GENETIC ANALYSIS OF PRODUCTION TRAITS IN GIR CATTLE 1673
dc.contributor.advisor | Dr. P. H. VATALIYA | |
dc.contributor.author | NIKHIL SHANTILAL DANGAR | |
dc.date.accessioned | 2019-02-16T12:17:23Z | |
dc.date.available | 2019-02-16T12:17:23Z | |
dc.date.issued | 2012-11 | |
dc.description.abstract | The production and reproduction records on 228 Gir cows with 680 lactations sired by 52 bulls, maintained at Cattle Breeding Farm, Junagadh Agricultural University, Junagadh, for 24 years (1987 - 2010) were studied. The data were analyzed to study the effect of period of calving, season of calving and parity as fixed effect and effect of sire as random effect on the production traits viz., lactation milk yield, 300-days milk yield, peak milk yield, lactation length and dry period, and reproduction traits viz., calving interval and age at first calving. Least squares means for production traits viz., lactation niilk yield, 300-days milk yield, peak milk yield, lactation length and dry period were 2276.60 ± 171.32 kg., 2115.89 ± 129.81 kg., 12.31 ± 0.51 kg., 328.27 ± 12.99 days and 109.81 ± 20.20 days, respectively. Least squares means for reproduction traits viz., calving interval and age at first calving were 456.36 ± 22.06 days and 1568.08 ± 39.82 days respectively. . I JLi|-LJLJi Ji.Ljt The analysis of variance revealed highly significant effect of period of calving on lactation milk yield, 300-days milk yield, peak milk yield, lactation length, dry period and age at first calving. While non-significant effect was observed for calving interval. Season of calving did not affect significantly to all these traits under study, except dry period and animals calving during July- October had shorter dry period as compared to those calving in other seasons. Parity of calving highly significantly affected lactation milk yield, 300-days milk yield, peak milk yield, lactation length, dry period and calving interval and significantly affected age at first calving. Lactation milk yield, 300-days milk yield, peak milk yield, lactation length, dry period and age at first calving had periodic trend. Lactation milk yield, 300-days milk yield and peak milk yield showed a significant drop during 1995-2002 and thereafter showed an increasing trend during 2003 - 2010. The Average lactation milk yield was rise to 2667.02 kg during 2007-10. Age at first calving had increasing periodic trend over the years rising from 1268.33 to 1787.96 days. Appropriate measures should be taken to improve the trait. Lactation milk yield, 300 days milk yield, peak milk yield, lactation length dry period and calving interval are affected by parity. There was significant drop in the lactation milk yield, 300-days milk yield, peak milk yield, lactation length and dry period after eighth parity. High heritability estimates for age at first calving (0.59 ± 0-07) and moderate heritability estimate for lactation milk yield (0.17 ± 0.04) and 300-days milk yield (0.20 ± 0.05) were obtained in present study, indicated more importance of additive genetic variance in phenotypic manifestation of these traits. The lower heritability estimates for rest of the traits viz., peak milk yield (0.11 ± 0.04), lactation length (0.04 ± 0.03), dry period (0.12 ± 0.04) and calving interval (0.06 ± 0.03) were observed in present study. The repeatability estimates for lactation milk yield, 300- days milk yield, peak milk yield, lactation length, dry period and calving interval were found to be 0.45 ± 0.04, 0.38 ± 0.04, 0.21 ± 0.04, 0.37 ± 0.04, 0.32 ± 0.04 and 0.23 ± 0.04 respectively. Highly significant (P<0.01) phenotypic correlations were observed between lactation milk yield and 300 days milk yield, peak milk yield, lactation length which were 0.901 ± 0.015, 0.684 ± 0.095 and 0.74 ± 0.137 respectively. Phenotypic correlations between lactation milk yield and age at first calving, calving interval and dry period were 0.158 i 0.179, 0.338 i 0.283 and -0.155 ± 0.223, respectively, which were non significant (P>0.05). Phenotypic correlations of 300 days milk yield with peak rnilk yield and lactation length were 0.808 ± 0.066 and 0.456 ± 0.209, respectively, which were highly significant (P<0.01). Phenotypic correlations between 300 days milk yield and dry period, cadving interval and age at first calving were nonsignificant (P>0.05) and were -0.183 ± 0.217, 0.171 ± 0.269 and 0.114 ± 0.178, respectively. Phenotypic correlations of peak milk yield with lactation length, calving interval, dry period and age at first calving were non-significant (P>0.05) and were 0.225 ± 0.295, 0.079 ± 0.309, -0.147 ± 0.255 and 0.104 ± 0.200, respectively. Phenotypic correlations between lactation length and dry period, calving interval and age at first calving were non-significant (P>0.05) and were -0.065 ± 0.346, 0.501 ± 0.432 and 0.191 ± 0.234, respectively. Phenotypic correlations of dry period with calving interval was highly significant (P<0.01) and was 0.520 ± 0.178. Phenotypic correlations of dry period with age at first calving was 0.021 ± 0.195, which was non-significant (P>0.05). Genetic correlations of lactation milk yield vj^ith 300 days milk yield, peak milk yield and lactation length were 0.985 ± 0.015, 0.813 ± 0.095 and 0.839 ± 0.137, respectively, which were highly significant (P<0.01). Genetic correlations of lactation milk yield with dry period, calving interval and age at first calving were non-significant (P>0.05) and were -0.454 ± 0.223, - 0.003 ± 0.283 and 0.144 ± 0.179, respectively. Genetic correlations between 300 days milk yield and lactation length and peak milk yield were 0.744 ± 0.209 and 0.868 + 0.066, respectively, which were highly significant (P<0.01). Genetic correlations between 300 days milk yield and calving interval, dry period and age at first calving were non significant (P>0.05) and were -0.100 ± 0.269, -0.472 ± 0.217 and 0.006 ± 0.178, respectively. Genetic correlation of peak milk yield with lactation length was 0.606 ± 0.295, which was highly significant (P<0.01). Genetic correlation of peak milk yield with age at first calving, dry period and calving interval were non-significant (P>0.05) and were 0.069 ± 0.200, -0.382 ± 0.255 and -0.009 ± 0.309, respectively. Genetic correlation between lactation length and dry period, calving interval and age at first calving were -0.518 + 0.346, 0.016 ± 0.432 and 0.752 + 0.234, respectively, which were non-significant (P>0.05). Genetic correlation of dry period with calving interval was 0.712 ± 0.178, which was highly significant (P<0.01). Genetic correlation of dry period with age at first calving was 0.058 ± 0.195, which was non-significant (P>0.05). Environmental correlation of lactation milk yield with 300 days milk yield, peak milk yield, lactation length, dry period, age at first calving and calving interval were 0.795 ± 0.015, 0.606 ± | en_US |
dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810095452 | |
dc.language.iso | en | en_US |
dc.publisher | JAU,JUNAGADH | en_US |
dc.sub | Animal Genetics and Breeding | en_US |
dc.theme | GENETIC ANALYSIS OF PRODUCTION TRAITS IN GIR CATTLE 1673 | en_US |
dc.these.type | M.V.Sc. | |
dc.title | GENETIC ANALYSIS OF PRODUCTION TRAITS IN GIR CATTLE 1673 | en_US |
dc.type | Thesis | en_US |
Files
Original bundle
1 - 1 of 1
Loading...
- Name:
- 1673.pdf
- Size:
- 26.57 MB
- Format:
- Adobe Portable Document Format
- Description:
- GENETIC ANALYSIS OF PRODUCTION TRAITS IN GIR CATTLE 1673