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Moawed, Sherif A.
- Modeling the Potential Risk Factors of Bovine Viral Diarrhea Prevalence in Egypt Using Univariable and Multivariable Logistic Regression Analyses
Authors
1 Department of Animal Medicine (Infectious Diseases), Benha University, P.O. Box 13736, Toukh, EG
2 Department of Animal Medicine (Infectious Diseases), Suez Canal University, Ismailia 41522, EG
3 Department of Animal Wealth Development, Biostatistics Division, Suez Canal University, Ismailia 41522, EG
4 Department of Virology, Benha University, P.O. Box 13736, Toukh, EG
Source
Veterinary World, Vol 11, No 3 (2018), Pagination: 259-267Abstract
Aim: The present cross-sectional study was conducted to determine the seroprevalence and potential risk factors associated with Bovine viral diarrhea virus (BVDV) disease in cattle and buffaloes in Egypt, to model the potential risk factors associated with the disease using logistic regression (LR) models, and to fit the best predictive model for the current data.
Materials and Methods: A total of 740 blood samples were collected within November 2012-March 2013 from animals aged between 6 months and 3 years. The potential risk factors studied were species, age, sex, and herd location. All serum samples were examined with indirect ELIZA test for antibody detection. Data were analyzed with different statistical approaches such as Chi-square test, odds ratios (OR), univariable, and multivariable LR models.
Results: Results revealed a non-significant association between being seropositive with BVDV and all risk factors, except for species of animal. Seroprevalence percentages were 40% and 23% for cattle and buffaloes, respectively. OR for all categories were close to one with the highest OR for cattle relative to buffaloes, which was 2.237. Likelihood ratio tests showed a significant drop of the −2LL from univariable LR to multivariable LR models.
Conclusion: There was an evidence of high seroprevalence of BVDV among cattle as compared with buffaloes with the possibility of infection in different age groups of animals. In addition, multivariable LR model was proved to provide more information for association and prediction purposes relative to univariable LR models and Chi-square tests if we have more than one predictor.
Keywords
Bovine Viral Diarrhea, Likelihood Ratio Test, Logistic Regression, Odds Ratio, Seroprevalence.Full Text
- Influence of Microclimatic Ammonia Levels on Productive Performance of Different Broilers’ Breeds Estimated With Univariate and Multivariate Approaches
Authors
1 Department of Animal Hygiene, Zoonosis & Animal Behavior, Suez Canal University, Ismailia-41522, EG
2 Department of Animal Wealth Development, Division of Biostatistics, Suez Canal University, Ismailia-41522, EG
3 Department of Animal Wealth Development, Division of Animal Production, Suez Canal University, Ismailia-41522, EG
Source
Veterinary World, Vol 10, No 8 (2017), Pagination: 880-887Abstract
Background and Aim: Birds litter contains unutilized nitrogen in the form of uric acid that is converted into ammonia; a fact that does not only affect poultry performance but also has a negative effect on people’s health around the farm and contributes in the environmental degradation. The influence of microclimatic ammonia emissions on Ross and Hubbard broilers reared in different housing systems at two consecutive seasons (fall and winter) was evaluated using a discriminant function analysis to differentiate between Ross and Hubbard breeds.Materials and Methods: A total number of 400 air samples were collected and analyzed for ammonia levels during the experimental period. Data were analyzed using univariate and multivariate statistical methods.
Results: Ammonia levels were significantly higher (p˂0.01) in the Ross compared to the Hubbard breed farm, although no significant differences (p>0.05) were found between the two farms in body weight, body weight gain, feed intake, feed conversion ratio, and performance index (PI) of broilers. Body weight; weight gain and PI had increased values (p˂0.01) during fall compared to winter irrespective of broiler breed. Ammonia emissions were positively (although weekly) correlated with the ambient relative humidity (r=0.383; p˂0.01), but not with the ambient temperature (r=−0.045; p>0.05). Test of significance of discriminant function analysis did not show a classification based on the studied traits suggesting that they cannot been used as predictor variables. The percentage of correct classification was 52% and it was improved after deletion of highly correlated traits to 57%.
Conclusion: The study revealed that broiler’s growth was negatively affected by increased microclimatic ammonia concentrations and recommended the analysis of broilers’ growth performance parameters data using multivariate discriminant function analysis.
Keywords
Ammonia, Broiler, Discriminant Function Analysis, Growth Performance Parameters, Humidity, Temperature.Full Text