Summary and Implications
The effect of feeding different lysine and metabolizable energy (ME) levels to 1221 crossbred Large White × Landrace developing gilts housed in groups from 100 d of age until slaughter (approximately 260 d of age) on age at puberty and reproductive tract measurements were evaluated. Gilts were randomly allotted to six corn-soybean diets formulated to provide two standardized ileal digestible lysine levels [100% (high, HL) and 85% (low, LL)] and threemetabolizable energy levels [ME, 90% (low, LME), 100% (medium, MME), 110% (high, HME). Average age at puberty was 193 d of age. There were no effects of the dietary treatments on age at puberty or any of the reproductive tract measurements. Despite significant differences in the lysine:energy ratio in the diets, the expected differences in reproductive traits were not observed. Other factors such as body weight (BW) and days of estrous cycle had a greater effect on the traits recorded than feed provided.
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Calderón Díaz, Julia A.; Vallet, Jeffrey L.; Lents, Clay; Nonneman, Danny; Miles, Jeremy; Wright, Elaine; Rempel, Lea; Cushman, Robert; Freking, Bradley; Rohrer, Gary; Phillips, Christina; DeDecker, Ashley; Foxcroft, George; and Stalder, Kenneth J.
"Optimal Dietary Energy and Protein for Gilt Development: Age at Puberty, Ovulation Rate, and Reproductive Tract Traits,"
Animal Industry Report:
AS 661, ASL R3022.
Available at: http://lib.dr.iastate.edu/ans_air/vol661/iss1/85