Relationships between alkaloid compounds in endophyte-infected tall fescue and ruminal metabolism were studied in two experiments. In the first experiment, different combinations of the pyrrolizidine alkaloids, N-formyl and N-acetyl loline, were incubated with ruminal fluid for 0, 24, or 48 h. Rate of disappearance of N-formyl and N-acetyl loline increased over time. After 48 h, disappearance of N-formyl loline and combinations of N-formyl and N-acetyl loline was greater than N-acetyl loline. Significant amounts of N-formyl and N-acetyl loline were metabolized and converted to loline. In the second experiment, abomasally cannulated sheep were fed increasing amounts of endophyte-infected feed to compare diet digestibility, alkaloid metabolism, and physiological responses. Total tract DM digestibility was greatest for the endophyte-free diet, as were ruminal and total tract ADF, ruminal NDF, and total tract CP digestibilities. N-Formyl and N-acetyl loline recoveries averaged 5% from abomasal contents and 0% in feces. Sixty-eight percent of the pyrrolizidine alkaloids recovered in abomasal contents had been metabolizable to loline. Ergot alkaloids administered in the diet were recovered (50 to 60%) in the abomasal contents, but recovery was only 5% in fecal collections. No significant differences occurred in the physiological parameters measured. Results indicate that response to endophyte-infected tall fescue may be influenced by ruminal metabolism.
Two trials were conducted to study ruminal lactic acid, histamine, tyramine and tryptamine concentrations following glucose engorgement in vitro and in vivo. Also, electrolyte changes in rumen fluid, blood plasma and urine during lactic acidosis were examined.Experiment 1 involved the addition of glucose to rumen fluid in vitro. After 30 hr of incubation, decreases in pH and increases in lactic acid were consistent with the expected development of acidosis. Tyramine levels increased dramatically. When graded levels of L-histidine were added with glucose, histamine concentrations increased accordingly.In the second experiment, four ewes were dosed with a mixture of 90% glucose and 10% casein. Ruminal pH values decreased while the ruminal lactic acid concentrations increased. Ruminal tyramine and tryptamine concentrations increased. The ruminal histamine concentration did not change significantly. Significant changes were observed in ruminal concentrations of calcium, magnesium and sodium in plasma, and concentrations of magnesium, sodium, potassium, and inorganic phosphate in urine. (
Interaction between deer and cattle took various forms. The potential for direct competition was greatest in spring. Both deer and cattle selected bluebunch wheatgrass and crested wheatgrass while Sandbergs bluegrass was most often used by deer. Evidence of indirect interaction was observed. Moderate or heavy fall grazing by cattle made the spring forage more attractive to deer by removing mature forage. Light grazing did not exert any appreciable effect on deer distribution. The spring range of mule deer in south central British Columbia is relatively restricted, usually below 775 m elevation. This range is also used by cattle in both spring and fall, providing forage at a time crucial to a viable ranching operation. Common use of the range ensures that interaction between cattle and deer will occur. The type and extent of interaction was not known but was believed to be most critical in the food niche. A project was initiated in 1972 near Kamloops, British Columbia, to study interaction between the two species of ungulates for the range resource in terms of food, time and space. The study was supported by the Agriculture Canada Research Station, the British Columbia Fish and Wildlife Branch, and the British Columbia Ministry of Forests. Some of these have been reported previously (Tucker et al. 1976; Willms et al. 1976; McLean and Willms 1977; and Tucker et al. 1977). Site Description The study area was on the north side of Kamloops Lake, about 24 km west of Kamloops. This area lies within the big sagebrush (Artemisia tridentuta), ponderosa pine (Pinusponderosa), and Douglasfir (Pseudotsugu menziesii) zones. The land rises steeply from the lake, at 335 m, to a series of knolls and a relatively flat area before rising again within the open forest. Maximum elevation on this range is 760 m. Snowfall is light and the direct southern exposure promotes early growth and a warm environment. The range had been heavily grazed from 1947 until 1965, when the grazing permit was cancelled to allow rehabilitation of overgrazed areas. One hundred hectares on the flat area were seeded to crested wheatgrass (Agropyron deserforum) in 1968. Cattle normally use this range from early November to mid-December and again from early April to the end of May. The same area may be occupied by deer from early December to the end of May, although the greatest use occurs in a l-month period in March and April. Some deer may remain on this range into the summer. Methods Four habitats were recognized on the study area. The forested range I IIC author\ arc pradudte student. Plant Science. Untver\lty ot Alberta; research \c'lc'ntl\t ,rnd range tcchllician. Research Station. Agmulture Canada; and wlldlit'e hlok~gl~t. Britt\h Columht~ Fish and Wtldlit'e Branch. Camloops. B.C. Contrthutton no. ,-I) I hc' authors m pratetul for the dedicated ushlstanct' ot L. Stroe\\er and L. Haupt, tcchnlcI,In\. during the courx ot the project. .\l,rnuxmpt raxIvcd April
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