224 Average Daily Feed Intake in Previous Lactations is Associated with Subsequent Reproductive Performance in Sows

The objective of this study was to investigate the influence of average daily feed intake (ADFI) in previous lactations on subsequent reproductive performance in multiparous sows. Data for this study were collected from 2017 to 2022 at Grangenia, a 2,800 L03 PIC sows farrow-to-wean commercial multiplier from Grupo Kerbest and integrated with Grupo UVESA. The farm is located in Ávila, Spain. In total, data on ADFI during lactation and litter size traits were available for 10,425 sows. Born alive (BA), stillborn (SB) and mummified (MM) piglets were expressed both as total numbers and as percentage from total born (TB) piglets. Sow parity was classified as parity 2, 3, 4 and 5+. Data were analyzed using linear mixed models in R v4.1.2. For all traits, initial models included ADFI for the immediate previous parity as a linear and quadratic predictor. ADFI ranged from 1.3 to 9.6 kg/day. Linear mixed models revealed that ADFI in the previous lactation had a positive linear association (P < 0.001, Table 1) with all studied traits except with BA % and SB % where a quadratic association (P < 0.001) was also observed (quadratic slope = 0.018 ± 0.0044 and - 0.016 ± 0.0051, respectively). Results indicate that on average, sows in the lower ADFI limit would have 2.1 TB, 1.6 BA, 0.13 SB and 0.16 MM less when compared with sows in the upper ADFI limit across all parities. The BA % decreased and SB% increased when ADFI in the previous parity was between 4.5 and 6 kg across all parities. Under the conditions of this study, increasing ADFI in the previous lactation improved subsequent reproductive performance across all parities. It is likely that this effect was at least partly mediated through the greater number of follicles with optimal preovulatory size, luteinizing hormone secretion, ovulation rates, and embryo mortality, although this requires further investigation. A limitation of this study was that it was not possible to elucidate if the observed effect of ADFI in the previous parity was mediated through greater amino acid and/or energy intake due to the observational nature of this study. Nonetheless, our results highlight the importance of optimal sow nutritional management during the lactation period for improved lifetime reproductive performance.