222 Effects of Nutritional Strategies of Growth Rate Manipulation During the Gilt Development Phases on Growth and Reproductive Performance

Abstract

Abstract Our objective was to evaluate the effects of nutritional interventions for growth rate manipulation during the gilt development phases on growth and reproductive performance. A total of 810 Camborough L42 gilts from three gilt groups were received between 9 to 11 weeks of age. Gilts were individually weighed, and pens of gilts were allotted to one of two dietary treatments balanced by lot (birth week) and pen weight for a total of 24 pens/treatment. Treatments consisted of two levels of dietary nutrients:1) diets based on corn, soybean meal, and wheat middlings formulated to meet or exceed the PIC standardized ileal digestible (SID) lysine (Lys) recommendations with a total dietary fiber content (TDF) of 10, 10, and 11% (Adeq); and2) slower growing diets based on corn, soybean meal, wheat middlings, and corn germ where SID Lys was reduced by 6, 11, and 11%, dietary metabolizable energy level was reduced by 2.7, 4.6, and 4.7%, and TDF content was increased to 15, 18, and 20% (Low). Diets were fed in three phases as 27.2 to 54.5 kg, 54.5 to 81.8 kg, and 81.8 to 113.6 kg of body weight (BW). At the end of phase 3, gilts were individually weighed and the number of selected gilts per pen was recorded. After selection, gilts were heat checked with the date of heat-no-service (HNS) recorded and then sent to sow farms for breeding in the next recorded heat. Data were analyzed using generalized linear mixed models considering treatment as fixed effect, lot as random effect, and covariates were included if they were statistically significant and improved model fit. Gilts fed the Low diets had less overall average daily gain compared with gilts fed Adeq diets (P < 0.05; Table 1). This response was mainly driven by a marginal significant reduction (P < 0.10) in average daily feed intake for the gilts fed Low diets compared with Adeq, with no evidence for differences (P > 0.10) in overall feed efficiency. As a result of the reduction in growth rate, gilts fed the Low diets were 4.8 kg lighter (P < 0.05) at selection compared with gilts fed Adeq diets. There was no evidence for treatment differences in selection rate, breeding rate, age at first HNS nor age at first breeding (P > 0.10). In summary, results from this study demonstrated that nutritional strategies can be applied to reduce developing gilts growth rate without negatively affecting puberty, selection rate, or age at first breeding.