Abstract
An investigation was conducted on 729 Hariana cows maintained at Government Livestock Farm, Hisar, from 1973 to 1999, with an objective to compare the efficiency of various selection indices for attaining desired genetic gains in the index traits. The various traits included were age at first calving (AFC), service period (SP), calving interval (CI), days to first service (DFS), number of services per conception (NSPC), lactation milk yield (LY), peak yield (PY), dry period (DP). Except for LY, PY and AFC the heritabilities of all other traits were low. Desirable associations among reproductive traits are supportive of the fact that any one of these traits incorporated in simultaneous selection is expected to cause correlated response in other traits. Production traits (LY and PY) were positively correlated, while DP had low negative genetic correlation with LY, and high genetic correlation with PY. Thus, DP can be taken as additional criteria in selection index for better over all improvement. Almost all production traits except DP had low negative correlation with AFC, SP, DFS and CI meaning that reduction in reproduction traits up to certain level may increase production performance. While, the correlation of NSPC with LY and PY was moderate positive. Among four trait indices I23: incorporating PY, AFC, SP and NSPC and among three trait indices I1: incorporating LY, AFC and SP were the best as these required least number of generations (4.87 and 1.35, respectively) to attain desired goals. Next in order of preference were PY or LY along with DP and SP as the best indices (I20 and I16) of which, index with PY may be preferred instead of LY as it produced considerably high correlated response in LY and reduction in NSPC as well. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 6 : 789-793)
Highlights
Several steps are involved in the process of designing an efficient breeding programme
For any dynamic breeding programme it is necessary to know about the changes occurring in a given population over the years to assess its efficiency in order to suggest appropriate breeding strategies to maximize genetic gain
Emphasis in most dairy cattle breeding programmes is on increasing milk production
Summary
Several steps are involved in the process of designing an efficient breeding programme. The efficiency of production of dairy cattle depends upon optimum combination of reproduction and production traits. This can be possible through multi trait selection indices based on early expressed traits. The relative economic value of component traits in aggregate genotype is the basic requirement of selection index. A selection index for attaining pre-determined desired genetic gain which does not require. Suggested a selection index, which attains pre-determined breeding goals in a minimum number of generations of selection. A practical advantage of this type of index is that the number of generations required to attain the desired goals can be estimated. The present investigation was carried out to suggest an appropriate selection index for desired gain in reproduction and production traits
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