Udder characteristics of importance for teat use in purebred and crossbred pigs.

Possible side effects of the current sow selection criteria on udder characteristics and their influence on teat use and functionality have not yet been investigated. The first aim of the present study was to investigate differences in udder morphology characteristics (distance between teats in a pair, teat length, and teat diameter) in 2 different pure breeds (Norsvin Duroc [ND; = 12] and Norsvin Landrace [NL; = 12]) and 1 crossbreed (Norsvin Landrace × Yorkshire [NL×Y; = 14]) at 3 different time periods (Days 1, 21, and 35) during lactation. Second, we also investigated the association between udder morphology and teat use on d 1 and if some of these characteristics influence whether teats become nonfunctional (from d 1 to 35) during lactation. During lactation, udder morphology (teat pair distance, teat length, and diameter of functional teats) and teat use (from 6 consecutive nursings: functional teats being used/not being used and which teat row [left or right] was uppermost) were documented. The NL had shorter distance between teat pairs than ND ( = 0.030). Teat pair distance increased with sows' parity ( = 0.010) and was affected by teat position ( < 0.001). The ND had shorter teats than NL and NL×Y ( < 0.001). Teat length and diameter increased with parity ( = 0.027 and = 0.043, respectively) and were affected by teat position ( < 0.001 and < 0.001, respectively). Functional teats were less used on d 1 postpartum (21.4%) than at 2 later time periods (10.4% on Day 21 and 4.7% on Day 35; < 0.001) during lactation. On d 1, the greater the distance between teat pairs in the middle and posterior position, the higher was the proportion of not-used functional teats ( = 0.003), with a larger decline in the lower teat row ( < 0.001), where approximately half of middle and posterior teats were not used. Proportion of not-used functional teats in the lower middle position increased when the teat pair distance exceeded 16 cm, whereas in the lower posterior position, this limit was 14 cm. Furthermore, the proportion of not-used teats on d 1 influenced teats becoming nonfunctional during lactation ( < 0.001). The greater the distance between pairs, the more teats became nonfunctional irrespective of teat position ( < 0.001). The present results suggest that teat pair distance is of importance for teat use in all breeds and should be included in the breeding program to ensure colostrum intake and maintain teat functionality during lactation.