Antibodies from healthy or paratuberculosis infected cows have different effects on Mycobacterium avium subspecies paratuberculosis invasion in a calf ileal loop model

In this work, we used a calf ileal loop model to evaluate whether the preincubation of Mycobacterium avium subspecies paratuberculosis (MAP) with antibodies from healthy, MAP-positive or Lipoarabinomannan (LAM) immunized cows could affect the results of infection after 3.5 h. Bacterial load in tissue was assessed by Ziehl-Neelsen and by culture for each loop. MAP was detectable in all infected loops after 3.5 h.p.i.; although the presence of antibodies from MAP-positive cows significantly reduced bacterial load in loops as compared with antibodies from healthy donors (by Ziehl-Neelsen and culture, p-value < 0.003 and 0.0203, respectively).
A possible direct effect of antibodies on MAP viability was shown to be not significant. Severity of histopathologic changes induced by MAP infection also varied according to the pretreatment: MAP induced less changes when inoculated in the presence of antibodies from MAP-positive cows as compared with antibodies from healthy donors. Overall, our results show that the presence of antibodies from MAP-positive cows reduced MAP invasion and consequent early histological changes in this ileal short-term loop model. These results may suggest a protective role of antibodies in the response against MAP at the portal of entry in cattle.

Effect of passive antibodies derived from rotavirus-like particles on neonatal calf diarrhea caused by rotavirus in an oral challenge model

Our objective was to evaluate the efficacy of bovine rotavirus antigen-specific passive antibody for reducing the duration of diarrhea induced by oral challenge with bovine rotavirus in a neonatal calf model. The bovine rotavirus-specific passive antibodies were produced before the study by hyperimmunization of pregnant cows during the dry period with an adjuvanted vaccine containing recombinantly-expressed rotavirus virus-like particles. Eighty-three calves were cleanly collected at birth and randomly assigned to 1 of 3 groups as follows: (1) control group that was colostrum deprived and fed milk replacer for first feeding, (2) group that was colostrum deprived and fed milk replacer mixed with antirotavirus antibodies for first feeding, or (3) group that was fed colostrum replacer mixed with antirotavirus antibodies and a product approved by the US Department of Agriculture containing antibodies against Escherichia coli K99 and bovine coronavirus for first feeding. One of the 3 treatments was administered within 6 h of birth to each calf, followed by oral challenge with bovine rotavirus 3 h later.
Calves were observed through 7 d of age and scored according to a standardized scale for clinical signs of diarrhea, change in appetite, depression, and dehydration. Twice daily, measurements of rectal temperature and collection of feces were performed. Fecal samples were assessed for infectious agents commonly associated with diarrhea, and bovine rotavirus shedding was quantified. There were 24 of 28 (86%) calves in the control group that received no antibodies that had signs of severe diarrhea, whereas 57% of the calves that received antirotavirus in milk replacer experienced severe diarrhea, and 7% of calves that received colostrum replacer mixed with antigen-specific bovine rotavirus antibodies showed signs of severe diarrhea. Calves that received colostrum replacer mixed with antigen-specific bovine rotavirus antibodies had a mean duration of 0.9 d of diarrhea compared with 2.7 d in the control group.
Calves in the group that was colostrum deprived and fed milk replacer with antirotavirus antibodies had a mean duration of diarrhea of 1.7 d. Rotavirus peak fecal shedding was 3.5 d in the group with milk replacer only, 5.5 d in the milk replacer with antibody group, and 6.5 d in calves in the colostrum replacer group. When bovine rotavirus antigen-specific antibody was fed in milk replacer to colostrum-deprived calves or in conjunction with colostrum replacer that also contained supplemental antibodies against Escherichia coli K99 and bovine coronavirus, those calves were observed to have reduced the onset, duration, and severity of diarrhea when compared with milk replacer placebo.

A new passive immune strategy based on IgY antibodies as a key element to control neonatal calf diarrhea in dairy farms

Background: Neonatal diarrhea remains one of the main causes of morbi-mortality in dairy calves under artificial rearing. It is often caused by infectious agents of viral, bacterial, or parasitic origin. Cows vaccination and colostrum intake by calves during the first 6 h of life are critical strategies to prevent severe diarrhea but these are still insufficient. Here we report the field evaluation of a product based on IgY antibodies against group A rotavirus (RVA), coronavirus (CoV), enterotoxigenic Escherichia coli, and Salmonella sp. This product, named IgY DNT, has been designed as a complementary passive immunization strategy to prevent neonatal calf diarrhea. The quality of the product depends on the titers of specific IgY antibodies to each antigen evaluated by ELISA. In the case of the viral antigens, ELISA antibody (Ab) titers are correlated with protection against infection in calves experimentally challenged with RVA and CoV (Bok M, et al., Passive immunity to control bovine coronavirus diarrhea in a dairy herd in Argentina, 2017), (Vega C, et al., Vet Immunol Immunopathol, 142:156-69, 2011), (Vega C, et al., Res Vet Sci, 103:1-10, 2015). To evaluate the efficiency in dairy farms, thirty newborn Holstein calves were randomly assigned to IgY DNT or control groups and treatment initiated after colostrum intake and gut closure. Calves in the IgY DNT group received 20 g of the oral passive treatment in 2 L of milk twice a day during the first 2 weeks of life. Animals were followed until 3 weeks of age and diarrhea due to natural exposure to infectious agents was recorded during all the experimental time.
Results: Results demonstrate that the oral administration of IgY DNT during the first 2 weeks of life to newborn calves caused a delay in diarrhea onset and significantly reduced its severity and duration compared with untreated calves. Animals treated with IgY DNT showed a trend towards a delay in RVA infection with significantly shorter duration and virus shedding compared to control calves.
Conclusions: This indicates that IgY DNT is an effective product to complement current preventive strategies against neonatal calf diarrhea in dairy farms. Furthermore, to our knowledge, this is the only biological product available for the prevention of virus-associated neonatal calf diarrhea.

Native Calf Rennin

NATE-0651 Creative Enzymes 50u 270 EUR

Calf thymus DNA

HY-109517 MedChemExpress 100mg 1910 EUR

Newborn Calf Serum

F0603-050 GenDepot 500ml 151 EUR

Calf Intestinal Alkaline Phosphatase antibody

20C-CR2110RP Fitzgerald 50 mg 864 EUR

Calf Intestinal Alkaline Phosphatase antibody

70-XR04 Fitzgerald 5 mg 137 EUR

Native Calf Alkaline Phosphatase

NATE-0054 Creative Enzymes 1KU 270 EUR

Native Calf Adenosine Deaminase

DIA-271 Creative Enzymes 2KU 378 EUR

Calf Thymus Acetone Powder

E61A00101 EnoGene 5g 180 EUR

Calf Thymus Acetone Powder

E61A00102 EnoGene 10g 278 EUR

Calf Thymus Acetone Powder

E61A00103 EnoGene 100g 2000 EUR

Calf Spleen Acetone Powder

E61A00201 EnoGene 5g 213 EUR

Calf Spleen Acetone Powder

E61A00202 EnoGene 10g 310 EUR

Calf Spleen Acetone Powder

E61A00203 EnoGene 100g 2325 EUR

Alkaline Phosphatase (calf/cow)

RP-1468 Alpha Diagnostics 200 ug 164 EUR

Non-sterile calf serum

BCSU05-0100 Equitech 100 ml 145.6 EUR

Non-sterile calf serum

BCSU05-0500 Equitech 500 ml 163.8 EUR

Calf Serum (Sterile Filtered)

88-NC10 Fitzgerald 100 ml 125 EUR

Immortalized Calf Thyrocytes-SV40

T0401 ABM 1x106 cells / 1.0 ml Ask for price

Immortalized Calf Thyrocytes-Ras

T0402 ABM 1x106 cells / 1.0 ml Ask for price

Immortalized Calf Thyrocytes-Myc

T0403 ABM 1x106 cells / 1.0 ml Ask for price

Immortalized Calf Thyrocytes-hTERT

T0404 ABM 1x106 cells / 1.0 ml Ask for price

Alkaline Phosphatase, Calf Intestine

7585-10 Biovision 158 EUR

Alkaline Phosphatase, Calf Intestine

7585-1000 Biovision 3421 EUR

Alkaline Phosphatase, Calf Intestine

7585-50 Biovision 387 EUR

Anti-Calf Collagen I and III antibody

STJ16101184 St John's Laboratory 1 mL 381 EUR

Rabbit Anti Calf Alkaline Phosphatase Polyclonal Antibody

CPBT-67303RC Creative Diagnostics 1 ml 777 EUR

FETAL CALF SKIN 1 EA*

57090-1 Pel-Freez 1 EA 268.36 EUR

Non-sterile newborn calf serum

NBU05-0100 Equitech 100 ml 150.8 EUR

Non-sterile newborn calf serum

NBU05-0500 Equitech 500 ml 167.7 EUR

Purified fetal calf/bovine Hemoglobin

HEMG18-N-1 Alpha Diagnostics 1 mg Ask for price

[Risk factors for calf mortality influence the occurrence of antibodies against the pathogens of enzootic bronchopneumonia].

  • Bovine respiratory diseases are a common cause of calf loss. This study aimed to analyse associations between an occurrence of enzootic bronchopneumonia (EBP), calf mortality and calving management.A total of 153 dairy farms participated in the study on a voluntary basis from November 2006 to July 2007. Calf management was inspected on-site during a farm visit and farm managers were required to complete a questionnaire on personal assessment of calving procedures, neonate management and environmental factors.
  • Results were collated and matched with the calf mortality rate of 2006 determined from the HI-Tier database for each farm. Randomly selected serum samples of a mean number of 7 calves at the age 6 months per herd were investigated for antibodies against bovine respiratory syncytial virus (BRSV-AB) and parainfluenzavirus type 3 (PIV3-AB). According to the proportion of calves with BRSV-AB or PIV3-AB (≤ 20 % or > 20 %) farms were divided into 2 groups.
  • Customary timing of the first colostrum feeding as well as the perceived level of importance of EBP to the farm manager, as described in the questionnaire, showed a positive correlation to calf mortality. BRSV-AB occurred more frequently on farms where managers stated that the first colostrum feeding occurred later than 4 hours after birth, that birth monitoring was rarely practiced and that the estimated level of dust in the calf barn was considered high. PIV3-AB was more frequently found at farms practicing tethered calving.
  • The results of this study indicate that peri- and postnatal calf management procedures may affect calf mortality and the frequency of occurrence of BRSV-AB or PIV3-AB. The influences of birth monitoring and the time of first colostrum feeding as well as dust exposure should be taken into account in future studies on the frequency of EBP and be included in the veterinary cause analysis of herd EBP-related problems.

Leave a Comment

Your email address will not be published.