A model for economic comparison of swine insemination programs

Optimal artificial insemination schedules are those that result in a high f arrowing rate and litter size, while minimizing costs of semen and labor by avoiding unnecessary inseminations. A simulation model programmed in a com mercial spreadsheet was developed to permit comparison of alternative sched ules. Farrowing rate and litter size for a particular schedule were depende nt on the timing of insemination relative to the time of ovulation. Economi c return was calculated by multiplying the number of pigs born per bred sow by $33.00 and subtracting the cost of producing a litter of pigs and raisi ng them to weaning ($222.88 per sow plus $2.44 per pig born) and the cost o f detection of estrus and breeding. Seven insemination schedules combined w ith once versus twice per day detection of estrus were simulated in 500 her ds of 100 sows each. Inseminations were simulated to occur on schedules of: 1) 0, 12, 24 and 36 h; 2) 12, 24 and 36 h; 3) 0 and 24 h; 4) 12 and 36 h; 5) 12 h; 6) 24 h; and 7) 36 h after first detection of estrus. Schedule 1 w as predicted to yield the highest farrowing rate and litter size. Economic return was highest for Schedule 2 with twice per day detection of estrus fo llowed closely by Schedule 1 with once per day detection of estrus at $14.9 0 and $13.75 per bred sow, respectively. High performance was dependent on insuring that inseminations occurred at an optimum time in as great a propo rtion of sows as possible. (C) 2000 by Elsevier Science Inc.