Additive effects of L-carnitine and chromium picolinate on sow reproductive performance

A total of 599 sows were used to determine the effects of added L-carnitine with or without chromium picolinate on reproductive performance. Experimental treatments were arranged in a 2×2 factorial with main effects of added L-carnitine and chromium picolinate. Starting on the first day of breeding, sows were provided a daily top dress containing the carnitine with or without chromium along with the standard gestation or lactation diet. The top dress was formulated to provide 90 mg/d and 250 mg/d of L-carnitine in gestation and lactation, respectively. Chromium from chromium picolinate was provided at 360 μg/d and 1000 μg/d during gestation and lactation, respectively. These inclusions were calculated to provide 50 mg/kg of carnitine and 200 μg/kg of chromium when sows were fed 1.8 kg/d of the gestation diet and an estimated 5.0 kg/d of the lactation diet (actual lactation feed intake was not recorded). Dietary treatments were administered daily through the initial gestation and lactation (parity 1), and a second gestation period (parity 2). At farrowing all pigs were cross-fostered across dietary treatments. During the first parity, there was a carnitine×chromium interaction (Pb0.01) for first service farrowing rate. Added dietary chromium increased (Pb0.01) first service farrowing rate, but there was no further increase when carnitine was added. No differences (PN0.05) were observed in number of pigs born alive, stillborn, mummies, or total born in the first or second parity. Added dietary L-carnitine decreased (Pb0.05) wean to estrus interval, and tended to increase (Pb0.08) the number of sows in estrus by d 7. In the second parity, supplementing both carnitine and chromium tended to improve (carnitine×chromium interaction, Pb0.08) farrowing rate. Based on all sows that started on test, for the two-parity period both added carnitine and chromium increased (Pb0.01) the number of pigs born and born alive. These results show that carnitine and chromium supplementation additively increased farrowing rate and thus total number born alive over two parities. © 2007 Elsevier B.V. All rights reserved.