Effect of feeding whole compared with cell-free colostrum on calf immune status: Vaccination response

Investigating the IgM and IgG B Cell Receptor Repertoires and Expression of Ultralong Complementarity Determining Region 3 in Colostrum and Blood from Holstein-Friesian Cows at Calving

In cattle, colostral maternal immunoglobulins and lymphocytes transfer across the neonate's intestinal epithelium to provide protection against pathogens. This study aimed to compare repertoires of B cell populations in blood and colostrum in cows for the first time, with an emphasis on ultralong complementarity determining region 3 (CDR3, ≥40 amino acids). Blood mononuclear cells (BMCs, n= 7) and colostral cells (n = 7) were isolated from Holstein-Friesian dairy cows. Magnetic-activated cell sorting was used to capture IgM and IgG B cells from BMCs. Colostral cells were harvested by centrifugation. RNA was extracted and cDNA was produced; IgM and IgG transcripts were amplified using polymerase chain reactions. Amplicons were sequenced using the Nanopore Native barcoding kit 24 V14 and MinION with R10.4 flow cells. In colostrum, there was a significantly greater percentage of IgM B cells with ultralong CDR3s (8.09% ± 1.73 standard error of the mean) compared to blood (4.22% ± 0.70, p = 0.05). There was a significantly greater percentage of IgG B cells in colostrum with ultralong CDR3s (12.98% ± 1.98) compared to blood (6.61% ± 1.11, p = 0.05). A higher percentage of IgM and IgG B cells with ultralong CDR3s in colostrum may be indicative of a potential role in protecting the neonate.

Feeding a Saccharomyces cerevisiae Fermentation Product to Mares in Late Gestation Alters the Biological Activity of Colostrum

The quality of equine colostrum is typically defined by refractometry or the concentration of maternal antibodies. However, the activity of other equine colostral bioactive molecules has not yet been investigated. This study analyzed whether the administration of a Saccharomyces cerevisiae fermentation product (SCFP) influences the biological activity of mare colostrum and whether the biological activity of colostrum has a lasting immunomodulating effect for foals. A total of fourteen pregnant mares received 20 g/day of a SCFP for a period of twelve weeks prior to the calculated date of birth (SCFP-group). Twelve pregnant mares without supplementation served as controls (CON). Colostral Brix values were determined within three hours after parturition. The concentration of IgG in blood sera and colostrum samples was determined with an ELISA. The biological activity was determined in a cell growth assay with a porcine epithelial cell line (IPEC-J2). Mares (at three weeks before the calculated date of birth) and foals (at the age of 5-8 months) received a parenteral active vaccination against influenza and tetanus. The administration of SCFP did not alter the mare's serum and colostrum IgG concentrations and did not exert a significant influence on the mares' early response to the vaccination. Growth and diarrhea episodes were comparable between foals of supplemented mares (SCFP) and foals of mares without supplementation (CON). Colostrum samples from SCFP-supplemented mares exhibited heightened biological activity. While SFCP and CON foals did not differ in their early response to vaccination, the vaccination-induced alterations in circulating neutrophilic granulocyte numbers were significantly correlated with the biological colostrum activity. These findings suggest that the supplementation of mares in late gestation with SCFP can enhance the biological activity of colostrum, which subsequently influences the innate immune responses of their offspring in later life.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Induction of NETosis in ovine colostral PMN upon exposure to Neospora caninum tachyzoites

Colostrum is one of the most important factors influencing the health and development of mammalian neonates. It is well-established that leukocytes, including polymorphonuclear neutrophils (PMN), migrate from the mother to the infant via colostrum uptake. In this study, for the first time, we studied the ability of ovine colostral-derived PMN to extrude neutrophil extracellular traps (NETs) against the abortive apicomplexan parasite Neospora caninum. Although this cell population plays a significant role in the transmission of maternal innate immunity to neonates, little is known about colostral PMN activities in sheep. However, this cell population is a significant source of the transfer of maternal immunity to the neonate. Colostral PMN continues to exert immunological effects even after transitioning into the colostrum. The present study aimed to investigate the extrusion of NETs by ovine colostral PMN exposed to the apicomplexan parasite, N. caninum, which is known to cause devastating reproductive disorders in cattle, small ruminants, wildlife animals, and dogs. The present study is the first to demonstrate that ovine colostral PMN can produce NETs after stimulation with vital N. caninum tachyzoites. Ovine colostrum-derived NETs were detected by chromatin staining and antibody-based immunofluorescence staining of NET-specific structures, including neutrophil elastase (NE) and global histones (H1, H2A/H2B, H3, H4), as well as scanning electron microscopy (SEM) analysis.

Neospora caninum-induced NETosis in canine colostral polymorphonuclear neutrophils

Neospora caninum represents an obligate intracellular apicomplexan parasite of the family Sarcocystidae causing severe reproductive disorders in cattle, small ruminants, wild animals and canids worldwide. Neutrophil extracellular traps (NETs) were recently described as effective host defense mechanism of polymorphonuclear neutrophils (PMN) derived from cattle, dogs, goats and dolphins against N. caninum tachyzoites. Nonetheless, nothing is known so far on canine colostral PMN immune reactions against N. caninum although breeding bitches represent a susceptible dog cohort and infected bitches may spread tachyzoites through transplacental transmission to their offspring. Thus, isolated colostrum PMN from bitches were assessed for PMN phagocytic activities as well as NETs release against viable N. caninum tachyzoites. In vitro interactions of canine colostrum-derived PMN with tachyzoites were analyzed at different ratios and time spans. Extracellular chromatin staining was applied in order to unveil classical molecules of NETs, such as neutrophil elastase (NE), global histones (H1, H2A/H2B, H3, H4) and myeloperoxidase (MPO), via antibody-based immunofluorescence microscopy analysis. N. caninum tachyzoites induced canine NETs in colostral PMN and scanning electron microscopy (SEM) analysis revealed NETs formation by colostral PMN thereby ensnaring tachyzoites after exposure. In summary, NETs released from canine colostral PMN might represent an early and effective maternal defense mechanism of the definitive host helping neonates to reduce initial intracellular replication of not only parasites but of other invasive pathogens after colostrum consumption.

Acceptable Young Calf Vaccination Strategies-What, When, and How?

Vaccination is an important component for the prevention and control of disease in calves. Too often vaccines are viewed as a catch-all solution for management and nutrition errors; the "best" vaccine can never overcome these deficiencies. Proper vaccination in the young calf and developing heifer is the key to long-term development of a productive dairy cow. To actually immunize animals, animals must be able to respond to vaccines, which is dependent on the level of animal husbandry. Each vaccine program needs to be designed based on animal flow, actual "disease" threats, and labor on the farm.

Implementation of a pre-calving vaccination programme against rotavirus, coronavirus and enterotoxigenic Escherichia coli (F5) and association with dairy calf survival

Background

Diarrhea is one of the most common diseases and causes of death in calves during the first month of life. Pre-calving vaccination programme (PVP) against the most common diarrhea-causing pathogens could help to avoid this threat if hyperimmune transition milk (TM) is fed to calves throughout the whole susceptibility period. The aim of this retrospective cohort study was to reveal the implementation practices of PVPs in large commercial dairy farms and to compare calf-level mortality hazards during the first year of vaccination (V+ period) and a year before implementing the vaccination programme (V- period). A questionnaire was filled out in 15 large-scale dairy farms in Estonia that used PVP. The farms were assigned into three groups based on compliance with the vaccine directions for use and TM feeding practices. Calf-level time-to-event data was analyzed with an observation period of 21 days and on-farm mortality due to diarrhea being the event of interest.

Results

During the V+ period, a significant decline in diarrhea-induced calf mortality was identified in three out of six herds that followed vaccination instructions and fed TM for at least 14 days. On average, calf mortality hazard due to diarrhea decreased among these herds (hazard rate ratio (HR) = 0.72, 95% confidence interval (CI) 0.63; 0.81). In the group of correctly vaccinating herds where TM was fed for less than 14 days, diarrhea-induced calf mortality decreased in two herds and remained unchanged in two herds with average diarrhea-induced calf mortality hazard declining significantly during the vaccination period (HR = 0.24, 95% CI 0.14; 0.41). Among the three farms that deviated from the vaccination instructions, the average calf mortality hazard increased in the V+ period (HR = 1.61, 95% CI 1.21; 2.14).

Conclusions

This study revealed that implementing a PVP might aid to reduce diarrhea-induced calf mortality in large commercial dairy farms. There is a need to increase veterinarians´ and farmers´ awareness about the importance of including pregnant heifers into the vaccination programme and emphasize the importance of prolonged feeding of hyperimmune TM to calves.

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.

Calf health from birth to weaning - an update

Research on calf health and welfare has intensified in the past decades. This is an update on a review series on calf health from birth to weaning published ten years ago.

Good colostrum management is still recognised as the single most important factor to preventing calf morbidity and mortality, however, it is now known that immunoglobulins are only one of many components of colostrum that are vital for the calf’s development. Other non-nutrient factors like leucocytes, hormones and growth factors, oligosaccharides as well as microRNAs have significant effects on the development and maturation of the intestinal and systemic immune functions. They also promote the maturation and function of the intestine, thus enabling the calf to digest and absorb the nutrients provided with colostrum and milk. The improved energetic status of colostrum-fed neonates is reflected by an accelerated maturation of the somatotropic axis, which stimulates body growth and organ development. Colostrum oligosaccharides are presumed to play a major role in the development of a healthy intestinal flora.

A biologically normal (intensive) milk-feeding programme is subsequently necessary for optimal body growth, organ development and resistance to infectious diseases. Ad-libitum or close to ad-libitum feeding in the first three to four weeks of life also leaves calves less hungry thus improving calf welfare. Only calves fed intensively with colostrum and milk are able to reach their full potential for performance throughout their life.

Public interest in farm animal welfare is growing in past decades, which makes it necessary to have a closer look at contentious management practices in the dairy industry like early separation of the dairy calf from the dam with subsequent individual housing. Public objection to these practices cannot be mitigated through educational efforts. Contrary to common opinion there is no evidence that early cow-calf separation is beneficial for the health of calf or cow. There is evidence of behavioural and developmental harm associated with individual housing in dairy calves, social housing improves feed intake and weight gains, and health risks associated with grouping can be mitigated with appropriate management.

In conclusion, there are still many management practices commonly applied, especially in the dairy industry, which are detrimental to health and welfare of calves.

Recent Advances in Camel Immunology

Camels are domesticated animals that are highly adapted to the extreme desert ecosystem with relatively higher resistance to a wide range of pathogens compared to many other species from the same geographical region. Recently, there has been increased interest in the field of camel immunology. As the progress in the analysis of camel immunoglobulins has previously been covered in many recent reviews, this review intends to summarize published findings related to camel cellular immunology with a focus on the phenotype and functionality of camel leukocyte subpopulations. The review also describes the impact of different physiological (age and pregnancy) and pathological (e.g. infection) conditions on camel immune cells. Despite the progress achieved in the field of camel immunology, there are gaps in our complete understanding of the camel immune system. Questions remain regarding innate recognition mechanisms, the functional characterization of antigen-presenting cells, and the characterization of camel NK and cytotoxic T cells.

Colostrum Management for Dairy Calves

Colostrum management is the single most important management factor in determining calf health and survival. Additional benefits of good colostrum management include improved rate of gain and future productivity. Successful colostrum management requires producers to provide calves with a sufficient volume of clean, high-quality colostrum within the first few hours of life. This article reviews the process of colostrogenesis and colostrum composition, and discusses key components in developing a successful colostrum management program. In addition, the article discusses approaches for monitoring and proposes new goals for passive immunity in dairy herds.

Immune cells transferred by colostrum do not influence the immune responses to foot-and-mouth disease primary vaccination

Little is known about the influence of maternal antibodies and immune cells transferred through colostrum on the immune responses of calves to the currently used foot-and-mouth disease (FMD) vaccines. Here we evaluated the humoral and cellular immune responses induced by vaccination of colostrum-deprived calves and calves that received equivalent amounts of colostrum preparations that differed in the presence or absence of maternal immune cells but contained the same quantity and quality of anti-foot-and-mouth disease virus (FMDV) antibodies. Three groups of 32-d-old calves (n = 3 per group) were deprived of colostrum and fed either whole immune colostrum or a cell-free colostrum preparation containing only anti-FMDV antibodies. All groups were immunized with 1 dose of an oil-adjuvanted commercial vaccine. Blood samples were collected periodically before vaccination and weekly after vaccination. Immune responses specific to FMDV were assessed based on T-cell proliferation, IFN-γ production, total and neutralizing serum antibodies, and isotype profile. All vaccinated calves developed IFN-γ and lymphoproliferative responses, irrespective of the colostrum received. Colostrum-deprived animals responded to vaccination with a primary IgM response followed by an increase of IgG₁ titers. Conversely, antibody titers decreased in all colostrum-fed calves after vaccination. This study demonstrates for the first time that maternal immune cells transferred to the calves through colostrum do not modify immune responses to FMD vaccine, and it confirms the interference of maternal antibodies in the induction of humoral but not cell-mediated immune responses.

Passive immune transfer in puppies

The puppy, born without immunoglobulins G (IgG), acquires a passive systemic immunity thanks to colostrum intake during the two first days of life. The quality of passive immune transfer (i.e. blood IgG concentration at two days of age), highly variable between litters and between puppies within litters, depends mainly on the time elapsed between birth and ingestion of colostrum, with limited influence of colostrum IgG concentration. Deficit in passive immune transfer, impacting puppy's health and neonatal mortality rate, can be indirectly diagnosed through blood gammaglutamyltransferases assay and evaluation of growth rate over the two first days of life. In the absence of maternal colostrum, few homo- and heterospecific immune sources are available and canine colostrum banking remains the optimal solution. Whereas passive immune transfer is crucial for survival during the neonatal period, it later interferes with response to vaccination. In addition to systemic passive immune transfer, maternal antibodies (mainly IgA) would provide local (digestive) immunity, ensuring mid-term protection of the puppies' gut together with probably long term training of the digestive immune system.

Exploratory cohort study to determine if dry cow vaccination with a Salmonella Newport bacterin can protect dairy calves against oral Salmonella challenge

Background

Salmonellosis is a major cause of morbidity and mortality in neonatal calves, often occurring before preventative vaccines can be administered.

Hypothesis/Objective

To evaluate the protective effect on calves of colostrum from cows vaccinated with a commercially available Salmonella Newport bacterin against a Salmonella Typhimurium challenge.

Animals

Twenty Holstein bull calves from a university dairy farm.

Methods

Nonrandomized placebo‐controlled trial in which colostrum was harvested from 30 cows that received 2 doses of either Salmonella bacterin or saline before calving. Colostrum collected from each group was pooled and fed to 2 groups of 10 calves at birth. At approximately 2 weeks of age, calves were challenged with Salmonella Typhimurium. Clinical, hematologic, microbiological, and postmortem findings were compared between the 2 groups.

Results

No differences in mortality, clinical findings, hematology results, blood and fecal cultures, or necropsy findings between the 2 groups were observed. Vaccinated cows had higher colostral titers, and calves fed this colostrum had higher serum titers (mean difference, 0.429; mean [SE], 0.852 [0.02] for vaccinated versus 0.423 [0.02] for control calves).

Conclusions and Clinical Importance

Transfer of colostral immunoglobulins from Salmonella enterica serotype Newport bacterin to neonatal calves was not sufficient to decrease mortality, clinical signs, sepsis, intestinal damage, or fecal shedding when exposed to a highly pathogenic Salmonella isolate. A large‐scale randomized controlled clinical trial is needed to evaluate the efficacy of this bacterin when administered in the dry period for prevention of salmonellosis in neonatal calves.

Genome-wide association study for response to vaccination in Angus calves1

Background

Bovine respiratory disease complex (BRDC) is one of the most important sources of loss within the beef cattle industry in the USA. Steps have been taken to reduce the incidence of BRDC through vaccination. Despite the effectiveness of vaccines, large proportions of cattle still experience morbidity and mortality. Identification of genomic regions that are associated with variation in response to vaccination would allow for the selection of individuals genetically predisposed to respond to vaccination based on specific markers, while heritability and accuracy estimates would help facilitate genomic selection. This in turn may lead to selection for beef cattle herds that may have lower incidence rate of BRDC after vaccination. This study utilizes an Angus herd of more than 2000 head of cattle to identify these regions of association.

Results

Genome wide association studies were performed for viral neutralization antibody level and response to vaccination traits against four different viruses associated with BRDC: bovine viral diarrhea virus 1 and 2 (BVDV1 and BVDV2), bovine respiratory syncytial virus (BRSV), and bovine herpesvirus (BHV1). A total of six 1-Mb windows were associated with greater than 1% of the genetic variance for the analyzed vaccination response traits. Heritabilities ranged from 0.08 to 0.21 and prediction accuracy ranged from 0.01 to 0.33 across 7 different vaccination traits.

Conclusions

Although six 1-Mb windows were identified as associated with 1% or greater genetic variance for viral neutralization antibody level and response to vaccination traits, few genes around these windows could readily be considered candidates. This indicates the need for further functional genomic annotation, as these regions appear to be gene deserts. Traits ranged from lowly to moderately heritable, which indicated the potential for selection of individuals that are genetically pre-disposed to respond to vaccination. The relatively low amount of genetic variance accounted for by any 1-Mb window indicated that viral neutralization antibody level and response to vaccination traits are polygenic in nature. Selection for these traits is possible, but likely to be slow due to the low heritabilities and absence of markers with high genetic variation associated with them.

Effects of gradual reduction in frequency of energy supplementation on growth and immunity of beef steers

This study evaluated the effects of gradual reduction in frequency of energy supplementation following vaccination on growth and measurements of innate and humoral immunity of beef steers. At 14-d postweaning (d 0), Angus steers (n = 42; 200 ± 5 kg of BW; 175 ± 4 d of age) were stratified by BW and age, and randomly assigned into 1 of 14 drylot pens (three steers/pen). From d 0 to 42, steers were provided ad libitum ground tall fescue hay (57% TDN, 13% CP of DM basis) and supplemented with concentrate at 1% of BW (50:50 soybean hulls and corn gluten feed; 71% TDN, 15% CP of DM basis). Treatments were randomly assigned to pens, and consisted of similar weekly concentrate DM supplementation (1% of BW multiplied by 7 d) that was divided and offered daily from d 0 to 42 (7X; 4 pens), 3 times weekly from d 0 to 42 (3X; Monday, Wednesday, and Friday; 5 pens), or daily from d 0 to 15 and then 3 times weekly from d 16 to 42 (7-3X; 5 pens). Steers were vaccinated against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3), Mannheimia haemolytica, and Clostridium on d 0 and 15. Individual shrunk BW was collected on d 0 and 42, following 12 h of feed and water withdrawal. Blood samples were collected via jugular venipuncture 4 h after concentrate supplementation on d 0, 1, 2, 3, 7, 15, 16, 17, 18, 22, and 42. Mean BW, ADG, G:F, hay DMI, and total DMI over the 42-d period did not differ among treatments (P ≥ 0.26). Plasma concentrations of cortisol and mean serum BVDV-1a titers also did not differ among treatments (P ≥ 0.35), but overall plasma haptoglobin concentrations were greater for 3X vs. 7-3X and 7X steers (P ≤ 0.05; 0.44, 0.37, and 0.33 ± 0.026 mg/mL, respectively). Also, 3X steers had less mean serum IBR titers (P ≤ 0.05; 0.29 vs. 0.88 and 0.79 ± 0.179 log2, respectively) and less seroconversion to PI-3 virus on d 15 than 7-3X and 7X steers (P ≤ 0.05; 36.0 vs. 76.6 and 57.8 ± 8.24%, respectively). In summary, a gradual reduction in frequency of energy supplementation during a 42-d preconditioning period did not negatively impact growth, but alleviated indices of inflammation and prevented reductions in vaccine response against BVDV-1a and PI-3 viruses compared to steers offered concentrate 3 times weekly during the entire study.