Animal Science, Veterinary Diagnostic and Production Animal Medicine
Journal or Book Title
Translational Animal Science
Improving sow lifetime productivity (SLP) is essential for maximizing farm profitability. Study objectives were to determine the accuracy for different vulva scoring methods in a commercial production system and to assess whether gilt reproductive tract scoring (evaluated by vulva width; VW) prior to puberty could serve as useful gilt selection criteria. To accomplish this objective, 958 prepubertal replacement gilts in a commercial system were evaluated at approximately 15 weeks of age. Gilt body weight was recorded in addition to four different methods to evaluate VW. Methods for VW assessment included digital caliper measurement (mm), visual evaluation and scoring by trained farm personnel (Farm Score; FS), and two methods using scoring tools (Vulva Score Method A and B; VSA and VSB, respectively) specifically calibrated from the VW distribution measured on gilts from previous studies. The VSA and FS methods assigned gilts to one of three categories (S, M, L and 1, 2, 3, respectively) whereas VSB classified gilts vulvas using a five-point scoring system (1 to 5). At 15-wk of age, a low proportion of variability in vulva size (27.8 ± 0.1 mm) could be explained by BW (62.2 ± 0.2 kg; R2 = 0.05). All three scoring methods were effective in categorizing gilts based upon VW, as the measured VW size within methods differed by score (P < 0.01). The proportion of gilts achieving their first parity increased with score for VSA (64.7, 73.2, and 84.4%; P = 0.02), VSB (66.0, 71.7, 79.2, 76.4, and 84.2%; P = 0.02), and FS (67.2, 75.0, and 88.8%; P = 0.03), but VSA, VSB, and FS did not influence percentage of gilts achieving their second parity (P = 0.32, 0.29, and 0.30, respectively). Litter performance of gilts scored as M or L using VSA improved with an increased total born over two parities compared to those scored as S (23.96 vs. 26.38 pigs; P < 0.01) as well as born alive (21.13 vs. 23.05 pigs; P < 0.05). Results were similar for VSB, where scores 2-5 had greater total born (23.97 vs. 26.33 pigs; P < 0.01) and born alive (21.11 vs. 23.02 pigs; P < 0.05) through two parities compared to gilts scored 1. Using the FS method, total born pigs tended to be increased (P = 0.06) through two parities for gilts having a 2 or 3 vulva score compared to those scored as a 1. Collectively, assessing VW at approximately 15 wk of age may identify sows with improved productivity through two parities as breeding herd females.
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Romoser, M. R.; Hale, B. J.; Seibert, J. T.; Gall, T.; Rademacher, C. J.; Stalder, K. J.; Baumgard, L. H.; Keating, A. F.; and Ross, J. W., "Methods for reproductive tract scoring as a tool for improving sow productivity" (2019). Animal Science Publications. 502.