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Replacement and Lifetime Production Traits: Effect of Non-genetic Factors and Sire Evaluation |
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S. Singh, A. S. Khanna, R. P. Singh |
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| Abstract |
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The present investigation was undertaken to study the effects of non-genetic factors and association among replacement and lifetime production traits. The data on 542 Holstein Friesian cows maintained during 1975-98 at State Cattle Breeding Project, Sector III, Hisar, were utilized. The average sex-ratio, abnormal births, mortality, culling and replacement rates on total calf born and total female calf born basis were 51.62, 8.50, 17.52, 31.05, 22.78 and 51.41 per cent, respectively. The study revealed that a minimum of 4 to 5 progenies are required per cow over its lifetime to replace itself. It indicated that each cow should produce a minimum of 2 female calves during its life so as to replace herself before being lost. The least-squares means for productive herd life, longevity and lifetime production were 1439.32 87.64 and 2419.18 8.25 days and 11317.95 913.15 kg, respectively. The heritability estimates for all replacement traits were very low indicating that sire selection may bring no desirable change in these traits. Heritability estimates were 0.178 0.157, 0.288 0.184 and 0.096 0.195 for corresponding lifetime production traits. Breeding values and ranking of sires were generated for replacement and lifetime production traits to estimate the rank correlations between these traits. Moderate desirable rank correlations were obtained between replacement rate and lifetime production traits indicating that sires proven on the basis of milk production are also expected to have better replacement rate. |
| Keywords:
Dietary Xylitol; Nitrogen Retention; Immunological Stimulation; Broiler Chicks |
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