordering and the frequency of FLM testing has decreased significantly (p=0.011) since 1998. The surfactant/albumin ratio is the most frequently offered FLM test and was the test of choice for 62% of physicians. Without the surfactant/albumin ratio, 68% of physicians would order the lecithin/sphingomyelin ratio and 44% would order the lamellar body count (LBC) which were offered by 18 and 13% of laboratories, respectively. 16% of laboratories were planning to offer the LBC within 24 months. CONCLUSIONS: FLM testing is decreasing. The loss of the surfactant/albumin ratio will increase the demand for the lecithin/sphingomyelin ratio and the LBC, yet few laboratories offer either test and most are not planning to offer the LBC.

Amniotic lamellar body counts determined with the Sysmex XE-2100 analyzer to predict fetal lung maturity during diabetic and other complicated pregnancies.

OBJECTIVE: The detection of amniotic lamellar bodies (LB) has been shown to be a rapid and simple way to assess fetal lung maturity (FLM). The maturity thresholds for LB vary due to different factors, one being the type of particle-count analyser used. MATERIAL AND METHODS: The Sysmex XE-2100 hematological analyser was evaluated in determination of amniotic LB counts and compared with lecithin/sphingomyelin (L/S) and phosphatidylglycerol (PG) determination. We analysed 132 amniotic samples from a total of 109 mothers (71 diabetic) with 112 infants. Results. The correlation between the LB counts obtained with the Sysmex XE-2100 and our reference thin layer chromatography (TLC) phospholipid method was good. Samples with low L/S ratio (< or = 2.0) and no PG (i.e. premature fetal lung status), had low LB counts (n = 18, mean 8500/L, range 1000-26000), whereas 51 samples with mature fetal lung status had high LB counts (mean 63600/uL, range 20,000-139,000). In all our four cases of respiratory distress syndrome the LB counts were low (range 1000-28000/uL). The reference values for FLM determination were established: < or = 6000/microL for immature, values between 7000 and 35,000/uL for borderline results and >35,000/uL for mature. CONCLUSIONS. The amniotic LB count analysis with Sysmex XE-2100 has many advantages being a repeatable, inexpensive and quantitative method with a very short turn-around time. Consequently, our routine is to perform LB counts initially from all amniotic samples and only borderline LB results are analysed with TLC.

Different medicaments in fetus maturation--corticosteroid usage.

OBJECTIVE: The object of work is pointing out the significance of improvement highly risk pregnancies by applying artificial fetal lungs maturation in relation to expected outcomes without adequate therapy. METHODS: We analyzed fetal lung maturation by using lecithin and sphingomyelin ratio in embryo fluid received by foam test. We examined successfulness of artificial fetal lungs maturation by applying corticosteroids to the embryo in a group of patients with serious form of growth retardation (group A), then to the mother (group B) and by inducing partial mild form of asphyxia with oxytocin infusion (group C). RESULTS: The success of the method is shown by the success of finished pregnancies. We followed the difference between expected and actual term of delivery. CONCLUSION: Artificial fetal lungs maturation by applying fetal corticosteroids efficiently increases the creation of lecithin and sphingomyelin and enables life of neonate even in period up to 30th week of gestation.

[Quantitative analysis of lamellar bodies in amniotic fluid as fetal pulmonary maturity indicator].

BACKGROUND/AIM: Although lamellar bodies have been the center of interest over the last years, the published results of fetal pulmonary maturity determination according to their concentration in amniotic fluid are controversial. The aim of this study was to determine the significance of lamellar bodies, as well as the ratio lecithin/sphingomyelin (L/S) in amniotic fluid for the assessment of fetal pulmonary maturity. METHODS: This prospective 2-year study included 102 female examinees, ranging from 17 to 44 years of age, in whom lamellar bodies concentrations in amniotic fluid were determined to check the efficacy of the applied therapy for obtaining arteficial fetal pulmonary maturity. The shake test was applied as a comparative test for determining a quantitative L/S ratio. To determine a fetus maturity and development stage we followed up biparietal diameter, abdominal circumference, femure length, ponderal index at birth and body mass. RESULTS: Out of a total of 102 amniocenteses within a period from 26th to 40th gestation week only 70 results were considered due to 32 unknown neonatal outcomes. Biparietal diameter was 224-362 mm, femur length 56 - 78 mm, ponderal index 1.22-2.84, fetus body mass 1300-4 350 g. There was found a significant relation between gestation age and lamellar bodies concentration (R = 0.396398, p < 0.01), as well as between gestation age and the ratio L/S (R = 0.691297, p < 0.01). Also, there was a significant correlation of lamellar bodies concentration to the ratio L/S determined (R = 0.493609, p < 0.01). CONCLUSION: Determination of lamellar bodies concentration values is a reliable method to confirm fetal pulmonary maturity.

The probability of neonatal respiratory distress syndrome as a function of gestational age and lecithin/sphingomyelin ratio.

We sought to define the risk of neonatal respiratory distress syndrome (RDS) as a function of both lecithin/sphingomyelin (L/S) ratio and gestational age. Amniotic fluid L/S ratio data were collected from consecutive women undergoing amniocentesis for fetal lung maturity at Yale-New Haven Hospital from January 1998 to December 2004. Women were included in the study if they delivered a live-born, singleton, nonanomalous infant within 72 hours of amniocentesis. The probability of RDS was modeled using multivariate logistic regression with L/S ratio and gestational age as predictors. A total of 210 mother-neonate pairs (8 RDS, 202 non-RDS) met criteria for analysis. Both gestational age and L/S ratio were independent predictors of RDS. A probability of RDS of 3% or less was noted at an L/S ratio cutoff of > or = 3.4 at 34 weeks, > or = 2.6 at 36 weeks, > or = 1.6 at 38 weeks, and > or = 1.2 at term. Under 34 weeks of gestation, the prevalence of RDS was so high that a probability of 3% or less was not observed by this model. These data describe a means of stratifying the probability of neonatal RDS using both gestational age and the L/S ratio and may aid in clinical decision making concerning the timing of delivery.

Lung maturation in small for gestational age fetuses from pregnancies complicated by placental insufficiency or maternal hypertension.

BACKGROUND: Clinical studies suggest that respiratory outcome of infants born preterm may be influenced by placental insufficiency and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. If so, one could expect to see differences in lung maturation indices (lecithin/sphingomyelin (L/S) ratio and lamellar body count (LBC)) in the amniotic fluid. The present study investigates lung maturation indices of preterm small for gestational age (SGA) fetuses with or without abnormal Doppler ultrasound examination and with or without maternal hypertension/HELLP syndrome. STUDY DESIGN: Retrospective cohort study of 76 neonates born in our center between 1997 and 2003 with gestational age (GA) <34 weeks, birth weight

Factors affecting the concentration of sphingomyelin in bovine milk.

Sphingomyelin is a phospholipid located in the outer leaflet of the plasma membrane of most cells and is a component of the milk fat globule membrane. Sphingomyelin and its digestion products participate in several antiproliferative pathways that may suppress oncogenesis. Although milk and dairy products are important sources of sphingomyelin in the human diet, little is known about factors that influence sphingomyelin concentrations in milk fat or whether concentrations can be modified via the nutrition of cows. Sphingomyelin concentrations were determined in milk from Holstein and Jersey cows matched for parity and stage of lactation. Sphingomyelin was more concentrated in milk fat from Holstein cows than in milk fat from Jersey cows (1,044 vs. 839 microg/g of fat). Concentrations in whole milk did not differ because of greater milk fat content for milk from Jerseys. Differences between breeds may be related to the greater fat globule size in milk from Jerseys. Sphingomyelin content in whole milk increased with increasing days in milk because of associated increases in milk fat content. Regardless of breed, primiparous cows had greater amounts of stearic acid and less palmitic acid in sphingomyelin than did older cows. The sphingomyelin concentration in milk fat of cows in a commercial Jersey herd was lower for cows in their fourth or greater parity. Sphingomyelin content in whole milk was greater for cows in late lactation because of greater milk fat content. Feed restriction of multiparous Holstein cows to 37% of ad libitum dry matter intake increased milk fat content but did not affect milk sphingomyelin content or milk fat globule size. Supplementation of the diet with 4% soybean oil did not affect milk composition, sphingomyelin content, or milk fat globule size. Milk was sampled seasonally from 7 herds throughout Illinois during a 2-yr period. Sphingomyelin concentration in milk fat was greatest during summer and least during winter, but whole milk concentrations did not vary across seasons. We conclude that 1) sphingomyelin content of milk fat is greater in milk from Holsteins than that from Jerseys, 2) sphingomyelin content in whole milk increases with stage of lactation, and 3) sphingomyelin content of milk fat is greater during summer. However, efforts to produce milk with a greater sphingomyelin content through altering management and nutrition are unlikely to be successful.