Abstract
Sow lifetime performance can be predicted by sow performance at an early age; however, few studies have examined the relationship between farrowing age (FA) after parity 1 and sow lifetime performance. Therefore, our objective was to examine the association between FA in different parities and sow lifetime performance. Data were extracted from 198,043 sows entered into 155 Spanish herds between 2011 - 2013 and removed between 2011 - 2016. The 1st to 99th percentiles of FA records were analyzed, with FA defined as the number of days from birth to the farrowing date in each parity. A two-level linear mixed-effects model was applied to examine the relationship between FA and lifetime performance of sows (SAS University Edition). Means of FA + SD (range) in parities 1 and 3 were 368.4 + 34.8 (238 - 460) days and 663.5 + 41.4 (501 - 773) days, respectively. The ranges of FA in parity 1 and 3 were 238 - 460 days and 501 - 773 days, respectively. Lifetime performance decreased with higher FA in both parities. For example, in parity 1, as FA increased from 290 to 410 days, lifetime piglets born alive (PBA) decreased by 4.4 piglets, annualized lifetime PBA decreased by 3.5 piglets and nonproductive days increased by 16.8 days. Similarly, in parity 3, as FA increased from 590 to 710 days, lifetime PBA decreased by 5.3 piglets, annualized lifetime PBA decreased by 3.0 piglets and nonproductive days increased by 39.5 days. Also, sows with a lower FA in parity 1 had fewer PBA in that parity than sow with a higher FA (P < 0.05). However, they also had fewer nonproductive days and a shorter weaning-to-first-mating interval and more annualized lifetime PBA. Therefore, these data indicate that FA can be used to predict lifetime performance of the sows.
A multiphase non-linear mixed effects model: An application to spirometry after lung transplantation
