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An experiment with 60 individually housed female pigs (Landrace × Large White) and 4 feeding regimens (n = 15/feeding regimen) was conducted. Pigs were sorted by BW and randomly allocated to 4 treatments: 1) ad libitum feed intake throughout (AL); 2) 85% of the mean intake of the AL group during the previous week (R); 3) 70% of the mean intake on 1 d, and on the following day, 100% of the mean intake of the AL group during the preceding week, with this pattern repeated every 2 d throughout (D); and 4) 70% of the mean intake for 3 consecutive days and then fed at 100% of the AL group for the next 3 d, with this pattern repeated throughout the experiment (3-D). Body weights and feed intake of pigs were recorded on a weekly basis. At approximately 104 kg of BW, pigs were slaughtered and after slaughter, viscera and flare fat (a fat depot comprising the perinephric and retroperitoneal fats) were collected from each pig, and the heart, liver, lungs, kidneys, and gastrointestinal tract were separated. The gastrointestinal tract was emptied, washed, patted dry with paper towel, and weighed before being frozen at -20°C. The viscera collected from each pig were later minced separately while frozen and then thawed, homogenized, and sub-sampled for chemical analysis of DM, fat, protein, and ash. The hot carcasses were weighed, and the backfat depth at the P2 site was determined on the hot carcass at 45 min after slaughter. Approximately 24 h post-slaughter, the right side of the carcass was separated and fat thickness (mm) in the shoulder, loin, belly, and ham were measured.
Pigs on the R and 3-D regimens were lighter at 28 d (P<0.05) and pigs on the R, D, and 3-D regimens were lighter at 63 d (P<0.05) than pigs on the AL regimen. Pigs on the R, D, or 3-D feeding regimens had a greater G: F between 15 to 42 d of the experiment than pigs fed AL throughout (P<0.05). The R, D, and 3-D feeding regimens seemed to have some effect on carcass weight and dressing percentage, and pigs had a decreased P2 backfat depth (P<0.05) compared with pigs fed AL. Pigs on the AL and 3-D feeding regimens had thicker subcutaneous fat at the last lumbar vertebrae on the dorsal edge of the loin than pigs on the R feeding regimen (P < 0.05). Carcass and visceral fat content and the F: L in the carcass and primal cuts, were not different among treatments. However, pigs on the AL and 3-D feeding regimes had decreased estimated bone content in the carcass compared with pigs on the R and D feeding regimens (P < 0.05).
In conclusion, the results indicated that continual fluctuation in feed intake either every other day or every 3 d had minimal effects on growth and carcass F: L compared with pigs fed the same restricted amount throughout the experiment.
BP Mullan, M Trezona, DN D'Souza and JC Kim. 2009. Journal of Animal Science.87:179-188
