Feed intake pattern during lactation and subsequent reproductive performance of sows.

Daily feed intake during lactation was recorded for 20,296 lactating sows on 30 commercial farms in the United States. Each lactation feed record was categorized into one of six patterns: RAPID, rapid increase in feed intake; MAJOR, major drop; MINOR, minor drop; LLL, low feed intake throughout lactation; LHH, low intake during the 1st wk then an increase in feed intake for the remainder of lactation; and GRADUAL, gradual increase. A database containing 24,340 farrowing records and 19,015 subsequent litter records were abstracted from the PigCHAMP data files of the farms enrolled in the study. Multiple regression analyses revealed that ADFI during lactation had nonlinear or linear associations with weaning-to-first service interval (WSI), weaning-to-conception interval (WCI), litter weight at weaning (WWT), and subsequent litter size (SLS). Sows having LLL and LHH had longer (P < .01) WSI and WCI than the other patterns. Sows with MAJOR had a longer WCI (P < .05) than females with RAPID. Further, sows having MAJOR had lighter (P < .01) WWT than those with RAPID, MINOR, and GRADUAL. Sows having MAJOR had a higher (P < .01) proportion of females culled for anestrus relative to RAPID. Furthermore, sows exhibiting a drop in feed intake in either wk 1 or 2 were more likely to be culled for anestrus than sows having no drop. These results suggest that both the amount and pattern of feed intake during lactation influence subsequent reproductive performance.