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Biomedical subjects

E D Marshall

Publications and source records attributed to E D Marshall.

5 recordsLinked to original sources
PubMed1997

Musculoskeletal symptoms in New South Wales dentists.

This study describes the prevalence and distribution of symptoms of musculoskeletal disorders occurring in New South Wales dentists and investigates the relationship between these symptoms and work practices. Four hundred and forty two members of the Australian Dental Association (New South Wales Branch), were randomly selected and sent questionnaires. Eighty per cent (n = 355) responded. No significant differences in reported symptoms were found when considering age, experience, handedness, operating position or period of working without a break. Eighty-two per cent of the respondents reported experiencing one or more musculoskeletal symptoms during the previous month. Sixty-four per cent of the sample reported suffering pain (the majority reported back pain) and 58 per cent headaches. Most severe symptoms reported were pain (39%) and headaches (25%). Those in the youngest age category of less than 35 years (26%), were significantly more likely to have headaches (chi 2 4df p < 0.05). Female dentists were more likely to rate the severity of their most severe symptom higher (chi 2 1df p < 0.05), and to report more frequent pain (chi 2 2df p < 0.05) and headaches (chi 2 2df p < 0.05). Those practising four-handed dentistry were significantly more likely to be in the 35-44 age range (chi 2 4df p < 0.01), to work for longer periods before taking a 10-minute break (chi 2 5df p < 0.05) and to report frequent pain (chi 2 2df p < 0.05). The results support the findings of previous studies conducted overseas but additional information about musculoskeletal symptoms in this occupational group has been identified.

Adult↗
PubMed1987

Economics of a dry-cow anthelmintic drenching programme for dairy cows in New Zealand. Part 1. Overall response in 47 herds.

Trials were conducted on 47 seasonal supply dairy farms (greater than 5500 cows) to assess the economics of a dry-cow anthelmintic drenching programme. The programme was administered during the autumn/winter of 1983 and consisted of two treatments, the first shortly after drying off (late April-early June) and the second shortly before calving (mid-July-late August). The effects of the programme on the body condition of cows over winter and their subsequent milk production and reproductive performance were assessed. Overall, the treatment did not result in a worthwhile improvement in cow condition over winter. However, there was a small, but significant overall increase in milk production (2.24 kg milkfat/cow/lactation = 51.5 l milk; P less than 0.01). Young cows (3 years old) did not respond significantly better than mature cows, but high quality cows (as assessed on the basis of the previous season's milk production) responded significantly better than those of poorer quality. The pre-calving condition of cows did not significantly influence the magnitude of their response. Calving data for the year following the trials indicated that conception rates and time of conception were unaffected by the drench programme. At prices prevailing at the time of the trials, the programme proved to be only marginally economic overall (approximately 1 kg milkfat/cow was required simply to cover the cost of the anthelmintic used). However, levels of response in the individual herds involved varied considerably.

Animals↗
PubMed1987

Economics of a dry-cow anthelmintic drenching programme for dairy cows in New Zealand. Part 2. Influence of management factors and other herd characteristics on the level of response.

The results of a series of trials conducted on 47 seasonal supply dairy farms in the southern North Island of New Zealand, which indicated a statistically significant overall production response of 2.24 kg milkfat/cow/lactation following a 2-treatment dry-cow anthelmintic drenching programme (Bisset et al., 1987), were subjected to further analyses in an attempt to identify any management factors or herd characteristics which may have influenced the levels of production response to treatment in individual herds. The management factors examined included calf drenching practices, types of grazing system, mean pre-calving condition of the herds, and 'nutritional status' of the herds over the milking season. The influence of herd quality, herd size and geographical location were also examined. Considered separately, only calf drenching practice had a significant influence on the level of herd response to treatment. Increases in milkfat production/cow due to the treatment programme were significantly greater (P less than 0.05, t-test) on farms where calves had received a minimal number of drench treatments (less than or equal to 2) between weaning and the end of March (mid-autumn) (+5.32 kg/cow/lactation, P less than 0.01) (= 108.2 l milk), than on farms where calves had received regular 3-4 weekly treatments over the same period (+0.42 kg/cow/lactation, N.S.) While none of the other factors, considered in isolation, appeared to significantly influence the production response of herds, observations on possible interactive effects suggested that the grazing system employed was probably of importance in so far as it determined the level of exposure of cows to calf-contaminated pasture. Thus, the greatest mean response to the treatment programme occurred in herds where cows were overwintered on areas grazed during the milking season by calves which had received less than or equal to 2 drench treatments from weaning until the end of March (+5.95 kg milkfat/cow/lactation, P less than 0.01).

Analysis of Variance↗
PubMed1987

Dynamics of Ostertagia spp. and Cooperia oncophora in field-grazed cattle from weaning to 2 years old in New Zealand, with particular reference to arrested development.

Gastrointestinal nematode parasite burdens were monitored in a herd of field-grazed cattle from weaning to 2 years old to allow observations to be made on the dynamics of burdens of arrested Ostertagia spp. and Cooperia oncophora. Arrested Ostertagia spp. accumulated in the herd over their first autumn and winter to reach a peak in late winter/spring (August-October). From October until late January they declined at a rate comparable to that at which they had accumulated. Numbers continued to decline at a slower rate until the following autumn (May) when they began to increase again. Observations on the decline of worm burdens in a group of animals which had been moved from pasture to worm-free conditions in October indicated that intake of infective larvae over late spring/summer contributed little to the number of arrested Ostertagia spp. in the herd. No clinical Type II ostertagiosis was observed in the field-grazed animals over the time of decline of the arrested worm burden, nor was there an increase in the number of adult Ostertagia spp. present. However, two of the animals removed from pasture to worm-free conditions developed Type II ostertagiosis approximately a month after the move. Worm burdens of successive groups of "tracers" grazed with the herd every 2 months indicated that there was a small seasonal increase in the propensity of Ostertagia spp. for arrested development. However, estimated accumulation rates of arrested larvae calculated from tracer worm burdens, suggest that this seasonal increase in propensity was not adequate in itself to account for the accumulation rate observed in "resident" animals of the herd. No comparable accumulation of arrested C. oncophora took place in resident animals over the first autumn and winter of the trial despite the fact that tracer worm burdens over this period indicated a marked seasonal increase in the propensity for arrested development by this species.

Animals↗