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Theses

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1980 - 198922000 - 20011
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Subject: Animal Genetics and Breeding × Author: KAU × End date: 2006 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on certain genetic and nongenetic factors affecting birth weight and growth rate malabari and crossbred goats
    (Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1980) Raghavan, K C; KAU; Krishnan Nair, B R
    The data on 1227 kids belonging to Malabari (309) Saanen x Malabari (389) and Alpine x Malabari (309) genetic groups born and brought up at the All India co – ordinated Research Project on Coats, Kerala Agricultural University, Mannuthy during the period from April 1974 to March 1979 were utilised to study the effects of various genetic and non genetic factors on body weight at different ages. Crossbred goats, S x M and A X M, registered higher weights at birth, at one month, at four months and at one year than the local Malabari goats. District sexual dimorphism in body weights at different ages could be observed in crossbred goats. Litter size significantly affected birth weight and weight at one month. Sason of birth had only non significant influence on weights at birth and that at one month, though the effect was significant on 4 month’s and one year weights. Even though the effect of gestation length undergone by kids was a significant source of variation for weights at birth alone in Saanen x Malabari and Alpine x Malabari kids, the same had significant effect on body weights at birth and at one month in Malabari. Significant effects of dam’s weight at kidding on weights at birth, one month and four months in Malabari ; at birth and a one month in Alpine x Malabari and at birth alone in Saanen x Malabari could be observed. Sire effect was significant on body weights at one month, 4 months and one year in Malabari, at birth and one year in Alpine x Malabari and one year alone in Saanen x Malabari. The growth rate was found to be highest in A x M upto four months of age and afterwards upto one year S X M showed highest rate of gain. The effect of genetic group on growth rate was found to be significant during all the periods of growth. The heritability estimate for weight at birth was near to zero. The h2 estimates were seen getting higher as the age advanced. Genetic correlations between body weights at different ages were found to be fairly high. But the phenotypic correlations between weight at different ages were found to be highly variable. Twins were more than singles in all the genetic groups and the secondary sex ratio was found to be 50:50. The results of the study indicated that crossbreeding of local goats with exotic breeds, Saanen and Alpine, is the desirable breeding plan to accomplish the improvement of body weight in goats, at different ages.
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    ThesisItemOpen Access
    Inheritance of chick weight and egg production in white leghorn birds
    (Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1983) Rose Job, T; KAU; Sosamma, Ipe
    A research work was undertaken in two strains of White Leghorn birds to study the inheritance of chick weight and egg production. The birds maintained at the poultry farm under All India Co – ordinated Research Project on Poultry for Eggs, Mannuthy were utilized for the study. The mean values for six – week body weight (g), eight week body weight (g) and egg production upto 280 days of age (number) were 319.4 + 1.4, 452.9 + 1.8 and 71.5 + 0.4 for N strain and 351.2 + 1.7, 513.7 + 2.2 and 80.6 + 0.5 for P strains. Least squares analysis for effect of generations and hatches within generations were carried out. Generation effects were significant for the three characters in both the strains. Effect of hatches within generations were also found to be significant except for egg production in first generation batches and for six – week body weight in second generation hatches in N strain. The data were adjusted for the generation and hatch effects. Adjusted data were used to estimate heritability, genetic, phenotypic and environmental correlations. The heritability estimates in N strain were 0.223 + 0.112, 0.642 + 0.078 and 0.433 + 0.099 for six – week body weight 0.278 + 0.108, 0.372 + 0.068 and 0.325 + 0.095 for eight – week body weight and 0.219 + 0.095, 0.379 + 0.077 and 0.298 + 0.095 for egg production based on sire, dam and sire + dam components of variance respectively. The respective estimates in P strain were 0.405 + 0.110, 0.341 + 0.103 and 0.373 + 0.101 for six – week body weight, 0.354 + 0.110, 0.443 + 0.094 and 0.398 + 0.118 for eight – week body weight and 0.530 + 0.102, 0.230 + 0.130 and 0.380 + 0.131 for egg production. The genetic correlation estimates between six – week and eight – week body weight were found to be high and positive in both the strains. The phenotypic correlations were also found to be positive but lower compared to genetic correlation and similar in both the strains. The environmental correlations had also been positive though of still lesser magnitude in both the strains. In general, the correlation estimates between chick weights and egg production were found to be very low in both the strains. The results were not suggestive of any strong relationship between chick weights and egg production. Out of these three characters, only egg production deserved consideration in selection as chick weight in White Leghorns cannot be considered as an economic trait. It was estimated that an improvement of 7.57 eggs per generation could be expected in both the strains for standard deviations of 16.04 and 15.41 and heritabilities of 0.219 and 0.230 in N and P strains respectively, when selection of males is 8.5 per cent and females 16 per cent.
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    ThesisItemOpen Access
    Association of bodyweight and milk production in Vechur and other dwarf desi cattle of Kerala
    (Centre for Advanced Studies in Animal Genetics and Breeding, College of Veterinary and Animal Sciences, Mannuthy, 2001) Bindya, Liz Abraham; KAU; Sosamma, Iype
    The present work is a study on the association between body weights, lactation milk yield and age at first calving in Vechur and other dwarf desi cattle maintained at Kerala Agricultural University. This information can be utilized in the selection programme to evolve a small cow weighing around 125kg and yielding 800 kg milk per lactation. The average body weights at birth, three, six, nine, twelve months and at adult stage for males of Vechur were 11.2 ± 0.2 kg, 28.7 ± 0.7 kg, 44.2 ± 0.8kg, 63.9 ± 4.0 kg, 76.1 ± 1.9 kg, 173.6 ± 6.9 kg and those for Kasargod, 11.1 ± 0.3 kg, 33.5 ± 3.0 kg, 49.5 ± 4.6 kg, 80.4 ± 6.8 kg, 86.8 ± 11.2 kg and 194?"3 ± 19.9 kg respectively. The corresponding estimates for females of Vechur were 10.2 ± 0.2 kg, 28.3 ± 0.7 kg, 43.3 ± 0.8 kg 52.7 ± 1.3 kg, 69.5 ± 1.2 kg and 138.5 ± 2.3 kg and those for Kasargod, 9.5 ± 0.4 kg, 29.1 ± 1.8 kg, 49.5 ± 2.7 kg, 54.3 ± 3.0 kg, 61.1 ± 3.8 kg and 147.7 ± 5.1 kg respectively. The average gain in weight for the four periods i.e., months 0-3, 3-6, 6-9 and 9 -6;12 when expressed as a percentage of initial weight for males of Vechur were 149.0, 54.7, 39.7, 25.3 and those for Kasargod, 198.4, 62.5, 59.5, 17.0 per cent respectively. The corresponding estimates for the females of Vechur were 178.1, 55,8, 31.8, 27.1 and those for Kasargod, 169.1, 58.4, 20.0, 13.3 per cent respectively. Male calves of Vechur gained 6.7 times and those of Kasargod 7.8 times the birth weight by twelve months of age. Males and females differed in body weight only at adult stage. Between breeds, male calves at nine months and female calves at twelve months differed. The average age at first calving and lactation milk yield of Vechur were 1080.3 ± 33.6 and 579.6 ± 35.7 kg and those of Kasargod were 1147.5 ± 68.0 days and 298.3 ± 35.6 kg respectively. The means for milk yield differed significantly. Weight at three months had a heritability of 0.61 and adult body weight, 0.81 in Vechur. The heritability for milk yield and age at first calving were 0.1 and 0.06 respectively. Estimation of phenotypic correlations in Vechur revealed that birth weight had a correlation of 0.446 with twelve months weight. Body weights at the adjacent stages had correlations ranging from 0.36-0.77. Age at first calving had correlation only with weight at nine months (0.668) and milk yield had only with adult body weight (0.406), 11 In Kasargod, body weight at different stages upto 12 . months had correlations around 0.8 but not with adult body weight. Adult body weight and milk yield were found to have a correlation of 0.918. Genetic correlation In Vechur for weight at three months and adult weight was 0.683, but that between adult weight and milk yield was not significant. The annual genetic gain from selection was estimated to be -4.35 kg and 12.968 kg for adult body weight and lactation milk yield respectively. Considering a take off time of five years, it would be possible to achieve the target of 800 kg per lactation from the present 579.5 kg, in a time period of 22 years. Vechur is the smallest breed not only of India, but probably of the wor ld is the highest milk yielder among the very light breeds with the lowest age at first calving among all Indian breeds. Kasargod males have the highest growth rate upto one year among all Indian breeds. The potential of the Vechur cow for milk and the Kasargod bull calf for meat can be advantageously utilized at present and improved with selection in the future.