Fatty acid profile characterization in colostrum, transition milk, and mature milk of primi- and multiparous cows during the first week of lactation.

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.

Fatty acid profile characterization in colostrum, transition milk, and mature milk of primi- and multiparous cows during the first week of lactation.

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 16% and 27% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 42% higher in PP cows throughout the milking period, as well as 15% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 13% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 23% higher in colostrum than mature milk and 25% higher in MP cows. Linoleic acid was also 13% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 63% higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 25% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.

ADSA Foundation Scholar Award: New frontiers in calf and heifer nutrition-From conception to puberty.

Dairy calf nutrition is traditionally one of the most overlooked aspects of dairy management, despite its large effect on the efficiency and profitability of dairy operations. Unfortunately, among all animals on the dairy farm, calves suffer from the highest rates of morbidity and mortality. These challenges have catalyzed calf nutrition research over the past decade to mitigate high incidences of disease and death, and improve animal health, growth, welfare, and industry sustainability. However, major knowledge gaps remain in several crucial stages of development. The purpose of this review is to summarize the key concepts of nutritional physiology and programming from conception to puberty and their subsequent effects on development of the calf, and ultimately, future performance. During fetal development, developmental plasticity is highest. At this time, maternal energy and protein consumption can influence fetal development, likely playing a critical role in calf and heifer development and, importantly, future production. After birth, the calf's first meal of colostrum is crucial for the transfer of immunoglobulin to support calf health and survival. However, colostrum also contains numerous bioactive proteins, lipids, and carbohydrates that may play key roles in calf growth and health. Extending the delivery of these bioactive compounds to the calf through a gradual transition from colostrum to milk (i.e., extended colostrum or transition milk feeding) may confer benefits in the first days and weeks of life to prepare the calf for the preweaning period. Similarly, optimal nutrition during the preweaning period is vital. Preweaning calves are highly susceptible to health challenges, and improved calf growth and health can positively influence future milk production. Throughout the world, the majority of dairy calves rely on milk replacer to supply adequate nutrition. Recent research has started to re-evaluate traditional formulations of milk replacers, which can differ significantly in composition compared with whole milk. Transitioning from a milk-based diet to solid feed is critical in the development of mature ruminants. Delaying weaning age and providing long and gradual step-down protocols have become common to avoid production and health challenges. Yet, determining how to appropriately balance the amount of energy and protein supplied in both liquid and solid feeds based on preweaning milk allowances, and further acknowledging their interactions, shows great promise in improving growth and health during weaning. After weaning and during the onset of puberty, heifers are traditionally offered high-forage diets. However, recent work suggests that an early switch to a high-forage diet will depress intake and development during the time when solid feed efficiency is greatest. It has become increasingly clear that there are great opportunities to advance our knowledge of calf nutrition; yet, a more concentrated and rigorous approach to research that encompasses the long-term consequences of nutritional regimens at each stage of life is required to ensure the sustainability and efficiency of the global dairy industry.

Metagenomic analysis revealed the individualized shift in ileal microbiome of neonatal calves in response to delaying the first colostrum feeding.

The aim of this study was to explore the effect of colostrum feeding time on the ileal microbiome of neonatal calves. In this study, 22 male Holstein calves were randomly assigned to different colostrum feeding time treatments: after birth (at 45 min, n = 7); at 6 h after birth (n = 8); and at 12 h after birth (TRT12h; n = 7). At 51 h after birth, calves were killed and ileum digesta was collected for microbiome analysis using shotgun metagenomic sequencing. Bacteria, archaea, eukaryotes, and viruses were identified from the ileum microbiome. For the bacteriome, Firmicutes and Proteobacteria were the predominant phyla, and Escherichia, Streptococcus, Lactobacillus were the 3 most abundant genera. For the archaeal community, Euryarchaeota and Crenarchaeota were the 2 major phyla, and Methanosarcina, Methanobrevibacter, and Methanocorpusculum were the 3 most abundant genera. In total, 116 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were identified from the ileal microbiome, with "biosynthesis of vancomycin group antibiotics," "biosynthesis of ansamycins," "valine, leucine, and isoleucine biosynthesis," "ribosome," and "d-alanine metabolism" as the top 5 functions. When the ileal microbiomes were compared among the 3 treatments, the relative abundance of Enterococcus was higher in TRT12h calves, suggesting that calves may have a higher abundance of opportunistic pathogens when the feeding of colostrum is delayed for 12 h. Moreover, among all KEGG pathways, the enriched "taurine and hypotaurine metabolism" (KO00430) pathway was identified in the ileal microbiome of TRT12h calves; however, future studies are needed to understand the effect on the host. Additionally, 2 distinct ileal microbial profiles were identified across all samples, indicating that that host factors may play a significant role in driving varied microbiome changes in response to colostrum feeding time. Whether such microbiome shifts affect long-term gut function and calf performance warrants future studies.

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: I. Effects on feed intake, growth efficiency, and metabolic and development indicators.

The objectives of this study were to determine the effects of pre- and postweaning planes of nutrition on feed and metabolizable energy (ME) intake, growth, concentrations of glucose, insulin, insulin-like growth factor 1 (IGF-1), and ß-hydroxybutyrate (BHB) in blood and rumen volatile fatty acids (VFA) from birth to 25 wk of age in Holstein heifers. Heifer calves (n = 36) were randomly assigned to receive either a low (5 L/d of whole milk) or high (10 L/d of whole milk) preweaning plane of nutrition from 1 to 7 wk of age, and either a low (70% concentrate dry total mixed ration) or high (85% concentrate dry total mixed ration) postweaning plane of nutrition from 11 to 25 wk of age. From birth to 25 wk of age, feed intake was recorded daily, and body measures were obtained weekly. Circulating hormone and metabolite concentrations were measured biweekly and total ruminal VFA, fecal starch, and body condition were assessed monthly. Overall, average daily gain and body weight were greater for heifers offered increased planes of nutrition during both the pre- and postweaning phases. Heifers offered the high preweaning plane had greater milk intake (7.7 ± 0.1 vs. 4.5 ± 0.1 L/d) but lower starter intake (0.3 ± 0.04 vs. 0.7 ± 0.04 kg/d) during the preweaning phase than those offered the low plane. High preweaning plane heifers also had greater ME intake from wk 1 to 7, but less ME intake at wk 9 (5.3 ± 0.3 vs. 6.6 ± 0.2 Mcal/kg) than those offered the low plane. Furthermore, overall glucose (118.8 ± 2.9 vs. 110.1 ± 2.9 mg/dL) and IGF-1 (101.6 ± 3.6 vs. 75.9 ± 3.6 ng/mL) concentrations were greater for high versus low preweaning plane heifers, although circulating insulin and BHB did not differ between preweaning plane groups. However, heifers offered the high preweaning plane had reduced total rumen VFA concentrations compared with heifers offered the low plane in the preweaning phase (47.3 ± 2.0 vs. 55.6 ± 2.1 mM). During the postweaning phase, dry matter intake and ME were consistently greater in heifers offered the high postweaning plane. Overall insulin (2.0 ± 0.1 vs. 1.8 ± 0.1 ng/mL), glucose (97.1 ± 0.6 vs. 92.1 ± 0.6 ng/mL), IGF-1 (178.0 ± 4.8 vs. 155.8 ± 4.8 ng/mL), and BHB concentrations (8.8 ± 0.2 vs. 8.1 ± 0.2 ng/mL) were greater in heifers offered the high than the low postweaning plane. In addition, heifers offered the high postweaning plane had increased VFA concentrations in the postweaning phase (73.4 ± 1.3 vs. 63.9 ± 1.3 mM) compared with heifers offered the low postweaning plane. The results indicated that increasing the pre- and postweaning planes of nutrition along with energy levels positively influenced several indicators associated with heifer development before 25 wk of age. Nevertheless, there was limited interaction in growth and development indicators between the 2 phases.

Short communication: Effect of delaying the first colostrum feeding on small intestinal histomorphology and serum insulin-like growth factor-1 concentrations in neonatal male Holstein calves.

The primary objective of this study was to determine the effect of delaying the first colostrum feeding on small intestinal histomorphology and serum insulin-like growth factor-1 (IGF-1) concentrations, and the secondary objective was to characterize the ultrastructure of the small intestine of neonatal calves at 51 h of life. Twenty-seven male Holstein calves were fed pooled, pasteurized colostrum (7.5% of birth body weight; 62 g of IgG/L) at 45 min (0H, n = 9), 6 h (6H, n = 9), or 12 h (12H, n = 9) after birth. At 12 h after their respective colostrum feeding, calves were fed milk replacer at 2.5% of birth body weight per meal and every 6 h thereafter. Blood samples were collected every 6 h using a jugular catheter and analyzed for serum IGF-1 concentrations using an automated solid-phase chemiluminescent immunoassay. At 51 h of life, calves were euthanized to facilitate collection of the duodenum, proximal and distal jejunum, and ileum. All segments of the small intestine were assessed for histomorphology, whereas scanning electron and transmission electron microscopy analyses were conducted only for the proximal jejunum and ileum. The results revealed that there was no overall effect of colostrum feeding time on serum IGF-1 concentrations; however, serum IGF-1 concentrations were influenced by time. Specifically, concentrations of serum IGF-1 at 48 h were 29% greater than concentrations at 0 h of life (312.8 ± 14.85 vs. 241.9 ± 14.06 ng/mL). Although there was no overall effect of colostrum feeding time on all histomorphological measures assessed, treatment × segment interactions were observed. Villi height was 1.4 times greater in the distal jejunum of 0H calves than in 6H and 12H calves, and 0H calves tended to have 1.2 times greater ileal villus height than 12H calves. In addition, 0H calves had 1.2 and 1.3 times greater ileal crypt depth than 6H and 12H calves, respectively, and 1.3 times greater surface area index than 12H calves in the distal jejunum. Qualitative ultrastructural evaluation of small intestinal enterocytes conducted irrespective of colostrum treatment revealed the presence of large vacuoles of electron-dense material, apical mitochondria, and apical canalicular systems in the jejunum and ileum. These results indicate that the calf intestine at 51 h of life contains unique enterocyte characteristics similar to fetal enterocytes and that delaying colostrum feeding may negatively influence intestinal growth and development.

Oligosaccharide concentrations in colostrum, transition milk, and mature milk of primi- and multiparous Holstein cows during the first week of lactation.

The objective of this study was to characterize the oligosaccharide (OS) profile of colostrum and transition milk from primiparous (Pp, n = 10) and multiparous (Mp, n = 10) Holstein cows. The experiment was conducted on a commercial dairy farm, where cows were assigned to the study at calving. Colostrum (milking 1) was collected at 5.3 ± 0.7 h after parturition, followed by collection of milkings 2 through 6, milkings 8, 10, 12, and 14 at 0500 and 1600 h each day. Samples were analyzed for OS concentrations using liquid chromatography-mass spectrometry and for IgG and milk components. Concentration of IgG was highest in colostrum and milking 2. Colostral IgG concentration was less in Pp cows than in Mp cows (82.1 ± 3.1 vs. 106.1 ± 16.2 mg/mL). Colostrum and milkings 2 and 3 had 3'-sialyllactose and 6'-sialyllactose concentrations greater than those of mature milk (milkings 8+). For colostrum and milking 2, 6'-sialyllactosamine concentrations were higher than all other milkings, while disialyllactose was only higher in colostrum. In addition, 3'-sialyllactose was the most abundant OS in colostrum and milkings 2 and 3 compared with all other OS. A parity difference was observed for 6'-sialyllactosamine, with Mp having a higher concentration over the first 7 d in milk than Pp (46.4 ± 8.7 vs. 16.9 ± 3.2 µg/mL). Similar results were observed between milkings for OS yields. Parity differences were detected for 3'-sialyllactose, 6'-sialyllactose, and 6'-sialyllactosamine yield, with Mp yield being greater than Pp over the first 7 d in milk. These findings demonstrate that colostrum and transition milk contain elevated concentrations of certain OS compared with mature milk and suggest further research should be conducted regarding the potential benefits of OS in colostrum and transition milk when fed to newborn calves.

Effect of amount of milk replacer fed and the processing of corn in starter on growth performance, nutrient digestibility, and rumen and fecal fibrolytic bacteria of dairy calves.

The aim of this study was to evaluate effects of milk replacer (MR) feeding rate and processing of corn in calf starter (CS) on growth performance, nutrient digestibility, and rumen and fecal fibrolytic bacteria in dairy calves. Holstein male calves (n = 48, 2-3 d of age) were randomly assigned to 1 of 4 treatments with a 2 × 2 factorial arrangement of MR level of 0.749 kg of MR/d (LO) or up to 1.498 kg of MR/d (HI); and whole corn or flaked corn in textured CS. Calves were weaned by reducing MR offered by 50% during wk 6. Intakes of MR and CS were recorded daily, whereas body weight (BW) was measured weekly. Rumen fluid and fecal matter were collected at wk 5 and 8 to quantify fibrolytic bacteria and nutrient digestibility. Data were analyzed as a completely randomized design using mixed model ANOVA. Repeated measures were used as appropriate. Calves fed HI had greater average daily gain than calves fed LO at wk 2, 3, 4, and 5, yet at wk 7 calves fed HI had lower average daily gain compared with calves fed LO. Starter intake was greater for calves fed LO compared with HI at wk 4, 5, 6, and 7. During wk 5 and 8, calves fed LO had increased ADF and NDF digestibility compared with calves fed HI. During wk 5, dry matter and organic matter digestibility were lower for LO-fed calves compared with HI-fed calves, but during wk 8 the opposite was observed, with HI-fed calves having lower dry matter and organic matter digestibility than LO-fed calves. At wk 5, Clostridium cluster IV and Butyrivibrio fibrisolvens proportions in rumen fluid tended to be higher and Clostridium cluster IV, Fecalibacterium sp., and Prevotella sp. proportions in fecal matter were higher in calves fed LO compared with HI. From wk 8 to 16, dry matter intake was unaffected by treatment; however, energy efficiency was greater in calves fed LO, causing LO calves to have higher BW gain during this period. Greater starter digestibility was observed for calves fed LO versus HI in concert with increased fibrolytic bacteria proportions (wk 5) in fecal and rumen samples, which resulted in greater postweaning BW gain and similar BW and frame measurements by 16 wk of age. Overall the results show that rate of MR feeding has a larger effect than the processing of corn in CS on performance, fiber digestibility, and rumen and fecal fibrolytic bacterial communities.