Recent Advances in Sire Evaluation Methods: A Review

This review deals with the various traditional and recent methods of sire evaluation. A sire evaluation is a method of prediction of sire’s next-generation produced by breeding with specified females and creating their records in a specific environment. Breeding worth of progeny tested sires are obtained through sire index method that assigns ranking to each sire based on their genetic merit. Numerous sire indices are broadly classified in two type’s viz., indices which are purely meant for ranking purposes and those which, besides, provide an estimate of the breeding worth of each sire. Sires can be evaluated in single or multiple herds. The statistical equations represent sire evaluation as linear or non-linear methods. Numerous methods can be incorporated as the advances are made in sire evaluation based on data structures, breeding approaches and selection methods. There are various approaches of sire evaluation such as Least Squares Method (LSM), Simple Regressed Least Squares (SRLS), Best Linear Unbiased Prediction (BLUP) and Derivative-Free Restricted Maximum Likelihood (DFREML) for single as well as multiple trait models which can be used to derive genetic worth of an individual. An efficient method of sire evaluation shows minimum within sire variance or error variance.

Sire Evaluation Based on First Lactation 305 Day Milk Yield and Individual Part Lactation Records in Frieswal Cattle

Background: Frieswal, the crossbred cattle, between sahiwal and Holstein Friesian breed with 62.50 per cent of exotic (inheritance) with total lactation milk yield of (4000 Kg) with average lactation length 300 days (PDC Annual Report, 2015-16). Presently, the Frieswal Animal is mainly maintained at 36 Military Farms located in various agro-climatic regions in the country.Methods: The present study was undertaken on first lactation 305 days and part lactation records of 1470 Frieswal cows maintained over a period of 10 years (2003-2012) from military farm at CIRC Meerut Uttar Pradesh as well as Ambala. The success of any breed improvement programme depends mainly on the Sire evaluation which involves the estimation of expected breeding value of the bulls on the basis of average first lactation 305-day or less milk yield and part lactation records of their daughters (FL305DMY).Result: The estimate breeding value of 55 Frieswal sires on the basis of first lactation 305-day or less milk yield and individually part lactation records, by LSM, BLUP and DFREML methods were 2701.48 kg and 2660.70 kg, followed by 333.40, kg and 329.17 kg, respectively. A number of 55 Frieswal sires with three or more daughters were evaluated and ranked on the basis of first lactation 305-day milk yield and individual third month part lactation was having better heritability and comparatively higher genetic correlations with the first lactation 305-days or less milk yield.

Comparative efficiency of different multiple linear regression prediction equations of first lactation 305-day milk yield for sire evaluation in Murrah buffaloes

In this study, first lactation 39059 weekly test-day milk yield records of 961 Murrah buffaloes were used to predict first lactation 305-day milk yield (FL305DMY) by stepwise backward regression method. The best single, two, three and four test day combinations were selected for prediction of FL305DMY based on adjusted R2 and RMSE values. The sires were evaluated for 305-day actual and predicted first lactation milk yield based on derived multiple regression equations using four methods viz. least squares (LSQ), simple regressed least squares (SRLS), best linear unbiased prediction sire model (BLUP-SM) and best linear unbiased prediction animal model (BLUP-AM) methods. The effectiveness of different sire evaluation methods were judged by error variance, coefficient of determination, coefficient of variation and spearman’s rank correlation. The accuracy of prediction of FL305DMY from weekly test day milk yields were observed to be best for TD-7 (48th day) and TD-22 (153rd day) combination with BLUP-AM as the most efficient method for sire evaluation. It was concluded that the FL305DMY can be predicted as early as 153rd day of lactation and further can be used for early genetic evaluation of Murrah sires.