Estimation of ‘relative economic value’ and ‘genetic cost of restriction’ in broiler

C.P.Malik, Didar Singh, Z.S. Malik and D.S. Dalal
Department of Animal Breeding, CCS Haryana Agricultural University
Hisar-125004 (Haryana)

Observations on 1663 progeny produced from 40 sires of broiler dam line were used for this study. The traits recorded were 5 /-nucleotidase (5 /-N), intestinal alkaline phosphatase (IAP) and glutamate pyruvate transaminase (GPT) enzymes at 6 weeks of age and body weight at 6 weeks of age (BW6) and at 20 weeks of age (BW20), age at first egg (AFE), egg production upto 40 weeks of age (EP40) and egg weight at 32 weeks of age (EW32). The traits included in aggregate genotype were BW6, BW20, AFE, EP40 and EW32. The relative economic value (REV) was estimated as per the method given by Hogsett and Nordskog (1958). Arbitrarily three more sets of REV were also derived as the efficiency of index does not suffer much from relatively large errors in economic values (Pease et al., 1967; Cunningham et al., 1970 etc.). The selection indices combining seven traits (excluding GPT) were constructed using four different sets of REV and gain in aggregate genotype, accuracy of index (R IH), genetic cost of restriction (GCR) of each trait, heritability of index and gain in individual traits were computed assuming selection intensity as 1.40. On the basis of genetic gain in individual trait, the set of REV with values 2.40, 0.21, -0.98, 1.00 and –0.16 for BW6, BW20, AFE, EP40 and EW32, respectively, were found satisfactory. The GCR was 32.38, 21.31, 8.13, 2.91, 1.69, 0.79 and 0.47 per cent for BW6, IAP, BW20, EP40, 5 /-N, EW32 and AFE, respectively and R IH and heritability of index was 0.893 and 0.888, respectively for this set of REV. It was concluded that the traits with higher GCR must be included in selection index.

Source : IPSACON-2005

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