Duroc’s are characterized by their excellent growth rate and intramuscular fat content ( Suzuki et al., 2003). Recently, the US swine industry has placed more emphasis on pork quality resulting in the use of more Duroc-based terminal sires. While genetic suppliers provide amino acid requirement estimates for the various weight ranges of their specific lines, validating these levels is needed within production systems to achieve optimum performance and economic return ( De La Llata et al., 2007 Main et al., 2008 Shelton et al., 2011).Ĭhoosing a terminal sire to use in a swine breeding program is important because it influences traits including growth rate, carcass characteristics, pork quality and alter nutrient requirements. Pigs have also become more feed efficient while being heavier in market weight and together these changes over time may increase amino acid requirement estimates. By 2019, the average market weight had increased to 128 kg ( National Pork Board, 2020). In 1980, the average market weight was 110 kg ( National Pork Board, 2016). Continuous improvements in genetics of modern pigs have resulted in increased growth performance and protein accretion. There are several factors that impact dietary lysine requirements including: genetics, environmental conditions, sex, and pig body weight ( Campbell and Taverner, 1988). In finishing pigs, establishing dietary lysine requirement estimates is crucial for maximizing lean growth and reducing feed cost ( Wei and Zimmerman, 2001). Lysine is typically the first limiting amino acid in corn and soybean meal-based swine diets ( Menegat et al., 2020). These data provide SID Lys estimates for current Duroc-sired genetic lines raised in a commercial environment. The SID Lys estimate for late finishing pigs was 0.74%–0.81% or 2.85–3.10 g SID Lys/Mcal of NE, and 0.69%–0.75% or 2.61–2.84 g SID Lys/Mcal of NE, for 90–106 kg and 106–136 kg pigs, respectively. In conclusion, the SID Lys estimate for growth and IOFC was 1.19% or 4.63 g SID Lys/Mcal of NE, 1.05% or 4.04 g SID Lys/Mcal of NE, and 0.94% or 3.58 g SID Lys/Mcal of NE for pigs weighing 49–59 kg, 59–71 kg, and 71–81 kg, respectively. Feed cost (linear, P < 0.01), revenue, and IOFC increased (quadratic, P ≤ 0.053) with increasing SID Lys. Overall, increasing SID Lys increased (linear, P < 0.05) G:F, Lys intake/kg of gain, live weight and HCW, and increased (quadratic, P = 0.020) ADG. Pens were randomly allotted to 1 of 4 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 93%, 100%, and 110%). Corn-soybean meal-based diets were fed in 2 phases (90–106 and 106–136 kg). 2, 2,099 pigs (DNA 600 ×PIC 1050, initially 90.1 kg) were used with 24–27 pigs per pen and 20 pens per treatment. Feed cost, feed cost/kg of gain, revenue (linear, P < 0.01) and income over feed cost (IOFC) increased (quadratic, P = 0.045) with increasing SID Lys. A marginally significant improvement (quadratic, P = 0.071) in G:F was observed as SID Lys increased. Increasing SID Lys increased (linear, P < 0.001) ADG and Lys intake/kg of gain. Pens were randomly allotted to 1 of 5 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 95%, 103%, 110%, and 120%).
Corn-soybean meal-based diets were fed in three phases (49–59, 59–71, and 71–81 kg). 1, 2,124 pigs (DNA 600 ×PIC 1050, initially 48.9 kg) were used with 24–27 pigs per pen and 16 pens per treatment.
Therefore, our objective was to determine the standardized ileal digestible (SID) Lys estimates for Duroc-based sired finishing pigs. Duroc sires have differences in ADG, ADFI, G:F, and carcass leanness compared to other sires. In the United States, emphasis has shifted toward improved pork quality and has resulted in greater use of Duroc-based terminal sires.