• Adverse effects of pine needles on aspects of digestive performance in cattle

      Pfister, J. A.; Adams, D. C.; Wiedmeier, R. D.; Cates, R. G. (Society for Range Management, 1992-11-01)
      Pine needles from ponderosa pine (Pinus ponderosa Lawson) consumed by cows during winter can cause abortions. Our study determined the nutritional impact of pine needles given to steers intraruminally. In Trial 1, 12 steers were given either grass hay alone (CONT), 15% pine needles (15PN), or 30% pine needles (30PN) substituted for hay, as fed basis. In Trial 2, a 4 X 4 Latin square design was used with 4 steers. Treatments were: (1) control-grass hay alone (CONT); (2) grass hay plus 454 g/day of cottonseed meal (CSM); (3) pine needles substituted for 40% (as fed basis) of the hay (PN); and (4) pine needles (40%) plus 454 g/day of CSM (PNCSM). In Trial 1, dry matter intake (DMI), fecal N, and DM digestibility were not affected by either 15PN or 30PN. N intake and N digestibility were reduced (P < 0.07) by 30PN. Fluid dilution rate (FDR) and fluid outflow rate (FOR) were depressed (P = 0.10) by 30PN. Total VFA and ruminal ammonia-N also were depressed by 30PN. In Trial 2, the PN treatment adversely affected DMI, N intake, and all digestibility coefficients, and elevated fecal N. FDR, FOR, and turnover time (TOT) were reduced by 40% PN. Total VFA were increased by PN, while ammonia-N concentrations were reduced. Cottonseed meal had few effects on rumen variables, and there were no CSM X PN interactions. We conclude that pine needles severely affect cattle nutrition, particularly N intake and digestibility and fluid rate of passage. Cottonseed meal, at 1 kg/day, does not ameliorate the adverse effects of pine needles. Fifteen to 30% pine needles in cattle diets appears to be the threshold level for toxic effects on ruminal fermentation.
    • An Automated Range-Animal Data Acquisition System

      Adams, D. C.; Currie, P. O.; Knapp, B. W.; Mauney, T.; Richardson, D. (Society for Range Management, 1987-05-01)
      An automated range-animal data acquisition system (ARADS) has been developed to collect individual animal data without human intervention. Records include date, time, identification, live-weight, water consumption, and weather variables. The system is presently being used to monitor free-ranging yearling steers and mature cows. ARADS is composed of 7 portable scale units, a weather station, and a central computer all linked together through a radio communication network. The system is expandable to include additional data stations and parameters, and the number of animals identified is not limited by the system. Scale units and the weather station operate in extreme temperatures (40 to -40 degrees C), precipitation and wind.
    • An Improved Method for Attaching the Esophageal Fistula Bag

      Kartchner, R. J.; Adams, D. C. (Society for Range Management, 1983-05-01)
      A simple, surgically established skin "neck loop" was tested for holding the collection bag in position on esophageal fistulated steers. The loop eliminated the need for a girth strap and reduced the time required for attaching and detaching the collection apparatus.
    • Cubed Alfalfa Hay or Cottonseed Meal-Barley as Supplements for Beef Cows Grazing Fall-Winter Range

      Cochran, R. C.; Adams, D. C.; Currie, P. O.; Knapp, B. W. (Society for Range Management, 1986-07-01)
      A 2-year study evaluated the efficacy of supplements for beef cows grazing mixed grass prairie during the fall and winter. Cows were allotted to 3 treatments: (1) range forage only, (2) range forage plus 1.2-1.3 kg alfalfa cubes hd-1 d-1, and (3) range forage plus .9 kg cottonseed meal-barley cake hd-1 d-1. Supplements were fed daily to provide approximately 50% of crude protein requirements. Treatment effects did not depend (P<0.10) on year for independent variables evaluated. Although weather conditions differed among years, observed changes in weight and condition score were similar (P<0.10) for both years. Supplemented cows gained weight; but supplement type did not influence weight gains. In contrast, unsupplemented cows displayed significant weight loss. Supplemented cows either maintained or slightly increased in body condition during the fall-winter period. However, body condition of unsupplemented cows decreased (P<.05) compared with condition of supplemented cows. Supplementation with alfalfa cubes resulted in similar performance compared with supplementation with cottonseed meal-barley cake. Supplementing diets of wintering range cows with feeds high in protein improved performance compared with no supplementation.
    • Diet quality of suckling calves and mature steers on Northern Great Plains rangelands

      Grings, E. E.; Adams, D. C.; Short, R. E. (Society for Range Management, 1995-09-01)
      A study was conducted over 2 years to evaluate the quality of forage selected by suckling calves compared to mature steers. Diets were collected from esophageally cannulated suckling calves or from steers that were two-years-old or older. Sampling was conducted in June, July, September, October, and November in each of 2 years. The forage portion of diets of esophageally fistulated suckling calves (beginning 115 to 136 days of age) were 21% greater (P < 0.01) in crude protein and 5% less (P < 0.06) in neutral detergent fiber relative to those consumed by mature steers in June and July. Diets of calves also contained 14% less (P < 0.01) acid detergent fiber than diets of mature steers in June. There were no differences in diet quality due to age during September, October, and November of either year. We conclude that suckling calves selected diets of higher quality than did mature steers early in the growing season. Forage quality may have allowed selective behavior at this time, low forage intakes of calves may have allowed more time for selection, or exploratory grazing by calves may have resulted in diets with increased nutrient quality in early summer.
    • Escape protein and weaning effects on calves grazing meadow regrowth

      Lardy, G. P.; Adams, D. C.; Klopfenstein, T. J.; Clark, R. T.; Emerson, J. (Society for Range Management, 2001-05-01)
      Forty spring-born calves grazing subirrigated meadow regrowth after haying in July were assigned to 2 weaning and 2 supplementation treatments in fall of 1995 and 1996. Weaning treatments were weaning on 1 September or nursing during the duration of the trial. Supplementation treatments were no supplement or supplemental undegraded intake protein (UIP). An 80:20 (dry matter basis) blend of sulfite liquor treated soybean meal and feather meal was the source of undegraded intake protein (undegraded intake protein = 45% of supplement dry matter). Supplemented nursing calves received 0.50 kg of supplement daily whereas supplemented weaned calves received 0.91 kg of supplement daily. Weaned and nursing calves grazed subirrigated meadow regrowth throughout the trial. The trials were conducted from 17 October to 18 November 1995 and 5 September to 4 November 1996. Milk intake was measured by the weigh-suckle-weigh technique. Diet samples collected from ruminally cannulated calves after rumen evacuation averaged 12.5% crude protein and 54.8% in vitro organic matter digestibility. No supplementation x weaning management interactions were detected (P > 0.18). Nursing calves had greater weight gains (0.95 vs. 0.59 kg day(-1); P = 0.001) and lower forage intakes (2.36 vs. 2.96 kg day(-1); P = 0.009) than weaned calves. Supplementation with undegraded intake protein increased (P = 0.03) daily gains of calves compared to nonsupplemented calves 0.88 vs 0.66 kg day(-1), respectively. Forage intake as a percentage of body weight tended to be higher in non-supplemented calves (P = 0.09). However, total intake (forage plus supplement) as a percentage of body weight tended to be higher in supplemented calves (P = 0.14). Total intake (kg day(-1)) was greater (P = 0.01) for calves supplemented with undegraded intake protein. Milk intake did not differ between supplemented and unsupplemented calves (P > 0.52). We concluded that subirrigated meadow regrowth forage was limiting in metabolizable protein and that milk represents an important source of metabolizable protein for grazing calves.
    • Estimation of fecal output with an intra-ruminal continuous release marker device

      Adams, D. C.; Short, R. E.; Borman, M. M.; MacNeil, M. D. (Society for Range Management, 1991-05-01)
      Efficacy of a continuous release marker device (CRD) containing chromium oxide to estimate fecal output was evaluated in two 12-day grazing trials with beef steers (n = 10, trial 1; n = 7, trial 2). Trial 1 was conducted on mature green irrigated tall wheatgrass (Elytrigia pontica [Podp.] Holub) pasture during September. Trial 2 was conducted on dormant native range during December. Fecal output was determined by total fecal collection (TFC) and the CRD for each steer. Fecal output estimates from the CRD were based on a chromium release rate (980 mg/day) provided by the manufacturer. Estimates of daily fecal dry matter output (kg) in trial 1 were 2.70 and 2.69, and in trial 2 were 3.19 and 2.89 from the TFC and CRD, respectively. Differences between TFC and CRD were not significant in trial 1 (P = 0.59) but were significant in trial 2 (P < 0.01). When averaged over days and animals, estimates of daily fecal dry matter from CRD were within 1% of TFC in trial 1 and 10% of TFC in trial 2. Estimates of daily fecal dry matter from CRD were influenced by sampling day and steer (P < 0.01); however, there was no consistent pattern to day or animal variation. Multiple days and animals are required for both TFC and CRD. We conclude that CRD provides an acceptable estimate of daily fecal output. However, to improve accuracy, TFC can be used on a subsample of animals as a double sampling technique to adjust estimates derived from CRD.
    • Examination of Methods for Estimating Rate of Passage in Grazing Steers

      Cochran, R. C.; Adams, D. C.; Galyean, M. L.; Wallace, J. D. (Society for Range Management, 1987-03-01)
      Understanding how rate of passage estimates are influenced by procedural variations may facilitate standardization of methodology and enhance comparisons among studies. Therefore, 12 ruminal-fistulated beef steers (mean wt. = 294 kg) were used in two 6-day grazing trials to evaluate influences of sampling site, intraruminal mixing, and mathematical model on particle passage rate estimates. Steers grazed a 13-ha pasture of immature crested wheatgrass. We estimated particle passage rate from the rumen by intraruminal administration of a pulse dose of Yb-labeled forage followed by serial collection of ruminal digesta or fecal samples. Treatments were (1) rectal sampling; (2) ruminal sampling-ruminal contents mixed before subsampling digesta; (3) ruminal sampling-ruminal contents not mixed before subsampling digesta. All steers were fitted with vibracorders to monitor grazing time before and during sampling periods. Fecal Yb curves were fitted with a one compartment, time-dependent (ICMPT-TD), a two-compartment, sequential time-dependent-time-independent (2CMPT-TD), and a two-compartment, time-independent (2CMPT-TI) model. All ruminal Yb curves were fitted with a single exponential decay model. Comparisons among models were limited to rate constants associated with the slower escape process. Intraruminal mixing did not alter (P>0.10) passage rates. The 2CMPT-TD model failed to fit some fecal profiles. Particle passage rates from the 2CMPT-TI model were greater (P<0.05) than those from the ICMPT-TD model. Similarity among passage rate constants derived from fecal Yb curves and those derived by semilogarithmic regression of ruminal Yb concentration on time depended on the model used to fit fecal Yb curves. Grazing time decreased (P<0.01) during intensive sampling periods. We conclude that for steers grazing immature grass pastures, intraruminal mixing before subsampling does not significantly alter rate of passage estimates; however, site of sampling and mathematical model may be important factors to consider in choosing appropriate methodology for estimating rate of passage.
    • Extended grazing systems for improving economic returns from Nebraska sandhills cow/calf operations

      Adams, D. C.; Clark, R. T.; Coady, S. A.; Lamb, J. B.; Nielsen, M. K. (Society for Range Management, 1994-07-01)
      Three winter treatments were cross classified with 2 spring treatments to create 6 feeding and grazing systems utilizing Nebraska sandhills range and subirrigated meadow forage. Systems were evaluated with multiparous crossbred beef cows over 4 years (240 head beginning year 1). Systems were: 1) owing range during winter; 2) grazing subirrigated meadow during winter; and 3) fur feed of meadow bay during winter; in combination with either: a) full feed of subirrigated meadow hay during May, or b) grazing subirrigated meadow during May. From June through November all cows grazed range. The feeding and grazing systems were compared with selected linear contrasts and evaluated with respect to variable input prices. Some differences in cow body weight and body condition occurred but differences were considered small. Throughout the study, cows on all systems generally maintained a body condition score of about 5 (1 to 9 scale) year long. Inputs of hay were reduced by grazing range or subirrigated meadow during winter and during May without affecting pregnancy rate. Weaning weight of calves was increased 5.0 kg by grazing meadow during May compared to feeding hay during May. When opportunity costs were included in the analysis, the most profitable system involved grazing subirrigated meadow during winter and during May. Grazing subirrigated meadow during May enhanced the profitability of all wintering systems.
    • Factors influencing pine needle consumption by grazing cattle during winter

      Pfister, J. A.; Adams, D. C. (Society for Range Management, 1993-09-01)
      Ponderosa pine (Pinus ponderosa Lawson) needles cause abortions in pregnant cows. We examined pine needle consumption by cattle in 2 trials in eastern Montana. Trial 1 compared pregnant and open cows (n=4) from January to March 1989; trial 2 compared pregnant cattle (n=4) that received either 9 kg alfalfa hay head-1 day-1 or 1.4 kg alfalfa pellets head-1 day-1 from December 1989 to February 1990. Diets were estimated using both bite counts and fecal analysis. During trial 1, bite counts revealed pregnant and open cows consumed 45 and 42% of their grazing diets as pine needles (P>0.1). Fecal analysis showed that pregnant cows consumed more pine needles than did open cows (36% vs. 27%, respectively) (P<0.05). During trial 2, cattle consumed < 1% of their diets as pine needles. In trial 1 cattle consumed less pine litter and consumed more needles from trees as snow depth increased. Consumption of needles from trees increased as ambient temperature declined; no needles were consumed from trees when the minimum daily temperature exceeded -5” C. During both trials, grazing times decreased as temperatures declined, and increased as snow depth and wind speed decreased. We conclude that weather is a major factor influencing needle consumption; other interrelated factors may be forage availability, snow cover, and grazing time. Plne needle consumption, and the risk of abortion, in pregnant cattle appears to be greatly diminished during mild winter weather.
    • First limiting nutrient for summer calving cows grazing autumn-winter range

      Lardy, G. P.; Adams, D. C.; Klopfenstein, T. J.; Clark, R. T. (Society for Range Management, 1999-07-01)
      Two trials were conducted in 1994, 1995, and 1996 to determine the first limiting nutrient for summer calving cows grazing Sandhills range. In Trial 1, 48 lactating summer calving cows grazing native range during the breeding season were assigned to 1 of 4 supplement treatments: 1) control-no supplement, 2) energy, 3) degradable intake protein (DIP), and 4) DIP + undegraded intake protein (UIP). Cows were group-fed supplements in 8 pastures (2 pastures/treatment). The trial began 4 September and ended 4 November each year. Diet samples from esophageally fistulated cows averaged 7.5% crude protein and 54.5% in vitro organic matter digestibility. Supplemented cows lost less body condition compared to control cows (P = 0.04). Cow and calf weight gains were increased by supplemental DIP or DIP + UIP combination compared to energy supplement (P = 0.09 and 0.08, respectively). Forage intake and digestibility were not different among treatments (P > 0.20). Milk production was lower for non-supplemented than supplemented cows (P = 0.10). Trial 2 began 5 November and ended 10 January in 1994-1995, 1995-1996, and 1996-1997. Treatments and pastures were the same as described in Trial 1, however, only 40 cows were used. In Trial 2, diet samples from esophageally fistulated cows averaged 6.2% crude protein and 52.3% in vitro organic matter digestibility. No differences (P > 0.10) in body condition score were detected. Total organic matter intake was lower for control compared to supplemented treatments (13.5 vs.15.5 kg day(-1); P < 0.10). We concluded that DIP was the first limiting nutrient for summer calving cows during the breeding season and during autumn-winter lactation after the breeding season.
    • Forage Maturity Effects on Rumen Fermentation, Fluid Flow, and Intake in Grazing Steers

      Adams, D. C.; Cochran, R. C.; Currie, P. O. (Society for Range Management, 1987-09-01)
      Eight ruminally fistulated steers were observed on native range from 4 May 1981 to 5 Nov. 1981 to determine effects of advancing forage maturity on rumen fermentation, fluid passage, fluid volume, and forage intake. Effects of these factors are poorly defined for cattle on the Northern Great Plains but are essential for developing management strategies for optimum animal production. On 6 different dates, the steers were given an intraruminal dose of cobalt ethylenediaminetetraacetate (CoEDTA), and samples of rumen fluid were drawn at 4-hour intervals over a 24-hour time period. Rumen fluid samples were analyzed for volatile fatty acid, ammonia-N, cobalt concentration, and pH. CoEDTA was used as a marker to estimate rumen fluid passage and volume. Forage intake was determined by total fecal collection and in vitro digestibility of the forage. Total ruminal volatile fatty acid, molar proportions of individual volatile fatty acid, pH, and ammonia-N concentrations varied (P<0.01) within each of the six 24-hour periods, but the changes were dependent on date. Advancing forage maturity was associated with reduction in individual and total ruminal volatile fatty acid, ammonia-N, pH, and fluid dilution rate. Rumen fluid volume increased with increasing forage maturity. Variation in organic matter intake was small (P>0.05) over the range of forage maturities studied. We concluded that variation in rumen fluid passage, volume, and fermentation depended on forage maturity, and protein supplementation may be beneficial during late summer-early fall to increase or sustain animal production.
    • Grass hay as a supplement for grazing cattle. I. Animal performance

      Villalobos, G.; Adams, D. C.; Klopfenstein, T. J.; Nichols, J. T.; Lamb, J. B. (Society for Range Management, 1997-07-01)
      Regrowth grass hay produced on subirrigated meadows in the Nebraska Sandhills was evaluated as a supplement for gestating beef cows grazing winter range. Ninety-six crossbred spring calving, gestating beef cows were used in a winter supplementation study on upland Sandhills range from 5 November to 27 February in 1990 and again in 1991. Cows were divided into 4 treatments (24 cows/treatment): 1) control (range forage only, no supplement); 2) range forage and 2.2 kg cow-1 day-1 of meadow regrowth hay (15.5% crude protein); 3) range forage and 1.2 kg cow-1 day-1 of a 30% wheat grain and 70% soybean meal:30% wheat supplement (36.0% crude protein); and 4) range forage with supplements in treatments 2 and 3 fed on alternate days. Meadow hay and soybean meal:wheat supplements provided 0.32 kg of crude protein/cow daily. Supplemented cows gained 3 to 53 kg body weight/year and maintained body condition, while control cows lost an average of 24.5 kg body weight/year and lost body condition. Intake of range forage was less (P < 0.05) by cows fed meadow hay and soybean meal:wheat supplements on alternate days than by cows on other treatments. Digestibility of range forage was lower (P < 0.05) for supplemented cows than control cows, but differences were small (avg. = 2%). Calving date, birth and weaning weights, and pregnancy rate were similar (P > 0.05) for all treatments. We concluded that subirrigated meadow regrowth grass hay was an effective alternative to traditional soybean meal-based supplements for maintaining body weight and body condition of gestating beef cows grazing winter range.
    • Grass hay as a supplement for grazing cattle. II. Ruminal digesta kinetics

      Villalobos, G.; Klopfenstein, T. J.; Adams, D. C.; Shain, D.; Long, T. E. (Society for Range Management, 1997-07-01)
      This study evaluated the effects of supplementing a diet of range hay (5.7% crude protein, 68% NDF) with grass hay from subirrigated meadows (16.5% crude protein, 53.5% NDF), or with a 70% soybean meal:30% wheat grain supplement (40% crude protein) on intake and ruminal digesta kinetics. Twelve ruminally fistulated steers were assigned to 3 treatments (4 steers/treatment) at 2 levels of intake. Treatments were: control, range hay; range hay supplemented with meadow hay (meadow hay was 20% of intake); and range hay supplemented with soybean meal:wheat supplement (supplement was 8% of intake). Intake levels were: ad libitum and equal intake (1.5% of body weight). Range hay was Yb-labeled, and meadow hay and soybean meal:wheat supplements were Er-labeled to measure passage. Intake and digestibility of range hay was not affected by supplementation (P > 0.05). During ad libitum intake, total intake (range hay + supplement) was greater (P > 0.05) for supplement treatments than for the control. No supplement treatment X level of intake interactions were detected (P > 0.05). Total digestibility (range hay + supplement) was greater (P < 0.01) for the soybean meal:wheat treatment than for the control or meadow hay treatments. Total digestibility was similar (P > 0.05) for control and meadow hay treatments. Ruminal passage rate (% hour-1), total tract mean retention time, and intestinal transit time of range hay did not differ among treatments (P > 0.05), but ruminal passage rate, total tract mean retention time, and intestinal transit time were greater (P < 0.01) with ad libitum than equal intake. We conclude that a meadow hay supplement produced similar effects on ruminal kinetics and intake of range hay as a soybean meal:wheat supplement.
    • Growth patterns of yearling steers determined from daily live weights

      Currie, P. O.; Volesky, J. D.; Adams, D. C.; Knapp, B. W. (Society for Range Management, 1989-09-01)
      Growth patterns for free-ranging yearling steers were quantified from daily live weights obtained with automatic scales which animals entered to obtain drinking water. Forty steers were monitored during each summer grazing period of 1986 and 1987. Frequency of watering and, thus, weighing on the automatic scales averaged 2.4 times/day. Significant (P < 0.01) quadratic relationships between live weight and Julian date were obtained. In 1986, predicted live weight of the steers peaked in late July to early August and then decreased through to the end of the grazing period in September. Live weight of the steers in 1987 followed a similar pattern although the late summer decrease was not as great as in 1986. When animals were periodically weighed using manual procedures, a lower rate of gain was measured in the second half than in the first half of the summer grazing period every year from 1983 through 1987. However, we were unable to specifically identify when these weight changes occurred until the automatic scales were used in 1996 and 1987. The automatic weighing equipment documented substantial within-day live weight variability among steers. This variability changed over the grazing period on a day-to-day basis. Within-day variability must be considered when establishing manual weighing schedules with conventional equipment. Live weight data in conjunction with other measurements will permit development of a more comprehensive animal-plant-climate model.
    • Intake and digestive kinetics of leaf and stem fractions

      Lamb, J. B.; Adams, D. C.; Klopfenstein, T. J.; Grant, R. J.; Sims, P. L.; White, L. M.; Waller, S. S. (Society for Range Management, 2002-01-01)
      Ruminally fistulated steers were used in a 4 x 4 Latin square to test effects of immature (vegetative) and mature (post reproductive) leaf and stem fractions from subirrigated meadow hay on organic matter intake (OMI), organic matter digestibility (OMD), and digestive kinetics. Hay was harvested 1 June (immature) and 1 October (mature), chopped into 3- to 5-cm lengths, then separated into leaf and stem fractions using a modified Clipper Cleaner Model Super 69D. Steers were provided ad libitum access to fractions and supplemented with urea so that diets were iso-nitrogenous. Particulate passage was determined using Yb labeled large hay particles [greater than or equal to 1.7-mm screen] and Er labeled small particles [< 1.7-mm and greater than or equal to 0.212-mm screen]. Samples were collected from the rumen, omasum, feces, and un-masticated diets for particle size determination. Particle size was determined using wet sieving techniques. Voluntary OMI of immature fractions (15.4 g kg(-1) BW) was greater (P < 0.05) than mature fractions (12.5 g kg(-1) BW). Within maturity OMI and OMD of leaves and stems were similar. Immature fractions had greater (P < 0.05) OMD (63.2%) than mature fractions (55.7%). Large and small particle passage rates were faster (P < 0.05) for immature fractions [3.2% hour(-1) (large) and 4.3% hour(-1) (small)] than mature [(2.3% hour(-1) (large) and 2.9% hour(-1) (small)]. Critical particle size for ruminal escape was less than or equal to 1.18 mm for both leaves and stems regardless of maturity. Differences in OMI and OMD between immature and mature fractions were explained by changes in structural components of the cell wall that made particles more resistant to mechanical and microbial breakdown.
    • N-alkane as an internal marker for predicting digestibility of forages

      Sandberg, R. E.; Adams, D. C.; Klopfenstein, T. J.; Grant, R. J. (Society for Range Management, 2000-03-01)
      Independent digestion trials with 5 forages were conducted to compare n-alkane with indigestible acid-detergent fiber (IADF) as internal markers to predict in vivo dry matter digestibility (digestibility). Forages were mixed grasses from subirrigated meadow (meadow), meadow regrowth (regrowth), native range (range), mature mixed grass hay from meadow, and alfalfa (Medicago sativa L.) hay. Meadow, regrowth, and range diets were immature grasses harvested 0.5 hours before feeding. Feces from the meadow hay and alfalfa hay trials were divided to compare freeze drying and oven drying (60 degrees C). All diets were subjected to in vitro fermentation for 0, 48, or 96 hours. N-alkane was separated from samples by 4.5-hour saponification with alcoholic KOH followed by extraction with n-hexane. Indigestible ADF was measured by 96-hour in vitro fermentation followed by ADF extraction. Digestibility estimated by markers was compared with in vivo digestibilities. N-alkane based digestibilities were lower (P < 0.01) than in vivo digestibility for all diets. N-alkanes provided higher estimates of digestibilities than IADF for meadow (P < 0.01), regrowth (P = 0.06), and alfalfa hay (P = 0.06), and lower digestibility for meadow hay (P = 0.02). Digestibilities calculated using n-alkanes for range tended to be higher (P = 0.14) than IADF values. Freeze drying increased (P < 0.01) the amount of n-alkane extracted from alfalfa hay, but did not affect (P = 0.1) the amount extracted from meadow hay. N-alkane disappeared (P < 0.001) from residue collected after 48 hours of in vitro fermentation, but no additional disappearance (P = 0.78) was evident at 96 hours. Neither marker was completely recoverable, although recovery of n-alkane was higher than indigestible ADF for 4 of the 5 forages tested.
    • Native or seeded rangeland for cows with high or low milk production

      Adams, D. C.; Staigmiller, R. B.; Knapp, B. W.; Lamb, J. B. (Society for Range Management, 1993-11-01)
      Multiparous cows (n = 91, 1986; n = 92, 1987) were selected from 2 populations to obtain cattle with high and low milk production. After March-April calving, high and low producing cows grazed either native range (treatment 1) or seeded range (treatment 2) until weaning in September. Seeded range included paddocks of crested wheatgrass (Agropyron desertorum, Fisch. ex [Link]Schult), contour furrowed native range interseeded with "Ladak" alfalfa (Medicago Sativa L.), and Russian wildrye grass Psathrostachys juncea[Fisch.]Nevski.). In treatment 2, crested wheatgrass was grazed mid-April to 17 June, followed by contour furrowed rangeland 18 June to 5 August, and ended with Russian wildrye 6 August to weaning (mid-September). Data were analyzed as a split plot with treatment and year in the main plot and cow type in the subplot. Number of cows exhibiting estrus before the beginning of the breeding season and fall pregnancy rate were not influenced (P > 0.05) by range treatment. Twelve-hour milk production during May, June, August, and September ranged from 11.3 to 6.8 kg and 7.6 to 3.9 kg for high and low producing cows, respectively. Cows with high milk production lost body condition during and after the breeding season, whereas cows with low milk production maintained body condition during the same period. Live weight gain of calves was greater (P < 0.01) for cows with high production than cows with low production but was not affected (P > 0.05) by range treatment. We concluded that native and seeded ranges were of similar nutritive value for cows with high and low milk production and that cows with high milk production may have greater nutrient requirements during late summer-early fall than what was provided by native or seeded ranges. Protein may be the primary limiting nutrient in forages during the late summer for lactating cows grazing Northern Great Plains range.
    • New concepts for assessment of rangeland condition

      Adams, D. C.; Short, R. E.; Pfister, J. A.; Peterson, K. R.; Hudson, D. B. (Society for Range Management, 1995-05-01)
      Range condition score or classification does not tell us, in a general sense, much of what managers and the public want to know about rangelands. Range condition is not a reliable indicator, across all rangelands, of biodiversity, erosion potential, nutrient cycling, value for wildlife species, or productivity. Succession, the basis for the current concept of range condition is not an adequate yardstick for evaluation of rangelands. The Society for Range Management (SRM) established the Task Group on Unity in Concepts and Terminology which has developed new concepts tor evaluation of the status of rangelands. These concepts are based on the premise that the most important and basic physical resource on each ecological site is the soil. If sufficient soil is lost from an ecological site, the potential of the site is changed. The Task Group made three recommendations, which were adopted by the SRM: 1) evaluations of rangelands should be made from the basis of the same land unit classification, ecological site; 2) plant communities likely to occur on a site should be evaluated for protection of that site against accelerated erosion (Site Conservation Rating, [SCR]); and 3) selection of a Desired Plant Community (DPC) for an ecological site should be made considering both SCR and management objectives for that site.
    • Pine needle effects on in vivo and in vitro digestibility of crested wheatgrass

      Adams, D. C.; Pfister, J. A.; Short, R. E.; Cates, R. G.; Knapp, B. W.; Wiedmeier, R. D. (Society for Range Management, 1992-05-01)
      In vitro and in vivo digestion trials with lambs were conducted to determine effects of ponderosa pine needles (PN; Pinus ponderosa Laws.) on digestibility of crested wheatgrass (CW; Agropyron desertorum [Link] Schultes) hay. Pine needles contained shikimic acid (15-28 mg/g) and several monomeric phenolics (p-hydroxy benzoid acid, caffeic acid, p-coumaric acid, ferulic acid) and flavonoids. Tannin concentration exceeded assay limits (>10%) and terpenes were not found, probably due to the drying procedure. In the in vitro trial, needles were mixed with CW in 10% increments from 0% to 100%. In the in vivo trial, PN were fed to lambs as follows: (1) 0%, (2) 12.5%, (3) 25%, and (4) 50%, with the remainder of the diet as CW. In vitro organic matter digestibility (IVOMD) was regressed on level of PN in the substrate. As the proportion of PN increased, IVOMD declined cubicly (P<0.01). The IVOMD values ranged from 54% for 100% CW to 24% for 100% PN. In vivo digestibility of organic matter, neutral detergent fiber and acid detergent fiber declined linearly (P<0.01) as PN were increased from 0% to 50% of the diet. Apparent crude protein digestibility and N retention by lambs declined cubicly (P = 0.02 and P<0.01, respectively) and urinary N increased cubicly (P<0.01) as dietary PN increased from 0% to 50%. We concluded that PN reduce in vitro and in vivo nutrient digestibility, reduced N retention by lambs, and effects were detectable even at low levels.