Belly Nosing by Group-Housed Sows Results in Functional Teat Loss

Oral presentation by M. Houben, PorQ, Netherlands.

Belly nosing in pigs is described as a rhythmic rubbing of the belly by the nose of another pig. This behavior, originates from suckling behavior, and becomes non-functional when expressed by weaned piglets. Udder seeking or exploratory rooting behavior may explain belly nosing. When expressed by group-housed sows, the motivation of this behavior is unclear.

This case reports the loss of functional teats due to mutilation by belly nosing and nipple suckling of group-housed sows during gestation.

The affected herd is a sow herd of 224 sows. Parity one to five are crossbred sows of Landrace and Yorkshire, while from parity 6 on sows are crossbred of Landrace and Large White. Gestating sows of all parities are housed together on concrete beds and slatted floors. Sows are fed by electronic feeding system (EFS).

Since November 2014 sows were detected that missed functional teats at farrowing. Function loss was due to blind teats, missing nipples or necrosis of the nipples. In April 2015, 126 pregnant sows were examined for normal or abnormal teats and nipples.

The average number of injured teats was 2.25 per sow. Thirty-four sows were not affected and two sows missed as many as ten nipples. When examining the herd, one sow was found belly nosing and belly suckling. In addition, 104 sows were found to have lesions of the vulva, ranging from lacerations to absence of external genitalia in 49 sows.

It is suspected that the lacerations were caused by the EFS. The abnormal wound healing and loss of vulva tissue may be related to the abnormal behavior of the sows.

The intervention plan was based on detecting and culling of sows that showed belly nosing behavior, and repair of the EFS. In addition, straw bedding was administered.

In May 2015 six Landrace Large White crossbred sows (parity 6 and older), were detected belly nosing and subsequently culled. Since September 2015 no new cases were detected.

Based upon the visual observations and upon the result of the intervention - culling the sows with the belly nosing behavior - we conclude that this aberrant and harmful behavior caused loss of functional teats in this herd.

No literature on belly nosing behavior in adult sows is available. How this behavior related to the observed vulva lesions, and what role genetics, feed or environmental enrichment plays, remains unclear.

Excellent stockman-skills are essential to recognize and to successfully intervene in such cases.

Risk factors associated with excretion of roundworm eggs in loose housed sows

Poster presentation by K. S. Pedersen and colleagues at Ø-Vet A/S, Denmark.

Loose housing systems for sows may have increased the occurrence and importance of Ascaris suum. Anthelmintic treatments can result in resistance development. Therefore, identification of risk factors and development of alternative control strategies is relevant.

The objective of this study was to identify risk factors associated with Ascaris suum egg counts in sows and gilts from intensive farms with loose housed sows.

Twenty sow farms (450 – 2500 sows) were selected from different regions of Denmark. Eight of the farms used routine anthelmintic treatment of breeding animals and 12 farms only performed anthelmintic treatment when considered necessary based on the results of faecal egg counts.

From 2012 to 2015, faecal samples were collected from the individual farms at three to five time points. The faecal samples were obtained from 10 gilts and 10 sows at each time point.

Nematode egg counts were determined using a McMaster technique. Poisson-regression was used to investigate risk factors associated with A. suum egg counts. Farm was included as a random effect, and fixed effects with a p-value below 0.05 was included in the final model. All statistical analyses were performed using Stata IC 13.

Egg counts were obtained from 784 gilts and 767 sows were included in the statistical analysis. A. suum eggs were detected in 20% of the faecal samples and egg counts were significantly different between breeding animals sampled at different time-points within the same herd (p<0.001).

Egg counts were significantly higher in breeding animals excreting Oesophagostomum spp. eggs (p<0.001) and in sows compared to gilts (p<0.001). Routine anthelmintic treatment of breeding animals (p<0.55) and herd size (p<0.48) were not significantly associated to egg counts.

Breeding animals in large herds did not have higher egg counts, indicating that increasing herd sizes are not causing increasing problems with A. suum despite the use of loose housing systems for gestating sows.

Breeding animals having an Oesophagostomum spp infestation were excreting a higher number of eggs suggesting that similar risk factors are associated with the occurrence of both parasites.

Egg counts for A. suum were not different between animals in herds with or without a routine use of anthelmintic treatment of breeding animals. This indicates that monitoring egg counts in faecal samples combined with anthelmintic treatments when necessary can be used to control infestation with A. suum.

The higher egg counts in sows compared to gilts indicate that sows are important targets for such monitoring procedures and anthelmintic treatment strategies.