GENETIC EVALUATION OF PRODUCTIVE AND REPRODUCTIVE TRAITS IN CROSSBRED LARGE WHITE YORKSHIRE PIGS (SVVU-T17)
| dc.contributor.advisor | PUNYA KUMARI, B(MAJOR) | |
| dc.contributor.advisor | GURU VISHNU, P | |
| dc.contributor.advisor | SURESH BABU, D | |
| dc.contributor.author | RAMYA NAIDU, B | |
| dc.date.accessioned | 2023-04-27T12:21:47Z | |
| dc.date.available | 2023-04-27T12:21:47Z | |
| dc.date.issued | 2022-07 | |
| dc.description | THESES | en_US |
| dc.description.abstract | Data collected on 4011 production records and 343 reproduction records of 75% Large White Yorkshire (SVVU-T17) crossbred pigs born during 2005 to 2020 maintained at All India Coordinated Research Project on Pigs (AICRP), Tirupati, Chittoor district was utilized in the present investigation to study the effect of various genetic and non genetic factors including inbreeding on productive, reproductive and litter traits. Single trait analysis were done by fitting a general linear model (GLM) to study the effect of various non-genetic factors (fixed factors) on each trait. The (co)variance components for different production and reproduction traits were estimated by Restricted Maximum Likelihood Method (REML) using WOMBAT programme of Mayer (2007). The (co)variance components and heritability were estimated using four different models with direct, maternal and permanent environment effects were fitted and best model was selected through log likelihood ratio test (LRT). Estimates of (co) variance between different production and reproduction traits were obtained through bivariate analysis. Estimates of breeding values (EBV) for different production traits were obtained by Best Linear Unbiased Prediction (BLUP) method. The overall least squares mean body weights were 1.09 ± 0.003, 1.54±0.004, 2.78±0.009,4.11±0.013,5.44±0.017,6.38±0.017,7.38±0.02,8.48±0.024,9.85±0.03,14.57±0.06,20.49±0.09,29.13±0.13 and 35.94 ± 0.17 kg at birth (BW0), BW1, BW2, BW3, BW4, BW5, BW6, BW7, BW8, BW12, BW16, BW20 and BW24 weeks of age, respectively. Period, Season of birth and inbreeding had significant influence (P<0.05) on body weights at all ages. Parity had significant influence on body weights at birth (BW0), BW7, BW8 and BW12 weeks of age only. Sex of the piglet had significant influence on body weights at birth (BW0), BW1, BW2, BW3 and BW4 weeks of age only. Body weights of piglets born in rainy and winter seasons recorded significantly higher body weights. The overall least squares means for AFF and FI in 75% crossbred LWY (SVVU-T17) pigs were 352.59 ± 6.42 and 249.14 ±2.15 days, respectively. The effect of period, season and inbreeding were significant on reproductive traits. The overall least squares means for LSAB, LSAW, LWAB and LWAW in 75% crossbred LWY (SVVU-T17) pigs were 7.71 ± 0.10, 7.44 ± 0.10, 8.58 ± 0.13 kg and 55.42 ± 0.91 kg, respectively. The effect of period and parity were significant (P<0.05) on majority of the litter traits. Effect of level of inbreeding on all litter traits was also found to be significant. Inbreeding co-efficient (Fx) values in the population varied from 0 to 25.5 percent with an overall mean of 0.36 percent. The direct heritability estimates (h2) obtained through the best model for body weights at birth (BW0), BW1, BW2, BW3, BW4, BW5, BW6, BW7, BW8, BW12, BW16, BW20 and BW24 weeks of age were 0.54, 0.91, 0.87, 0.86, 0.93, 0.94, 0.81, 0.82, 0.18, 0.16, 0.16, 0.20 and 0.87, respectively. Maternal heritability (m2) values were 0.05, 0.07, 0.12, 0.05, 0.02, 0.04, 0.17, 0.16, 0.16, 0.20 and 0.007 at BW1, BW2, BW3, BW4, BW5, BW6, BW8, BW12, BW16, BW20 and BW24 weeks of age in 75% Crossbred LWY (SVVU-T17) pigs. Heritability estimates from REML for age at first farrowing (AFF), litter size at birth (LSAB), litter weight at birth (LWAB), litter size at weaning (LSAW), litter weight at weaning (LWAW) and farrowing interval (FI) were 0.70, 0.96, 0.95, 0.87, 0.93 and 0.70, respectively. The repeatability estimates for LSAB, LWAB, LSAW, LWAW and FI were 0.97, 0.96, 0.88, 0.94 and 0.80, respectively. The highest heritability (0.96) and repeatability (0.97) estimates were recorded for LSAB. All the estimates of genetic correlations among body weight traits were positive. Estimates of genetic correlations for birth weight with weight at later ages were medium to high (0.40 to 0.98). All the estimates for phenotypic correlations among body weight traits were positive. Birth weight had the highest phenotypic correlation with the other traits (0.03 to 0.98). Phenotypic correlations among litter traits were positive and ranged from 0.11 ± 0.10 to 0.91± 0.01. Phenotypic correlations between AFF and FI was low and positive (0.05±0.01) in direction. The estimated overall average breeding values of sires for BW0, BW1, BW2, BW3, BW4, BW5, BW6, BW7, BW8, BW12, BW16, BW20 and BW24 weeks of age were 1.09, 1.53, 2.77, 4.08, 5.39, 6.27, 7.22, 8.26, 9.53, 13.21, 14.40, 20.92 and 24.48 kg, respectively by BLUP method. Highest range of EBV was observed for 24 weeks body weight. The top ranking sires had higher genetic superiority of 51.63% and 64.48% over the average breeding values at BW1 and BW20 weeks of age, respectively. | en_US |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810196817 | |
| dc.keywords | GENETIC EVALUATION; PRODUCTIVE; REPRODUCTIVE TRAITS; CROSSBRED; LARGE; WHITE; YORKSHIRE PIGS; SVVU-T17 | en_US |
| dc.language.iso | English | en_US |
| dc.pages | 148 | en_US |
| dc.publisher | SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA | en_US |
| dc.sub | Animal Genetics and Breeding | en_US |
| dc.theme | GENETIC EVALUATION OF PRODUCTIVE AND REPRODUCTIVE TRAITS IN CROSSBRED LARGE WHITE YORKSHIRE PIGS (SVVU-T17) | en_US |
| dc.these.type | M.V.Sc. | en_US |
| dc.title | GENETIC EVALUATION OF PRODUCTIVE AND REPRODUCTIVE TRAITS IN CROSSBRED LARGE WHITE YORKSHIRE PIGS (SVVU-T17) | en_US |
| dc.type | Thesis | en_US |