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Sri Venkateswara Veterinary University, Tirupati


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  • ThesisItemOpen Access
    ABSTRACT : To find out the incidence of subclinical mastitis (SCM) 1599 quarter milk samples from 417 apparently healthy lactating cows of seven local organized dairy farms and lactating animals from individual holdings came to Teaching veterinary clinical complex, Tirupati, Andhra Pradesh, were subjected to California Mastitis Test (CMT) and Electrical Conductivity (EC) Test. The quarter wise incidence of SCM as detected by CMT and EC was 27.83 and 19.95 per cent respectively. Whereas the animal wise incidence was 52.28 and 38.13 per cent for CMT and EC respectively. The incidence of SCM in relation to lactation number was highest in fourth and above (53.33%) followed by third (52.94%), first (52.83%) and second (49.45%) lactations as detected by CMT. Whereas the incidence of SCM as per EC was highest in first (43.40%), followed by third (42.48%) lactations, fourth and above (34.17%) and second (32.97%). It was also observed that the fore quarters were more frequently affected (28.87%) than the hind quarters (26.85%). Further, incidence of SCM in relation to stage of lactation was observed in cows in early lactation (51.24% with CMT and 40.50%with EC) than mid (55.07% with CMT and 37.68% with EC) and late (50.63% with CMT and 36.71% with EC) lactations. The mean electrical conductivity readings of infected and uninfected quarters from cows were 270±30 and 360±40 respectively. Taking cultural test as standard, the per cent accuracies of CMT, EC and SCC were 73.33, 70.37, and 71.00 respectively. The false positive reactions were more in CMT(24.60) than SCC (23.70%) and EC (20.4%), whereas the false negative reactions were highest in EC (34.9%) followed by SCC (31.60%) and CMT (28.6%). EC test had the highest specificity (84.84%) and predictive value (79.59%) with lowest sensitivity (56.52%) than CMT and SCC taking cultural test as standard and thus it can be used as the decision criteria to cull or to treat the animals in herds with high prevalence of SCM. Cultural examination of milk from the affected quarters revealed the frequency of isolation of Staphylococci spp (55.12 per cent), Streptococcus Spp(15.61 per cent), E. coli (13.17 per cent), E. coli + Streptococcus Spp (5.17 per cent), Staphylococcus Spp + Streptococcus Spp (3.42 per cent), E. coli + Staphylococcus Spp (4.39 per cent) and pseudomonas Spp (0.98 per cent). In vitro drug sensitivity test was conducted on 425 whole milk cultures which revealed that 28.94 per cent were sensitive to chloramphenicol (123) followed by 24.71 percent ceftriaxone + sulbactum (105), 24.47 per cent ceftrioxone + tazobactum (104), 23.06 per cent gentamicin (70), 20.00 per cent ciprofloxacin(85), 13.88per cent amoxycillin + sulbactum (59),12.71 per cent enrofloxacin(54), 1.65 per cent amoxycillin + clavulonic acid (7), 1.41 per cent ceftizoxime(6), 1.18per cent ampicillin (5),0.94 per cent streptomycin (4), and only few isolates (3) were sensitive to tetracycline(0.71). Based on in vitro drug sensitivity cows of therapeutic trials subclinical mastitic cows in early stage of lactation were divided into five groups. Therapeutic trials were conducted by administering Enrofloxacin, Chloramphenicol, Amoxycillin + Sulbactum, Ceftrioxone + tazobactum, Ceftrioxone + Sulbactum and Ceftizoxime into the affected cows. In Group –I out of 14 subclinically infected quarters from 7 cows subjected to enrofloxacin treatment, milk from 12 quarters from 6 cows were test negative on both CMT and cultural examination on 8th day post treatment, milk from the remaining 2 teats was test negative (CMT, cultural) on 15th day post treatment. In Group-II out of 14 subclinically infected quarters from 7 cow subjected to chloramphenicol treatment, 11 quarters from 6 cows gave negative reaction on both CMT and cultural examination on 8th day post treatment. Milk from 3 quarters from one cow was test negative on 15th day post treatment. In Group-III out of 14 sub clinically infected quarters from 8 cows subjected to ceftizoxime treatment, all the 14 quarters milk samples were test negative on both CMT and cultural examination on 8th day post treatment. In Group–IV, 14 subclinically infected teats from 7 cows were treated with ceftrioxone + Tazobactum, and all the 14 milk samples were test negative with both CMT and cultural examination on 8th day post treatment. Whereas the milk from cows in Group-V was test negative on 7th, 15th day post treatment, with CMT and cultural examination. To find out association between SCM vs. Hypocalcaemia and Hypoglycemia seven cows with SCM + hypocalcaemia were treated (Group –A).Of them, 6,7 and 7 cows were culturally negative on 1st, 2nd and 3rd week post treatment respectively. While 3, 5 and 7 cows had normal calcium levels (9-11 mg. / dl.) during first, second and third weeks post treatment. In Group-C all the 7 cows were culture positive and had low serum calcium levels throughout the study period. In Group-B a total of 7 cows witch SCM and hypoglycemia were treated. Of them, 5 cows were test negative on cultural examination and 3 were cows had normal BHBA values below (1.4 m.mol. /Lt) during the 1stweek post treatment. All the seven cows were test negative for SCM on cultural examination and had normal BHBA on 2ndand 3rd week post treatment. Seven animals in Group – D with SCM and high BHBA values were kept as untreated controls. All the 7 cows were culturally positive and had higher BHBA values (Mean) during the study period (1 to 3 weeks).
  • ThesisItemOpen Access
    ABSTRACT : Canine parvovirus (CPV) is one of the causative agent of enteritis and myocarditis in young pups. Since there was no earlier report on the prevalence of CPV in and around Tirupati, So the present study was under taken to study the epidemiology and diagnosis of CPV infection. A total of 217 faecal samples were collected from canine parvovirus suspected cases over a period of 6 months from 8th March 2012 to 31st August 2012 at Teaching Veterinary Clinical Complex , Tirupati. The faecal samples were screened by HA, HI tests and Scan VetTM PARVO kit. Out of 217 dog faecal samples screened, 72 samples were positive for CPV infection with an overall prevalence of 33.17 percent. Breed wise analysis of data indicated that highest prevalence (43.75%) in Spitz and least prevalence (28.71%) in Mongrel. CPV infection in relation to age, was highest (40.74%) in 0-6 months and least (10%) in above 1year old dogs. Sex wise analysis of data revealed the higher prevalence (37.30%) in male dogs than female (27.47%) dogs. Month wise prevalence of CPV infection revealed highest prevalence (48.97%) in the month of July and lowest (20%) in the month of March. The prevalence of CPV infection was high (35.41%) in un-vaccinated dogs than the vaccinated dogs (16.00%). In the present study out of 72 dogs positive for canine parvoviral infection 48 (66.66%) dogs had secondary bacterial infection (mixed-infection) and remaining 24 dogs had solo-infection with CPV. Secondary bacteria such as Escherichia coli, Salmonella spp, Klebsiella spp, Enterobactor aerogens and Staphylococci. were isolated from CPV infected dogs. In the present study CPV infected dogs exhibited the clinical signs such as diarrhoea, elevated mean rectal temperature (104.78 ± 0.30oF), heart rate (198.88 ± 3.2/min ) and respiratory rate (45.94 ± 3.44) when compared to healthy dogs. Further the bloody diarrhoea, dehydration, depression was recorded in more number of dogs with mixed-infection compared to dog with solo- infection. 27 CPV infected dogs were successfully treated with Inj. Cefotaxime @ 25mg/kg body weight once/day, I/V for 5days, Inj. Perinorm (Metaclopramide) @ 0.2mg/ kg body weight once/day, I/V for 3days, Inj. Rantac (Ranitidine) @ 0.5mg/ kg body weight, I/V once/day for 3 days, 5% Dextrose and Ringers Lactate (R.L). However 3 dogs died in spite of tre
  • ThesisItemOpen Access
    ABSTRACT : New Castle disease (ND) is an infectious, highly contagious and destructive viral disease of poultry causing serious constraint to poultry rising and has a devastating effect on the productivity and survival of commercial and village poultry. The circulating strains of ND in the village chicken act as source of infection to the commercial poultry flocks. Vaccination is the only strategy for the control of the NewCastle disease in the poultry flocks. However, the presently available ND vaccines though they are effective in eliciting good immune response, they require maintenance of a cold chain from the point of production until they are delivered in the field which is very difficult under the village conditions. Administration of vaccines for the rural scavenging birds and in commercial poultry where the chickens are housed, it is difficult to catch individual bird for vaccination which leads to stress. Hence, in the present study an attempt was made to develop thermostable mutants from the ND vaccine strains and the delivery of these vaccines through different routes. In the present study, lentogenic strains Lasota and F, and mesogenic strains R2B and K were cultured in the embryonated eggs and they were subjected to different heat treatments for thermostabilisation. Vaccine strains were subjected to 56°C directly for different time intervals in the current study. The mesogenic R2B and K could withstand 180 minutes after 21 and 20 successive thermal cycles. The thermostable mutants of Lasota (135 minutes, 19 Thermal cycles) and F (90 minutes, 16 Thermal cycles) which were developed previously in the department were given further thermal treatments. Then the Lasota strain could withstand for 165 minutes after a total of 21 thermal cycles and F strain could withstand for 150 minutes after a total of 20 thermal cycles at 56°C. Mesogenic strains were found to be more thermostable than Lentogenic strains. The thermostable mutants were found to have better thermostability than the parent viruses and they did not revert back to original even after back passages in the embryonated eggs. The infected allantoic fluids were titrated and checked for sterility. The thermostable mutant strains K and Lasota were administered to experimental chicken to evaluate their immunogenicity and efficacy in comparison with conventional vaccines. Further, these thermostable vaccines were administered through different routes to know the comparative efficacy. The control group of birds were vaccinated with the conventional parent strains were also maintained. The results of the experiment revealed that there was no significant difference between thermostable vaccines and the conventional vaccines. Further, there was no significant difference between different routes of administration (ANOVA). The stability of thermostable mutant strains of K and R2B were checked by incubating the infectious allantoic fluids at 25°C and at 37°C for 80 days with and without addition of the stabilizers. The thermostable mutants were found to be more stable in the presence of stabilizers which improved the keeping quality of the strains. In the present study, an attempt was made to develop thermostable mutants from the conventional ND vaccine strains. These mutants were found to be highly stable and equally immunogenic in eliciting immune response to ND when administered through different routes. As these vaccines can withstand high environmental temperatures, they can be used successfully under village conditions without any need for cold chain facilities with great ease of administration. Further administration of thermostable protective nanoencapsulated vaccine tablet and drinking water methods were found to be easy for the use in rural and commercial poultry flocks.