Sire evaluation and selection of Indian dromedary females for milk production: issues and strategies

Abstract

Sire evaluation through estimation of breeding value was done for seven dromedary sires utilising 74 lactation records spanning over last five years. The average daily milk production (Mean ± SEM) from two-teat was 3.13±0.15 litres and 300 days’ yield was 905.18±46.3 litres. The effect of breed on daily milk production and 300 days’ yield was non-significant (P>0.05) but the effect of parity was significant (P<0.05) with highest production in third parity (3.54±0.24 litres). The effect of year was also highly significant with highest average daily production in the year 2008 (4.02±0.28 litres). The unadjusted two-teat average daily milk yield and the 300 days’ milk yield was utilised for the estimation of random effect due to sire and fixed effects due to parity and year after deleting records of progeny with unknown sires. The breeding values for sires used ranged from 2.88±0.25 to 3.42±0.23 litres for daily milk yield and 828.78±72.00 to 975.93±67.13 litres for 300 days’ yield. Though, the mean ± 1 standard deviation (S.D.) encompassed the entire range of the breeding values of all the sires evaluated, still the top ranking sires or their progeny may be preferred over others in breeding. The repeatability of average daily milk yield and 300 days ‘yield was estimated to be 0.40 and 0.39 respectively, indicating the potential use of present performance as an indicator of future performance. In order to rank the females, the production data was adjusted for the significant effects of parity and year. The overall mean ± standard deviation for the two-teat average daily yield was 3.18 ± 0.70 litres and that for 300 days’ yield was 922.9 ± 211.2 litres. The animals below mean – 1 S.D. may be culled and the animals above mean + 1 S.D. may be utilised for the production of more number of progeny over a period of time utilising advanced reproductive techniques. With the reduction in cost of thorough put sequencing, appropriate phenotype measurement coupled with selection of diverse animals may help us in identifying associated markers of high genetic merit for subsequent utilisation in the breeding programme.