EFFECT OF PERFORMANCE RECORDING OF ANIMALS BY FARMERS THEMSELVES ON GENETIC EVALUATION OF SIRE OF HOLSTEIN FRIESIAN CROSSBRED CATTLE
Loading...
Date
2016
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
AAU, Anand
Abstract
Present study was conducted to study effect of performance recording of animals by farmers themselves on genetic evaluation of sire and comparison of various milk recording strategies for sire evaluation in Crossbred Holstein Friesian cattle. A total of 63,098 test day records of 7,419 daughters sired by 209 sires were collected from INAPH - MIS for three districts, viz., Sabarkantha, Panchmahal and Surat of Gujarat state. Additionally, information on 300 animals and owners/ milkers was collected from 82 villages under field progeny testing project for the same districts. Least square analysis was carried out to evaluate the factors having significant effect on error pattern while reporting performance of animals by farmers as compared to milk yield recorded by official milk recorder. The three factors, i.e., total no. of animals with farmer, possibility of milk recording at regular interval by farmer and possibility of milk recording twice a day at monthly interval by farmer were found significantly (P < 0.05) affecting the error pattern. Random Regression Model (RRM) was fitted on test day milk yield data for sire evaluation with HYMR (Herd * Year of milk recording * Month of milk recording) as random effect, HA (Herd * Age at first calving) and YS (Year of calving * Season of calving) as fixed effects, random regressions were fitted for additive genetic (AG) and permanent environment (PE) effects and fixed regressions was fitted for DIM (days in milk). Total five milk recording strategies were considered for sire evaluation, i.e., STl for existing milk recording strategy, ST2 for only morning milk recording strategy, ST3 for only evening milk recording strategy, ST4 for bimonthly milk recording strategy and ST5 for milk recording by farmer strategy. The average breeding values of sires for 305-day milk yield under STl, ST2, ST3, ST4 and ST5 were estimated to be 65.34 kg, 34.37 kg, 32.93 kg, 59.48 kg and 173.13 kg, respectively. The average reliability per cent of breeding values for STl, ST2, ST3, ST4 and ST5 were 37.10 %, 37.41 %, 36.83 %, 34.77 % and 36.42 %, respectively. Criteria for comparison of different milk recording strategies involved heritability 2 (h ) of test day milk yield. Log likelihood (LogL), Akaike information criterion (AIC), Bayesian information criterion (BIC), Percentage squared bias (PSB) and rank correlation coefficient. 2 The average estimates of h from 5-330 days in milk (DIM) for test day milk yield were 0.31, 0.32, 0.33, 0.30 and 0.16 for STl, ST2, ST3, ST4 and ST5, respectively. The LogL value for STl, ST2, ST3, ST4 and ST5 were -53772.63, -16178.10, -15097.60, -31925.81 and -101178.31, respectively. The values of AIC: BIC for STl, ST2, ST3, ST4 and ST5 were -53794.63: -53892.59, -16200.10: -16298.06, -15119.60: -15217.36, -31947.81: -32037.81 and -101200.31: -101297.63, respectively. The PSB values for STl, ST2, ST3, ST4 and ST5 were 0.7122 %, 0.7092 %, 0.7176 %, 0.6211 % and 10.45 %, respectively. The rank correlations of STl with ST2, ST3, ST4 and ST5 were 0.964, 0.961, 0.881 and 0.561, for top 50 sires with reliability greater than or equal to 70 %, respectively. ST5 had lower rank correlation with all other strategies. Based on the criteria for comparison of different milk recording strategies, it was observed that STl provided best fit for given data followed by ST2, while ST5 was unfit for sire evaluation. The existing standard test-interval milk recording strategy under PT project provided the best mean for sire evaluation, so it should be continued; as alternative strategies result to change around 4 % (by ST2 and ST3) in sire rankings (as per STl, for top 50 sires irrespective of R %). However, if standard test-interval milk recording strategy is not feasible, mainly on account of financial reasons, first alternate could be milk recording in morning only at monthly interval, ST2 (based on PSB of ST2 (0.7092) and sire rank correlation of ST2 with ST1(0.964) for top 50 sires with reliability greater than or equal to 70 %). Bimonthly milk recording strategy (ST4) was not found acceptable based on LogL (-31925.81), AIC (-31947.81) and BIC (-32037.81) values and sire rank correlation with STl (0.881), ST2 (0.841) and ST3 (0.845) for top 50 sires with reliability greater than or equal to 70 percent. Farmer milk recording strategy (ST5) is not at all recommended, as shown by poor sire rank correlation with STl (0.561), low h2 (0.16), PSB (10.45), LogL (-101178.31), AIC (-101200.31) and BIC (-101297.63) values.