GENETIC STUDIES ON ECONOMIC TRAITS OF ONGOLE CATTLE
| dc.contributor.advisor | Narasimha rao, G(MAJOR) | |
| dc.contributor.author | VINOO, R | |
| dc.date.accessioned | 2018-08-23T10:07:22Z | |
| dc.date.available | 2018-08-23T10:07:22Z | |
| dc.date.issued | 2003-08 | |
| dc.description.abstract | ABSTRACT: A study was undertaken to know the extent of genetic and phenotypic variation present in the growth, production and reproduction characters, number of days for change of coat colour and age till survival of Ongole cattle in four farms in Andhra Pradesh, covering the period 1978 – 2002. An attempt was also made to predict the body weight based on body measurements. The draught ability of Ongole cattle under thermal stress conditions was evaluated and sire evaluation by different methods based on 305-day lactation milk yield was studied. The effects of farm, period of birth, season of birth and sex on body weights and measurements at different ages and age at first calving and the effects of farm, period of calving, season of calving, sex and parity on other production and reproduction traits were studied by subjecting the data to least squares analysis. The genetic parameters were estimated after adjusting the data for the effects of farm, period and season. The overall least squares mean body weights at birth, 1, 3, 6, 9, 12, 18 and 24 months were 26.08 + 0.26, 46.70 + 0.96, 72.92 + 0.95, 112.38 + 1.39, 137.77 + 3.37, 164.34 + 3.01, 222.68 + 3.93 and 271.78 + 4.81 kg, respectively. The calves born in Lam farm had the highest body weights at all the ages studied. The body weights at birth, 3, 6, 9, 12, 18 and 24 months were significantly affected by the farms. Period of birth had significant influence on the body weights of Ongoles at 1, 3, 6, 9, 12, 18 and 24 months of age. Season of birth significantly influenced the body weight at 6 months age only, whereas the effect of sex was significant on the body weights of Ongoles at all ages studied. The overall means of height at withers at birth, 1, 3, 6, 9, 12, 18 and 24 months were 70.90 + 0.89, 84.02 + 0.62, 90.48 + 0.52, 102.64 + 0.54, 107.14 + 1.43, 123.77 + 0.71, 122.29 + 0.77 and 129.11 + 0.68 cm, respectively. The overall means of chest girth at birth, 1, 3, 6, 9, 12, 18 and 24 months were 70.80 + 0.76, 83.74 + 0.64, 93.58 + 0.56, 106.89 + 0.59, 115.98 + 1.81, 124.14 + 0.89, 137.72 + 0.95 and 148.32 + 0.99 cm, respectively and the overall means for body length at these ages were 60.58 + 0.81, 72.54 + 0.55, 82.74 + 0.70, 96.89 + 0.61, 105.21 + 1.94, 109.06 + 0.85, 119.08 + 0.85 and 127.42 + 0.94 cm, respectively. The effect of farm was significant on height at withers in all ages studied, except at 12 months, whereas it was significant on chest girth and body length at all the ages studied. The period of birth had significant influence on height at withers at all ages studied except at one and 12 months of age, whereas it had significant effect on chest girth from one to 24 months of age and on body length at all ages studied. The season of birth had significant influence on height at withers only at birth, whereas it had significant influence on body length at 3, 6, 18 and 24 months of age. The sex effects were significant on height at withers in all ages studied except at 12 months, whereas they were significant on chest girth in all age groups except at nine months of age and on body length at 9 and 18 months of age only. The R2 values of the step-down multiple regression equations fitted for predicting the body weights at birth, 3, 6, 9, 12 and 18 months of age based on the height at withers, chest girth and body length at the same ages were 65.96, 53.13, 82.48, 67.82, 87.75 and 82.05 per cent, respectively. The overall least squares mean total lactation milk yield and 305-day lactation milk yields were 712.27 + 23.14 and 707.77 + 22.16 kg, respectively. The farm, period of calving and parity significantly influenced these traits, whereas season of calving had no significant influence. The overall least squares mean lactation length was 237.71 + 5.78 days. Lactation length was significantly affected by farm and period of calving while season of calving and parity had no significant effect. The overall average peak yield was 3.84 + 0.13 kg. The effects of farm, period of calving and parity exerted significant influence, whereas the season of calving did not influence the peak yield. The overall mean days to reach peak yield was 42.28 + 3.08 days and only the effect of farm exerted significant influence on this trait. The overall mean milk yield per day of lactation and milk yield per day of calving interval were 3.02 + 0.05 and 1.48 + 0.06 kg, respectively. The farm, period of calving and parity significantly affected these traits, while the effect of season was not significant. The overall mean fat and SNF were 4.89 + 0.09 and 8.44 + 0.01 per cent, respectively. The effects of period and season of calving studied at Lam farm were significant on fat percentage but not on SNF percentage. The overall least squares mean age at first calving was 52.95 + 2.21 months. The effects of farm and period of birth were significant while the effect of season of birth was not significant on age at first calving. The overall mean gestation period in the present study was 287.78 + 0.84 days and it was significantly affected by farm and period of calving but not by season of calving. The overall means for service period, dry period and calving interval were 270.19 + 11.81, 311.88 + 11.90 and 561.55 + 11.82 days, respectively. The effects of farm, period of calving and parity were significant, while the effect of seasons was not significant on these traits. The overall least squares mean number of inseminations per conception was 1.81 + 0.11. The farm and period of calving exerted significant influence on this trait but not the season of calving and parity. The overall mean number of days taken for change of coat colour was 315.13 + 12.53 days. The number of days for change of coat colour at Lam farm studied was significantly affected only by the period of birth but not by the season of birth and sex. The overall mean age till survival was 64.37 + 4.70 months. The effects of farm, period of birth and sex significantly influenced the age of animals at death but not season of birth. The heritability estimates for the body weights at birth, 3, 6, 12 and 18 months were 0.05 + 0.05, 0.05 + 0.05, 0.36 + 0.12, 0.40 + 0.33 and 0.02 + 0.25, respectively. Higher heritability estimates of body weights at 6 and 12 months of age could be relied upon for selecting the animals for faster growth. The heritability estimates for height at withers at birth, 3, 6, 9 and 12 months were 0.15 + 0.07, 0.18 + 0.08, 0.15 + 0.07, 0.41 + 0.03 and 0.27 + 0.30, respectively, while the estimate was negative for the measurement at 18 months of age. The heritability estimates for body length at birth, 3, 6, 9, 12 and 18 months were 0.18 + 0.08, 0.06 + 0.05, 0.20 + 0.09, 0.50 + 0.34, 0.69 + 0.37 and 0.96 + 0.40, respectively. The heritability estimates for chest girth were 0.25 + 0.10, 0.10 + 0.06, 0.23 + 0.09, 0.03 + 0.26 and 0.30 + 0.31 at birth, 3, 6, 9 and 12 months of age, respectively. The heritability for chest girth at 18 months of age was negative. The estimates of heritability of age at first calving, total lactation milk yield, 305- day lactation milk yield, lactation length, milk yield per day of lactation, milk yield per day of calving interval, gestation period, service period, dry period and calving interval were 0.95 + 0.24, 0.26 + 0.09, 0.24 + 0.08, 0.27 + 0.09, 0.12 + 0.06, 0.25 + 0.08, 0.24 + 0.08, 0.17 + 0.07, 0.22 + 0.08 and 0.18 + 0.07, respectively. Higher heritability estimate of age at first calving indicated that it could be reduced by selective breeding. The heritability estimates for number of inseminations per conception and number of days for change of coat colour were negative due to negative sire components of variance. The estimate of heritability for age till survival was 0.37 + 0.27. The genetic correlation among the body weights at different ages varied from 0.57 to 0.96 and those between the body weights and measurements ranged from –0.79 to 0.99 at birth and –0.24 to 0.98 at 12 months of age. The age at first calving was correlated negatively with all the traits studied except with dry period. The genetic correlations for the other production and reproduction traits studied, were positive among themselves except with gestation period and dry period. The phenotypic correlations between body weights and measurements were in general, positive. The phenotypic correlations among the production and reproduction traits studied were in general, lower in magnitude but similar in direction when compared to the genetic correlations. The draught ability of Ongole bulls was evaluated by overall draught ability and horse power generation methods. The overall draught ability of the bulls was measured in terms of carting and ploughing abilities. The overall means for per cent increase in respiration rate, pulse rate and rectal temperature were 55.84, 22.76 and 1.71, respectively in carting ability and 92.7, 30.38 and 2.07, respectively in ploughing ability. The overall per cent increase in the respiration rate, pulse rate and rectal temperature after work in horse power generation method were 101.36, 25.17 and 1.20, respectively and the overall mean for the speed, draught force and horse power generated were 1.59 meters per second, 28.19 kg and 0.57 horse power, respectively. The phenotypic correlations between the age, body weight and body measurements of the bulls included in draught ability studies were observed to be highly positive and significant. The bulls were ranked by overall draught ability and horse power generation methods and the rank correlation was negative and not significant. The sire indices obtained by simple daughter average index, dairy search index and adjusted least squares method for 305-day first lactation milk yield ranged from 341 to 668, 363 to 577 and 367 to 547 kg, respectively. Positive and highly significant rank correlation coefficients indicated that these three methods of sire evaluation could be used with equal efficiency. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810067117 | |
| dc.keywords | ONGOLE CATTLE;GENETIC STUDIES; ECONOMIC TRAITS | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 192 | 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.subject | null | en_US |
| dc.theme | GENETIC STUDIES ON ECONOMIC TRAITS OF ONGOLE CATTLE | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | GENETIC STUDIES ON ECONOMIC TRAITS OF ONGOLE CATTLE | en_US |
| dc.type | Thesis | en_US |