Integrated systems analysis of sow replacement rates in a hierarchical swine breeding structure

摘要: Sow replacement rates in a three-tiered breeding structure were investigated for 10-yr planning horizon using stochastic life-cycle swine production model. Market hogs produced three-breed static crossing program and marketed on liveweight basis. Growth reproductive traits of individual pigs simulated genetic, environmental, economic parameters. Sows culled after maximum 1, 5, or 10 parities. Systems defined by sow age at culling included combinations 1- 5-parity nucleus 1-, 5-, 10-parity multiplier commercial tiers. Economic response to index selection was considerable all alternatives with yearly increases system profits ranging from $1.06 1.44 each hog marketed. When sows one parity nucleus, multiplier, tiers, respectively (1,1,1), annual changes net returns cost measures 40 50% larger than responses systems lower rates. Based averages returns, low multiplier- commercial-level more profitable higher The most (5,10,10) differed the least (1,1,1) $10 per pig, but when excluded, range only $3 pig. lowest supported 3,388 34,151 750-sow level system. Output two extremes > 664,000 market sold.(ABSTRACT TRUNCATED AT 250 WORDS)