Adequate feed consumption prior to and at the time of weaning is of critical importance. Failure to consume enough feed at weaning can increase susceptibility to disease, decrease the absorptive capacity of the gastrointestinal system, exacerbate other stressors and result in increased time needed to reach market weight.

Although the swine industry has grown in leaps and bounds with regards to improvements in feeds, feeding systems and genetic potential for growth, studies considering the 'hardware' required to consume that feed, i.e. teeth, and thus fulfill that potential, have largely been neglected.

Given that the majority of a piglet's pre-weaning nutrition is derived via suckling motor patterns and not chewing, the authors wanted to determine whether newly piglets have the necessary dentition for chewing of their post-weaning diet. Surprisingly, dental eruption in commercial large breed pigs has not been formally examined except in classic growth experiments conducted in the 1970s. As such, normal profiles for the eruption of the deciduous (primary) teeth are generally unknown. Likewise, no previous studies have investigated the influence of having teeth or teething on feed-oriented behaviour or feed intake in young pigs.

Objectives

1. To determine the natural time course of deciduous dental eruption in commercial piglets from birth to five weeks of age, examining influential sow, litter and piglet factors, and
2. To determine if premolar eruption or premolar occlusion, i.e. the contact of premolars in opposing jaws, is associated with creep feeding behaviour or creep feed intake in piglets under 28 days of age.

Methods

Twenty-four litters of Yorkshire piglets (n=233) were given dental exams at ages 2, 6, 9, 13, 16, 20, 23 and 27 days. On day 5, piglets were provided with creep feed that was mixed at one per cent inclusion with chromic oxide (Cr₂O₃) that colours the faeces green. Faecal samples were obtained from each piglet on the same days as dental exams and were visually assessed for the presence of Cr₂O₃ indicating prior ingestion of creep feed.

The duration of time piglets spent with their head in the creep feeder and the number of feeder visits were determined from continuous video recordings for six hours per day (07:00-10:00, 13:00-16:00) on days 7, 10, 14, 17, 21 and 24.

Birth and weekly weights were recorded, as were sow parity, sow age, number of piglets born alive, number of stillbirths, number of mummies and male:female ratio of the litter.

Results

Figure 1 gives a diagrammatic representation of the pig's deciduous dentition. All piglets had their eight 'needle' teeth present at birth (c¹, c₁, i³, i₃).

The mean age of eruption for all other teeth seen to erupt during the course of the experiment are presented in Table 1.

Gilts were found to have earlier eruption than barrows for m³, m₄, m⁴, and i₁ (P<0.05).

Heavier piglets at birth had earlier eruption of all teeth except i¹ (P<0.05).

Piglets gaining more in week 1 had earlier eruption of m³, m₄ and i¹ (P<0.05), and this trend continued into week 2 for m₄ (P<0.05).

Older sows and sows of higher parity had piglets with earlier eruption of i₁ (P<0.05).

Piglets 17 days of age and younger that had their premolars erupted and occluded spent less time at the feeder and visited it less frequently, possibly in response to the gingival sensitivity and inflammation that was occurring. However, piglets 21 days of age and older that had their premolars erupted and occluded spent more time at the feeder and visited it more often compared to piglets without these dental conditions.

However, ingestion of creep feed was not found to be associated with dentition, though problems with detecting consumption may have occurred.

Table 1. Age (in days) of deciduous tooth eruption in the maxilla¹ and mandible¹ for gilts and barrows (n=233)

Conclusions

In summary, this study determined the normal time course of 'teething' in commercial piglets. In general, gilts and larger-weight-for-age piglets got their teeth earlier. Feeding behaviour was influenced by dentition though it was an age-dependent response.

This aspect of a piglet's biology should be considered with regards to when piglets are weaned given certain premolars associated with increased feeding behaviour, e.g. m₃ and m⁴, did not erupt until after 19 days of age.

Further Reading

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