Effects of Standardized Ileal Digestible Lysine Levels Fed to Gilts during Lactation on the Post-Weaning Growth, Feed Conversion, and Carcass Quality of Their Progeny.

The effects of Standardized Ileal Digestible (SID) lysine (Lys) levels fed to gilts during lactation on their offspring’s growth and carcass performance have not been documented in the literature. The objectives of this trial were to determine long-term carryover effects of the SID Lys levels fed to lactating gilts on wean-to-finish performance of their progeny. A sub-sample of 923 pigs (PIC 359 × Camborough, 5.9 ± 0.21 kg) were randomly selected for the study. Lactating gilts were randomly assigned to 1 of 5 SID Lys treatments fed during the lactation period: 0.90, 1.03, 1.15, 1.28, and 1.40%. Pigs were identified to the dietary treatment of their parent gilt by using different colored button tags. Pen was the experimental unit. Two complete litters of the same Lys level were allotted to each pen. Pen weights and feed intake were captured at each phase change and used to calculate efficiency. Pigs were fed common diets that met the NRC (2012) recommendations throughout the wean-to-finish period. Data was fit using the MIXED procedure of SAS^© (Cary, NC) with Lys level as the main effect. Linear and quadratic responses for the lactating gilts lysine levels were estimated by fitting orthogonal polynomial coefficients for equally spaced treatments to the least squares means. Initial weight and carcass lean reduced and then increased (quadratic, P<0.05) as SID Lysine for the lactating gilts increased. There were no statistical differences for final weight, ADG, ADFI, G:F, carcass G:F, and backfat between treatments (P>0.10). In conclusion, this study with this sub-sample population does not seem to show any major effects of SID Lys fed to gilts during lactation on offspring growth and carcass performance.

	SID Lysine for lactating gilts, %a
	0.90%	1.03%	1.15%	1.28%	1.40%		SEM
BW, kg
Initial wt.b	5.87	5.88	5.36	5.83	6.23		0.210
Final wt.	138.6	139.8	137.3	138.5	138.4		1.07
ADG, g	714	695	719	665	699		20.1
ADFI, kg	1.82	1.81	1.85	1.74	1.82		0.040
G:F	0.392	0.385	0.388	0.382	0.383		0.020
Carcass G:F	0.305	0.299	0.300	0.302	0.297		0.014
Backfat, mm	13.4	14.8	14.0	13.8	12.9		0.54
Carcass leana, %	57.4	56.9	56.9	57.0	57.3		0.22
anumber of pens: 0.90% = 8, 1.03% = 7, 1.15% = 9, 1.28% = 8, 1.40% = 8
bQuadratic, P<0.05.