Restricted feed intake in lactating primiparous sows. I. Effects on sow metabolic state and subsequent reproductive performance

Abstract

The effects of feed restriction (60% of anticipated feed intake; Restrict; n=60) during the last week of a 21-day lactation in primiparous sows compared with feeding at 90% of anticipated feed intake (Control; n=60) on sow metabolic state, litter growth and sow reproductive performance after weaning were compared. Metabolisable energy (ME) derived from feed was lower, ME derived from body tissues was higher and litter growth rate was reduced (all P<0.05) in Restrict sows during the last week of lactation. Treatment did not affect weaning-to-oestrus interval, pregnancy rate, ovulation rate, embryonic survival or the number of live embryos (P>0.05) at Day 30 of gestation: However, embryo weight was greater (P<0.05) in Control than in Restrict sows (1.55±0.04vs 1.44±0.04g, respectively). These data suggest the biology of the commercial sow has changed and reproductive performance of contemporary primiparous sows is increasingly resistant to the negative effects of lactational catabolism. Overall, catabolism negatively affected litter weaning weight and embryonic development of the next litter, but the extent to which individual sows used tissue mobilisation to support these litter outcomes was highly variable.

Impact of feed restriction on the performance of highly prolific lactating sows and its effect on the subsequent lactation

“…In addition, the sows submitted to feed restriction presented greater backfat thickness loss (+1.9 mm). This result is consistent with the findings of other authors (Foxcroft et al, 1995;Eissen et al, 2003;Vinsky et al, 2006;Quesnel, 2009;Schenkel et al, 2010;Patterson et al, 2011). Although backfat thickness does not reflect total fat body reserves, changes in this parameter may indicate that the sow is in negative energy balance (Jittakhot et al, 2012).…”

“…Restricted-fed sows presented higher protein (+2.92 kg) and lipid (+6.95 kg) losses compared with control-group sows. Vinsky et al (2006) and Patterson et al (2011) observed similar losses in sows submitted to feed restriction during lactation. Several authors suggest that the nutritional and metabolic changes in lactating sows may have deleterious effects on dam biology, with negative impacts on follicle development, and consequently on embryo development and on the number of piglets born in the next litter (Foxcroft et al, 2007;Ashworth et al, 2009;Quesnel, 2009;Schenkel et al, 2010;Hoving et al, 2011).…”

“…Similarly, other studies evaluating the effects of feed restriction in primiparous sows during lactation reported BW losses of 3.1% and 8.7% (Vinsky et al, 2006) and 3.7% and 11.0% (Patterson et al, 2011) in sows fed ad libitum compared with sows fed restrictively, respectively. The greater BW loss observed in restricted-fed sows in our study can be attributed to the fact that they produced, on average, 34% more milk than that reported in the above-mentioned studies, explaining their higher nutritional requirements, and consequent greater BW loss.…”

“…The effects of nutrient restriction and consequent catabolism during lactation on sow reproduction and longevity have been extensively studied in the last few years (Foxcroft et al, 1995;Vinsky et al, 2006;Quesnel, 2009;Schenkel et al, 2010;Patterson et al, 2011). However, the metabolic behavior of sows under intense catabolism needs to be further understood (Bergsma et al, 2009;Patterson et al, 2011).…”

“…According to Foxcroft et al (2009), the mechanisms affecting fertility may involve hormonal changes, as well as epigenetic changes and/or changes in the expression of genes related to embryo development. Sows under severe catabolism present reduced IGF-1 levels (Patterson et al, 2011), inducing the mobilization of endogenous protein (Zak et al, 1997). Protein mass losses >12% during lactation may reduce follicle number and diameter, and decrease IGF-1 levels in sows submitted to dietary protein restriction during lactation (Clowes et al, 2003a and2003b).…”