The effects of feeding strategy on subcutaneous, perirenal adipose tissue and ribeye (longissimus dorsi) muscle fatty acid profiles were evaluated from 60 bison (Bison bison) bulls from Western Canada. Treatments included Forage Fed (n=19); short term concentrate feeding, <90 Day (n=9); mixed forage and concentrate feeding, 50:50 Forage:Grain (n=20); and Feedlot Finishing (n=12), and were analyzed for interactions and main effects between treatment and tissue type. Saturated fatty acids were found in larger (P<0.05) proportions within perirenal tissue for all treatments. Polyunsaturated fatty acids were concentrated (P<0.05) in the intramuscular tissue. Polyunsaturated fatty acid content was greater (P<0.05) in Forage Fed and 50:50 Forage:Grain than in <90 Day or Feedlot Finishing treatments. The polyunsaturated to saturated fatty acid ratio was greatest (P<0.05) for Forage Fed followed by 50:50 Forage:Grain, with <90 Day and Feedlot Finishing treatments having the lowest ratio. Linoleic acid content within intramuscular tissue was greatest (P<0.05) in the 50:50 Forage:Grain followed by the <90 Day treatment, with the Forage Fed group being intermediate, and the Feedlot Finishing being the lowest (P<0.05). Subcutaneous tissue contained more (P<0.05) conjugated linoleic c-9, t-11 acid than did intramuscular tissue. The conjugated linoleic c-9, t-11 acid content of intramuscular tissue was greater (P<0.05) in the Forage Fed and <90 Day treatments than in the 50:50 Forage:Grain and Feedlot Finishing treatments. Alpha-linolenic acid content was greatest (P<0.05) in intramuscular tissue of Forage Fed bison than the other treatments. Total omega-3 fatty acid concentration was greater (P<0.05), in the intramuscular tissue of Forage Fed bison, followed by <90 Day and 50:50 Forage:Grain being similar (P>0.05) with Feedlot Finishing having the lowest (P<0.05) content. Eicosapentaenoic, docosapentaenoic, and docosahexaenoic acid were all found in the greatest (P<0.05) proportion in the Forage Fed, and least (P<0.05) in the Feedlot Finishing treatment. </p> <p>The total omega-6 and arachidonic fatty acid content of intramuscular tissue was greater (P<0.05) in the Forage Fed and 50:50 Forage:Grain than in the <90 Day or Feedlot Finishing treatments. The omega-6 to omega-3 fatty acid ratio was greatest (P<0.05) for the 50:50 Forage:Grain followed by <90 Day with Feedlot Finishing being intermediate, and Forage Fed bison having the lowest (P<0.05) ratio. </p><p>Feedlot bison were compared to beef (<i>Bos taurus</i>) steers (n=4) and sheep wethers (<i>Ovis aries</i>) (n=3). Sheep had lower (P<0.05) saturated fatty acid content than did bison or beef in intramuscular tissue. Polyunsaturated fatty acid content of intramuscular tissue was greater (P<0.05) in bison than in beef or sheep. The ratio of polyunsaturated to saturated fatty acids was greater (P<0.05) for bison than for beef or sheep. The omega-6 to omega-3 fatty acid ratio was lower (P<0.05) for the bison than the beef, while sheep were intermediate (P<0.05).</p><p>Forage Fed bison compared to forage fed sheep wethers (n=3) showed that the ratio of polyunsaturated to saturated fatty acids was greater (P<0.05) in bison than sheep. The ratio of omega-6 to omega-3 fatty acids was similar (P>0.05) for both species.</p><p>Forage Fed bison yielded the greatest proportion of beneficial fatty acids amongst the bison treatments. Comparison of species under feedlot and forage finishing systems indicated bison to have a more desirable fatty acid profile than did beef or sheep finished under their respective systems.

Cattle consuming low-quality forage may have decreased forage organic matter intake as a result of decreased nitrogen (N) intake. To date, a value has not been assigned to dried distillers' grains as a protein supplement to cattle consuming low-quality Bermudagrass forage. To address this shortcoming in the data, 13 duodenally and ruminally fistulated steers were arranged in an incomplete 13 x 4 Latin square with 13 treatments and 4 periods. Treatments were arranged as a 4 x 3 factorial plus a negative control (NC), which received no supplement. The first factor consisted of 4 levels of supplemental protein provided at 52, 104, 156, and 208 mg N/kg BW. The second factor consisted of one of three supplemental protein sources, cottonseed meal (CSM), dried distillers' grains (DDG), and dried distillers' grains plus urea (DDGU). Total digestible organic matter (TDOMI), and total organic matter intake (TOMI) increased in response to the increasing level of supplemental protein (P <0.01). Similarly, digestible neutral detergent fiber intake (DNDFI) increased as a result of supplementation (P = 0.06). Forage organic matter intake did not increase as a result of protein supplementation (P = 0.20). However, forage organic matter intake (FOMI) responded quadratically to provision of CSM (P = 0.02). In contrast, DDG and DDGU did not significantly increase FOMI. Organic matter digestibility (OMD) tended to increase (P= 0.09) as a result of protein supplementation. Ruminal ammonia concentrations increased linearly in response to increasing provision of supplemental protein and were greater than control steers (P less than 0.01). Supplementation with DDGU resulted in the greatest increase in ruminal ammonia concentrations. Plasma urea nitrogen (PUN) concentrations increased in a linear fashion in response to CSM and DDGU supplementation (P less than 0.01), while provision of DDG resulted in a quadratic response (P = 0.08). Based on these results, DDG can be utilized as a protein supplement to increase TDOMI, however, it accomplishes this without significantly impacting FOMI which is in contrast to CSM.

A growth room experiment compared seedling growth after nine weeks of two wheat genotypes in pure cultures and mixtures with Italian ryegrass at a low phosphorus (P) level and the P level recommended by soil testing. At the recommended P level in both pure and mixed culture, Mit, a semi-dwarf genotype, had a greater height, leaf area, tiller number, and dry weight of leaves, stems and roots than did Kharkof, a landrace. These results reflected the visual selection criteria for seedling vigor and tillering used in the initial development of the semi-dwarf cultivars. Field experiments compared total dry matter, calories, and percent crude protein and acid detergent fiber of oats, wheat, and ryegrass in pure culture and mixtures at four locations in central Texas at first clipping, second clipping, and unclipped. Although, forage yield was lower for the first clipping than the second clipping or the unclipped treatment, the first clipping had the best forage quality. There was a strong environmental influence on yield and quality. The best forage was pure wheat at College Station, pure ryegrass at Marlin, the wheat-ryegrass mixture at Temple, and pure oats at Thrall. Since Temple had the greatest yield of any site, the wheat-ryegrass mixture demonstrated the highest yield potential. The soil adsorption characteristics of halosulfuron was examined using six soils. Soil adsorption of halosulfuron appeared to be a function of organic matter. Low Kf,ads values indicated that a relatively high plant availability of halosulfuron could be available for plant uptake. Sorghum produced in soils with a low organic matter content may experience injury because of the high plant availability.

The effects on vegetation of three small mammalian herbivores were determined experimentally in a subalpine meadow in southwestern Colorado. Pikas (Ochotona princeps) inhabit talus and forage on surrounding vegetation. Their foraging was consistent with predictions of central place foraging theory. Amount of foraging decreased with distance from talus, whereas selectivity increased. These patterns are expected to influence the resources used by pikas, and plant abundance and species richness increased with distance from talus, as predicted. Experimental exclusion of pikas demonstrated that a significant portion of the lower vegetational cover and species richness was due to pikas. A model postulating that the effects of pikas on vegetation resulted from a gradient in herbivory, and a corresponding gradient in the relative importance of herbivory and competition among plants, was generally supported. Total vegetational abundance and species richness increased in the absence of pikas. The increase in pika exclosures compared to controls was greatest near talus and decreased with distance. The initial effect of pika exclusion on cushion plants (assumed to be the poorest competitors among the plants in the absence of herbivory) was positive near talus, but was insignificant and tended to be negative at greater distance from talus. The prediction of eventual decline of cushion plant populations in the absence of pikas was supported in two of three sites after three years. The effects on vegetation of two co-occurring herbivores, pocket gophers (Thomomys talpoides) and voles (Microtus montanus), were evaluated using a factorial exclusion experiment. Non-independence of effects was assessed as presence of a significant interaction term in 2-way ANOVA. Gopher x vole interaction terms were at least marginally significant for many analyses. Results only weakly suggested direct foraging interactions between gophers and voles, but showed considerable importance of indirect, plant-plant interactions. Exclusion of either gophers or voles significantly increased vegetational abundance, however, no additional change in abundance resulted when both were excluded simultaneously. Exclusion of either increased forb abundance, and exclusion of gophers increased grass abundance. Only simultaneous exclusion of both, however, altered proportional abundances of plant groups.

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Throughout the history of man, and today more than ever, the ruminant animal has played and continues to play a role of great economic importance. The reason for this importance is due to the presence in these animals of the reticulo-rumen as part of their gastro-intestinal system,which enables the ruminant to utilize roughages as sources of energy, protein, vitamins, and other nutrients. The ruminant has traditionally been the intermediary for the conversion of forage crops into meat, milk and wool. Probably, without ruminant animals, much of the crops now consumed by them would be returned to the soil or consumed by organisms that cannot be utilized by man. [...]