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The primary objective of this survey was to investigate the relationship between qualitative maternal behavioral scores (nest building activities, sow communication, and sow carefulness), piglet mortality, and the number of weaned piglets on commercial farms with loose-housed lactating (Norsvin Landrace × Yorkshire) sows. Second, the impact of these scores on productivity compared with the physical condition of sows (movement disorders, body condition, and shoulder lesions) was assessed. Data on maternal care behaviors and physical condition were collected on 895 sows from 45 commercial farms. Farmers scored sows on their physical condition (movement disorders [MD], BCS, and shoulder lesions [SL]) and qualitative maternal care behaviors (nest building activities [NEST] prior to farrowing and sow communication [COM] and sow carefulness [CARE] after farrowing, while sows were standing and moving and just before lying down). There was a low positive correlation between NEST and COM ( = 0.10, = 0.026) and between NEST and CARE ( = 0.15, = 0.010) but a high positive correlation between COM and CARE ( = 0.57, < 0.001). Higher COM and CARE were associated with lower piglet mortality ( ˂ 0.001 and = 0.013, respectively), and a greater number of weaned piglets was associated with higher scores for NEST ( = 0.009), COM ( < 0.001), and CARE ( = 0.009). Maternal care behavior had a greater impact on piglet mortality and the number of weaned piglets than sow physical condition (MD, BCS, and SL). We tested 7 different models (combinations of behavioral scores) and compared their relative predictive accuracies using Akaike information criteria. The model including COM and CARE had the best predictive accuracy for piglet mortality/weaned piglets. There was between-sow variation in maternal care behaviors (COM and CARE), and both were unaffected by litter size. Because these behaviors were also easy to score for the farmers, combining COM and CARE has the greatest potential to be tested in nucleus herds for calculation of genetic variation and heritability and should be taken into account in future breeding programs for sows.

Piglet mortality is still a significant welfare and ethical matter in pig production, as well as an economical challenge for the farmer. Most of the mortality occurs early after farrowing, and previous studies have shown that the farm`s management routines, especially around farrowing, are important factors to reduce it. When sows are loose-housed at farrowing and in the following lactation period, it puts higher demands on management input from the farmer to keep piglet mortality low. The objective of this study was to assess the importance of different management routines around the time of farrowing, and other farm qualities for piglet survival in loose-housed herds. To study risk factors for herd piglet mortality, a cross-sectional field survey was carried out in Norway in the year 2013, and included 52 commercial herds with hybrid LY sows (Norwegian Landrace x Swedish Yorkshire). The farms were visited once, and the farmers answered a questionnaire about their management practices. The outcome was the average herd pre-weaning mortality in the years of 2012-2013. To include as many management factors as possible into the multivariable linear regression model, we generated a new variable based on 4 management routines: 3 routines at farrowing (presence at 80-100% of the farrowings, drying newborn piglets, and practice split suckling), and one concerning farmer´s contact with the sows. This variable was called "Management type" (M), and were divided into 4 categories with increasing effort; M1 herds without any of the 4 mentioned routines, M2 had contact with sows >2 times per day, M3 performed the 3 routines at farrowing, and M4 combined the high sow contact and the 3 routines. The predicted values of mean herd piglet mortality for M1, M2, M3 and M4 were 20.1%, 17.0%, 16.2% and 13.3% respectively. The farmer`s increased management effort was associated with lower piglet mortality (P<0.05). The farmer`s effort at critical times together with systematic and important routines, and having frequent contact with the sows, makes a huge difference for piglet survival. The farmers are credited for this work by having lower piglet mortality as a result.

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.