Lifetime sow performance is a critical indicator for producers managing a commercial sow herd. It is comprised of sow longevity, lifetime piglets born alive, lifetime number of pigs weaned and lifetime non-productive sow days. Increased lifetime performance and longevity in sows reduces costs of replacement gilts and improves herd performance and profitability (Sasaki et al., 2008, 2011). One of the most critical factors driving the performance of sow herds is gilt management. Decisions regarding gilts have profound effects on sows’ lifetime performance. Age at first breeding of a gilt is a management decision that has been shown to affect performance and retention of the gilt in a herd.
The main aim of this review is to establish factors affecting age of first breeding of gilts and its impact on lifetime performance.
An observational retrospective study was done to provide up-to-date information on recent sow removal patterns from 9 breed-wean herds of Midwest USA. The study comprised of sow’s removal reasons and removal types of F1 Landrace x Yorkshire gilts entered in the herds between 1st Jan 2014 and 31st July 2016. Data was extracted from existing database on Dec 2018 and 15% of the sows were still active in the herds hence not included in the study. Descriptive statistics showed that out of the 20,009 removed sows, planned removals comprised of farrowing productivity (FP) 3,523 (17.6%) and old age (OA) 1,785 (8.9%) while unplanned removals consisted of reproductive failure (RF) 7,786 (38.9%), health problems (HP) 2,629 (13.1%), locomotion problems (LP) 1,473 (7.4%) and conformation issues (CI) 1,350 (6.8%).‘Did not conceive’ and “No heat” were observed as the main contributing factors accounting for 37.6% and 32.9% respectively for gilts & sows removed by RF.13.5% of the gilts (Parity 0) were removed from the herds before attaining their first litter of which 64.1% of their removals was due to RF. Removal type consisted of slaughter (S) 85.0%, found dead on the farm (DoF) 10.8% and euthanized (E) 4.2%. The research findings depict an upward trend of sow RF removals in the US swine herds posing a serious concern for US swine producers. Characterization and quantification of sow removals gives a revelation on the deeper intrigues about the vulnerability of the various parity in respect to common causes of RF. This helps swine producers to decisively improve on gilt replacement selection, reproductive efficiency, health and nutrition management all aimed at increasing overall swine productivity and efficiency in management. Swine farmers in the US can now focus their efforts towards curbing unnecessary RF removal within parity specifics.
Age at first breeding and lifetime reproductive performance was analyzed on 17,558 F1 Landrace x Yorkshire gilts from 9 piglet producing herds of Midwest, United States entered in herds between 1st Jan 2014 and 31st July 2016. At the time of data collection Dec 2018, 15% of the sows were still active in the herds hence excluded from the analysis. Individual gilt data included date of birth, age in days at first mating, piglet total born by parity, lifetime piglet total born and reason for culling. Quality data checks were done before analysis to eliminate all outlier values together with sows that had no entry information for any listed category. The total database of the sows was classified into 6 classes according to age at the first mating in days 170-190(n=754), 191-211(n=4683), 212-232(n=7123), 233-253(n=3385), 254-274(n=1002) and 275-369 (n=611). Piglet total born obtained from each sow during the lifetime production was significantly (P < 0.05) greater for gilts bred between 233-253 days of age at first mating. Gilts that were bred at <233 days appeared to have a higher risk of removal by farrowing productivity as compared to the other groups. However, the results show that the risk of being culled due to health problems and conformation issues increases as the age at first mating is delayed. Overall reproductive failure appears to be the most economical culling reason across all age groups. There is a need to evaluate the best management decisions for gilt initiation in a herd to maximize her lifetime performance. The results indicate that gilts mated for the first time at the right age, 233–253 days, are more productive, both in lifetime total born and have a minimal risk of culling due to farrowing productivity.