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ABSTRACT: Three dosage levels of febantel were tested for anthelmintic activities in calves under field conditions. A total of 20 feeder calves affected with naturally occurring gastrointestinal parasites were used in the controlled test. The calves were allotted to 4 groups of 5 each on the basis of degree of parasitism, body weight, age, and sex. Calves in groups II through IV were treated with febantel paste formulation at dosage levels of 5, 7.5, and 10 mg/kg of body weight; calves in group I were used as nonmedicated controls. Calves were euthanatized and necropsied 7 days after treatment. Medications were 97% to 100% effective against the adult forms of Haemonchus placei, Trichostrongylus axei, Cooperia pectinata, C oncophora, Nematodirus spathiger, and Oesophagostomum radiatum; 93% to 98% against Ostertagia ostertagi; and 78% to 95% against Trichuris sp. There were no differences in efficacies of the 3 dosage levels used against adult worms. Efficacy varied from 61% to 96% against larvae of O ostertagi. Activity was not detected against the tapeworm Moniezia benedeni. Medicated cattle did not show signs of intoxication.
American Journal of Veterinary Research 01/1983; 43(12):2248-9. · 1.27 Impact Factor
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ABSTRACT: Two established tall fescue pastures were used in a 4-year study of the relationship between the level of gastrointestinal parasitism in cattle and the level of nitrogen fertilization of the pasture. One pasture was fertilized with 224 kg of NH4NO3/ha each year and served as the control. A second pasture, referred to as the low-fertilized (LF) pasture, was fertilized with N at 84 kg/ha the first year and 74 kg/ha in each of the next 3 years. Both pastures were stocked with Angus cows (2.5/ha) and their calves. Rectal fecal samples obtained every 6 weeks from 10 cows and as many calves as possible in each pasture were examined for nemotode eggs and coccidia oocysts. Two calves from each group were slaughtered at the end of each of the last 3 years to determine the numbers and species of parasites. Cows had significantly lower egg counts than did the calves. Egg counts did not differ between the two groups of cows, but the control cows had higher average weights than the cows on the LF pasture. Control calves had significantly lower egg counts than the calves on the LF pasture, but only slightly higher mean adjusted 205-day weights. At necropsy, significantly fewer worms were recovered from the controls (17,977) than from the LF-pastured calves (52,332). Cooperia oncophora was the predominant species. The level of coccidia infection did not differ between the two groups of cows and calves. The greater availability of forage in the control than in the LF pasture probably was responsible for the lower level of parasitism in the control calves and for the greater weight gains made by the control cows and calves.
American Journal of Veterinary Research 07/1980; 41(6):893-8. · 1.27 Impact Factor
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Journal of Animal Science 04/1979; 48(3):673-82. · 2.10 Impact Factor
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ABSTRACT: Sixty commercial-grade calves naturally infected with tapeworms (Moniezia benedeni and M expansa) were used in a controlled experiment to evaluate the anthelmintic efficacy of 4 dose levels of albendazole. Calves were randomly divided into 5 groups of 12 each. One group served as non-medicated controls. Other groups were drenched with albendazole (methyl [5-(propyltion)-1H-benzimidazol-2-yl] carbamate) at dose rates of 20, 10, 5 and 2.5 mg/kg of body weight. Calves were necropsied 14 days after treatment. Doses of 20 and 10 mg/kg were 100% efficacious in reducing the number of tapeworm scolices, and doses of 5 and 2.5 mg/kg were 97.8%. Medicated cattle did not show signs of intoxication.
American Journal of Veterinary Research 04/1978; 39(3):517-8. · 1.27 Impact Factor
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American Journal of Veterinary Research 10/1977; 38(9):1335-9. · 1.27 Impact Factor
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ABSTRACT: The efficacy of the morantel sustained release bolus (MSRB) in controlling gastrointestinal parasitism in beef cattle was assessed during the 1982 spring-autumn grazing season. Forty-eight cows and their calves were allotted to three equal groups. One group (T-1) served as a nonmediated control group. One MSRB was administered to each calf of the T-2 group, and to each cow and calf of the T-3 group at the beginning of the study. The efficacy of the bolus was assessed by comparison of weight gain performance and parasitological data (fecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial calves, and plasma pepsinogen level determinations).Though not statistically significant, treated calves from Group T-2 had a numerical mean weight gain advantage of 2.6 kg, and those from Group T-3 of 4.7 kg, over control calves. Average daily gains (ADG) for the three groups of calves were 0.69, 0.72, and 0.73 kg, respectively. Untreated cows from Group T-2 and treated cows from Group T-3 outperformed the control cows by 12.3 and 7.5 kg, respectively. Fecal worm egg counts from both groups of treated calves were significantly (P < 0.01) lower than counts from control calves during the entire 169-day trial; notably, egg counts were reduced by 99% 28 days after MSRB administration to both groups of calves. There were no significant differences in the number of eggs counted from the three groups of cows, probably because of the very low numbers of eggs encountered. Mean total worm burdens of principal calves (six per group) necropsied at trial termination indicated a 91% (P < 0.01) reduction in Group T-2 and an 87% reduction (P < 0.01) in Group T-3. Worm-free tracer calves were introduced onto pastures every 28 days to monitor availability of infective larvae. The mean number of worms recovered at necropsy from tracer calves that grazed with control cattle increased as the season progressed. However, the numbers of parasites recovered each month from mid-August through mid-October from tracers that grazed pastures with treated cattle were lower (P < 0.05) than those levels displayed at trial initiation. In addition, the mean numbers of worms from treated group tracers were lower than from the controls for each necropsy period. From 84 days post-treatment through the end of the experiment plasma pepsinogen levels remained lowest (P < 0.05) in the treated calves and cows throughout the grazing season.
Veterinary Parasitology.
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ABSTRACT: The pathophysiology of fescue toxicosis is discussed relative to observed symptoms and the inhibition of animal production (average daily gain and decreased reproductive efficiency). Hyperthermia, vasoconstriction and perhaps increased activity of hepatic mixed-function oxidases are important effects. Perhaps secondarily intake is reduced by the above mechanisms and possibly by unpalatability factors. The decreased milk yield is considered a function of decreased intake and suppressed prolactin secretion. Evidence is discussed that corpora lutea in cattle are morphologically altered and consequently may not support a pregnancy. The effect of endophyte presence upon the outcome of pregnancy in the mare is considered a function of an alteration in placental function as a result of vasoconstriction.
Agriculture, Ecosystems & Environment.
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ABSTRACT: Soil organic C (SOC) and total soil N (TSN) sequestration estimates are needed to improve our understanding of management influences on soil fertility and terrestrial C cycling related to greenhouse gas emission. We evaluated the factorial combination of nutrient source (inorganic, mixed inorganic and organic, and organic as broiler litter) and forage utilization (unharvested, low and high cattle grazing pressure, and hayed monthly) on soil-profile distribution (0–150 cm) of SOC and TSN during 12 years of pasture management on a Typic Kanhapludult (Acrisol) in Georgia, USA. Nutrient source rarely affected SOC and TSN in the soil profile, despite addition of 73.6 Mg ha−1 (dry weight) of broiler litter during 12 years of treatment. At the end of 12 years, contents of SOC and TSN at a depth of 0–90 cm under haying were only 82 ± 5% (mean ± S.D. among treatments) of those under grazed management. Within grazed pastures, contents of SOC and TSN at a depth of 0–90 cm were greatest within 5 m of shade and water sources and only 83 ± 7% of maximum at a distance of 30 m and 92 ± 14% of maximum at a distance of 80 m, suggesting a zone of enrichment within pastures due to animal behavior. During 12 years, the annual rate of change in SOC (0–90 cm) followed the order: low grazing pressure (1.17 Mg C ha−1 year−1) > unharvested (0.64 Mg C ha−1 year−1) = high grazing pressure (0.51 Mg C ha−1 year−1) > hayed (−0.22 Mg C ha−1 year−1). This study demonstrated that surface accumulation of SOC and TSN occurred, but that increased variability and loss of SOC with depth reduced the significance of surface effects.
Agriculture, Ecosystems & Environment.
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ABSTRACT: A 168-day study was conducted to evaluate the effect of a strategically timed treatment with fenbendazole on anthelmintic efficacy and performance of beef cows and calves. Eight groups of 10 Angus cow/calf pairs were alloted on 7 May 1987 to eight similarly managed 4.86-ha pastures (bermudagrass/tall fescue) on the basis of cow age, and calf sex and weight. At that time, four groups of cows received a dose of fenbendazole (5 mg kg−1) with their calves receiving fenbendazole at the same dosage 28 days later. Treated calf average daily gain (ADG) was 0.04 kg greater (P < 0.05) than control calves (0.82 vs. 0.78 kg) during the 168-day study. Treated cow ADG was 0.09 kg greater (P < 0.05) than control cows (0.40 vs. 0.31 kg). Although there was a reduction (P < 0.05) in fecal egg counts following treatment of the cows, the numbers of eggs generally were low compared with egg counts of calves. From Day 28 through Day 112 post-treatment, fecal egg counts of treated calves were lower (P < 0.05) than those of control calves. However, fecal egg counts from treated calves increased post-treatment until there were no differences (P > 0.05) between treated and control calves at the end of the study. The pregnancy rate tended to be higher (P = 0.12) for treated cows (98%) than for untreated control cows (75%). The actual calving rate was higher (P = 0.03) for treated cows (90%) than for untreated control cows (68%). Results indicated that a strategic anthelmintic treatment can improve cow and calf performance, but that calves born in late winter or early spring may need more than one therapeutic dose during the nursing period on pasture.
Veterinary Parasitology.
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ABSTRACT: Escherichia coli is a ubiquitous component of the intestinal microflora of warm-blooded animals, and is an indicator of fecal contamination of surface waters. Ribotype profiling of E. coli is one of several genotypic methods that has been developed to determine the host origin of fecal bacteria. Like most genotypic methods of source tracking, ribotyping requires a host origin database to identify environmental isolates. To determine the extent of temporal variability of ribotypes and its effect on a host origin database, E. coli isolates were obtained from fecal samples of two herds of Black Angus steers at a long-term experimental site at four sampling times from October 1999 to July 2000. Fecal samples were taken from six randomly chosen steers at each time. At a similarity index of 90% as calculated by unweighted pair-group method using arithmetic averages (UPGMA), 240 ribotypes were identified from 451 E. coli isolates. Only 20 ribotypes (8.3%), comprising 33% of the total isolates, were shared among sampling times and were considered resident ribotypes. Two of the twenty resident ribotypes appeared at three sampling times, and the remaining eighteen appeared at two. The majority of the ribotypes, therefore, were transient and unique to each sampling time and steer. Both the apparent turnover of E. coli ribotypes and a clonal diversity index of 0.97 (indicative of extensive ribotype variability) suggest the necessity of ribotyping a large number E. coli isolates per host to establish a host origin database that is independent of temporal variability, or complete enough to be effective.
Journal of Environmental Quality 32(1):305-9. · 2.32 Impact Factor
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ABSTRACT: An understanding of the long-term cycling of trace elements in soil with broiler litter fertilization under various forage utilization strategies is needed to develop sustainable agricultural production systems. We evaluated differences in Cu, Mn, Zn, and six other trace elements in response to 5 yr of bermudagrass [Cynodon dactylon (L.) Pers.] management varying in fertilization and harvest strategies on a Typic Kanhapludult in Georgia. Chicken (Gallus gallus) broiler litter was a significant source of trace elements that led to 3.4 +/- 0.5 times higher Cu, 2.0 +/- 0.3 times higher Mn, and 2.1 +/- 0.2 times higher Zn in the surface 3 cm of soil than when forage was fertilized inorganically. There were variable effects of broiler litter fertilization on other trace elements, depending upon element, depth of sampling, and forage utilization strategy. Concentrations of all trace elements in soil were below levels considered toxic to plants. Soil at a depth of 0 to 3 cm under grazed paddocks had 33 +/- 5% greater Cd, 18 +/- 1% greater Cr, 53 +/- 24% greater Cu, and 24 +/- 7% greater Zn compared with unharvested and hayed management. Trace elements in soil were unaffected whether forage was unharvested or removed as hay. These results suggest that broiler litter is a significant source of several trace elements and that ruminant processing of forage and subsequent deposition of excreta on the paddock allow these trace elements to accumulate more at the soil surface where they might interact with the high concentration of organic matter.
Journal of Environmental Quality 33(2):778-84. · 2.32 Impact Factor
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ABSTRACT: Estimates of potential soil organic C (SOC) and total N (TN) sequestration at depths below the traditional plow layer (i.e., 0-0.3 m) in agricultural systems are needed to improve our understanding of management influences on nutrient cycling and potential greenhouse gas mitigation. We evaluated the factorial combination of nutrient source (inorganic, inorganic + cover crop, and broiler litter) and forage utilization (unharvested, hayed monthly, and low and high grazing pressure) on profile distribution of and changes in SOC and TN during the first 5 yr of 'Coastal' bermudagrass [Cynodon dactylon (L.) Pers.] management. Nutrient source did not affect SOC and TN in the soil profile. Contents of SOC and TN under haying were lower than under other management systems throughout the soil profile. Averaged across nutrient sources, SOC sequestration to a depth of 0.9 m was 3.6 Mg ha(-1) (P = 0.06) under low grazing pressure and 2.4 Mg ha(-1) (P = 0.19) under high grazing pressure. Sequestration of TN was 0.49 Mg ha(-1) (P = 0.03) under low grazing pressure and 0.56 Mg ha(-1) (P = 0.02) under high grazing pressure. The minimum change in SOC and TN needed to detect significant (P = 0.1) sequestration increased an average of 0.6 and 0.10 Mg ha(-1), respectively, for each additional 0.3-m layer of soil. This study demonstrated that plow-layer accumulation of SOC and TN occurred, but that increased variability with depth and small loss of SOC and TN with an additional 0.3 m below the plow layer erased the significance of surface effects.
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ABSTRACT: Tall fescue (Festuca arundinacea Schreb.) is an important cool-season perennial forage for cattle production in the humid regions of the USA and throughout the world. While endophyte (Neotyphodium coenophialum Glenn, Bacon, & Hanlin) infection of tall fescue has many benefits, it also results in accumulation of toxic alkaloids in leaf tissue known to cause animal health disorders when ingested. We hypothesized that pastures containing these alkaloids may alter soil organic matter dynamics. A set of three grazed field experiments representing low (0-29%) and high (65-94%) endophyte infection of tall fescue was evaluated at the end of either 8 or 15 yr. Soil samples from 12 paddocks (0.7-0.8 ha) were collected at depths of 0 to 25, 25 to 75, 75 to 150, and 150 to 300 mm. Soil under tall fescue with high endophyte infection had 13 +/- 8% greater concentrations of soil organic C and N and particulate organic N to a depth of 150 mm than with low endophyte infection. However, with high endophyte infection, microbial biomass and basal soil respiration per unit of soil organic C or particulate organic C were 86 +/- 5% of those with low endophyte infection. Only small differences in soil microbial community structure, estimated via fatty acid methyl ester profiles, were observed between soils under fescue with 0 and 100% endophyte infection. Endophyte infection of tall fescue may perform an important ecological function, allowing more soil organic C and N to accumulate, perhaps because of reduced soil microbial activity on plant residues containing endophyte byproducts.
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ABSTRACT: Conservation practices have often been located without the use of geospatial data to help site practices for improved resource conservation. On a watershed scale, geospatial information can be used to identify water supplies and recreational areas that are least buffered from sources of contamination. Implementing conservation practices near these strategic locations could provide a more rapid means of increasing the ability of the watershed to support its designated uses. In grazing systems, rotation can prevent concentration of animals in one location. However, cow-calf pairs are difficult to move in the first few weeks after calving and producers often concentrate animals prior to calving to simplify animal care. Such practices may pose environmental threats to water quality by concentrating nutrients and exposing soil to erosion because of treading damage. Geospatial data can be used to identify pastures best suited for extended grazing and to select sites for conservation practices.
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ABSTRACT: Tall fescue (Festuca arundinacea Schreb.) is an important cool-season perennial forage used for grazing animals in the humid regions of the USA and throughout the world. The fungal endophyte Neotyphodium coenophialum Glenn, Bacon, & Hanlin naturally inhabits the majority of tall fescue stands producing a variety of alkaloids in leaf tissue that can cause animal health disorders on ingestion. We hypothesized that endophyte infection would modify the stock and activity of various soil C and N pools (total, particulate, microbial biomass, and mineralizable), but that fertilization (13.4-1.5-5.6 vs. 33.6-3.7-13.9 g N-P-K m(-2) yr(-1)) and cultivar ('Kentucky-31', K-31; 'AU-Triumph'; and 'Johnstone') might alter these responses. Soil organic C and total N at a depth of 0 to 20 cm under K-31 with high fertilization were greater with high (4197 g C m(-2) and 266 g N m(-2)) than with low (3872 g C m(-2) and 242 g N m(-2)) endophyte infection at the end of 20 yr. Under low fertilization, soil organic C and total N were not different between low and high endophyte infection. Differences in C and N pools among cultivars with low fertilization were as large as among K-31 fertilization-endophyte comparisons, but appeared to be related to factors other than endophyte infection frequency. Carbon and N contents of small macroaggregates (0.25-1.0 mm) were the only soil properties that were related (r = 0.70, P = 0.001) to endophyte infection frequency (range of 1-79%) across all treatments. Soil C and N pools can be modified by endophyte infection, but these results narrowed this phenomenon to (i) conditions of higher fertility and (ii) predominantly in small macroaggregates.
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ABSTRACT: Productivity, quality, and persistence of 'Coastal' bermudagrass [Cynodon dactylon (L.) Pers.] pastures are affected by fertilization, but possible interactions with defoliation regime including animal grazing are not fully known. We evaluated three sources of fertilization with equivalent N rates [inorganic, crimson clover (Trifolium incarnatum L.) cover crop plus inorganic, and chicken (Gallus gallus) broiler litter] factorially arranged with four defoliation regimes [unharvested, cattle (Bos taurus) grazing to maintain high (4.5 +/- 1.6 Mg ha(-1)) and low (2.5 +/- 1.1 Mg ha(-1)) forage mass, and hayed monthly] on estimated forage dry matter production, forage and surface residue C/N ratio, and ground cover of pastures on a Typic Kanhapludult in Georgia during 5 yr. Mean annual forage dry matter production was 7.5 +/- 0.7 Mg ha(-1) with hay harvest but declined (1.3 Mg ha(-1) yr(-1)) significantly with time as a result of lower precipitation. With grazing, estimated production was 8.3 +/- 1.0 Mg ha(-1) and did not change with time, suggesting that grazing cattle sustained forage productivity by recycling nutrients and creating better surface soil conditions. Coastal bermudagrass as a percentage of ground cover (initially 81%) declined 5 +/- 2% yr(-1) with unharvested and grazing to maintain low forage mass, declined 3 +/- 1% yr(-1) with haying, and remained unchanged (-1 +/- 1% yr(-1)) with grazing to maintain high forage mass. Pastures with high forage mass were more productive than with low forage mass (9.2 +/- 1.6 vs. 7.5 +/- 1.1 Mg ha(-1)) from a forage sustainability perspective, primarily by avoiding encroachment of undesirable plant species.
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ABSTRACT: Soil aggregation is important for maintaining soil surface integrity and allowing water to infiltrate, rather than runoff and cause erosion. The effect of grazing animals on soil aggregation compared with other conservation management strategies in the Southern Piedmont USA is not well known. We tested a hypothesis that grazing animals might negatively affect soil aggregation characteristics. Water-stable macro-aggregates (>0.25 mm), mean-weight diameter, and their stabilities were (i) similar between conservation-tillage cropping and tall fescue (Festuca arundinacea Schreb.)-common bermudagrass (Cynodon dactylon L.) pasture; (ii) similar between 15- to 19-yr-old grazed and hayed hybrid bermudagrass; (iii) 7 to 14% greater in 30-yr-old than in 10-yr-old grazed tall fescue and hybrid bermudagrass pastures; (iv) similar among long-term grazingland, hayland, and forestland; and (v) 5 to 11% lower under cattle grazing than under monthly haying or unharvested management during the first 4 yr following conversion of cultivated cropland to pastureland. Water-stable aggregate distribution at a depth of 0 to 50 mm was 0.30 +/- 0.07 g g-1 in the 1.0- to 4.75-mm class, 0.46 +/- 0.07 g g-1 in the 0.25- to 1.0-mm class, 0.15 +/- 0.02 g g-1 in the 0.05- to 0.25-mm class, and 0.07 +/- 0.01 g g-1 in the <0.05-mm class, averaged across management systems and replications (n = 56). Total glomalin of the 1.0- to 4.75-mm dry-stable aggregate class was highly related to whole soil organic C content, but neither of these properties was particularly well related with water-stable macroaggregation, mean-weight diameter, or their stabilities. We conclude, overall, that grazing of pastures in the Southern Piedmont USA has little detrimental effect on soil aggregate distribution and stability and is comparable in soil conservation with other land conservation strategies.
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ABSTRACT: Improved forage management impacts on soil organic C and S depth distribution and surface residue accumulation could be large, but detailed temporal data are not available. We evaluated the factorial combination of three levels of N fertilization [inorganic, crimson clover (Trifolium incarnatum L.) cover crop plus inorganic, and broiler litter] and four levels of harvest strategy (unharvested, low grazing pressure, high grazing pressure, and hayed monthly) on soil bulk density, soil organic C, and total S, and surface residue C and S during the first 5 yr of 'Coastal' bermudagrass [Cynodon dactylon (L.) Pers.] management. Soil bulk density of the 0- to 6-cm depth responded very little to management, but across treatments it decreased 0.06 Mg m(-3) yr(-1) due to increasing soil organic matter with time. Soil organic C did not respond significantly to fertilization strategy during the 5 yr, but total S of the 0- to 6-cm depth was greater under broiler litter than under other fertilization strategies at the end of 3, 4, and 5 yr. Low and high grazing pressure were similar in their effect on soil organic C accumulation, averaging 140 g m(-2) yr(-1). Most of the net change in soil organic C occurred in the 0- to 2-cm depth. Soil under unharvested and hayed management accumulated organic C at rates less than one-half of those observed under cattle grazing. Cattle grazing shunted C more directly from forage to the soil, which contributed to greater sequestration of soil organic C than with haying or unharvested management.
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ABSTRACT: Runoff and nutrient losses were monitored over two and half years from different fescue management systems that are used by producers in the Georgia Piedmont. A randomized complete block arrangement of 14 paddocks under combinations of a grazing (grazed or hayed), fertilization (poultry litters or inorganic fertilizer) and tall fescue type (high endophyte high alkaloid, high endophyte low alkaloid, and endophyte free) treatments was used. The study was located at the USDA-ARS J. Phil Campbell Sr. Natural Resource Conservation Center, near Watkinsville, GA. Treatments did not influence amount of runoff. Mean concentrations of ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N) in runoff were low (< 1 ppm). However, concentrations of dissolved reactive phosphorus (DRP) were elevated in the grazing treatments, and were higher with poultry litter (mean: 1.2 to 3.3 ppm) compared to hayed treatments (mean 0.5 ppm). The study suggests that management practices that reduce DRP losses from grazing lands fertilized with poultry litter or inorganic fertilizer are needed to protect water resources.
