Lice and mite infestations of cattle in Iceland
The aim of the present study was to survey lice and mite species infesting cattle in Iceland and to evaluate their prevalence on farms, prevalence and site preferences on the animals and correlation with dermatological symptoms. The survey included two separate investigations, a combing study including 50 calves and 50 dairy cows, and a study of skin samples including 27 bullocks and 28 dairy cows. The animals came from farms in Southwest Iceland. In the combing study five preselected areas on each animal were combed. Two lice species were found, the chewing louse Bovicola bovis and the sucking louse Solenopotes capillatus. Lice were found at 7 of 10 farms. B. bovis was found at 50% and S. capillatus at 40% of the farms and both species occurred at 20% of the farms. Lice were found on 40% of the calves and 4% of the cows. B. bovis was found on 28% of the calves and 2% of the cows. S. capillatus was detected on 16% of the calves and 2% of the cows. B. bovis was most prevalent on back and rump, less prevalent on the head, neck and tail and was not detected on the front leg. S. capillatus was most prevalent on the neck, then head and front leg, and was least prevalent on the posterior back and rump and on the tail. Minor dermatological signs were seen on two cows and three calves. In the study of skin samples, samples were taken from five preselected sites of the animals. In this study the hair follicle mite Demodex bovis was found in the skin of the neck of one bullock (1.8%). No macroscopic skin disorders were observed on the samples.
A longitudinal study of a natural lice infestation in growing cattle over two winter periods.
A group of 61 cattle which were naturally infested with lice was followed over two winter periods. Data were collected on the number of lice found at various body sites over this period. Summary statistics were produced and due to the repeated measured and hierarchical structure of the data, multi-level analysis was used to model the population dynamics of Bovicola bovis and assess the influence of the various hierarchical levels. A four level Poisson model was produced-level one, the individual number of lice at each parting; level two, the body site examined (shoulder, midline or rump); level three, the time of the inspection and level four, the animal. Seasonal fluctuation in lice numbers was modelled using a cosine function transformation of time. A seasonal pattern was seen in both years with lice counts higher in the first than the second year. The midline area was the most sensitive to detection of B. bovis. Variance contributed by the individual animal was less than that contributed by the body site examined and the time of the inspection. The model suggested that lice numbers within the shoulder and rump sites were near random following a Poisson distribution, but aggregation of lice occurred at the midline site with the distribution between animals following a Negative Binomial Pattern. The midline site was the most sensitive site for detecting B. bovis. Infestation numbers were higher in the first winter when cattle were younger. In the second winter, there was no difference in lice numbers between cattle exposed to infection for the first or second time.
Analogy, Supposition, and Transcendentality in Narrative Argument
Rodden writes, “How do stories persuade us? How do they ‘move’—and move us? The short answer: by analogies.” Rodden’s claim is a natural first view, also held by others. This chapter considers the extent to which this view is true and helpful in understanding how fictional narratives, taken as wholes, may be argumentative, comparing it to the two principal (though not necessarily exclusive) alternatives that have been proposed: understanding fictional narratives as exhibiting the structure of suppositional argument, or the structure of a kind of transcendental argument. Three key aspects of understanding a fictional narrative as an argument from analogy are identified. First, the argument will be relativistic or depend in an essential way upon the circumstances or intentions of the auditor or author. Second, in view of the first aspect, the argument will be loose and subjective, and accordingly less likely to yield knowledge. Third, the argument will not exhibit a distinctive structure applicable only to fictional narratives. I find that the third, and sometimes the first and second, of these same three aspects apply to understanding fictional narratives as suppositional arguments. I present considerations that point to a way of establishing that some extended fictions exhibit the structure of a kind of transcendental argument that is neither relativistic nor subjective, is knowledge-generating, and is uniquely applicable to fictional narratives. This supports literary cognitivism—the thesis that “literary fiction can be a source of knowledge in a way that depends crucially on its being fictional.”