Diet selection by steers using microhistological and stable carbon isotope ratio analyses.

Two methods of determining diet botanical composition, microhistological (MH), and stable carbon isotope ratio (CR) analyses were used to determine botanical composition of ingesta and fecal grab samples in steers grazing rhizoma peanut-mixed tropical grass pastures. Three pastures were used over two grazing seasons, 1992 and 1993, in Brooksville, FL. A weighted-disc double-sampling technique was used to determine forage mass and botanical composition, percentage of rhizoma peanut (Arachis glabrata), grass (Paspalum notatum and Cynodon dactlyon), and forb (primarily Chenopodium ambrosioides) on offer every 28 d throughout the grazing seasons. There was an effect of sampling date (P<.001), sampling date x pasture (P<.001), and sampling date x year (P<.001) on forage mass on offer. There was a pasture x year x sampling date interaction (P<.001) for all botanical components. In 1992 and 1993, using cannulated steers sampled every 56 d, there were interactions with year for rhizoma peanut and forb (P<.05), but not for grass with MH analysis (components: rhizoma peanut, grass, and forb). Ingesta and fecal rhizoma peanut (r = .73 and .92 for 1992 and 1993, respectively) and ingesta and fecal forb (r = .86 and .98 for 1992 and 1993, respectively) were positively correlated (P<.001). Ingesta and fecal grass were positively correlated (r = .52, P<.001), but the correlation was not as high. With the CR analysis (components: Calvin cycle [C3] plants and C4-dicarboxylic acid pathway [C4] plants), ingesta and corrected fecal (corrected for in vitro organic matter digestibility [IVOMD]) C3 plants were positively correlated (r = .62; P<.001). Diet composition of fecal grab samples from noncannulated steers, collected on the same sampling schedule as for hand-clipped pasture samples, differed at times due to the complexity of the sward (both rhizoma peanut and forb constituted a single component, C3, in the CR analysis). Based on these results, if there is a substantial contribution of forb to the diet, fecal microhistological analysis may be more informative than fecal carbon ratio analysis for estimating diet selection by cattle grazing tropical pastures.     

Molecular phylogenetic analysis of felid herpesvirus 1.

The position of felid herpesvirus 1 within the alphaherpesvirus subfamily was investigated using molecular phylogenetic techniques applied to multiple sequence alignments of recently reported FHV-1 gene homologs (glycoprotein B, ribonucleotide reductase and DNA polymerase). FHV-1 was most closely related to other carnivore alphaherpesviruses, (phocid herpesvirus 1 and canid herpesvirus 1) and to the equid herpesviruses 1 and 4.     

Preliminary estimates of the direct costs associated with endemic diseases of livestock in Great Britain.

Many 'economic' studies of livestock diseases in Great Britain have been carried out over time. Most studies have considered just one or two diseases and used a different methodology and valuation base from other studies, hampering any comparative assessment of the economic impact of diseases. A standardized methodology was applied to the estimation of the direct costs to livestock production of some 30 endemic diseases/conditions of farm animals in Great Britain. This involved identification of the livestock populations at risk, estimation of the annual incidence of each disease in these populations, identification of the range and incidence of physical effects of each disease on production, valuation of the physical effects of each disease and estimation of the financial value of output losses/resource wastage due to a disease and the costs of specific treatment and prevention measures. The wider economic impacts of disease (such as the implications for human health, animal welfare and markets) were not included in the assessments. Using this standardized methodology with common financial values, a simple spreadsheet model was constructed for each disease. Given the paucity of appropriate disease data for economic assessment, 'low' and 'high' values were used to reflect uncertainties surrounding key disease parameters. Preliminary estimates of the value of disease output losses/resource wastage, treatment and prevention costs are presented for each disease. Despite the limitations of the spreadsheet models and of the estimates derived from them, we conclude that the models represent a useful start in developing a system for the comparative economic assessment of livestock diseases in Great Britain.     

The ecogeography and collection of grain, forage and pasture legumes in south-west Turkey

A collecting mission took place in June and July 1996 to collect legume species from south-west Turkey and western Anatolia. Sites were chosen to maximise the diversity of legumes collected and detailed passport data were recorded at each site. A total of 96 sites were visited, and 1307 accessions collected. In total 23 genera were collected, of which the most frequently seen were Trifolium, Medicago and Vicia. Sites were found to be almost exclusively calcareous with a pH range of 7 to 10, and varied from sea level to 1750m. Many of the Trifolium species are of economic importance for southern Australia and have been shown to display characters such as a high productivity (T. michelianum) and waterlogging tolerance (T. resupinatum and T. tomentosum). The Medicago species were found to prefer well-drained habitats in open areas. Many of these species can tolerate heavy grazing. The two main forage legume genera collected were Lathyrus and Vicia. Both of these occurred on the higher pH soils and were most frequently collected from the lower altitudes. Four species of grain legume were found, Cicer arietinum, Lens culinaris, Pisum sativum and Vicia faba. The material collected during this mission is important in the drive to preserve the legume genetic diversity of Turkey, the species' centre of diversity, for utilisation both within and outside of Turkey.     

Investigating decadal changes in persistent organic pollutants in Scottish grey seal pups

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