The Influence of Age and Winter Environment on Protein Block Intake Behavior of Beef Cattle Winter Grazing Mixed-Grass Rangelands

This study evaluated the influence of cow age and temperature adjusted for windchill (Twindchill) on supplement intake behavior of cattle winter grazing rangelands. A mixed-age herd of Angus-based cows (291 and 316 in year 1 and 2, respectively) were classified by age (1-, 2-, 3-, 4-, 5–7-, and ≥8-year-old) and grazed rangeland pasture (329-ha) for two consecutive winters. Cows were provided free-choice access to supplement protein blocks in a SmartFeedPro self-feeder system. An Onset HOBO Weather Station collected data throughout the grazing period. Supplement intake (expressed as kg∙d−1 and g∙kg body weight−1), the coefficient of variation in supplement intake and intake rate (g∙min−1) displayed Twindchill × cow age × year interactions (p ≤ 0.02). In general, cow age displayed a quadratic effect on all supplement intake variables (p ≤ 0.04), where 3- to 4-year-old cattle had the greatest supplement intake with the least variation, while yearling cattle had the least amount of supplement intake and the greatest variation. In conclusion, winter environmental conditions interacted with cow age to affect cattle supplement intake behavior and, consequently, the efficacy of nutrient delivery systems for beef cattle winter grazing on rangelands.

Grazing Sheep in Organic Vineyards: An On-Farm Study about Risk of Chronic Copper Poisoning

Many winegrowers and sheep breeders are interested in wintertime grazing in vineyards, as an agroecological alternative to mowing or herbicide spraying, and additional supply of forage. Still, strong concern is raised by the use of copper-based fungicides, particularly in organic vineyards, since copper is known to induce chronic toxicosis in sheep. We conducted an on-farm study with n = 12 1-year-old Merinos × Mourerous ewes grazing the cover vegetation of vineyard plots during wintertime, in order to check whether this agricultural practice might be harmful to sheep. Our results indicate that most copper found in the cover vegetation originates from fungicide spraying versus plant uptake from the soil, and that rain-induced washing-off and plant growth-triggered dilution of copper are crucial to reach close-to-safe grazing conditions. Furthermore, we found that while sheep remained globally healthy during the 2 months of the experimental period, the plasma activity of Glutamate Dehydrogenase increased by 17.3 ± 3.0 U/L upon vineyard grazing (p < 0.001), reflecting liver storage of copper. We also discovered that the dynamics of molybdenum in sheep plasma are strongly affected by exposure to copper, suggesting a possible adaptation mechanism. Overall, our results suggest that winter grazing of sheep in organic vineyards is reasonably safe, but that care should be taken about grazing period duration. More research should be conducted with respect to long-term copper accumulation, spring and summer grazing, and possible protective mechanisms against copper chronic poisoning.

Intake and digestibility of nutrients during the grazing period in sheep on deferred marandu pastures with four initial heights

The objective of this study was to verify the effect of reducing in pasture height at the beginning of the deferment period (PHBD) of Brachiaria brizantha cv. Marandu on nutrient intake and digestibility in sheep during winter. The combinations between average sward heights (15, 25, 35 and 45 cm) at the beginning of the deferment period and the times of sward use during the winter were evaluated; intake and digestibility evaluations were carried out at the beginning, middle and end of the grazing period, which lasted 90 days. The experimental design used was completely randomized, with three replications. The parameters evaluated were: intake and digestibility of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) and potentially digestible dry matter (pDDM). The pDDM contents were similar in pastures kept with 15 and 25 cm, but higher than those observed in pastures with 35 and 45 cm at the beginning of the deferment period. The NDF contents were lower and the CP and NDF digestibility were higher in 15 and 25 cm deferred pastures than in 35 cm at the beginning of deferment period, except for pastures lowered to 45cm. The improvement in nutritional value of the forage apparently ingested by sheep, promoted by ISP reduction, did not result in a variation in pasture consumption by the animals. DMI, expressed as percentage of body weight (%BW), ranged from 1.10 to 1.63. At the beginning of the grazing period, higher values of pDDM, CP and DM digestibility (DMD) were verified in simulated grazing samples. The same response pattern observed for nutritional value traits also occurred for DMI (g.day-1 and %BW) and CP intake. These were higher at the beginning, than at the middle and end of the grazing period. The use of lower sward heights at the beginning of the deferment period allowed the production of pasture with better nutritional quality, but these changes in the nutritional value of the pasture were insufficient to result in higher nutrient intake and digestibility. Furthermore, there was a reduction in nutritional value of the forage apparently consumed by sheep, in the intake and digestibility of deferred pastures throughout the grazing period, in winter. The lower pastures at the beginning of the deferment period (15 cm) improves the nutritional value of forage and nutrient digestibility at the beginning of the winter grazing period. The nutritional value and intake of deferred forage by sheep are compromised by the grazing period.

Reindeer Herding and History in the Mountains of Southern Sápmi

During the summers of 1998-2000 four Saami villages in southern Sapmi carried out a survey of traditional reindeer herding sites. Reindeer herding of today engages a small Saami minority, but the reindeer herders are important as bearers of Saami culture and language. Reindeer herding has, however, been called into question from several different directions. In this process, which often leads to court, the ability of the Saami villages to present evidence of previous reindeer herding in a region, either in written records or as remains in the landscape, has become an argument for the continued rights of use of certain winter-grazing areas. As a result, archaeology has acquired a new relevance for the Saami villages. But the procedures of archaeological surveys and of the cultural heritage conservation in Sweden are based on ethnocentric assumptions. In a cultural sense, Sapmi of the past and present-day Sweden belong to two different continents, even though they happen to be situated in the same comer of the world. When working with Saami history it is necessary to do away with the distinction between "nature" and "culture", just like a number of other dualisms that are relevant only in a (modern) Western context. If we replace "nature" and "culture" with "environment", we will increase our possibilities to translate Saami history into the language of archaeology and to make archaeology relevant to local people in the mountain region.

Use of Soapweed Yucca (Yucca glauca) by rodents and other vertebrates in western Nebraska

Soapweed Yucca (Yucca glauca) is a conspicuous and common shrub in the Great Plains of North America, characterized by tall woody flower stalks, large flowers and seed pods, and dense masses of ground-level evergreen leaves. These plant structures can provide a variety of resources or functions to animals. In general, studies focus on single species associated with Y. glauca. We examined three groups of vertebrates that interacted with Y. glauca and the functions this plant provided for organisms in western Nebraska. We experimentally examined small mammals in areas with and without Y. glauca, and we descriptively noted birds and reptiles that used Y. glauca. We documented six mammalian, 13 avian, and four reptilian species using Y. glauca for cover, perches, basking sites, homes, and/or nests. We documented a greater species richness and relative abundance of rodents in areas with Y. glauca compared to areas without Y. glauca. Deer Mice (Peromyscus maniculatus) showed the greatest difference in relative abundance, with about six times as many individuals in areas with Y. glauca (83 individuals) compared to areas without Y. glauca (14 individuals). Upon release, a majority of Deer Mice (94%) ran from trap sites to Y. glauca, as did most other mammalian species. We observed birds mainly perching on flower stalks, as well as a few nesting activities. Soapweed Yuccas provided herpetofauna homes, sites for thermoregulation, perches to watch for predators or prey, and protective cover under leaves. Our findings demonstrated some of the ecological functions for Soapweed Yucca and a variety of vertebrate species using this shrub in grassland ecosystems. Soapweed Yucca is considered a weed in some regions of the Great Plains due to its high abundance in pastures with domestic livestock. On ranches where American Bison (Bos bison) have been reintroduced, individuals consume and actively remove yuccas, especially during winter grazing, and large, multi-headed, aboveground complexes of Y. glauca are less common across such ranches. Our study assisted in understanding the role of this native shrub in managed grassland systems.

How Long Before a Second Defoliation of Actively Growing Grass Plants in the Desert Grassland?

In the Desert Grassland, second and subsequent defoliations on perennial grasses during the active growing season can have substantial impacts on grass recovery and reproduction following herbivory. Land managers implement tactics to avoid multiple defoliations on plants by way of rotational grazing, reduced stocking rates, and/or reduced time spent within a given pasture. We explored frequency and rate of defoliation by cattle on perennial bunchgrasses within an 11-day grazing period in three pastures including distance to water (300 and 600 m) and plant height to determine their influence on animal diet selection. Results indicate that 32% of all marked plants were defoliated by cattle and only 5% of defoliated plants were defoliated a second time by day 10 of the grazing period. Defoliation patterns in the studied pastures did not differ between two distances from water, or in relation to plant height. However, at the second defoliation cattle grazed plants that were shorter than at the first defoliation suggesting a selection for high quality re-growth over larger forage on offer. The results of this study show that a 10-day grazing period during the growing season of the Desert Grassland is an effective strategy to avoid second defoliations on individual perennial grass plants while maintaining sufficient forage for use during the dormant winter grazing season.