Nurse Sows’ Reproductive Performance in Different Parities and Lifetime Productivity in Spain

Our objective was to characterize use of nurse sows in Spanish breeding herds. We analyzed 466 111 parity records and lifetime records of 92 716 sows farrowed between 2011 and 2017 in 69 herds having nurse records. Nurse sows were defined as sows that had weaned 2 or 3 litters in the same lactation period. Mixed-effects models were applied to the data to compare reproductive performance and lifetime productivity between nurse and non-nurse sows. Of all the sows, 6 705 (7.2%) sows served as nurse sows at least once in their lifetime, with 10.2% of the nurse sows having a second nurse event in a later parity. Mean values (SE) of lactation length and number of piglets weaned were 31.0 (0.11) days and 21.9 (0.04) piglets in nurse sows, respectively. Across parities 2-6, nurse sows had 1.9-3.0% greater proportions of weaning-to-first-mating interval 7-20 days than non-nurse sows (P < 0.05). There was no difference between nurse sows and non-nurse sows in farrowing rate in any parity (P ≥ 0.13) and piglets born alive in parities 1-5 (P ≥ 0.15). Also, nurse sows had 3.7-7.4 more annualized lifetime piglets weaned than non-nurse sows (P < 0.01), because nurse sows had similar lifetime non-productive days with non-nurse sows (P ≥ 0.07), but produced 9.3-12.0 more lifetime piglets weaned than non-nurse sows (P < 0.01). Using nurse sows could be a good practice to cope with highly prolific sows.