Staff Publications

In this study we aimed to identify possible causes of within-litter variation in piglet birth weight (birth weight variation) by studying follicular development of sows at weaning in relation to their estimated breeding value (EBV) for birth weight variation. In total, 29 multiparous sows (parity 3 to 5) were selected on their EBV for birth weight variation (SD in grams; High-EBV: 15.8±1.6, N=14 and Low-EBV: −24.7±1.5, N=15). The two groups of sows had similar litter sizes (15.7 v. 16.9). Within 24 h after parturition, piglets were cross-fostered to ensure 13 suckling piglets per sow. Sows weaned 12.8±1.0 and 12.7±1.0 piglets, respectively, at days 26.1±0.2 of lactation. Blood and ovaries were collected within 2 h after weaning. The right ovary was immediately frozen to assess average follicle size and percentage healthy follicles of the 15 largest follicles. The left ovary was used to assess the percentage morphologically healthy cumulus-oocyte complexes (COCs) of the 15 largest follicles. To assess the metabolic state of the sows, body condition and the circulating metabolic markers insulin, IGF1, non-esterified fatty acid, creatinine, leptin, urea and fibroblast growth factor 21 were analysed at weaning. No significant differences were found in any of the measured follicular or metabolic parameters between High-EBV and Low-EBV. A higher weight loss during lactation was related to a lower percentage healthy COCs (β= −0.65, P=0.02). Serum creatinine, a marker for protein breakdown, was negatively related to average follicle size (β= −0.60, P=0.05). Backfat loss during lactation was related to a higher backfat thickness at parturition and to a higher average follicle size (β=0.36, P<0.001) at weaning. In conclusion, we hypothesise that modern hybrid sows with more backfat at the start of lactation are able to mobilise more energy from backfat during lactation and could thereby spare protein reserves to support follicular development.

Abstract

The Dutch pig sector is attempting to address citizens’ concerns about animal welfare practices. Measures to improve animal welfare that were introduced by the pig sector did, however, not have the desired effect on citizens’ attitudes toward pig husbandry. This indicates that an improvement of animal welfare does not necessarily result in an improvement of citizens’ attitudes. This thesis aimed to estimate the effects of measures to improve animal welfare in sow husbandry in the Netherlands on animal welfare, farm income and citizens’ attitudes. First, the attitudes of citizens and other stakeholders of sow husbandry, i.e., pig farmers (conventional and organic), pig husbandry advisors and pig veterinarians, were investigated using a survey. It was shown that the large majority of respondents of citizens have negative attitudes toward sow husbandry with respect to aspects related to animals, humans and the environment. Citizens differed in these attitudes from the other stakeholders, except organic pig farmers. Based on their attitudes, citizens could be divided into four separate clusters. These clusters differed in terms of their attitudes toward sow husbandry and in their socio-demographic features.

Basic values underlie attitudes, but this thesis showed that basic values related to sow husbandry are not one-on-one related to attitudes toward sow husbandry of citizens and conventional pig farmers. Between conventional pig farmers and clusters of citizens there were differences in basic values related to sow husbandry. The two clusters with the most negative attitudes toward sow husbandry did not agree on the valuation of basic values with conventional pig farmers, while the other two clusters did on most of the basic values. The biggest cluster of the latter two clusters did agree on the valuation of several basic values with the former two clusters. This cluster can be useful for pig farmers to learn to understand the interpretation and weighing of basic values by citizens. An understanding that can be used in the development of new systems and measures to improve animal welfare within sow husbandry and in the communication between the pig sector and citizens.

Furthermore, in this thesis a simulation model was developed in which the effects of different measures for sow husbandry on animal welfare and farm income can be estimated. For each of the defined issues of sow husbandry, i.e., piglet mortality, tail biting and indoor housing, four measures were defined to improve animal welfare in an existing reference sow farm, representative for the Netherlands. The measures that aimed to reduce piglet mortality were the only measures with a positive effect on farm income. These measures had the best cost-effectiveness ratio compared to the other defined measures. When extending the simulation model with estimating the effects on citizens’ attitudes, the measure that includes straw provision, daylight and increased group sizes of gestating sows was the most efficient compared to the other defined measures. Results show that a positive effect of a measure on animal welfare does not necessarily lead to a similar relative improvement of citizens’ attitudes or a deterioration of farm income.

This thesis has shown that in order to achieve an improvement of citizens’ attitudes, it is essential for the pig sector to evaluate animal welfare measures using an approach that integrates the effects of measures on animal welfare, farm income and citizens’ attitudes.