Year: 2009
Type: dissertation
Abstract: Commercial pig production presents the animals with a multitude of potentially stressful challenges. Distress is a threat to animal welfare and may impair productivity. This research aimed to investigate productivity of pigs in relation to some common practices of pig production known to be stressful, to estimate the amount of stress or the level of welfare of the animals, and to establish relationships between stress or animal welfare measures and productivity. To address these issues, four studies were carried out. Studies I and II investigated effects of moderate enrichment on behaviour, basal cortisol secretion, health and daily gain in growing pigs (0-21 weeks of age). Effects of both current and early environmental enrichment were investigated. Small groups with siblings were accommodated in pens either barren or enriched with a moderate amount of chopped straw and wood shavings. Six enrichment regimes were used involving a stable environment or changes in enrichment status at 5 and/or 9 weeks of age. Enriched as compared to barren housing increased average daily gain and decreased post-weaning diarrhoea in the nursery. Current housing, as well as the early environment (0-4 or 0-9 weeks of age), affected stress physiology as measured by behaviour and basal cortisol secretion. Barren housing or experience thereof caused signs suggestive of chronic stress. Stress indicators were not associated with productivity. These results support the use of enrichment for pigs in early life, especially if bedding is scarce later in life. Study III compared the fertility of sows housed either individually or in groups on deep litter from weaning to four weeks of pregnancy. Stall housing decreased the odds for early disruption of pregnancy and increased the odds for pregnancy at day 28 post-service. The causes remained undisclosed, but social stress during short periods of time around oestrus and early pregnancy was proposed. Behavioural indicators showed clear signs of stress in stalls, but behaviour was not associated with fertility. The level or type of stress in stalls may have been insufficient to affect reproduction. These results emphasize the need for a better understanding of factors impairing fertility in sow groups. In Study IV the welfare status of pigs on commercial farms was assessed using an environment-based index comprising several subscales. Welfare scores were regressed on fertility measures. Good-quality floors and stockmanship were the most influential predictors of good fertility, providing some evidence of an association between higher levels of animal welfare (i.e. low levels of distress) and good reproductive performance.
Source: Työväentutkimus Vuosikirja
Author: Camilla Munsterhjelm
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1588894234