Investigating risk factors behind piglet facial and sow teat lesions through a literature review and a survey on teeth reduction

Introduction

Piglet facial and sow teat lesions are the main reported reasons why pig producers routinely practice teeth resection. This is a painful procedure performed on piglets, where their needle teeth are clipped or ground to resect the pointed tip. The practice raises welfare concerns. In contrast to other procedures, such as tail docking, we know little about the risk factors for these two types of lesions.

Methods

We employed two methods to answer these questions: (1) reviewing the literature to identify potential risk factors, and (2) surveying pig production stakeholders worldwide to identify the occurrence of these lesions and the strategies used in practice that enable pig producers to manage or prevent these lesions while avoiding teeth resection. For the literature review, we used Google Scholar to include peer-reviewed publications and gray literature. We distributed the survey using convenience sampling and documented information on the current situation regarding teeth resection, including the methods, frequencies, and reasons for resecting piglets' teeth, the occurrence of piglet facial and sow teat lesions, and measures used to prevent and control these lesions.

Results

The literature review identified six major risk factors for both lesions, including the presence or absence of teeth resection, housing system, litter size, piglet management, environmental enrichment, milk production and other piglet management practices. However, most studies focused on the effects of the first two factors with very few studies investigating the other risk factors. There were 75 responses to the survey from 17 countries. The survey showed that half of the respondents practiced teeth resection with many recognizing that facial and teat lesions are the main reasons behind this practice. However, many producers used other interventions rather than teeth resection to prevent these lesions. These interventions focused on improving milk production of the sow, managing large litters, and providing environmental enrichment.

Discussion

More research is needed to validate these interventions and more science-based advice is needed to bridge the gap between research and practice to help more producers further understand the cause of piglet facial and sow teat lesions to transition toward the cessation of routine teeth resection.

From the Point of View of the Chickens: What Difference Does a Window Make?

We aimed to investigate what broiler chickens prefer when given free choice between a barn side with artificial lighting only as opposed to the other barn side with natural light through glass windows and artificial light. Eighty-five 1 day-old male Cobb 500 broiler chickens were divided into 10 pens; half of each pen area was provided with only artificial light (OAL) and the other half with natural and artificial light (NAL), and birds were free to move across sides. Environmental indicators and external conditions such as temperature, relative humidity, air velocity, ammonia and illuminance were monitored inside and outside the barn. Chickens' preference was registered each three days, divided in categories: I (at 9, 12, and 15 days), II (at 18, 21, 24, and 27 days), and III (at 30, 33 and 36 days). The effect of the interaction between environmental indicators and week was statistically different only for illuminance. Chickens preferred NAL to OAL from 18 days onwards (II p < 0.001; III p = 0.016). Drinking (p = 0.034) and exploration or locomotion (p = 0.042) behaviours were more frequent, and "not visible" behaviours (p < 0.001) were less frequent, in NAL. Foraging was the only behaviour with an interaction effect between age category and light treatment, as birds during period II expressed this behaviour more frequently in NAL than OAL (p = 0.003). For our experimental conditions, the chickens preferred NAL from 18 days of age onwards, when the confounding effect of the heating light was removed, and their behavioural repertoire was also different according to each side of the barn and to their ages.