Effects of Genetic and Non-Genetic Factors on First Lactation Traits and Replacement Rate and its Components in Crossbred Cattle

The present study was undertaken on 2,204 calvings of 390 crossbred cattle produced by 54 sires over 36 years. The FLTs showed that the notion due to sires were significant for AFC, FLMY-305, FLMY, FLL and FSP. The effects due to the period of calving were found significant for FLL and FSP. The effect due to the season of calving was found significant on FLMY-305. The effect due to the AFC was found highly significant (P ≤ 0.01) for FLMY. The period notion on replacement rate and its parts viz., mortality, culling and replacement rate was found to be significant. The season of birth had significant effects on abnormal birth and replacement rate. About half (45.18percent) of total female calves were thrown off from the herd till they achieve AFC due to mortality and culling. Only 25.27 percent of the total pregnancies got into replacement heifers. It may be concluded that the performance of the crossbred herd understudy is comparable to other herds maintained elsewhere. Low to moderate heritability estimates obtained indicated the presence of adequate genetic variation within the herd and hence improvement in traits under study is possible by genetic selection along with managemental interventions.