title: Effect of nutrient intake in lactation on sow performance: determining the threonine requirement of the high-producing lactating sow.
abstract: Reproductive performance is steadily increasing within the pork industry; logically, amino acid requirements need to be redefined for sows producing larger litters. The objective of this study was to determine the threonine requirement of the high-producing lactating sow and to determine the effect of lysine on this requirement. A total of 419 PIC C-15 sows were assigned randomly to treatment within parity groups (1, 2, and 3+) and gestation treatment at d 110 of gestation. Lactation diets were formulated to contain 0.80% total lysine (tLYS) with 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, or 0.65% total threonine (tTHR) or 1.06% tLYS with 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, or 0.70% tTHR. Litters were standardized to a minimum of 11 piglets within 48 h after farrowing, and sows had free access to feed throughout lactation (lactation length = 20.1 +/- 0.1 d). Sow ADFI exceeded expectation, averaging 6.90, 7.40, and 7.20 kg/d for Parities 1, 2, and 3+, respectively. Daily tLYS intake was 58 g/d (47 g of apparent ileal digestible lysine [dLYS] per day) and 74 g/d (59 g dLYS/d) for the low- and high-lysine group, respectively. Lysine intake did not affect sow or litter performance (P > 0.10). Sows gained an average of 4.8 kg in lactation. Using regression analysis, BW gain was maximized at 0.54% tTHR for all parity groups (quadratic; P < 0.05). Litter weaning weight (67.1, 67.9, and 66.2 kg for Parities 1, 2, and 3+, respectively) and litter weight gain (2.49, 2.53, and 2.44 kg/d for Parities 1, 2, and 3+, respectively) were maximized at 0.53% tTHR using regression analysis, for all parity groups (quadratic; P < 0.05). Based on regression analysis, plasma urea nitrogen on d 10 and 18 was minimized at 0.54% tTHR (P < 0.05). Lysine levels in excess of 58 g of tLYS/d did not benefit sow or litter performance. The requirement for threonine to minimize sow tissue mobilization was 37, 40, and 38 g tTHR/d (28, 30, and 30 g of apparent ileal digestible threonine [dTHR] per day) for Parities 1, 2, and 3+ sows, respectively. The threonine required to maximize litter performance was 36, 39, and 38 g of tTHR/d (28, 30, and 29 g of dTHR/d) for Parities 1, 2, and 3+ sows, respectively. Alternatively, the requirement can be expressed as 14.3 g tTHR (11.8 g dTHR) per kilogram of litter gain.
authors.affiliation: Prairie Swine Centre Inc., Saskatoon, SK, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Cooper
authors.forename: J F
authors.initials: JF
authors.lastname: Patience
authors.forename: R T
authors.initials: RT
authors.lastname: Zijlstra
authors.forename: M
authors.initials: M
authors.lastname: Rademacher
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development; D001806:Blood Urea Nitrogen; D005260:Female; D007774:Lactation / Q000187:drug effects / Q000502:physiology*; D008098:Litter Size; D008239:Lysine / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D009751:Nutritional Requirements; D010298:Parity; D011247:Pregnancy; D011897:Random Allocation; D013552:Swine / Q000378:metabolism / Q000502:physiology*; D013912:Threonine / Q000008:administration & dosage*
chemical_list: D013912:Threonine; D008239:Lysine