Rearing in female-only groups and dietary mineral supplementation improves sow welfare in the early parities and lifetime performance

Abstract

The lifetime performance of commercial sows relies on longevity, which is dependent on good health and reproductive performance. However there is a high rate of wastage of sows in the early parities which is influenced by the way they are managed and housed during rearing. This study investigated the carry-over effect of gilt rearing strategy on measures of welfare and performance. Eighty sows were reared using a 2 × 2 factorial design; rearing group composition (GC; female only (FEM) or mixed sex (MIX) from weaning) , with or without supplementary minerals (MIN; CON = control diet; SUPP= control + Cu, Zn and Mn) from five weeks into the finisher stage . Once served, gilts were managed in a dynamic group gestation pen and fed a standard gestating sow diet. Locomotory ability was scored (0-5) and salivary cortisol measured 5 times during the 1 st gestation, and human approach tests carried out at d108. Hooves were scored for injuries and legs for bursas at d70 of the 1 st gestation, at 1 st weaning, and at the 2 nd farrowing. Sow behavior in the hoof scoring crate (movement, vocalization, handling ease) was also recorded. The numbers of piglets born alive and dead during the first 5 parities was recorded, as was the performance of the first litter to finish. Data were analyzed using general or generalized linear mixed models, as appropriate, using SAS (v 9.4). There was no effect (P > 0.05) of rearing treatment on locomotory ability, bursa score, the total number of piglets born or on offspring growth. However, there was an interaction between GC and MIN (P < 0.05) on salivary cortisol levels with MIX × SUPP sows having the highest levels. Total hoof scores and heel erosion scores were higher in sows reared in MIX groups (P < 0.01), and CON sows tended to have higher horizontal crack scores (P=0.06). Sows from MIX kicked more at weaning than FEM (P <0.05) and tended to be more fearful in the forced human approach (FHA) test (P = 0.1) where they are scored on their reaction to being approached. They also had more stillborn piglets across all 5 parities than FEM (P < 0.05). Overall, rearing replacement sows in FEM groups and dietary mineral supplementation had minimal but beneficial effects on their subsequent welfare and performance.

Early Detection of Locomotion Disorders in Gilts Using a Novel Visual Analogue Scale; Associations with Chronic Stress and Reproduction

“…Moreover, perhaps this could explain the positive association between locomotion scores at service and the numbers of piglets born dead, and the trend for a higher number of piglets mummified with increasing overall locomotion score. This finding is in line with Hartnett et al [52]; in that study, replacement gilts reared alongside males had impaired leg health in terms of higher hoof lesion scores. These gilts went on to have higher numbers of piglets born dead over their first five parities, which the authors hypothesised was due to the elevated stress levels associated with impaired leg health [52].…”

“…This finding is in line with Hartnett et al [52]; in that study, replacement gilts reared alongside males had impaired leg health in terms of higher hoof lesion scores. These gilts went on to have higher numbers of piglets born dead over their first five parities, which the authors hypothesised was due to the elevated stress levels associated with impaired leg health [52]. Our finding is also in line with Pluym et al [53], who found higher numbers of born dead and mummified piglets with an increasing incidence of claw lesions and wall cracks.…”

Indicators of improved gestation housing of sows. Part II: Effects on physiological measures, reproductive performance and health of the offspring

“…In that study, sows infected with PRRSV gave birth to more mummified piglets (Lewis et al 2009 ). It is also in line with Hartnett et al ( 2020 ) who found fewer piglets born dead to sows reared in female-only groups as gilts. These sows also had lower salivary cortisol concentration, indicating lower stress levels resulting from a more optimal rearing environment, with carry-over benefits for their future performance (Hartnett et al 2020 ).…”

“…It is also in line with Hartnett et al ( 2020 ) who found fewer piglets born dead to sows reared in female-only groups as gilts. These sows also had lower salivary cortisol concentration, indicating lower stress levels resulting from a more optimal rearing environment, with carry-over benefits for their future performance (Hartnett et al 2020 ). It is likely that healthy, less-stressed sows redirect fewer energy and metabolic resources away from developmental and maintenance processes such as pregnancy, towards processes aimed at ensuring survival, e.g.…”

Animal welfare research – progress to date and future prospects

“…More recent work by Hartnett et al (2019Hartnett et al ( , 2020a confirmed that integrating supplementary minerals into maternal line gilt diets improved joint health (i.e. less cartilage damage), reduced claw lesion severity and improved production performance throughout life (Hartnett et al, 2020b). Hartnett et al (2020a) showed that keeping replacement gilts in all-female groups from weaning was likely responsible for the benefits described above, as gilts were exposed to less sexual and aggressive behaviour performed by the males.…”