PI Calves Research Articles

THE EFFECTIVENESS OF PROBIOTIC PRODUCT VETOM-2 IN CALVES DURING REHABILITATION PERIOD AFTER ANTIBIOTIC THERAPY

One of the functions of the intestinal microflora is to maintain the internal environment of the macro-organism. Along with this, even minor changes in the microflora of the gastrointestinal tract result in the development of dysbacteriosis. Often, dysbacteriosis in farm animals develops as an aftereffect of the active antibiotic treatment. Modern approaches to the treatment of such dysbacteriosis cases are based on the application of probiotic drugs. Our research goal was to study the effect of the probiotic product Vetom-2 on the gastrointestinal microflora in calves after antibiotic therapy. The studies were carried out on the farm of the AO “Uchkhoz Prigorodnoye” on comparable Black Pied calves. Two groups of calves were selected. The first group included apparently healthy calves (n = 10); the second group – calves with dyspepsia (n = 10). After a course of antibiotic therapy, the group of calves with dyspepsia was divided into 2 groups; one of the groups received Vetom-2, and the second group did not receive this probiotic. Bacteriological fecal tests in calves were to detect Escherichia, streptococci, staphylococci, salmonella and Pseudomonas aeruginosa. It was found that in sick calves before antibiotic therapy, the number of opportunistic pathogens was by an order more than that in the group of healthy animals. During treatment, these indices decreased. In calves that received Vetom-2 during rehabilitation after antibiotic therapy, the number of opportunistic pathogens was lower than in the group of calves that did not receive Vetom-2 during rehabilitation; this was due to the inhibition of growth and development of opportunistic pathogens in calf intestines after antibiotic therapy by bacterial strains contained in Vetom-2.

Case report

Bovine viral diarrhea virus (BVDV) continues to be a challenge for the cattle industry despite routine vaccination that includes killed or modified-live BVDV antigens. At a commercial dairy, 1,081 newborn calves were tested for BVDV antigen by pooled reverse transcription polymerase chain reaction as part of a screening program. Immunohistochemistry confirmed persistent BVDV infections in 13 calves. Ten of the PI calves were available for BVD typing. Both cytopathic and non-cytopathic BVD viruses were isolated. The non-CPE viruses typed as BVD type lb with a total of 3 different strains found; an identical strain found in 2 calves, another identical strain found in 2 other calves, and a third identical strain found in 3 other calves. A BVDV control program relying solely on BVD vaccination using a modified-live vaccine did not protect calves in this herd from persistent infection with type lb BVDV. These results demonstrate that control programs that rely only on vaccination to control BVDV without testing for the presence of PI animals are not adequate to control BVD.

Comparison of ‘HoBi’-like viral populations among persistent infected calves generated under experimental conditions and to inoculum virus

Like other members from the Pestivirus genus, ‘HoBi’-like pestiviruses cause economic losses for cattle producers due to both acute and persistent infections. The present study analyzed for the first time PI animals derived from a controlled infection with two different ‘HoBi’-like strains where the animals were maintained under conditions where superinfection by other pestiviruses could be excluded. The sequence of the region coding for viral glycoproteins E1/E2 of variants within the swarms of viruses present in the PI calves and two viral inoculums used to generate them were compared. Differences in genetic composition of the viral swarms were observed suggesting that host factors can play a role in genetic variations among PIs. Moreover, PIs generated with the same inoculum showed amino acid substitutions in similar sites of the polyprotein, even in serum from PIs with different quasispecies composition, reinforcing that some specific sites in E2 are important for host adaptation.

Experimental infection of calves, sheep, goats and pigs with HoBi-like viruses by direct inoculation or exposure to persistently infected calves

HoBi-like viruses are an emerging species of pestiviruses associated with respiratory and reproductive disease in cattle and in water buffaloes. Although cattle appear to be the main natural hosts, little is know about the potential for HoBi-like viruses to be transmitted to other livestock. In this study, seronegative calves, goats and pigs, and sheep harboring pestivirus antibodies (probably due to previous exposure to BVDV) were exposed to HoBi-like viruses either by direct inoculation (GIn) or by contact with calves persistently infected with HoBi-like viruses (GEx). Both GIn and GEx groups were monitored for clinical signs, lymphocyte count, virus in buffy coats and nasal swabs up to day 18 post-inoculation (pi). Evidence of transmission of HoBi-like virus by PI calves was observed in all studied species. No difference in clinical presentation was observed between animals in the GIn or GEx groups. Evidence of infection, depending on the species included lymphocyte depletion, fever, viral RNA detection, and/or seroconversion. Depletion of lymphocytes was observed in calves and goats (35% and 50%, respectively) but not in pigs. Seroconversion was observed in at least one animal of each group and for all exposed species. The rate of seroconversion was higher in animals in the GIn experimental groups. In sheep, pre-existing moderate to high neutralizing titers against BVDV did not prevent viral replication and shed. The study demonstrated that naive cattle, goats and pigs, in addition to antibody positive sheep, can be infected by HoBi-like virus via persistently infected calf and potentially transmit the virus.

Survival time of calves with positive BVD virus results born during the voluntary phase of the Irish eradication programme

A retrospective case–control study was undertaken to investigate the temporal pattern of, and factors associated with, the survival of BVD virus-positive calves, identified between January and July 2012 during the voluntary phase of the Irish national eradication programme. Potential statuses for case and control calves consisted of: alive in birth herd; slaughtered; sold; dead (due to culling or death from natural causes and termed ‘involuntary removal’).An initial comparison of cases and controls found significant differences between the outcomes for cases and controls and also between cases in relation to herd type (beef, dairy, dual purpose), sex, age and test status (BVDPOS – no confirmatory test; BVDPI – positive on confirmatory test). Key differences included a higher level of case animals still alive in, or slaughtered from, beef herds, a greater proportion of BVDPI animals being retained relative to those with a BVDPOS status and a significantly lower slaughter weight (89kg) for case animals relative to controls.Separate multivariable models were constructed for dairy and beef cases. In the final dairy model breed (Jersey or non-Jersey), county and BVD status were retained, with the last two found to be time-varying covariates with significant changes in hazard ratios (HR) over time. In the beef model, herd size, county and BVD status were retained, with the HR for the last two factors again varying significantly over time. With the exception of the addition of the number of BVD positive calves in the herd to the dairy model, the same factors were identified when models were restricted to the first 90 days following the birth of case animals.A greater knowledge and understanding of all of these factors will allow refinement of programme communications and incentives to encourage prompt removal of PI calves from all sectors of the Irish breeding herd during the compulsory phase of the national eradication programme.

ANTIDIARRHEAL ACTIVITY OF <i>APUS</i> BAMBOO (<i>GIGANTOCHLOA APUS</i>) LEAF EXTRACT AND ITS BIOACTIVE COMPOUNDS

Most of every part of bamboo plants had economical value. The wood is used as building and furniture, the shoot is processed as health foods and medicines, t he root and culms are used as traditional medicine. The leaf has been believed that it could heal diarrhea in pi glets, rabbit, poultry and calves. This research wa s designed to investigate the inhibition activity of apus bamboo leaf extracts against four strains pathogen ic Escherichia coli . The leaf of apus bamboo ( G. apus ) was extracted in methanol, ethanol and methanol-e thanol (1:1), subsequently dried and assayed for their antibacter ial activity using diffusion and dilution. Among th ree solvents used in this study, ethanol was the best w ith a yield of 18.74% and its effectivity was about 0.44% compared to tetracycline. The bioactive compounds in the extract were fatty acids, esters and alcohols .

Hemostatic system activity in milk- and plant-fed calves

Experiments were conducted on 36 healthy Simmental and Black Pied calves. Hemostatic indices were determined on days 31, 45, 60, 75, and 90. Maximum increase in platelet aggregation activity was noted on day 45 with the use as inducers ADP + collagen + epinephrine (17.1 s), ADP + thrombin + epinephrine (16.9 s), and ADP + collagen + thrombin + epinephrine (14.1 s). In this case, control of the vessel wall over platelet aggregation in the blood stream increased: the vessel wall antiaggregation activity index (VWAAI) was respectively 1.41, 1.39, and 1.36. An increase in the production by endotheliocytes of antithrombin III and tissue plasminogen activators was revealed in animals at this age. An increase in the level of fibrinogen and factors II, VII, I, X, XI, and XII with stability of factors V and VII and subsequent weakening of activated factors by the end of the examined stage of early ontogeny was established.

Activity of platelet hemostasis in newborn calves

Healthy newborn Simmental and Black Pied calves with a normal number of platelets in bloodstream don’t have reliable dynamics of the aggregation function of blood platelets with adenosine diphosphate, collagen, thrombin, ristocetin, epinephrine, as well as combinations of ADP + epinephrine, ADP + collagen, and collagen + epinephrine inducers. The level of discocytes in blood on days 1–2 was 78.5, not reliably changing until the end of the neonatal stage. In this case, the number of disco-echinocytes, spherocytes, spheroechinocytes, and bipolar forms of platelets in the bloodstream remained stably low. Maintenance during colostrum feeding of a low intensity of metabolism of endogenous arachidonic acid in platelets and of a low content of ATP, ADP, actin, and myosin in them can be considered important mechanisms providing stability of platelet aggregation activity in calves in the neonatal stage.

Seroepidemiology of Bovine Viral Diarrhoea Virus (BVDV) in the Adamawa Region of Cameroon and Use of the SPOT Test to Identify Herds with PI Calves

Bovine viral diarrhoea, caused by the bovine viral diarrhoea virus (BVDV) in the Pestivirus genus of the Flaviviridae, is one of the most important diseases of cattle world wide causing poor reproductive performance in adult cattle and mucosal disease in calves. In addition it causes immunosuppression and increased susceptibility to other infections, the impact of which is uncertain, particularly in sub-Saharan Africa where animals are exposed to a much wider range and higher intensity of infections compared to Europe. There are no previous estimates of the seroprevalence of BVDV in cattle in Cameroon. This paper describes the serological screening for antibodies to BVDV and antigen of BVDV in a cattle population in the Adamawa Region of Cameroon in 2000. The estimates of herd-level and within herd seroprevalences adjusted for test imperfections were 92% and 30% respectively and 16.5% of herds were classed as having a persistently infected calf (PI) in the herd within the last year based on the “spot” test approach. There was evidence of clustering of herds with PI calves across the north and west of the Region which corresponds with the higher cattle density areas and of self-clearance of infection from herds. A multivariable model was developed for the risk of having a PI calf in the herd; proximity to antelope, owning a goat, mixing with 10 other herds at grazing and the catchment area of the veterinary centre the herd was registered at were all significant risk factors. Very little is known about BVDV in sub-Saharan Africa and these high seroprevalences suggest that there is a large problem which may be having both direct impacts on fertility and neonate mortality and morbidity and also indirect effects through immunosuppression and susceptibility to other infections. Understanding and accounting for BVDV should be an important component of epidemiological studies of other diseases in sub-Saharan Africa.

Bovine Viral Diarrhea Viruses (BVDV) in Beef Breeding Herds and Feedlots

Bovine viral diarrhea viruses (BVDV) represent significant pathogens in cattle affecting several organ systems, particularly involving the respiratory tract and fetal infections. The principal reservoir of BVDV is the persistently infected (Pl) animal. The PI cattle are born to susceptible heifers/cows exposed during pregnancy, carried to term, and are lifetime shedders of the virus. Current control programs focus on biosecurity using testing of new additions including calves born to negative dams, isolation of new animals until testing completed, and vaccination. Identification by testing and removal of PI cattle are critical to control programs. PI cattle may expose susceptible breeding females resulting in more PI calves; and/or cause primary infections in acute/transient infections and predispose the BVDV exposed animal to other pathogens. The purpose of this study was: (1) detect PI cattle in beef breeding herds and cattle entering feedlots; and (2) determine distribution of BVDV subtypes in PI cattle.

Genetic diversity of bovine viral diarrhoea viruses (BVDV) in Denmark during a 10‐year eradication period

A 243 base-pair fragment of the 5'- untranslated region (5'-UTR) of bovine viral diarrhoea virus (BVDV) was RT-PCR amplified from tissue samples (after one passage) or from plasma collected from Danish cattle in 1962 (1), 1993 (7), or in 2002-03 (28) when BVD was almost extinct as a result of a 6-year eradication programme. The PCR products were sequenced and phylogenetically analysed. All 36 samples were BVDV species 1 (BVDV-1), 29 sequences belonged to the BVDV 1d subtype, 6 to the BVDV 1b subtype, and one sequence to the BVDV 1e subtype. While all samples from 1993 and 1962 were of 1d subtype, the samples collected in 2002-2003 belonged to 1d (22 samples), 1b (5 samples) and 1e (1 sample) subtypes. In five herds, materials from two animals were obtained for PCR analysis. In four of five herds the sequences of the two viruses were identical, but in one herd the obtained sequences belonged to two different subtypes. Routine analysis detected 11 PI calves older than 2 months of age. For early detection of infected calves it is recommended that antigen ELISA be replaced by PCR detection. Here we present the first sequence analysis of Danish BVDV strains.

Protocol for Identification of BVD PI Calves with Maternal Antibodies in Beef and Dairy Operations

Bovine Virus Diarrhea (BVD) virus was first recognized as a pathogen in1946, and has been implicated as the cause of one of the most widespread and economically important diseases of cattle.
 The importance of bovine virus diarrhea-persistently infected (BVD-PI) cattle in the spread and propagation of BVD virus has been well documented. A persistent BVD infection occurs when a fetus is exposed to the BVD virus in the first 120 days of gestation. At this stage, the developing fetal immune system recognizes the virus as part of "self", therefore, no immune response occurs. After birth, these BVD-PI cattle excrete tremendous amounts of virus from every body orifice throughout most of their lives, and thus are considered to be the most important reservoir for BVD virus. It is estimated that approximately 1% of all cattle are persistently infected.

Epidemiology of Bovine Viral Diarrhea Virus

Prevalence studies around the world show that BVDV is widespread in most cattle raising countries. There are significant differences, however, in prevalence between areas, probably the result of differences in cattle population structure and management practice. Direct contact with PI animals is probably the most important method of transmission of infection; however, field studies have shown that some limited spread of infection also occurs in the absence of PI animals. This may be due to contact with acutely infected animals or contact with other species infected with BVDV. Different ways of indirect transmission such as contaminated needles and equipment have been proven experimentally, and indirect transmission is considered to have some importance. If a PI animal is introduced directly into a dairy herd, most animals will be infected within a few months. On many occasions, however, a herd gets infected by other means than direct introduction of PI animals. In these cases, the infection is often spread to only a few animals after which the infections stops. The infection is then reinforced when PI animals are born. Slow and hence prolonged spread of infection in herds without PI animals also has been described, but the mechanism is not fully understood. Family lines of PI animals delivering PI calves are fairly common and can cause the infection to continue for several years. The clinical manifestations, acute BVDV, reproductive disorders, birth of malformed, weak and undersized calves, unthrifty PI animals, and mucosal disease often appear within certain periods. Large variation, however, can occur between herd outbreaks due to variation in virulence of the BVDV strain, housing of the cattle, and variation in transmission patterns. The extensive transmission of infection from PI animals makes different surveillance methods possible. Thus testing of a screening sample of a few young stock of antibodies and determination of antibody titer in bulk milk will often give good indication of presence of PI animals in herds not using BVDV vaccines. In herds using killed vaccine, determination of antibody titers among few young stock can show the presence of PI animals. The high incidence of infection combined with all the different damages that are seen after BVDV infection cause huge economical losses, which on a national level in the UK and Denmark (i.e., areas with widespread occurrence of infection) has been calculated as between 7 and 27 million pounds (between $11 and $42 million) per million calvings. Epidemiologic studies are important as a basis for selection of control strategy. Because of the variation in epidemiology between geographic areas, evaluation of a control strategy in an area preferentially should be based on epidemiologic studies in the same area.

Impact of Bovine Viral Diarrhea Virus on Reproductive Performance in Cattle

The major economic impact of BVDV infections is in producing reproductive dysfunctions. The virus can have a detrimental impact on the developing fetus at all stages, but the most severe consequences occur early in gestation. The virus is maintained in the bovine population through the production of PI offspring. Only the NCB biotype of the virus can produce PI calves. The NCB biotypes is the one that produces the vast majority of BVDV infections and, as a consequence, the greatest economic losses. Biotype and antigenic variation are two independent variables and vaccines should emphasise antigenic composition, not biotype. A BVDV control program that does not emphasize heifers is doomed to failure.