254 Impact of Preweaning Factors on Nursery Throughput

The objective was to evaluate factors associated with nursery throughput. Data consisted of 3,260 piglets from 320 litters at the NCDA Tidewater Research Station. At weaning, piglets were housed nine per pen (0.23m2 per pig) in onsite nursery facilities for 35 d. Using linear models, farrowing batch (BATCH), gender, litter size (LS), average piglet birth weight (BWT), birth weight CV (BWT_CV), piglet weaning weight (WWT), weaning weight CV (WWT_CV) and weaning age (WEANAGE) were associated with nursery average daily gain (NurADG), nursery exit weight (NurEXITWT), nursery survival (SURVIVAL) and full-value nursery pigs (FULLVALUE, pigs >13.6kg at nursery exit). Litter was the experimental unit. Average WEANAGE, WWT, SURVIVAL and FULLVALUE were 28.1 (±4.7 d), 7.8kg, 98.7% and 94.3%, respectively. Correlations between NurADG with gender, LS, BWT, BWT_CV, WWT, WWT_CV and WEANAGE were zero, -0.04, 0.24, 0.09, 0.81, 0.10 and 0.73, respectively. Factors related (P < .01) to NurADG included BATCH, BWT, WWT and WEANAGE (R2 = 0.80). Within these factors, WWT and WEANAGE explained 70% of the variation in NurADG. A 1kg increase in BWT and WWT increased (P < 0.01) NurADG by 60.3 and 19.4g per pig per d, respectively. A 1 d older WEANAGE increased (P < 0.01) NurADG by 9.36g per pig per d. Increased NurEXITWT was associated (P < 0.05) with BATCH and greater BWT, WWT and WEANAGE (R2=0.88). Within these, WWT and WEANAGE explained 83% of the variation in NurEXITWT. A 1kg increase in BWT and WWT increased (P < 0.01) NurEXITWT by 2.09 and 1.68kg per pig, respectively. A 1 d older WEANAGE increased (P < 0.01) NurEXITWT by 323g per pig. Increased BWT was associated (P < 0.01) with greater SURVIVAL, explaining 4% of the variation. Improved FULLVALUE was associated with (P < 0.05) BATCH and generally greater BWT, WWT and WEANAGE (R2 = 0.44). Of the factors studied, WWT had the greatest impact on the percentage of FULLVALUE at nursery exit (R2 = 0.36).