Surprisingly long body length of the lungworm Parafilaroides gymnurus from common seals of the Dutch North Sea.

Lungworms of the genera Parafilaroides and Otostrongylus are responsible for parasitic bronchopneumonia, the foremost disease of eastern Atlantic common seals (EACS, Phoca vitulina vitulina) in the Dutch North Sea. Recently, there have been increased reports of lungworm cases and observations of unusually long Parafilaroides sp. adults in this location. The initial aim of this study was to confirm the identity of the Parafilaroides species infecting this population. Parafilaroides are usually small and delicate, making them difficult to extract from host tissue, and there is often difficulty accessing fresh specimens for morphological study. The large size of the Dutch worms and the accessibility of specimens from numerous animals enabled the description and measurement of many intact specimens (N = 64) from multiple host animals (N = 20). Species identity was confirmed by targeted sequencing of ribosomal and mitochondrial DNA amplicons from a subset of worms. Worm morphology was consistent with descriptions for P. gymnurus, but the mature females were 1.9-fold and 3.4-fold longer than those recovered from French EACS (P ≤ 0.001) and Canadian western Atlantic common seals (Phoca vitulina concolor; P ≤ 0.0001). They were also significantly longer than mature female P. gymnurus described from other seal species, with the exception of those from harp seals of Les Escoumins, Quebec. We suggest that intraspecific genetic differences in P. gymnurus and the environment within the host could contribute to the variation reported here. This study is the first to describe P. gymnurus using morphological and molecular methods and should serve as a reference for identification of the species.

Responsiveness to a novel preening stimulus long after partial beak amputation (beak trimming) in laying hens.

Thirty beak-trimmed and thirty intact hens were reared in mixed groups and individually housed in battery cages; partial beak amputation took place 6 weeks after hatching. All hens were tested with a novel stimulus when they were 42 weeks old: a small paper sticker (36 mm(2)) was attached to the distal parts of the feathers at the back of the hen. It took beak-trimmed hens on average 27 seconds and the intact ones 8 s to start preening the sticker. This difference was statistically significant. Beak-trimmed hens tended to preen the sticker less than intact birds. Lighting conditions had no effect on the response latency, while the amount of eating and drinking did not differ between both groups, indicating that lack of light, anxiety or other types of disturbances did not affect the preening responses. It is concluded that beak trimming has long lasting consequences in reducing the responsiveness to a novel preening stimulus. This result is in agreement with the long term passivity in beak-trimmed hens found in other studies. The development of a reduced responsiveness as a result of beak trimming suggests poor animal welfare.

Dustbathing as related to proximal and distal feather lipids in laying hens.

After a prolonged experience with wood-shavings or with sand, 2 x 11 hens (Gallus gallus domesticus) were litter-deprived. Prior to the 7 to 8 day deprivation period feather samples were taken. This was repeated immediately after the deprivation had ended and right after the first bath in the familiar litter. Each feather was cut at the transition between the proximal plumulous and distal pennaceous part and lipids were extracted from separate samples, containing one type of feather parts. Hens on wood-shavings bathed 10 minutes longer after deprivation than hens on sand. This was due only to an extension of the second phase of the dustbath, which included rubbing; the first phase of tossing did not differ. In the extended phase of the wood-shavings bath the tendency to rub was lower, whereas the tendency to toss was higher than in the comparable phase of the sand bath. Thus, litter quality affected the amount of rubbings and of tossings in between. Rubbing did not effectuate a close contact between wood-shavings and the proximal integument, as wood-shavings could not be tossed into the plumage. This contrasted with baths in sand and only these baths resulted in a removal of excessive lipids from the plumulous parts. Therefore rubbing seems functionally crucial. The lipid level immediately after deprivation and the change in the quantity of lipids due to deprivation positively correlated with the amount of tossings in wood-shavings and with the amount of rubbings in sand. This indicates that the lipid condition is causally involved in dustbathing.

Oiling behaviour and the effect of lipids on dustbathing behaviour in laying hens Gallus gallus domesticus.

Laying hens oiled the plumage twice a day, while oiling behaviour consisted of a bout of five oilings (median value). During one oiling, a hen collected lipids from the preen gland with her bill and subsequently performed (as a median) five strokes or rubs over and through the feathers. The breast was oiled most, whereas during later oilings within an oiling bout the wings and the flanks were oiled as well. The back and the tail were seldom oiled. An artificial distribution of stale uropygial gland lipids in a more or less natural way on the breast feathers within a 3-day period of sand deprivation resulted in an increase of the duration of the first dustbath after the deprivation by 12%, compared with a control treatment. Within the dustbath, the total number of the side-lying and side-rubbing elements - two related consummatory dustbathing elements - doubled and tripled, respectively. In contrast to these highly significant effects, the duration of the dustbathing did not change after a fresh uropygial gland lipid treatment, while the effects on side-rubbing and side-lying were not straightforward; the total number of the side-rubbing element was doubled, but the duration of side-lying was reduced by 29%. The results are discussed in relation to the chosen methodology and the maintenance of the lipid condition of the integument.