Body weight at birth of dams and their calves as a basis for heifer selection 2nd Paper:Improvement of days open and number of times serviced per conception
1996
Amin, A.A. | Gere, T. (Godolloi Agrartudomanyi Egyetem, Gyongyos (Hungary). Mezogazdasagi Foiskolai Kar)
Days open (DO), number of times serviced per conception (NOS) and birth weight of dams and their heifers (BW1, BW2) were used as variables in heifer selection subindices. 3225 complete lactation records of 812 cows were involved in the construction of dam-heifer selection subindices (I1: all four traits were included, I2: only BW1, BW2 and DO, and I3: only BW1, BW2 and NOS). Cows were progeny of 185 sires. Number of cows per sire ranged from 4 to 5. Variance and covariance estimates, as well as fixed random effects, were estimated using the mixed model of Maximum Likelihood Procedures. The selection subindices and traits were estimated according to their effect on genetic gain. Relative efficiency of I2 and I3 to I1 were 84.18 percent and 84.27 percent in selection for DO, respectively, and 163.84 percent and 77.84 percent in selection for NOS in the same order. The best subindices for DO and NOS improvement were I1 and I2. The expected genetic gain in NOS and DO per generation was low and ranged between 0.89 to 0.95 services and 7.81 to 9.28 days, respectively
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