Age adjustment factors for milk production in Hariana cattle
KrishiKosh
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Title |
Age adjustment factors for milk production in Hariana cattle
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Creator |
Navneet Kumar
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Contributor |
Malik, Z.S.
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Description |
The present investigation was carried out to study the effect of various non-genetic factors on production and reproduction traits and to develop age correction factors for milk production by additive correction factors (ACF) and multiplicative correction factors (MCF) methods in Hariana cattle. The study was further extended to compare the efficiency of ACF and MCF. The data on first to fifth lactation performance records of 589 Hariana cattle maintained at Germplasm Unit, CCS HAU, Hisar; Govt. Livestock Farm, Hisar; Kurukshetra Gaushala, Hisar; Gaushala Bhiwani and Gaushala, Jind over a period of 12 years from 1995-2006 were analyzed. The production traits -xxiv- vstudied were milk yield (MY), peak yield (PY), lactation length (LL) and dry period (DP) and reproduction traits under study were service period (SP) and calving interval (CI). The overall least squares means for MY, PY, LL, DP, SP and CI were 1069.82±8.89 kg, 5.65±0.08 kg, 251.34±2.53 days, 183.23±3.35 days, 153.22±3.43 days and 437.85±3.31 days, respectively. The herd effect was significant for all the traits studied. Period of calving significantly affected MY, PY, DP, SP and CI while effect of period of calving on LL was non-significant. Milk yield and PY were significantly affected by season of calving whereas, the effect of season of calving on LL, DP, SP and CI was non-significant. The ACF were ranging from -133.47 to 232.39 while the range of MCF was 0.81 to 1.15. The comparison of efficiency of ACF and MCF was based on F-value, means, coefficient of variation (CV), repeatability, R2-value and phenotypic correlation. On the basis of F-value, CV and phenotypic correlation of age at calving with uncorrected and milk yield corrected by ACF and MCF, both methods were equally efficient to correct milk yield for age at calving. Whereas, ACF retained constant least-squares means and it reduced R2-value to the maximum than MCF, so ACF was more effective than MCF. But on the basis of repeatability estimates, MCF was found more efficient than ACF. From these results, it may be concluded that both additive and multiplicative age correction factors were equally efficient for correcting milk yield for age at calving and hence either of these methods may be preferred in sire evaluation programme to obtain accurate estimates of sire’s breeding value. |
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Date |
2017-08-04T09:12:16Z
2017-08-04T09:12:16Z 2009 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/5810027445
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Language |
en
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Format |
application/pdf
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Publisher |
LUVAS
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