| dc.description.abstract |
The economic value of a genetic difference between rams was estimated for stud and commercial tiers in the Australian Merino industry. Discounted returns were predicted using the method of Hill (1974). Results were generated for breeding schemes considering natural mating (Scheme A), artificial insemination (Scheme B), the use of home-bred sires at daughter stud level (Scheme C) and the use of culled stud ewes in lower tiers (Scheme D). The effects of discount rate and ram flock life were assessed. The value of one extra unit of genetic merit in three traits (Clean Fleece Weight, Fibre Diameter and WOOLPLAN index score) was found for commercial, daughter and parent tiers. One extra kilogram of clean fleece weight (CFW) was worth around $817 for a commercial level ram (all Schemes) and up to $390000 for a parent level ram in Scheme B. The same improvement was worth $4 per semen dose used at commercial level, and up to $3977 at parent stud level (Scheme B). Increasing the discount rate devalued later returns, reducing the number of discounted expressions. Increasing ram flock life increased ram value but reduced semen value. The results are discussed for current industry practice and values obtained previously for commercial rams. The economic value of multiple ovulation and embryo transfer is considered. |
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