A total of 50 mixed parity sows of a high-prolificacy genetic line were used to evaluate the impact of feed restriction during
lactation on their production and reproductive performance and their performance in the subsequent lactation. From day 7 of
lactation, sows were distributed according to a completely randomized experimental design into two treatments. In treatment 1,
sows were fed 8.0 kg feed/day (control) and in treatment 2, sows were fed 4.0 kg/day. The same suckling pressure was maintained
until weaning on day 28 of lactation. Average minimum and maximum temperatures measured during the experimental period
were 32.1°C and 16.5°C, respectively. Control sows presented significantly higher feed intake ( P<0.001) compared with the
restricted sows (6.43 v. 4.14 kg/day, respectively). Treatments influenced BW and backfat thickness losses ( P<0.001). Control
sows lost less BW than the restricted-fed sows (7.8 v. 28.2 kg). Restricted-fed sows lost more backfat thickness than those in the
control group (3.97 v. 2.07 mm; P<0.01). Restricted-fed sows tended ( P<0.10) to be lighter at weaning compared with the
control sows (211 v. 227 kg). The composition of BW loss was influenced by the treatments ( P<0.001), as the restricted-fed sows
lost more body protein, lipids and energy compared with the control sows (3.90 v. 0.98 kg, 11.78 v. 4.83 kg and 584 v. 224 MJ,
respectively). Litter weight gain was greater ( P<0.05) in control sows than in restricted-fed sows (2.70 v. 2.43 kg/day). Daily milk
production was 19% higher ( P<0.01) in the control sows compared with the restricted-fed sows (8.33 v. 6.99 kg/day). However,
restricted-fed sows presented a higher ( P<0.05) lactation efficiency than the sows of the control group (82.30% v. 72.93%). No
differences were detected ( P>0.10) in weaning-to-estrus interval and averaged 4.3 days. No effect of the treatment ( P>0.10)
was observed on any of the studied performance traits in the subsequent lactation, except for litter size at birth that tended (15.2
v. 14.1; P<0.10) to be lower for the restricted sows. In conclusion, the present study demonstrated that feed restriction during
lactation leads to intense catabolism of the body tissues of sows, negatively affecting their milk production, and the litter weight
gain and possibly number of piglets born in the next litter. On the other hand, restricted-fed sows are more efficient, producing
more milk per amount of feed intake.
DeBettio_2015_Impact of feed restriction on the performance of highly prolific lactating sows
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