摘要Background This study investigated the potential impacts of increasing linoleic and α-linolenic acid intake dur-ing lactation and wean-to-breeding on subsequent reproduction of sows.A total of 309 sows(PIC Camborough L42)were balanced by parity(140 and 169 sows representing parity 1 to 2[P1-2]and 3 to 9[P3+],respectively)and assigned within parity to a 2×2 factorial arrangement.Factors included essential fatty acid(EFA)supplementation(control diets containing 1.2％ linoleic and 0.15％ α-linolenic acid or diets with 3.0％ linoleic and 0.38％ α-linolenic acid)and supplementation period(lactation or wean-to-breeding).Tallow(low EFA diets)or soybean oil(high EFA diets)were included at 4％ in sorghum-soybean meal-wheat middlings-based diets to attain targeted EFA levels.Results High levels of EFA fed during lactation had no effect on feed intake or litter performance,but increased subsequent farrowing rate(P=0.027;82.1％vs.70.4％),tended to reduce the proportion of sows removed(P=0.070;12.4％vs.20.8％),decreased the number of total pigs born in the following litter(P=0.072;15.3 vs.16.2),and increased total pigs born alive per 100 sows weaned(P=0.062;1,122 vs.974),regardless of sow parity.Young sows(P1-2)consuming the high EFA diet during lactation displayed a shorter wean-to-estrus interval(P=0.035;4.2 vs.4.6),but P3+sows were unaffected.Increasing EFA intake for P3+sows,but not P1-2 sows,resulted in more sows bred by d 5(P=0.028;91.1％vs.81.7％)and more mummies in the subsequent litter(P=0.040;0.32 vs.0.16).Feeding increased EFA to P1-2 sows during the wean-to-breeding period decreased subsequent farrowing rate(P=0.042;72.0％vs.87.7％),and increased removal rate(P=0.003;28.8％vs.9.4％).Total pigs born alive per 100 sows weaned was reduced(P=0.007)in P1-2 sows when supplemented with EFA during wean-breeding(939 vs.1,149)but was not impacted in P3+sows(1,131 vs.982).Conclusions Supplemental EFA in lactation diets benefited subsequent reproduction of sows,regardless of parity.Increasing dietary levels of EFA during the wean-to-breeding period to younger sows negatively impacted subse-quent reproduction.