The effect of cat Felis catus predation on three breeding Procellariidae species on Marion Island     

P.J.J. van Rensburg  M.N. Bester 《African Zoology》2013,48(4):301-305

Breeding success of Pterodroma macroptera, Procellaria aequinoctialis and Pachyptila vittata salvini in three cat-free and three control areas were used to evaluate the effects of cat Felis catus predation on the avifauna of Marion Island. Breeding success of all three species was significantly higher in the combined cat-free areas than in the combined control areas. However, breeding success in one cat-free area failed to show a significant difference from its particular control area, probably as a result of higher skua (Catharacta antarctica) predation inside the cat-free area. Chicks of P. macroptera and P. aequinoctialis were especially vulnerable to cat predation, since cats can enter their nesting burrows. P. macroptera was seriously affected by cat predation because it is the most abundant of only two winter-breeding petrels. Significant changes in the number of nest visits by these petrels during their breeding season followed hatching dates, which in turn were concomitant with, or were followed by significant differences in the combined breeding success between the cat-free and control areas. The cat-free areas show that an elimination of cat predation would still favour the recovery of the petrel population.  相似文献   

Observations on the attachment of a piscine gill parasitic ergasilid (Crustacea: Copepoda)     

W.H. Oldewage  J.G. van As 《African Zoology》2013,48(4):313-317

The attachment of the piscine gill parasite, Ergasilus mirabilis Oldewage & van As, 1987 is described by means of scanning electron microscopy and light microscopy. A variety of sensory structures occur on and around the host contact surface of the parasite and proliferation of gill tissue occurs at the site of attachment. It would appear that this proliferation of host tissue results from the feeding behaviour of the parasite rather than the actual attachment thereof.  相似文献   

A key for the identification of African piscine parasitic Ergasilidae (Copepoda:Poecilostomatoida)     

W.H. Oldewage  J.G. van As 《African Zoology》2013,48(1):42-46

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Influence of hatching order and brood size on growth in jackass penguins     

Yolanda van Heezik  P.J. Seddon 《African Zoology》2013,48(4):199-203

Jackass penguins Spheniscus demersus hatch two different-sized eggs asynchronously: the second-hatched chick, being, on average, 59% of the weight of the first-hatched chick on hatching. We examined the effect of hatching order on growth rates of mass, culmen length and culmen depth by comparing: (i) growth rates of first-and second-hatched chicks, and (ii) chicks from experimentally synchronized broods to chicks from normal asynchronous broods. Only growth rates in mass showed significant variation. Within a brood, B chicks grew more slowly than A chicks. The effect of synchronizing a brood was to lower the growth rate of both chicks to that of a B chick, suggesting that equal-sized siblings feed less efficiently. Chicks hatching from larger A eggs, that had been synchronized for age and size with chiçks from B eggs, did not grow faster, indicating that chicks hatching from A and B eggs do not have intrinsically different growth rates. Single-chick nests result usually from egg infertility. Singletons showed only a non-significant trend towards faster growth in mass than offspring in two-chick broods, even though food availability in one-chick nests should be better than in two-chick nests. Overall, hatching order had more impact on growth rates of mass than did brood size or egg dimensions.  相似文献   

The molecular identification and genetic diversity of economically important wireworm species (Coleoptera: Elateridae) in Canada     

Carly M. Benefer  W. G. van Herk  J. S. Ellis  R. P. Blackshaw  R. S. Vernon  M. E. Knight 《Journal of pest science》2013,86(1):19-27

Click beetle larvae (wireworms) are significant crop pests in Europe and North America. In Canada, there are ~30 economically important species which are morphologically difficult to identify, but for which sequence data are lacking. Accurate knowledge of damage-causing species and the population genetics and phylogeography of elaterids will provide insight into their sustainable management. Here, we use interspecific variation in mitochondrial 16S rRNA as a robust method of identification, consider the intra- and interspecific genetic variation of some important Canadian wireworm pests and assess the genetic structure and isolation by distance for a re-emerging major pest species, Hypnoidus bicolor Eschscholtz. Wireworms were sampled from Canada and the USA, identified as morphospecies, and sequenced at the 16S rRNA region (294–442 bp). Within some species unusually high intraspecific genetic distances between samples suggested the possibility of cryptic wireworm species or misidentifications, though this was <1 % for most species. Phylogenetic analyses gave some indication of the likely identity of these ambiguous samples. There was a significant correlation between genetic and geographic distance and significant genetic structuring within and between H. bicolor populations, which appeared to be composed of two species comprising several haplotypes. These data provide a starting point for determining the distribution of damage-causing species throughout Canada. The inclusion of data from other nuclear and mitochondrial loci, and use of sequence data from known adult samples, would further aid identification and relationships of wireworm species.  相似文献   

Response of the dusky wireworm, Agriotes obscurus (Coleoptera: Elateridae), to residual levels of bifenthrin in field soil     

Willem G. van Herk  Robert S. Vernon  Selina McGinnis 《Journal of pest science》2013,86(1):125-136

To determine if bifenthrin residues elicit morbidity and surfacing behavior in wireworms, larvae of the dusky wireworm, Agriotes obscurus (Coleoptera: Elateridae) were placed in field soil treated with the pyrethroid insecticide bifenthrin ~1 year previous. Morbidity was immediate and lasted as long as wireworms remained in the soil, disappearing quickly after transfer to clean soil. In 2009, field soil treated 336 days previous with bifenthrin at 340 g AI/ha elicited morbidity symptoms similar to that elicited by soil freshly amended with bifenthrin at 100 g AI, and analysis of the field soil confirmed residual levels of bifenthrin exceeding 100 g AI/ha. In 2010, wireworms placed in field soil treated 343 days previous with bifenthrin at 100, 200, and 300 g AI/ha responded as in 2009, with the degree of morbidity increasing with the rate of insecticide, and with wireworms in a non-feeding state more affected than those in a feeding state at each rate. In both 2009 and 2010, moribund wireworms moved to the soil surface within 1 day of placement in the soil containing residual bifenthrin and remained there until reburied, after which they often resurfaced. To confirm that the bifenthrin residues elicited repellency, wireworms were placed in soil window bioassays containing field soil with residual bifenthrin. Wireworms behaved markedly different upon contacting soil containing the residues than when exposed to untreated soil, both in the presence and absence of an attractant, but were less likely to avoid soil containing residual bifenthrin when attracted by wheat seedlings placed inside it.  相似文献   

Vaccination in the field of veterinary science today     

J.H. van der Kolk 《The Veterinary quarterly》2013,33(2)

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Influence of ante‐ and peri‐mortem factors on biochemical and physical characteristics of turkey breast muscle     

J. van Hoof 《The Veterinary quarterly》2013,33(1):29-36

Summary

The course of post‐mortem breakdown of glycogen and ATP in turkey pectoralis major muscle was markedly influenced by several ante‐ and peri‐mortem variables. Application of a proper stunning procedure was highly effective in preventing peri‐ and post‐mortem muscle stress reactions.

The physiological level of glycogen and ATP was not significantly affected by road transportation covering 260 km. Birds which rested for 24 hrs following transportation had lower glycogen and ATP levels at the moment of slaughter than non‐rested birds.

According to the changes in the rate and extent of post‐mortem biochemical reactions, several meat characteristics such as water‐holding capacity, colour, and tenderness were significantly changed.

Furthermore, the results also indicate that turkey breast muscle is susceptible to a PSE‐like condition as described in pork.  相似文献   

Streptococcus suis type 2 infections in pigs in the Netherlands (part two)     

L. A. M. G. van Leengoed  U. Veche  E. R. M. Verheyen 《The Veterinary quarterly》2013,33(2):111-117

Summary

Since 1983 some pig breeding and fattening farms in the Netherlands have been faced with a considerable mortality in pigs due to Streptococcus suis type 2 infections. The most predominant clinical feature of S. suis type 2 infection is meningitis, although sudden deaths often occur. It was noted that some affected farms had imported breeding stock from the United Kingdom.

Tonsils of slaughter pigs were collected from herds with and without a history of S. suis type 2 infections. Bacteriological examination was done by using an elective‐selective medium. No significant difference was found in carrier rates of S. suis type 2 between clinically healthy and affected herds (38% vs. 45%).

A cohort study was carried out by regular bacteriological examination of tonsil biopsies on a farm with a high incidence of streptococcal meningitis. Twenty‐seven percent of the pigs were carriers of S. suis type 2 at nine weeks of age. Possible methods for disease control are discussed.  相似文献   

Destructive cholangiolitis in seven dogs     

T. S. G. A. M. van den Ingh  J. Rothuizen  H. M. S. van Zinnicq Bergman 《The Veterinary quarterly》2013,33(4):240-245

Summary

In seven dogs presented with clinical signs and laboratory data suggestive of extrahepatic cholestasis, destructive cholangiolitis was diagnosed. The diagnosis was based on the absence of extrahepatic cholestasis at laparoscopy, laparotomy and/or post‐mortem examination, and the presence of specific liver lesions i.e. loss of bile ducts in the smaller portal areas. The disease is compared with drug‐induced (chlorpromazine) cholestasis in man. In two dogs clinical signs were preceded by longstanding respectively repeated sulphonamide medication.  相似文献