Effect of increasing arginine:lysine ratio during the transition period and lactation on farrowing kinetics, milk composition, and sow and litter performance.

The present study aimed to determine the effects of feeding increasing Arg concentrations during late gestation (transition) and lactation of sows on farrowing kinetics, colostrum and milk concentration of immunoglobulins G (IgG), and sow and litter performance. A total of 90 sows (Line 241, DNA Genetics, Columbus, NE) were blocked by parity (average 2.14) and body weight (BW) on d 108 ± 1 of gestation and allotted to one of three dietary treatments of increasing SID Arg:Lys ratio (90, 105, or 120%). Sows received approximately 2.7 kg/d of their treatment diet starting from d 109 of gestation until farrowing, then allowed ad libitum access to their treatment diet. Litters were cross fostered within 48 h after farrowing to equalize litter size. At farrowing, colostrum was collected for IgG concentration analysis. Colostrum yield and intake were also calculated. Sows and one average weight barrow per litter were bled on day 18 for blood urea nitrogen analysis (BUN). On the same day, milk was also collected for proximate composition and IgG concentration. Increasing SID Arg:Lys ratio did not affect sow BW or backfat change during lactation, nor influence sow average daily feed intake (ADFI) either pre-farrow or during lactation. Average SID Arg intake increased (linear, P < 0.001) with increasing SID Arg:Lys ratio. Wean to estrus interval decreased then increased (quadratic, P = 0.044) with increasing SID Arg:Lys ratio. No differences were observed for the number of total pigs born or the percentage of total born alive, stillborn, and mummified. The SID Arg:Lys ratio did not influence litter size, litter weight, or pre-wean mortality at any time point. However, on day 10, piglets' ADG and BW tended to increase (linear, P = 0.051 and 0.061, respectively) as SID Arg:Lys ratio increased. Despite these increases on d 10, no differences in piglet performance were observed at the other time points. Increasing the SID Arg:Lys ratio from 90% to 120% did not affect farrowing duration, colostrum yield, colostrum intake, IgG concentration in colostrum or milk, milk composition, or BUN concentration in either sows or piglets. This data suggests that increasing SID Arg:Lys ratio from 90 to 120% from day 109 of gestation through weaning did not impact farrowing kinetics or sow and litter performance.