Swine

Five generations of selection for functional teat number enhances reproductive throughput and sustainability

---

Abstract

The objective of this study was to examine changes in reproduction after five generations of selection for functional teat count. The importance of functional teat number in relation to piglet throughput has been recognized for decades (Enfield and Rempel, 1961); however, as litter sizes have increased over the past ten years, selection for functional teats has not kept pace. In 2019, selection lines for functional teat count were created at the NCDA Tidewater Research Station (Plymouth, NC) using a composite Landraceà—Large White genetic line. A Control line was established and selected to maintain a functional teat count of 14 teats, while the High line was selected for an increased number of functional teats. Teats were evaluated at 21 days and again at 165 days of age. Teats were labeled non-functional or substandard if they were ≤75% the size of the surrounding teats. Selection lines were batch farrowed annually. For their second parity, selection line females were mated to Duroc boars (Smithfield Premium Genetics) to create piglets for production research. Each generation, approximately 55 gilts were kept from each the Control and High lines, and eight to ten sire families were maintained. Data were analyzed in SAS using PROC GLM. All models included fixed effects of generation and genetic line. Models for the number and percentage of stillborn piglets included the total number born as a covariate. Functional teat number for Generations 1, 2, 3, 4, and 5 were 14.6, 14.4, 14.1, 14.1, and 14.1 for the Control line and 15.1, 15.7, 16.2, 16.6, and 17.3 for the High line, respectively. Control sows had significantly greater (P< 0.01) average piglet birth weights than High sows in both Parity 1 (1.38 vs. 1.30kg) and Parity 2 (1.51 vs. 1.42kg). Control sows also produced heavier (P=0.01) average piglet weaning weights in Parity 1 (5.73 vs. 5.50kg), but this difference was not significant in Parity 2 (P=0.55). Second parity sows from the High teat count genetic line weaned more (P=0.03) piglets than those from the Control line (10.7 vs. 10.0 piglets). This increase resulted from a numerically greater (P=0.20) number of piglets born alive (12.40 vs. 11.91) and an increase (P=0.05) in piglet survival (83.9% vs. 81.2%). Results suggest selection for increased functional teat count enhanced piglet survival and sustainability, yet impaired piglet birth weight. While lower birth weight in the High sows was unexpected, perhaps the difference occurred due to the larger litter size from the High sows and the fact that pigs with high teat counts were retained for breeding regardless of growth rate. Hence the importance of including functional teat number in a selection index.

Keywords: 2026

How to Cite:

Knauer, M. & Wiegert, J., (2026) “Five generations of selection for functional teat number enhances reproductive throughput and sustainability”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2287378. doi: https://doi.org/10.31274/wcgalp.24281

Rights: 1