Management factors affecting the growth of pigs and the impact of pig removal strategies at market on growth performance and production efficiencies.

摘要

Experiments were conducted to evaluate effects of management factors impacting growth performance before and after the heaviest pigs were removed from a pen and implications for optimizing pig removal strategies at market. Results of the first study indicated that double stocking pigs for 8 wk post weaning reduced growth performance (P 0.001), but in the subsequent period, the pigs that were previously double stocked grew faster (P 0.05) resulting in similar BW at slaughter. These results were confirmed in two later studies which demonstrated that pigs exhibiting a decreased growth rate due to restricted floor- and feeder-space allowance had similar (P > 0.05) ADG and higher (P 0.01) G:F in the subsequent period after pig removal. In addition, while previous group size had little effect on subsequent growth performance, pigs previously housed at low floor-space allowances had a greater change in ADG (9.2%) and ADFI (4.6%) and had less of a reduction in G:F (5.5%) from before to after pig removal than pigs with high floor-space allowance. Two additional studies determined that as the proportion of pigs removed from a pen increased, growth rate increased linearly (P 0.01) while the total feed consumed during the study decreased linearly. Two later studies evaluated the timing of pig removal and found that removing pigs at wk 18 compared to wk 20 post-weaning improved (P 0.001) the growth rate of the remaining pigs and resulted in a lower (P 0.01) variation in BW of all pigs marketed. The last study evaluated the independent effects of increased floor space, increased feeder space and removing pigs from pens on the subsequent performance of finishing pigs. Results show that the single greatest independent factor responsible for the increased growth rate of pigs after pig removal is the increase in floor space. In conclusion, results from these studies show that previous space allowance, the proportion of pigs removed from a pen and the frequency of pig removal affects pig performance, total feed consumption, total live weight produced, and BW variation at market.