GENETIC ANALYSIS OF PRODUCTION TRAITS OF SURTI BUFFALO ON AN ORGANIZED FARM
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Date
2005
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AAU, Anand
Abstract
Buffaloes are considered to be the principal milk producing livestock species in India. Surti is one of the well-defined buffalo breeds of India. Estimation of genetic parameters for production traits is important to know the genetic basis for production performance of the animal and to access how much improvement is possible in the next generations. Detailed genetic analysis of production traits in Surti buffalo maintained on an organized farm help us in identifying various factors affecting the productivity of animals. Estimation of genetic parameters for various production traits also help the breeder in identification of various selection criteria and planning of breeding programs for genetic improvement in Surti buffalo. The studies on lactation curve and persistency is very much helpful to know the sustainability of the lactation. The data for the present study were collected from breeding and production records of Livestock Research Station, Navsari from 1988 - 2002. The data pertaining to body weight, milk production and other records of Surti buffaloes were collected. Total there were 545 body weight records at BWQ, BW3, BWe and BW12 under 13 sires and daily milk production records (morning and evening) for 298 lactations from 130 buffaloes were collected under 15 sires. Maximum data up to four lactations were collected of each animal. Other records i.e. Age at First Calving (AFC), lactation length, Service period (SP), Dry Period (DP), Gestation Period (GP), Calving Interval (CI) were collected for animals under study. The records were analyzed using least squares analysis procedures. The Harvey (1990) programme was used to estimate the genetic parameters i.e. heritability (h2), genetic and phenotypic correlations by Paternal Half sib method. Period of birth, period of calving, season of birth, season of calving etc. non-genetic factors were incorporated in appropriate statistical model. Lactation curve was prepared through Statistical Packages for Social Sciences programme. Two functions, i.e. Gamma function and Inverse Polynomial functions were fitted to the daily milk yield records. Persistency was calculated through simple analysis in Microsoft Excel 2000 on the weekly records of the milk yield. BWo, BW3 and BWe were significantly affected by period of birth and season of birth. The sex of calf significantly affected only body weight at birth. BW12 was not affected by any of the non genetic factors under study. Body weights at different ages were found to be moderate to highly heritable and were favorably genetically correlated with each other. Lactation traits were not affected by any of the non genetic factors except age at first calving by season of birth. The heritability estimates for first lactation yield, age at first calving, first gestation period, and first calving interval were found to be high. Heritability estimates for other traits i.e. first lactation length, first service period and first dry period could not be calculated on account of negative sire component of variance. The first lactation yield and age at first calving, and age at first calving and first gestation period were found to be negatively correlated. Gamma function was found to be more effective as compare to Inverse Polynomial function with higher R2 value. The value of persistency ranged from 97.94% in fourth lactation to 98.56 % in first lactation, indicating Surti buffaloes as fairly persistent in milk production throughout the lactation.
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AN ANALYSIS