Native Range Pastures Research Articles

Efficacy of Saber Ear Tags on Horn Flies and on Calf Weaning Weights, Gudmundsen Sandhills Laboratory, Whitman, Nebraska, 1990

Abstract Crossbred cow/calf pairs, maintained on University of Nebraska-Lincoln Sandhills native range pastures were selected for use in this study. Saber (10% Lambdacyhalothrin) ear tags were applied to 30 cow/calf pairs (2 tags/cow). A second group of 30 cow/calf pairs were left untreated and served as a control. All calves were weighed 4 Jun, the same day the cows were tagged, and the cow/calf pairs were placed in appropriate pastures. The pastures were of equal size (623 acres) and had a good stand of native grass. Horn fly poulations were recorded weekly by counting the total number of flies on both sides of a cow. A minimum of 15 cows was included during each fly counting session.

Comparison of the Copper and Molybdenum Status of Yearling Steers Grazing Reclaimed Mined-Land and Native Range

Spoil material replaced after strip mining for lignite coal may differ from the original top soil with respect to concentrations of copper (Cu) and molybdenum (Mo), consequently levels of these elements may be affected in plants grown on this soil. The objective of the study was to compare the Cu and Mo status of yearling steers grazing mined-land and native range forage to determine whether mined-land grazed steers were more prone to molybdenosis and/or Cu deficiency. Vegetation samples were collected from both mined-land and native range pastures. Copper was marginal and Mo was slightly high, for beef cattle, in forage obtained from both study sites. Blood serum and liver biopsy samples were taken from yearling steers at the initiation and termination of grazing on reclaimed mined-land and native range in 1978, 1979, 1982, and 1983. For the 4 years, there was no significant difference between forage sources with respect to Cu and Mo levels in the liver or Mo levels in the serum. However, serum Cu was slightly (P<.10) lower in steers grazing on mined-land. Liver Cu levels were marginal in steers grazing on either mined-land or native range. Initial liver Mo levels were slightly above normal but did not increase to levels expected if animals were consuming a diet excessively high in Mo. No symptoms of Cu deflciency or molybdenosis were observed during the course of the study. However, marginal serum, liver and forage Cu levels measured suggest that central North Dakota ranchers should be alert to the possibility of a Cu deficiency, whether cattle are grazing reclaimed mined-land or native range.

Efficacy of Saber Ear Tags Against Pyrethroid Resistant Horn Flies, West Central Research Center, North Platte, Nebraska, 1989

Abstract Saber (10% Lamdacyhalothrin) ear tags were applied to 180 crossbred replacement heifers which grazed a native range pasture. A similar group of 15 heifers were without fly control and considered the control. Horn fly counts were made weekly by counting the total number of horn flies/animal with a minimum of 15 animals included during each counting session.

Efficacy of Terminator and Atroban Ear Tags on Resistant Horn Fly Populations, Meat Animal Research Center, Clay Center, Nebraska, 1987

Abstract Three groups of 200 crossbred cow/calf pairs, maintained on separate native range pastures at the Meat Animal Research Center, Clay Center, Nebraska, were used in this study. Terminator ear tags were applied to one group of cows (one tag/cow); Atroban tags were applied to another group of cows (one tag/cow); and the third group of cows received no insecticide treatment. There were about 200 cow/calf pairs/treatment. Ear tags were applied during the first wk of Jun. Fly numbers were recorded on a bi-monthly basis, counting the total number of horn flies on both sides of a cow. A minimum of 15 cows were included at each fly oounting period.

Efficacy of Terminator Ear Tags on Pyrethroid-Resistant Horn Flies and on Calf Weaning Weights and Performance, Gudmundsen Sandhills Laboratory, Whitman, Nebraska, 1987

Abstract Crossbred cow/calf pairs, maintained on University of Nebraska-Lincoln Sandhill native range pastures, were selected for use in this study. Three treatments were evaluated: Treatment I, cows tagged with one Terminator ear tag, calves not tagged; Treatment II, calves tagged with one Terminator ear tag, cows not tagged; and Treatment III, cows and calves not treated. Cow/calf pairs were allotted to treatment by cow weight with an equal number of steers and heifers/treatment. The number of cow/calf pairs/ treatment were as follows: Treatment I, 49 cows/calf pairs; Treatment II, 50 cow/calf pairs; Treatment III, 50 cow/calf pairs. The animals were tagged and weighed 2 Jun, and the cow/calf pairs were then placed in appropriate pastures. The 3 pastures were of equal size (623 acres) and had an excellent stand of native grass. Pretreatment horn fly numbers were recorded prior to the start of the study, and on a bi-monthly basis thereafter. Fly numbers were recorded by counting the total number of horn flies on both sides of a cow. A minimum of 15 cows were included during each fly counting period.

TRAPPING MALE MOTHS OF GRAMMIA BLAKEI (GRT.) (LEPIDOPTERA: ARCTIIDAE) WITH FEMALE-BAITED TRAPS AT GROUND LEVEL

Woolly-bear caterpillars of Grammia blakei (Grt.) are sometimes abundant in early spring on overgrazed native range pastures in southern Alberta and southwestern Saskatchewan, occasionally reaching population densities exceeding 50 per square metre (Byers 1988). Grammia blakei has a wide distribution in the Great Plains and Intermountain regions of western North America. Although the brownish-black caterpillars are quite often abundant, the moths (Fig. l), which are not attracted to food baits or light traps, have been rarely collected and few field-caught specimens are present in collections (D.C. Ferguson, U.S. National Museum, Washington, DC; J.D. Lafontaine, Biosystematics Research Centre, Ottawa, personal communication).

WOOLLY-BEAR CATERPILLARS OFGRAMMIA BLAKEI(GRT.) (LEPIDOPTERA: ARCTIIDAE) — AN OCCASIONAL PEST OF NATIVE RANGE PASTURES AND ADJACENT CROPS IN SOUTHERN ALBERTA AND SOUTHWESTERN SASKATCHEWAN

AbstractThe woolly-bear caterpillars ofGrammia(=Apantesis)blakei(Grt.) are sometimes abundant on native range pastures in the short-grass region of southern Alberta and southwestern Saskatchewan and occasionally cause early season damage to adjacent cultivated crops. The larvae overwinter as mid- to late-instars in protected sites on the soil surface and begin feeding in the spring as soon as new plant growth is available. They are general feeders on both mono- and dicotyledonous plants. Larval densities exceeding 10/m2were found at several locations from 1982 to 1985 and historical records indicate that densities sometimes exceed 50/m2. The moths are present in late May through June but are rarely observed or collected. In Canada the species is univoltine with a mid-larval summer diapause.