Preweaning nutrient supply alters serum metabolomics profiles related to protein and energy metabolism and hepatic function in Holstein heifer calves

Serum lipidomic profiling of dairy calves fed milk replacers containing animal or vegetable fats

Vegetable fat blends are commonly used as fat sources in milk replacers (MR) for calves, but their composition differs considerably from that of bovine milk fat. The aim of this study was to investigate the serum lipid profile of pre-weaned calves fed twice-daily MR containing 30% fat (% DM). Upon arrival, 30 male Holstein-Friesian calves (BW = 45.6 ± 4.0 kg, age = 2.29 ± 0.8 d) were randomly assigned to 2 experimental diets (n = 15 per treatment): one MR was derived from either vegetable fats (VG; 80% rapeseed and 20% coconut fats) or animal fats (AN; 65% Packer's lard and 35% dairy cream). The 2 MR formulas contained 30% fat, 24% CP, and 36% lactose. Calves were housed indoors in individual pens with ad libitum access to chopped straw and water. Daily milk allowances were 6.0 L from d 1 to 5, 7.0 L from d 6 to 9, and 8.0 L from d 10 to 35, divided into 2 equal meals and prepared at 13.5% solids. An untargeted liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method was employed to analyze the lipid profiles in the serum of calves sampled from the jugular vein at 35 d of age. In total, 594 lipids were characterized, comprising 25 different lipid classes. Principal component analysis (PCA) showed significant separation between VG and AN, indicating different lipid profiles in the serum. An orthogonal partial least squares discriminant analysis (OPLS-DA) classification model was used to further validate the distinction between the 2 treatment groups. The model exhibited a robust class separation and high predictive accuracy. Using a Volcano plot (fold change threshold ≥1.5 and false discovery rate ≤0.05), it was observed that calves fed AN had higher levels of 39 lipid species in serum than calves fed VG, whereas 171 lipid species were lower in the AN group. Lipid classes, such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (SM), triglycerides (TG), lysophosphatidylcholine (LPC), and lysophosphatidylethanolamine (LPE), were different. In particular, PC and PE were observed at lower levels in calves fed AN, possibly indicating shifts in cell membrane characteristics, intracellular signaling, and liver functions. In addition, a decrease in certain triglyceride (TG) species was observed in calves fed AN, including a decrease in TG species such as TG 36:0 and TG 38:0, possibly related to variations in the content of certain fatty acids (FA) within the AN MR, such as C10:0, C12:0, C14:0, and C18:0 compared with the VG MR. Calves fed AN had lower levels of LPC and LPE, and lyso-phosphatidylinositol (LPI), SM, and phosphatidylinositol (PI) species than calves fed VG, suggesting shifts in lipoprotein and lipid metabolic pathways. In conclusion, these results deepen the understanding of how lipid sources in MR can modulate the serum lipidome profiles of dairy calves.

Incremental supply of fat, lactose, or protein influences the diurnal pattern of heat production and substrate oxidation in pre-weaning calves

Increasing nutrient supply to dairy calves has well known benefits; however, the effects of milk replacer (MR) composition when supplied in higher amounts are not fully understood, particularly in the first weeks of life. To better understand the metabolism of macronutrient supply in young calves (21 d old), we investigated diurnal patterns of heat production and substrate oxidation in young calves fed MR with an incremental supply of fat, lactose, or protein. Thirty-two groups of 3 mixed-sex Holstein-Friesian newborn calves (3.4 ± 1.6 d of age), were randomly assigned to one of 4 dietary treatments and studied for 21 d. Diets consisted of a basal MR (23.3% CP, 21.2% EE, and 48.8% lactose of DM) fed at 550 kJ/kg BW0.85 per day (CON; n = 24), or the basal MR incrementally supplied with 126 kJ of DE/BW0.85 per day as milk fat (+FAT; n = 23), lactose (+LAC; n = 24), or milk protein (+PRO; n = 23). Calves were fed MR in 2 daily meals and had ad libitum access to water, but were not supplied with any calf starter nor forage. After 2 weeks of adaptation to the diets, groups of 3 calves were placed for 1 week in an open-circuit respiration chamber for nitrogen and energy balance measurements (lasting 7 d). On d 3, glucose oxidation kinetics was estimated by using [U-13C]glucose. Measurements included total heat production (total energy [HP], activity [Hact] expenditure, resting metabolic rate [RMR]), respiration quotient (RQ), carbohydrate (COX) and fat oxidation (FOX) in 10 min. intervals and averaging these values per hour over days. Incremental supply of lactose and fat increased body fat deposition, with observed patterns in RMR indicating that this increase occurred primarily after the meals. Specifically, the average daily RMR was highest in the +PRO group and lowest in the CON treatment. The HP was higher in the +PRO group and throughout the day, hourly means of HP were higher in this treatment mainly caused by an increase in Hact. The recovery of 13CO2 from oral pulse-dosed [U-13C]glucose was high (77%), and not significantly different between treatments, indicating that ingested lactose was oxidized to a similar extent across treatments. Increasing lactose supply in young calves increased fat retention by reduction in fatty oxidation. Calves fed a MR with additional protein or fat raised RMR persistently throughout the day, while extra lactose supply only affects RMR after the meal. Dietary glucose was almost completely oxidized (77% based on (13C) glucose measurement) regardless of nutrient supplementation. Extra protein supply increased HP and FOX compared with similar intakes of fat and lactose. Fasting heat production (FHP) of young, group-housed calves is comparable to literature values and unaffected by energy intake. Overall, these findings deepen our understanding of how different nutrients impact metabolic processes, fat retention, and energy expenditure in young dairy calves.

Higher abundance of 2-dehydro-d-gluconate in the plasma of sub-fertile or infertile Bos taurus heifers

Infertility or subfertility impacts approximately 5% and 15% of dairy and beef heifers (Bos taurus), respectively. Heifers that do not produce a calf within an optimum window of time have a significant negative impact on the profitability and sustainability of the cattle industry. Selection of heifers based on their fertility potential remains a challenge yet to be resolved. Here, we tested the hypothesis that heifers of different fertility potential have differing metabolome signatures in their plasma. We obtained blood from Bos taurus heifers at their first artificial insemination and processed the samples to separate the plasma. The heifers were classified based on their reproductive outcome as fertile (pregnant and delivered a calf after their first artificial insemination (AI)) or sub-fertile (Angus heifers: no pregnancy after two AI and exposure to a bull; Holstein heifers: no pregnancy by the third AI). We tested the relative abundance of 140 metabolites obtained from 22 heifers (Angus fertile n = 5, Angus sub-fertile n = 7, Holstein fertile N = 5, Holstein sub-fertile N = 5). The metabolite 2-Dehydro-D-gluconate (C6H10O7) was significantly more abundant in the plasma of sub-fertile heifers in both breeds (1.4-fold, false discovery rate < 0.1). In the context that a small proportion of circulating metabolites in the plasma were quantified in this study, the results show that the metabolomic profile in the blood stream may be associated with heifer fertility potential.

l-Glutamine supplementation reduces gastrointestinal permeability and biomarkers of physiological stress in preweaning Holstein heifer calves

l-Glutamine supplementation improves gastrointestinal and immune function in dairy calves during controlled immune and stress challenges. However, it is unknown whether supplementing milk replacer (MR) with l-glutamine improves preweaning dairy calf health and welfare under production conditions. Therefore, the study objective was to evaluate the effects of supplementing MR with l-glutamine on gastrointestinal permeability, immune function, growth performance, postabsorptive metabolic biomarkers, and physiological stress response in preweaning dairy calves. In 3 repetitions, Holstein heifer calves (n = 30; 1.5 ± 0.5 d old; 37.1 ± 0.86 kg body weight) were blocked by serum total protein, body weight, and age, and provided MR (3.8 L/calf per d; 24% CP, 17% fat, 12.5% solids) supplemented with l-glutamine (GLN; 10g/kg MR powder; n = 5 calves/repetition) or nonsupplemented (NSMR; n = 5 calves/repetition). Calves were individually housed with ad libitum starter grain and water access until weaning (56.4 ± 0.5 d old). At 1 and 6 wk of age, urinary catheters were placed, and calves were orally dosed with 1 L of chromium (Cr)-EDTA. Urine samples were collected over a 24-h period for Cr output analysis as an in vivo biomarker of gastrointestinal permeability. Blood was collected on study d 1, 5, 7, 14, 21, 42, and 56 to measure white blood cell counts, cortisol, insulin, glucose, nonesterified fatty acids, serum amyloid A, haptoglobin, and neutrophil: lymphocytes. Two study intervals were used in the statistical analyses, representing greater (P1; wk 1-3) and reduced (P2; wk 4-8) enteric disease susceptibility. Data were analyzed using PROC GLIMMIX in SAS 9.4 (SAS Institute Inc.) with calf as the experimental unit. Overall, total urinary Cr output was reduced in GLN versus NSMR calves. Total Cr output was reduced at 1 wk of age in GLN versus NSMR calves, but no differences were detected at 6 wk of age. Neutrophil:lymphocyte was decreased both overall and during P2 in GLN versus NSMR calves, and neutrophil counts tended to be reduced in GLN versus NSMR calves during P2. No MR treatment differences were detected for average daily feed intake, average daily gain, body measurements, postabsorptive metabolic biomarkers, disease scores, and therapeutic treatments between GLN and NSMR calves. In summary, l-glutamine supplementation reduced gastrointestinal permeability and biomarkers of physiological stress in preweaning Holstein heifer calves.

A Preliminary Study of the Potential Molecular Mechanisms of Individual Growth and Rumen Development in Calves with Different Feeding Patterns

At present, it is common to feed calves with "Concentrate", "Concentrate + hay" and TMR "Total Mixed Rations" feeding patterns in China, which achieved well feeding efficiency, but the three feeding patterns molecular regulation mechanism in actual production is still unclear. The study aimed to explore the most suitable feeding pattern for Chinese Holstein calves to improve the rumen fermentation function and growth performance of calves. In this regard, the interactions between rumen microorganisms and host metabolism were investigated. The rumen volume and weight of calves in the GF group were significantly higher than those in the GFF and TMR groups (p < 0.05), and the rumen pH of calves in the GF group was 6.47~6.79. Metagenomics analysis revealed that the rumen microbiome of GF and GFF calves had higher relative abundances of Methanobrevibacter, Methanosphaera, and Methanolacinia (p < 0.05). Prevotella multisaccharivorax was significantly more abundant in the rumen of GF calves (p < 0.05), indicating that GF group calves had a stronger ability to ferment sugars. Notably, in the pyruvate metabolic pathway, phosphoenolpyruvate carboxylase was significantly up-regulated in GF calves compared with the TMR group, and pyruvate-phosphate dikinase was significantly down-regulated. Metabolomic results showed that Ursodeoxycholic acid was significantly up-regulated in GF calves, and most of the differential metabolites were enriched in Bile secretion pathways. The association analysis study found that the microorganisms of Prevotella and Ruminococcaceae might cooperate with the host, which was helpful for the digestion and absorption of lipids and made the calves have better growth. The three feeding modes had similar effects, but the 'GF' feeding pattern was more beneficial to the individual growth and ruminal development regarding ruminal morphology, contents physiology and microorganisms. Furthermore, the synergistic effect of rumen microorganisms and the host could more effectively hydrolyze lipid substances and promote the absorption of lipids, which was of great significance to the growth of calves.

Invited review: The effect of milk feeding practices on dairy calf behavior, health, and performance-A systematic review

The aim of this systematic review was to summarize the literature assessing the effects of milk feeding practices on behavior, health, and performance on dairy calves. Peer-reviewed, published articles, written in English, directly comparing the effects of milk allowance, milk feeding methods, or milk feeding frequency on dairy calves were eligible for inclusion. Outcome measures could include sucking behavior, sucking on a teat (nutritive sucking, non-nutritive sucking on a teat), abnormal sucking behavior (non-nutritive sucking on pen fixtures, other oral behaviors, or cross-sucking), signs of hunger (vocalizations or unrewarded visits at the milk feeder), activity (lying time or locomotor play), feeding behavior (milk intake, starter intake, milk meal duration, or starter meal duration), growth (body weight or average daily gain), and health (occurrence of diarrhea, respiratory disease, or mortality). We conducted 2 targeted searches using Web of Science and PubMed to identify key literature. The resulting articles underwent a 2-step screening process. This process resulted in a final sample of 94 studies. The majority of studies investigated milk allowance (n = 69). Feeding higher milk allowances had a positive or desirable effect on growth, reduced signs of hunger, and increased locomotor play behavior during the preweaning period, whereas starter intake was reduced. Studies addressing health pointed to no effect of milk allowance, with no consistent evidence indicating that higher milk allowances result in diarrhea. Studies addressing milk feeding methods (n = 14) found that feeding milk by teat reduced cross-sucking and other abnormal oral behaviors. However, results on the effect of access to a dry teat were few and mixed. Milk feeding frequency (n = 14 studies) appeared to have little effect on feed intakes and growth; however, there is some evidence that calves with lower feeding frequency experience hunger. Overall, findings strongly suggest feeding higher volumes of milk using a teat; however, further work is needed to determine the optimal feeding frequency for dairy calves.

Evaluation of the Metabolic Relationship between Cows and Calves by Monitoring Calf Health and Cow Automatic Milking System and Metabolic Parameters

With this study, we investigated the relationship between a cow's and calf's metabolic state, and its effect on health status. To achieve this, 20 calves of primiparous and 20 calves of multiparous cows were selected. The calves were monitored for 30 days and scored for signs of disease, as described in McQuirk (2008); according to score, they were divided into healthier calves; the Low calf score group (LCS, 5-8), Medium calf score group (MCS, 9-12) and High calf score group (HCS, 14-17); or calves most prone to disease. Their mothers were monitored for the same period with a Lely Astronaut 3 herd management system (Lely, Maassluis, The Netherlands) for rumination time, milk yield, milk fat, protein, lactose concentrations and milk fat to protein ratio. Both cows and calves were sampled for blood, and concentrations of glucose with β-hydroxybutyrate were registered. The results indicate that primiparous cows had a 16% higher blood glucose concentration (3.03 mmol/L SE = 0.093) compared with multiparous cows (2.61 mmol/L, SE = 0.102) (p < 0.01), but no difference in calf glucose was recorded. Β-hydroxybutyrate levels did not differ significantly between cows and calves by parity group. Rumination time was longest in the HCS group at 550.79 min/d. and was 16% longer compared with the LCS group (461.94 min/d.; p < 0.001) and 8% longer compared with the MCS group (505.56 min/d.; p < 0.001). The MCS group rumination time mean was statistically significantly higher compared with the LCS group by 8% (p < 0.001). Milk yield was also highest in the HCS group (44.8 kg/d.): 19% higher compared with the MCS group (36.31 kg/d., p < 0.001) and 13% higher than the LCS group (38.83 kg/d., p < 0.001). There was also a significant difference between the MCS and LCS groups of 6% (p < 0.001). The HCS group had the highest milk fat concentration (4.47%): it was 4% higher compared with the LCS group (4.28%, p < 0.001) and 5% higher than the MCS group (4.25%, p < 0.001). Milk fat to protein ratio was highest in the HCS group (1.21) and was 7% higher than in the MCS group (1.12, p < 0.001) and 8% higher than in the LCS group (1.11, p < 0.001). The LCS group was determined to have the highest concentration of milk lactose (4.66%). It was 1% higher compared with the MCS group (4.62%, p < 0.001) and 1.07% higher than the HCS group (4.61%, p < 0.001). We can conclude that parity did not affect calf health status and that cows of the HCS group showed symptoms of negative energy balance expressed through higher milk yield, higher milk fat concentration and higher milk fat to protein ratio, with lower milk lactose concentration. Further and more thorough research is needed to evaluate the relationship between pregnant cows and calves.

Host metabolome and faecal microbiome shows potential interactions impacted by age and weaning times in calves

BACKGROUND

Calves undergo nutritional, metabolic, and behavioural changes from birth to the entire weaning period. An appropriate selection of weaning age is essential to reduce the negative effects caused by weaning-related dietary transitions. This study monitored the faecal microbiome and plasma metabolome of 59 female Holstein calves during different developmental stages and weaning times (early vs. late) and identified the potential associations of the measured parameters over an experimental period of 140 days.

RESULTS

A progressive development of the microbiome and metabolome was observed with significant differences according to the weaning groups (weaned at 7 or 17 weeks of age). Faecal samples of young calves were dominated by bifidobacterial and lactobacilli species, while their respective plasma samples showed high concentrations of amino acids (AAs) and biogenic amines (BAs). However, as the calves matured, the abundances of potential fiber-degrading bacteria and the plasma concentrations of sphingomyelins (SMs), few BAs and acylcarnitines (ACs) were increased. Early-weaning at 7 weeks significantly restructured the microbiome towards potential fiber-degrading bacteria and decreased plasma concentrations of most of the AAs and SMs, few BAs and ACs compared to the late-weaning event. Strong associations between faecal microbes, plasma metabolites and calf growth parameters were observed during days 42-98, where the abundances of Bacteroides, Parabacteroides, and Blautia were positively correlated with the plasma concentrations of AAs, BAs and SMs as well as the live weight gain or average daily gain in calves.

CONCLUSION

The present study reported that weaning at 17 weeks of age was beneficial due to higher growth rate of late-weaned calves during days 42-98 and a quick adaptability of microbiota to weaning-related dietary changes during day 112, suggesting an age-dependent maturation of the gastrointestinal tract. However, the respective plasma samples of late-weaned calves contained several metabolites with differential concentrations to the early-weaned group, suggesting a less abrupt but more-persistent effect of dietary changes on host metabolome compared to the microbiome.

Macronutrient profile in milk replacer or a whole milk powder modulates growth performance, feeding behavior, and blood metabolites in ad libitum-fed calves

Milk replacers (MR) for calves usually contain more lactose and less fat than bovine whole milk (WM). There are insufficient data to determine whether these MR formulations are optimal for calves fed at high planes of nutrition. Thus, the effect of 3 MR formulations and a WM powder were evaluated on growth, feeding behavior, and blood metabolites in 96 male Holstein calves fed ad libitum and with 45.5 ± 4.30 kg (mean ± SD) BW at arrival. Calves were blocked based on arrival sequence, and randomly assigned within block to one of the 4 treatments (n = 24 calves/group): a high-fat MR (25.0% fat, dry matter basis; 22.5% protein, 38.6% lactose; 21.3 MJ/kg; HF), a high lactose MR (44.6% lactose, 22.5% protein, 18.0% fat; 19.7 MJ/kg; HL), a high protein MR (26.0% protein, 18.0% fat, 41.5% lactose; 20.0 MJ/kg; HP), and a WM powder (26.0% fat; 24.5% protein, 38.0% lactose; 21.6 MJ/kg; WP). In the first 2 wk after arrival, calves were individually housed and were fed 3.0 L of their respective liquid feed 3 times daily at 135 g/L. They were then moved to group housing and fed ad libitum until d 42 after arrival. Weaning was gradual and took place between d 43 and 70 after arrival; thereafter, calves were fed solids only. Concentrates, chopped straw, and water were available ad libitum throughout the study. Body weight was measured, and blood was collected at arrival and then weekly thereafter from wk 1 to 12. Weight gain and height were greater in HL than WP calves. In the preweaning phase, HL and HP-fed calves consumed more milk than WP, and HL-fed calves consumed more milk than HF calves. In wk 10, starter feed intakes were lower in HF calves than in the other groups. In the preweaning phase, ME intakes were the same for all treatments. This suggests that milk intakes were regulated by the energy density of the milk supplied. The percentage of calves requiring therapeutic interventions related to diarrhea was greater in WP-fed calves (29%) than HF and HL calves (4%), whereas HP (13%) did not differ with other groups. This was coupled with lower blood acid-base, blood gas, and blood sodium in WP than in MR-fed calves. Calves fed HF had greater serum nonesterified fatty acids compared with other groups, and greater serum amyloid A compared with WP and HL calves. Among the serum parameters, insulin-like growth factor-1 and lactate dehydrogenase correlated positively with MR intake and average daily gain. The high lactose and protein intakes in HL and HP calves led to greater insulin-like growth factor-1 concentrations than in WP-fed calves. Although growth differences were limited among MR groups, the metabolic profile largely differed and these differences require further investigation.

Defining Fatty Acid Changes Linked to Rumen Development, Weaning and Growth in Holstein-Friesian Heifers

After birth, as effectively monogastric animals, calves undergo substantial physiological changes to become ruminants by 3 months of age and reach sexual maturity at approximately 15 months of age. Herein, we assess longitudinal metabolomic changes in Holstein-Friesian (HF) heifers from birth until sexual maturity during this developmental process. Sera from 20 healthy, HF heifers were sampled biweekly from 2 weeks of age until 13 months of age and then monthly until 19 months of age. Sera were assessed using flow infusion electrospray high-resolution mass spectrometry (FIE-HRMS) on a Q Exactive hybrid quadrupole-Orbitrap mass spectrometer for high-throughput, sensitive, non-targeted metabolite fingerprinting. Partial least squares discriminant analysis (PLS-DA) and unsupervised hierarchical clustering analysis (HCA) of the derived metabolomes indicated changes detectable in heifers’ sera over time. Time series analyses identified 30 metabolites that could be related to rumen development and weaning at ~3 months of age. Further time series analysis identified 40 metabolites that could be correlated with growth. These findings highlight the role of acetic acid and 3-phenylpropionate (3-PP) in rumen development and growth, suggest that weaning induces elevated levels of fatty acyls in response to a post-weaning stress-induced innate immune response and demonstrate the utilization of fatty acyls in growth. The identified metabolites offer serum metabolites which could inform the nutrition and healthy development of heifers.

Dietary Concentrate Supplementation Alters Serum Metabolic Profiles Related to Energy and Amino Acid Metabolism in Grazing Simmental Heifers

Supplementation plays a vital role in the growth performance of grazing heifers. We investigated the effects of maize-based concentrate supplementation on the serum metabolome in grazing heifers. Twenty-four 7-month-old heifers (211.65 ± 4.25 kg BW) were randomly divided into a supplement (SUP) group and a control (CON) group. The results indicated that concentrate supplementation increased the final body weight (BW) of grazing heifers, and the average daily gain (ADG) was 61.5% (P = 0.011) higher in the SUP group than in the CON group. Serum concentrations of total protein (TP), triglyceride (TG), and leptin were higher in the SUP group than in the CON group (p < 0.05). Supplementation increased serum metabolites and amino acids and markedly altered glucose, lipid, and protein metabolism, which contributed to the heifer growth. Furthermore, by multivariate analysis, 45 serum metabolites were identified as significantly different between the two groups. Enrichment analysis revealed that arginine biosynthesis and tryptophan metabolism as well as glycerophospholipid metabolism were significantly enriched between the two groups. We concluded that the growth potential of heifers could be improved by maize-based concentrate supplementation, and the main biological pathways affected were those related to energy and amino acid metabolism.