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Survival Analysis of Hungarian Large White, Duroc and Pietrain Sows
31-36Views:228The aim of the present study was to perform lifetime performance analysis in three pig breeds; Hungarian Large White (n=295), Duroc (n=76) and Pietrain (n=91) on a commercial farm using analysis of survival sows. We took into consideration the age of sows at the time of their inclusion into breeding, their age at the time of culling, time spent in production, number of mating and parities, parity percentage, intervals between litters, number and mean of piglets born alive and born dead, number of raised piglet litters, number and mean of 21 days old piglets, the weight and mean of raised litter and raise percentage.
We carried out the analysis by SPSS 22.0. Single factor analysis of variants, Kaplan-Meier analysis and Cox PH model were used. The determination of the significance of risk rates differences was done by Wald chi square test.
Our results showed that the average culling age were 1056 (±33.52) days for the Hungarian Large White, 735 (±73.56) days for Duroc and 818 (±71.98) days for the Pietrain.
The log rank test of the survival analysis indicated a significant difference between the three tested genotypes (χ2=16.981, P<0.001), which means that the survival percentage of the individual breeds varied significantly from one another. In comparison with the Hungarian Large White genotype the Duroc genotype has a 1.6 times higher (P<0.001) culling risk while that of the genotype Pietrain was 1.36 times higher (P<0.001).
Our results can be used to compare the breeds kept under the same conditions and to compare the life span of one genotype under different farming conditions. Factors that increase survival and improve the profitability of pig farming can be determined by this method.
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Effect of floor type and bedding system on sows lifespan
155-160Views:105The paper studies two nucleus pig farms in the Great Plain region of Hungary which have same management, same feeding system but different breeding technology (Farm A had solid floor with straw and Farm B had slatted floor without straw). The genetics of sows were crossbred Dutch Large White and Dutch Landrace. The comparative examination was based on the causes of culling according to the different floor type. To the analysis of culling reasons was applied the methods of survival analysis.
In the analysis there were used the Kaplan-Meier method and the Cox Proportional Hazard model to the estimate the difference between the farms. The results of survival analysis showed significant difference (p<0.05) between the lifespan of sows that caused the difference between the survival probabilities of sows culled due to lameness. Furthermore there was showed that the sows kept on solid floor with straw have stayed in production longer than on slatted floor without straw. The hazard ratio was 1.434 that means that the culling due to lameness is 1.434 times higher by the slatted floor without straw facing by solid floor with straw.
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Examination of the interval between litters (IBL) of different genotype HLW sows using survival analysis
13-17Views:157In this study our aim was to find out if there is a difference between the genotypes determined for the previously identified mutations of seven genes of the Hungarian Large White in terms of the time spent in production. We identified the previously determined alleles of the seven genes (BF, EGF, ESR, FSHβ, H2AFZ, LEP, PRLR) related to proliferation that were and performed the survival analysis between breeds indicating the risk of culling and the time spent in production on the given farm. Based on the results of survival analysis by Log-rank test, Breslow (Generalized Wilcoxon) and Tarone-Ware test we concluded that they indicated a significant difference in case of the genes BF (Breslow and Tarone-Ware tests) the EGF (Log-rank and Tarone-Ware tests) and ESR (Log rank test) based on which the curves of the survival of the certain genes varied form one another significantly.
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The methodology of Event History analysis and its application in the quality control of raw milk
74-79Views:62Event-history analysis is among the most frequently adopted mathematical methods, mainly due to the numerous types of models, available in the analysis. This method is also appropriate for analysing risk. Specifically, it has been employed in medical and animal-breeding science to manage risks. In this article, I give a presentation of the basic concepts, the basic types of models and their theoretical basis. I deal with the nonparametric Kaplan Meier and the parametric Cox proportional hazard model. The case study is also analysed with these methods. The results shows, that the 16-stall caroussel is the most effective facility from the viewpoint of quality. Milking into assay crucible (sample- cup) is more effective than to the floor after 16 decades.
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Comparison of growth parameters of 40 varieties/clones short rotation coppice willow (Salix)
99-104Views:123The plantation of willow varieties was established in 2009. The 40 different varieties and clones of Salix were planted at a research field in Kolíňany (Nitra district). The paper evaluates results from the first growing season in 2009. The survival rate of planted cuttings ranged from 55.56 % to 100.00 % after the first year. The lowest survival rate was reached by Terra Nova variety. The stem numbers per plant ranged from 1.17 ±0.37 to 2.53 ±0.98. The average height of one-year old stem varied from 65.82 ±36.60 cm to 225.58 ±68.61 cm. The average stem diameter ranged from 6.90 ±2.63 mm to 14.34 ±3.39 mm. There were statistically very significant differences in parameters of stem height stem diameter and stem numbers per plant among studied varieties/clones. The statistic method used was analysis of variance ANOVA. The varieties were then divided into 6 groups according to their similarity in observed parameters after the first growing season by cluster analysis. The best results were reached by varieties/clones classified in the second group. The survival rate, stem diameter and stem height values of these varieties/clones were above average.
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Survival analysis of sow longevity and lifetime reproductive performance – Review
75-80Views:254Sow longevity plays an important role in economically efficient piglet production. Improving sow longevity results increase in the productivity and profitability of a sow herd. Longevity is a complex trait with many factors that can contribute to a sow having a long and productive life. Not only the sow’s genetics, but also nutrition, environment and the management policies are important. In addition, the removal of non-productive sows along with the introduction of replacement gilts is an essential part of maintaining herd productivity at a constantly high level. The objective of this paper was to summarize the current knowledge about the sow longevity and lifetime performance values, as well as, discusses the survival analysis methods for sow longevity traits. This method can estimate the hazard rate indicating proportional risk of sows being culled at any given time, in addition, it is able to investigate the effects of different factors on longevity. Identifying factors that influence the longevity could assist many commercial pig producers in becoming more efficient.
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Analysis of the Station Test Results of the Hungarian Large White and Hungarian Landrace Populations Applying Survival Analysis
37-40Views:64Authors analysed the days of fattening in relation to the station test for Hungarian Large White and Hungarian Landrace pig populations using, survival analysis. Survival and hazard functions were calculated in both groups separately for castrates and females. The log-rank test was applied to determine the significance of the differences across the groups. Authors established that within the breeds the functions of the castrates and females were significantly different, namely the castrates reached final weight sooner or, in cases where final weight was not reached by a certain period, castrates reached this weight during the next time unit with a higher probability than the females.
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An Analysis of Rotational Line Mating Using Computer Simulation
35-39Views:112In a simulation examination, we analyzed the effect of the family size and the rate of pairing on the survival of rare genes, to keep the level of variation of the genepool and to avoid the loss of alleles.
The population size was 360 animals. In the simulation, we calculated on the basis of a discrete population. We placed the 360 animals into different clusters, with 3 types of frequencies of alleles and 3 types of groups. We assumed 2, 3 or 4 alleles in 8 loci. We generated 15 generations using the same mating and selection system used in practise. The simulation was written with Scilab 2.7.2 software, and evaluated with SPSS software.
There were significant changes in the effect of family size on the genetic variation in the following cases: when the base population had the same gene frequencies in all loci, and when the gene frequencies were between 0.125-0.75. In these cases, we found that the smaller families (10 animals/cluster) were better than the larger families (30 or 90 animals/cluster). The first generation where there accured a loss of alleles was averagely earliest in larger families (90 animal/cluster). This average was 3.37 generations. When we are searched the effects of the different rates of pairing we found those cases most favourable when the ratio of males and females was 1:2 or 1:4 as compared to 1:9. The first generation where there was a loss of alleles was averagely earliest at the ratio of pairing male and females of 1:9 (the mean was 3.05 generations) when the frequency of the rarest allele was 0.0069.
The recently introduced rotating-random mating system is an eligible method for small populations for the preservation of genes. -
Evaluation of the relationship between main type traits and longevity in Hungarian Simmental cows
205-209Views:108The Hungarian Simmental cattle is a dual-purpose breed, having good milk and meat production characteristics. Simmental cows have some other important traits, for example, a longer productive life. The longevity or productive life is the time period between first calving and culling. The conformation contributes to productive life, reproduction, and milk production.
The aims of this study were to analyze the longevity of Hungarian Simmental dual-purpose cows, to evaluate the effects of the size of the herd, age at first calving, main type traits (frame, musculature, feet and legs, mammary system), and combination of main type traits (frame and musculature, feet and legs and mammary system).
Animal, age at first calving, herd*calving, musculature, the mammary system as well as the combination of mammary system and feet and legs were significant effects on longevity. The highest risk ratio was observed for cows first calved after 31 months. The risk of culling increased with increasing scores of musculature and decreasing scores of the mammary system. The highest risk ratio was estimated in category 11 (lower scores of mammary system with lower scores of feet and legs). In this case, the risk ratio was 36% higher than the reference group.