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|Advisor:||Dr. V. CHINNI PREETAM|
|Title:||GENETIC EVALUATION OF GROWTH AND PRODUCTION TRAITS IN JAPANESE QUAILS (Coturnix coturnix japonica)|
|Abstract:||The present investigation was carried out on the Black strain Japanese quails (Coturnix coturnix japonica) maintained at the Poultry Experimental Station (PES), Department of Poultry Science, Rajendranagar, Hyderabad to evaluate the performance of different traits such as body weight, average daily gains (ADGs), age at first egg (AFE), egg production (EP) and carcass traits. For slaughter parameters 50 birds were randomly selected comprising of 25 males and 25 females during 6 weeks of age. Hatchability on TES varied from 66.5 to 77.4 among the hatches. Significant (p<0.01) effect of hatch was observed on body weights at all ages studied except at 3rd week of age. The overall least squares mean for body weight at day-old, 1, 2, 3, 4, 6, 8, 12 and 16 weeks of age were 8.26±0.03, 26.07±0.11, 65.18±0.23, 109.66±0.34, 155.02±0.46, 203.93±0.56, 251.53±0.75, 266.23±0.69 and 284.26±0.67 grams, respectively. Sexual dimorphism in favour of the females was evident by their higher body weight ranging from 0.02 g to 23.01 g over males, from hatch to 16 weeks of age, respectively. The overall least squares mean ADGs during 1, 2, 3, 4, 5 to 8, 9 to 12 and 13 to 16 weeks of age were 2.54±0.16, 5.58±0.02, 6.35±0.03, 6.48±0.03, 2.98±0.02, 0.52±0.01 and 0.64±0.01 grams, respectively. Sex and hatch effect was significant on ADGs at all ages with an exception to that of 9 to 12 weeks of age. The highest ADGs of 6.38 g and 6.57 g were obtained in males and females, respectively, during 4 weeks of age. The overall least squares mean for age at first egg and cumulative egg production from 6, 8, 10,12, 14, 16, 18 and 20 weeks of age were 45.93±0.31 days, 0.66±0.07, 8.45±0.26, 20.31±0.32, 32.22±0.36, 44.23±0.37, 55.65±0.38, 67.89±0.40 and 80.11±0.41 eggs, respectively. Hatch had a significant influence on AFE and egg production up to 20 weeks of age except at 6th week of age. The overall least squares mean for pre-slaughter weight and dressed weight were 226.70±2.51 and 141.27±1.50 grams, respectively, while the means for wings, neck, legs, thighs, drumsticks, breast and back were 10.63±0.15, 4.56±0.20, 30.37±0.39, 17.55±.28, 12.82±0.17, 54.00±0.64 and 31.62±0.53 grams, respectively. Significant influence (P<0.01) of sex was found on majority of the carcass traits studied. The overall least squares mean dressing percentage was 62.42 and the wings, neck, legs, thighs, drumsticks, breast and back formed 7.53, 3.23, 21.51, 12.43, 9.08, 38.23 and 22.35 percent of dressed carcass, respectively. Heritability estimates for body weight at day old, 1, 2, 3, 4, 6, 8, 12 and 16 weeks of age was measured based on sire component of variance by half sib method in general. Heritability estimates were medium in magnitude. The heritabilities of AFE and egg production were moderate in magnitude. The estimates of genetic and phenotypic correlations for body weights were positive, moderate to high in magnitude and ranged from 0.51 to 0.99 and 0.22 to 0.94, respectively. The magnitude of genetic correlations was higher between body weights at nearest age and the values decreased as the interval between two successive body weights increased. Genetic correlations between AFE and egg production were negative and high in magnitude. Genetic correlations among the egg production traits were positive and high. The phenotypic correlations between AFE and egg production traits were negative and moderate to high in magnitude while those among egg production traits were positive and moderate. Present study revealed existence of sufficient additive genetic variability with respect to most of the traits studied and positive genetic correlations among growth and production traits. Thus, selective breeding might help improve the performance of this population.|
|Appears in Collections:||Thesis|
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