Lysine (protein) requirements of lactating sows

Abstract

Five experiments were conducted to evaluate the lysine (Lys) requirements of lactating sows. All diets were formulated to be isocaloric 3.46 Mcal ME/kg and met or exceeded National Research Council recommendations. In all studies, sow feed intake, body weight loss/gain, subsequent reproduction, and litter growth rate (LGR) were evaluated. The data were analyzed as randomized complete block design using generalized linear model in SAS with parity as a block. Two hundred and sixty-four primiparous sows (PIC Camborough 22) were randomly allotted to one of five lactation treatments (total Lys of 0.95%, 1.05%, 1.15%, 1.25%, and 1.35%) in Exp. 1 from August 2005 through October 2005. As daily total dietary Lys intake increased from 52.10 to 77.53 g, piglet ADG and daily litter gain linearly improved (P < 0.01). From February 2007 through April 2007, 336 multiparous sows (parity 4 and older, PIC Camborough 29) were randomly allotted to one of five lactation treatments (total Lys 0.85%, 0.95%, 1.05%, 1.15%, or 1.25%) in Exp. 2. As dietary total Lys increased from 0.85% to 1.25% of the diet, there were no significant differences in litter performance, such as ADG, daily litter gain, and the number of pigs weaned. Experiment 3 was conducted from October 2008 through January 2009. Two hundred and seventy-nine primiparous gilts (PIC Camborough 29) were randomly allotted to one of five lactation treatments (total Lys 1.14%, 1.25%, 1.35%, 1.46%, and 1.57%). Actual total Lys intakes increased from 56.74 to 77.12 g/d. Feeding total dietary Lys quadratically decreased (P < 0.01) weaning-to-estrus interval and increased percentage bred by 10 d (P = 0.02). In Exp. 4, 200 sows (parity 4 and older, PIC Camborough 29) were randomly allotted to one of five treatments (0.85%, 0.95%, 1.05%, 1.15%, or 1.25% total Lys) from January 2008 through March 2008. As dietary total Lys increased from 42.40 to 66.15 g/d, sow body weight and LGRs were not influenced by dietary total Lys intakes. In Exp. 5, 324 parity 3 sows (PIC Camborough 29) were randomly allotted to one of five treatments (0.77%, 0.92%, 1.08%, 1.23%, and 1.38% total Lys) from August 2009 through October 2009. As daily dietary total Lys intake increased from 39.44 to 67.32 g, the percentage of sows bred by 10 d increased (P = 0.02), as well as the LGR. A broken-line quadratic regression analysis demonstrated that the total Lys requirement for LGR for parity 1 females is calculated as 72.68 - [6.04 × (3.55 - LGR)] and for parity 3+ females as 92.03 - [11.9 × (4.24 - LGR)].

Keywords: lactation; lysine; sow.

Figure 1.

Broken-line quadratic regression analysis of total daily Lys intake requirement of the sow for optimal litter growth rate for first parity gilts. The regression equation is: 72.68 − [6.04 × (3.55 − LGR)] with a BIC of 4,093.

Figure 2.

Broken-line quadratic regression analysis of total daily Lys intake requirement of the sow for optimal litter growth rate for mature females (parity 3 and 4+). The regression equation is: 92.03 − [11.90 × (4.24 − LGR)] with a BIC of 7,199.

Figure 3.

Broken-line quadratic regression analysis of total daily Lys intake requirement of the sow for optimal litter growth rate for all parities. The regression equation is: 84.14 − [10.31 × (3.55 − LGR)] with a BIC of 11,491.

Figure 4.

Broken-line with ascending linear model analysis of daily digestible Lys intake requirement (grams per day) of the sow for optimal litter growth rate (kilograms per day) for the older parity (P4+) sow. This graph combined the data from Exp. 2 and 4.