| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Department of Animal and Dairy Science;
and
Department of Crop and Soil Sciences;
and
College of Veterinary Medicine; and
and
Department of Biological and Agricultural Engineering, The University of Georgia, Athens 30602
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
Key Words: Beef Cattle • Behavior • Endophytes • Ergot Alkaloids • Festuca arundinacea • Grazing
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
). Despite agronomic attributes that make it an attractive forage, toxicosis problems in cattle result from grazing wild-type toxic endophyte-infected (E+) tall fescue. Fescue toxicosis is a condition that alters ruminant grazing behavior (Seman et al., 1999) and adversely affects cattle performance (Stuedemann and Hoveland, 1988). Endophytes (Neotyphodium coenophialum) within tall fescue plants impart positive agronomic qualities (e.g., enhanced drought tolerance [Thompson et al., 2001] and improved vigor [Stuedemann and Hoveland, 1988]). Plant breeders developed endophyte-free (E-) cultivars, which are nontoxic to livestock. However, plant persistence is lower in E- than in E+ tall fescue (Hill et al., 1991), and a higher level of management is required to maintain productive E- forage stands.
Nonergot alkaloid-producing endophyte-infected tall fescue was developed by reinfecting E- tall fescue cultivars with nonergot alkaloid-producing endophyte strains (AR502 and AR542). Better stand survival than Jesup and Georgia-5 E- controls and survival that did not differ from Jesup and Georgia-5 E+ controls has been observed in Jesup and Georgia-5 tall fescue reinfected with AR502 and AR542 when subjected to close grazing in bermudagrass (Cynodon dactylon) sod (Bouton et al., 2002). Grazing trials conducted in lambs (Fletcher et al., 2000; Bouton et al., 2002; Parish et al., 2003) and steers (Nihsen et al., 2000) demonstrated that nonergot alkaloid-producing endophyte-infected tall fescue pastures provided livestock performance that did not differ from that on E- tall fescue and was superior to that on E+ tall fescue without indications of toxicosis. The objectives of the present study were to evaluate growth performance, toxicosis, and grazing behavior in stocker cattle grazing AR502, AR542, E-, and E+ tall fescue.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
At the Northwest Georgia Branch Station near Calhoun, GA (lat 34.5577°N; long 84.8158°W; elevation 209 m), four Kentucky-31 tall fescue pasture treatments—AR542-infected (K542), AR502-infected (K502), E- (KE-), and E+ (KE+)—were compared for toxicosis and growth performance in cattle for 3 yr. A completely randomized design was used with two replications of each paddock treatment. The 0.81-ha paddocks were tall fescue monocultures established in October 1998. Seed supplied by J. H. Bouton was precision drilled into well-prepared seedbeds of Sequatchie loam and Pope fine sandy loam soil at a seeding rate of 33.6 kg/ha. Pastures were fertilized uniformly with 67 kg of N/ha and P and K according to soil tests at establishment and in February and September of each subsequent year.
The cattle in these studies were managed under Protocol A2000-10092 approved by the University of Georgia Animal Care and Use Committee. Angus crossbred cattle (mean BW = 227 ± 4.3 kg) were assigned randomly to the treatment paddocks. Heifers were used during spring 1999, autumn 1999, and spring 2000, whereas steers were used in the subsequent grazing seasons of autumn 2000, spring 2001, and autumn 2001 (Table 1). The cattle were supplied at all times with fresh water, free-choice mineral blocks (Godfrey’s Warehouse, Madison, GA) (Table 2), and shade in each paddock. Cattle were treated for internal and external parasites at the initiation of each trial with Ivomec Pour-On (active ingredient is 5 mg of ivermectin/mL; Merial, Duluth, GA) at a rate of 1 mL/9.98 kg of BW. In an attempt to maintain similar forage availability among paddocks, put-and-take grazing management was used. Based on forage availability, stocking rate was adjusted by removing or adding grazer cattle with tester cattle remaining on the paddocks for the duration of the experiment. Cattle were taken off of the experimental pastures at the conclusion of each autumn grazing period, grazed on E- tall fescue, and fed bermudagrass hay until they were reallocated to treatment pastures at the beginning of the following spring grazing period. Between autumn and spring grazing periods, pastures were neither grazed nor mechanically clipped. Differential forage growth among pastures was not observed during this time. Paddocks were restocked with new cattle at the beginning of the fall grazing seasons. Grazing was initiated when there was adequate forage available—approximately 1,800 kg of DM/ha. Grazing continued until forage availability dropped below approximately 1,300 kg of DM/ha. Precipitation and soil water holding capacity played a role in decisions regarding the management of available forage levels.
|
|
. Tillers collected on the same sampling schedule as available forage samples at 10 randomly selected sites within each paddock were lyophilized, ground through a 1 mm screen in a Wiley mill (Arthur A. Thomas, Philadelphia, PA), and analyzed for total ergot alkaloid concentration using an ELISA procedure described by Adcock et al. (1997). Cattle weights, blood samples, and rectal temperatures were collected at the onset of each grazing season, on d 14, d 28, and then at 28-d intervals thereafter. Initial and final cattle weights were collected on two consecutive days and averaged. Approximately 7 mL of blood was collected from each steer or heifer in the caudal vein at the base of the tail. Blood samples were centrifuged at 3,000 x g to separate and harvest serum that was then frozen (0°C). Analysis was then performed to determine serum prolactin (PRL) concentrations according to the RIA procedure of Mizinga et al. (1992). Prolactin analysis was performed in one assay and had an intraassay CV of 9%. Post-treatment PRL concentrations and rectal temperatures were averaged from d 14 through the end of the grazing season. Cattle grazing days for each paddock were calculated as the sum of the days each steer or heifer, tester or grazer, spent grazing the paddock during a given grazing season. Cattle ADG was computed by dividing mean tester cattle gain in a particular paddock by the number of days in the grazing season. Gain/hectare was calculated as the number of cattle grazing days multiplied by tester cattle ADG. Mean stocking rate was computed by dividing cattle grazing days by the duration of the grazing season in days.
Experiment 2
Five tall fescue pasture treatments were compared for beef cattle toxicity and growth performance for 3 yr at the Central Georgia Branch Station near Eatonton, GA (lat 33.3972°N; long 83.4883°W; elevation 167 m): 1) ‘Georgia-5’ (Bouton et al., 1993) infected with AR542 (G542), 2) ‘Jesup’ (Bouton et al., 1997) infected with AR542 (J542), 3) Jesup infected with AR502 (J502), 4) Jesup E- (JE-), and 5) Jesup E+ (JE+). A randomized complete block design was used with two replications of each paddock treatment. The 0.81-ha paddocks were tall fescue monocultures established in October 1998. Seed supplied was precision drilled into well-prepared seedbeds of Pacolet sandy loam soil at a seeding rate of 33.6 kg/ha. Pastures were fertilized uniformly with 67 kg of N/ha and P and K according to soil tests at establishment and in February and September of each subsequent year. During spring 1999, paddocks were stocked with cattle for 49 d.
Hereford crossbred steers (mean BW = 254 ± 5.3 kg) were assigned randomly to the treatment paddocks. The cattle were managed as described in Exp. 1. Grazing was initiated when there was adequate forage available—approximately 2,700 kg of DM/ha. Grazing continued until forage availability dropped below approximately 2,300 kg of DM/ha. Available forage, endophyte infection rate, ergot alkaloid concentrations, cattle weights, rectal temperatures, and serum prolactin concentrations were sampled according to the procedures described for Exp. 1.
Experiment 3
Steer grazing behavior during spring and fall 2001 was compared on three Jesup tall fescue pasture treatments at the Eatonton location: 1) J542, 2) JE-, and 3) JE+. The replicated (n = 2) 0.81-ha tall fescue pastures were a subset of the pastures used in Exp. 2. Eighteen Hereford steers (mean BW = 377 ± 2.5 kg) were stocked on tall fescue pastures at an initial stocking rate of three steers per paddock in early March 2001. In September 2001, the pastures were restocked with a new set of 18 Hereford steers (mean BW = 280 ± 2.0 kg). Two steers in each paddock were designated before the start of each grazing season as testers, whereas a third steer was used as a grazer in a put-and-take grazing management system. The 12 tester steers were halter broken for ease of handling before the start of the trial and were a subset of the cattle used in Exp. 2.
Behavioral measurements were taken on tester steers over four 5-d collection periods during spring 2001 (March 5 to 10, April 9 to 14, May 14 to 19, and June 18 to 23) and three 5-d collection periods during fall 2001 (September 24 to 29, October 29 to November 3, and November 26 to December 1). The onset of the March and September behavioral data collection periods coincided with d 0 of the grazing trials. Before beginning grazing on the treatment pastures, steers were grazed on E- tall fescue and fed bermudagrass hay. Automatic jaw movement sensors (Rutter et al., 1997), leg movement sensors (Champion et al., 1997), and data recorders (Ultra Sound Advice, London, U.K.) (Figure 1) were used to measure grazing time, ruminating time, number of jaw movements, number of steps taken, and lying time. During each 5-d collection period, behavioral data were collected for five 24-h periods that were staggered to allow time to handle cattle to change recorder data cards and batteries. The difference in the time when cattle in the first paddock were handled until cattle in the final paddock were handled on a given collection date ranged from approximately 1.5 to 4 h, thus exposing the cattle to varying weather conditions and time-related events according to paddock handling order. Data were downloaded from recorder data cards to a laptop computer after every 24 h of behavioral data collection. In addition, in-line water flow meters attached to automatic watering tanks measured paddock water usage. Meter readings were recorded daily during behavioral data collection periods. Paddock water usage was converted to a steer BW water usage basis by adjusting for stocking rate and steer BW.
|
) of the ANKOM procedure. The NDF and ADF were sequentially determined using the ANKOM200 Fiber Analyzer (ANKOM Technology Corp.). Indigestible ADF (IADF) was determined according to the procedure of Bernard and McNeill (1991).
Controlled-release chromic oxide boluses (Captec Ind., New Zealand) were orally administered as an external marker to tester steers one wk prior to each behavioral data collection period. After an 8-d equilibration period, fecal grab samples were collected for five consecutive days at the conclusion of each 24-h period during the 5-d behavioral data collection periods. Fecal grab samples were dried in a forced-air oven at 50°C for 96 h, composited over 5-d periods by steer, ground to pass through a 1-mm screen, and analyzed for DM and IADF content according the procedures detailed for esophageal extrusa samples. Chromium content was determined using the procedure of Fenton and Fenton (1979).
Daily fecal output was estimated by dividing the quantity of chromium released daily from the chromic oxide bolus as supplied by the manufacturer by the concentration of fecal chromium. Forage indigestibility was calculated using IADF as an internal marker by dividing forage IADF content from esophageal samples by fecal IADF content. DMI was computed by dividing fecal output by forage indigestibility. Steer DMI was then adjusted for steer BW. Mean bite size in kg/prehension was determined by dividing mean daily DMI by mean daily prehensions. Biting rate was calculated by dividing prehensions by grazing time.
Statistical Analysis
The PROC GLM/LSMEANS of SAS (SAS Inst., Inc., Cary, NC) was used to separately analyze the data from each experiment. For Exp. 1, a completely randomized experimental design was used with paddock as the experimental unit. There were two replications of each experimental unit. Main effects were endophyte and cultivar treatment, season, and grazing year. Treatment effects were tested using pasture within treatment as the error term. Season and year effects were tested using season x year as the error term. Season x treatment and year x treatment were tested using season x year x treatment as the error term. For Exp. 2, a randomized complete block experimental design was used with paddock as the experimental unit and paddock exposure to possible deer infestation as the blocking factor. Each treatment occurred once in each of the two blocks. Main effects were endophyte and cultivar treatment, season, year, and block. Each grazing year in Exp. 1 included a spring period and the subsequent autumn period, while each grazing year in Exp. 2 included a spring period and the preceding autumn period. Each model included main effects and their interactions. Treatment effects were tested using pasture within treatment as the error term. Season and year effects were tested using season x year as the error term. Season x treatment, year x treatment, season x block, and year x block were tested using season x year x treatment as the error term. Ergot alkaloid concentration and serum PRL means showed non-homogeneity among their variances due to some treatments having near-zero values and others with values in the hundreds or even thousands. Thus, these data were subjected to square root transformations to address data non-normality prior to statistical analysis, and nontransformed least squares means are reported. Because the ergot alkaloid and serum PRL data were not normally distributed, the variations around the means are not reported.
For Exp. 3, GRAZE (Ultra Sound Advice, London, U.K.), a software program designed to analyze the behavior data files (Rutter, 2000), was used to identify periods of grazing, ruminating, and lying, and to count prehensions, mastications, and steps. Forage availability, forage quality, steer performance, grazing behavior, and water intake data were analyzed with PROC GLM/LSMEANS of SAS as a randomized complete block design. Paddock was the experimental unit. Main effects were endophyte and cultivar treatment, period, and block. The model included main effects and their interaction. Treatment effects were tested using pasture within treatment as the error term. Period effects and period x treatment were tested using period x pasture within treatment as the error term.
|
Results and Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
Forage Variables
. Mean rate of endophyte infection exceeded 59% in nonergot alkaloid-producing and E+ pastures throughout the duration of the studies (Table 3). Mean available forage was higher (P < 0.05) on KE+ pastures than on K542 pastures during the fall, and on K542 and K502 pastures during spring at Calhoun (Table 3). Mean available forage at Eatonton was higher (P < 0.05) on JE+ pastures than AR542, AR502 and E- tall fescue pastures during spring. In addition, mean available forage was higher (P < 0.05) in spring than autumn at both locations. This was likely due to increased forage growth during spring due to extended daylight hours and tall fescue entering a reproductive state. Mean ergot alkaloid concentrations were higher (P < 0.01) in E+ tall fescue than AR542, AR502, or E- tall fescue at both locations during both seasons (Table 3).
|
; Fribourg et al., 1991; Rice et al., 1997). The only treatment difference among pretreatment (d-0) PRL concentrations was at Eatonton during spring, when concentrations on G542 exceeded (P < 0.05) those on J502 (Table 4). A treatment x season interaction (P < 0.01) existed for post-treatment PRL concentrations at both locations. Mean post-treatment PRL concentrations were depressed (P < 0.01) at both Calhoun and Eatonton on E+ compared with AR542, AR502, and E- tall fescue in both fall and spring. Post-treatment PRL concentrations of cattle grazing E+ pastures declined to near zero within the detection limits of the assay. The spread between mean post-treatment serum PRL concentrations in cattle on nonergot alkaloid-producing endophyte-infected and E- tall fescue pastures over concentrations on E+ tall fescue pastures was greater during spring than autumn. This was likely due to photoperiod-based seasonal variations in cattle PRL concentrations previously documented (Stanisiewski et al., 1988; Petitclerc et al., 1989; Cho et al., 1998). Cattle serum PRL concentrations vary with the photoperiod and tend to increase with increasing daylength. In both trials, post-treatment PRL concentrations were higher (P < 0.01) during spring than fall. The treatment results for both the Calhoun and Eatonton grazing trials agree with the findings of Nihsen et al. (2000) for cattle grazing KE+, HiMag E-, and nonergot alkaloid-producing endophyte-infected HiMag tall fescue.
|
). At Calhoun, post-treatment rectal temperatures were elevated (P < 0.05) during spring in cattle grazing KE+ tall fescue compared with K542, K502, and KE- tall fescue. However, no differences (P = 0.61) were observed among post-treatment rectal temperatures at Calhoun during autumn. This may have been due to confounding variables (i.e., cattle handling-induced stress, ambient temperature, humidity, and exposure to sunlight). Cattle on KE+ tall fescue were observed exhibiting signs of heat stress during periods of elevated environmental temperatures (i.e., panting and seeking shade), whereas cattle on KE-, K542, and K502 continued to graze.
|
). During fall at Eatonton, post-treatment rectal temperatures were higher (P < 0.05) in cattle grazing JE+ tall fescue compared with cattle grazing G542 and J502 tall fescue. Cattle on JE+ tall fescue had higher (P < 0.05) post-treatment rectal temperatures than cattle grazing G542, J542, J502, and JE- tall fescue during spring. This treatment difference is consistent with findings of other researchers in cattle grazing nonergot alkaloid-producing endophyte-infected tall fescue (Nihsen et al., 2000), E-, and E+ tall fescue (Hoveland et al., 1983; Schmidt et al., 1983). Alkaloids produced in E+ tall fescue have been shown to have vasoconstrictive effects on bovine vasculature (Oliver et al., 1993). Reduced blood flow could result in tissue death and impaired ability to dissipate heat (Rhodes et al., 1991; Al-Haidary et al., 2001). This may explain the thermoregulatory challenge evident in cattle grazing E+ tall fescue.
Stocking Rate
. Stocking rate treatment differences were not present at Eatonton (P = 1.00) (data not shown). A grazing year effect (P < 0.01) was present for stocking rate at Eatonton. The number of cattle grazing days may have played a role in the year effect for stocking rate. At Calhoun, a treatment x season x year interaction (P < 0.01) existed because stocking rate was increased in each subsequent grazing year to a greater extent on KE+ tall fescue than on the other treatments, particularly during spring. In 1999, mean stocking rate at Calhoun for each pasture treatment was 0.75 ± 0.11 heifers/ha. In 2001, mean stocking rates were 1.21 ± 0.11 steers/ha on the K542, K502, and KE- pastures, and 1.29 ± 0.11 steers/ha on the KE+ pastures. Increased alkaloid production in KE+ forage after the first year may have led to decreased forage consumption on KE+ pastures. Ergot alkaloid consumption produces a negative feedback on forage intake by grazing cattle. Lower forage intake on E+ tall fescue compared with E- tall fescue has been reported in both steers (Stuedemann et al., 1989) and cows (Peters et al., 1992). Mean spring stocking rate was higher (P < 0.01) than mean fall stocking rate at both locations. This was possible because spring available forage was higher (P < 0.05) than autumn available forage.
Average Daily Gain
. For the Eatonton grazing trial, a treatment x season interaction (P < 0.01) was detected for ADG (Table 6). Cattle ADG was decreased during spring grazing relative to autumn grazing on JE+ tall fescue. This was likely related to higher plant ergot alkaloid concentrations in forage leaves during the spring (Rottinghaus et al. 1991) and the presence of seed in which endophyte and alkaloid concentrations tend to be concentrated during spring as tall fescue enters a reproductive state (Siegal et al., 1984; Ball, 1997). This may have enhanced the toxicosis condition in JE+ pastures during spring and depressed ADG further. Another possible explanation may involve more mature forage in the JE+ pastures because of lower spring grazing pressure compared to the other treatment pastures.
|
). This is consistent with the results of Nihsen et al. (2000), in which higher steer ADG on nonergot alkaloid-producing endophyte-infected and E- tall fescue over E+ tall fescue were reported. Additionally, during spring at Eatonton, ADG was higher (P < 0.05) on J502 and JE- than J542 pastures. A treatment x grazing year interaction (P < 0.05) was found for the Calhoun trial in which ADG increased on all treatments in the second year. The most dramatic annual increases in ADG were exhibited on K502 pastures. The use of different cattle each year may have played a role in this interaction, while flooding in the second year on a K542 pasture may have also contributed to the significance of this interaction.
Gain per Hectare
. Gain/ha treatment x season (P < 0.10; Table 6) interactions for both grazing trials resulted for the same reasons as the corresponding ADG interactions discussed previously. As was the case with ADG, gain/ha was higher (P < 0.05) on AR542, AR502, and E- than on E+ tall fescue in both seasons at each location (Table 6). At both locations, there were seasonal effects for gain/ha with values being higher (P < 0.05) in spring than in autumn. This finding is reasonable as the grazing seasons were longer and the mean available forage was greater (P < 0.05) in the spring periods. A treatment x grazing year interaction (P < 0.05) was detected at Calhoun for gain/ha and may be explained by the factors that influenced the ADG treatment x grazing year interaction at Calhoun described previously. Differences in annual stocking rate and restocking with new cattle at the beginning of year two may account for the difference (P < 0.01) in annual gain/ha values for each grazing trial.
Experiment 3
Forage Availability and Quality
. Using put-and-take grazing management, mean forage availability was maintained at levels that did not differ among treatments (P = 0.19) during the fall. However, mean spring available forage was higher (P < 0.05) on JE+ pastures than JE- pastures. Forage IVDMD concentrations were lower (P < 0.05) on JE+ tall fescue pastures compared with JE- pastures during spring (Table 7). Forage CP (P = 0.74), NDF (P = 0.21) and ADF (P = 0.23) concentrations did not differ across pasture treatments during spring. Similarly, forage CP (P = 0.52), NDF (P = 0.18), and ADF (P = 0.28) concentrations did not differ across pasture treatments during autumn. IVDMD and CP concentrations were highest (P < 0.05) in March and September and lowest (P < 0.05) in May and November during spring and autumn grazing, respectively. NDF and ADF increased (P < 0.05) from March through May and from September through November.
|
). This is consistent with observations by Howard et al. (1992), in which steers on high E+ (>60% wild-type endophyte infection) tall fescue grazed for a shorter duration than did steers on low E+ (<1% wild-type endophyte infection) tall fescue. Ruminating time was higher (P < 0.05) on J542 pastures than on JE- and JE+ pastures across April, May, and June. Idling (neither grazing nor ruminating) time was higher (P < 0.01) on JE+ tall fescue than on J542 and JE- tall fescue across April, May, and June. Howard et al. (1992) reported longer idling time for steers grazing high E+ over low E+ tall fescue pastures. Across October and November, steers grazing J542 pastures spent more (P < 0.10) time grazing than steers on JE+ pastures. No treatment differences were observed in the amount of daily ruminating (P = 0.88) or idling (P = 0.83) activity during late autumn.
|
Lying time was higher (P < 0.01) on J542 and JE- pastures than on JE+ pastures across April, May, and June (Table 9). Thus, steers spent more time standing (P < 0.01) on JE+ tall fescue in spring. Forage treatment effects may be the result of elevated ambient temperatures in late spring. Low et al. (1981) suggested that cattle assume a standing posture over a lying posture during heat stress in an attempt to maximize evaporative cooling. Increased time standing in shaded areas during the heat of the day has been reported for cattle grazing E+ tall fescue over cattle grazing E- tall fescue (Seman et al., 1990). No treatment differences (P = 0.39) were detected for proportion of daily steer lying or standing activity across October and November. This may be related to late autumn ambient temperatures being in a low enough range to avoid a heat stress-induced behavior response in the cattle grazing the JE+ pastures.
|
). Howard et al. (1992) obtained similar results for daily prehensions in cattle grazing low E+ tall fescue compared with high E+ tall fescue. Biting rate (prehensions/min of grazing) was higher (P < 0.01) on J542 and JE- tall fescue than on JE+ tall fescue across April, May, and June, as well as across October and November. Bite size did not differ among forage treatments in spring (P = 0.50) or fall (P = 0.34). In the Howard et al. (1992) study, bite size and biting rate did not differ between steers grazing high-E+ tall fescue and those grazing low-E+ tall fescue.
|
Daily DMI estimates appear in Table 11. Daily DMI was greater (P < 0.10) in steers grazing J542 and JE- tall fescue than in steers grazing JE+ tall fescue across April, May, and June. Across October and November, steer daily DMI was higher (P < 0.05) on JE- pastures than JE+ pastures. Paterson et al. (1995) indicated that in the absence of temperature stress (i.e., >32°C), cattle DMI of E+ and E- tall fescue did not differ. However, when environmental temperature exceeded 32°C, cows grazing E+ tall fescue consumed less forage than did cows grazing E- tall fescue. Daily DMI estimates in the present study were considerably lower than those reported by Elizalde et al. (1998) for Angus steers of comparable weights grazing E+ tall fescue pastures and than those reported by Judkins et al. (1997) for steers of comparable weights grazing E- tall fescue pastures.
Daily steer water usage adjusted for BW was higher (P < 0.01) in JE+ tall fescue pastures than J542 and JE- pastures across April, May, and June. Additionally, steers used more (P < 0.05) water during April, May, and June than in March. Elevated ambient temperatures during late spring may have been a factor in both treatment and period effects. Steers likely used more water in response to heat stress. Excessive salivation (Stuedemann and Hoveland, 1988) and increased respiration rates (Osborn et al., 1992) have been documented for cattle grazing E+ tall fescue and could enhance water intake needs. However, inconsistent findings have been reported for the effects of tall fescue endophyte status on water intake (Aldrich et al., 1993a,b). During October and November in the present study, steers grazing J542 and JE- pastures used more (P < 0.10) water than steers grazing JE+ tall fescue. Ambient temperatures during late fall may not have been elevated to a level and for a duration that would have induced heat stress-related increases in water usage on JE+ pastures. In addition, the higher (P < 0.10) fall water usage by steers on J542 and JE- tall fescue over JE+ tall fescue may have been a reflection of increased intake, particularly an increased CP intake. Increased water consumption may have facilitated urea excretion from increased CP intake.
|
Implications |
|---|
|
TopAbstractIntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
|
Footnotes |
|---|
2 This research was supported by state and Hatch funds allocated to the Georgia Agric. Exp. Stn., as well as funding from AgResearch (Palmerston North, New Zealand), Pennington Seed, Inc. (Madison, GA), and the Southern Region Sustainable Agriculture Research and Education Program.
4 Present address: Dept. of Anim. and Poultry Sci., Virginia Polytechnic Institute and State Univ., Blacksburg 24061.
3 Correspondence: 2301 S. University Ave., P.O. Box 391, Little Rock, AR 72203 (phone: 501-671-2162; fax: 501-671-2185; E-mail: jparish{at}uaex.edu).
Received for publication February 10, 2003. Accepted for publication July 21, 2003.
|
Literature Cited |
|---|
|
TopAbstractIntroductionMaterials and MethodsResults and DiscussionImplicationsLiterature Cited |
|---|
This article has been cited by other articles:
|
|
 |
|
  P. A. Beck, C. B. Stewart, S. A. Gunter, and D. Singh Evaluation of Tall Fescues for Stocker Cattle in the Gulf Coastal Plain Professional Animal Scientist, October 1, 2009; 25(5): 569 - 579. [Abstract] [PDF]
|
|
|
|
 |
|
 C. A. Roberts, R. L. Kallenbach, N. S. Hill, G. E. Rottinghaus, and T. J. Evans Ergot Alkaloid Concentrations in Tall Fescue Hay during Production and Storage Crop Sci., June 26, 2009; 49(4): 1496 - 1502. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. A. Young, B. A. Tapper, K. May, C. D. Moon, C. L. Schardl, and B. Scott Indole-Diterpene Biosynthetic Capability of Epichloe Endophytes as Predicted by ltm Gene Analysis Appl. Envir. Microbiol., April 1, 2009; 75(7): 2200 - 2211. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. E. Drewnoski, E. J. Oliphant, B. T. Marshall, M. H. Poore, J. T. Green, and M. E. Hockett Performance of growing cattle grazing stockpiled Jesup tall fescue with varying endophyte status J Anim Sci, March 1, 2009; 87(3): 1034 - 1041. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Stewart Jr., G. Scaglia, O. A. Abaye, W. S. Swecker Jr., G. E. Rottinghaus, H. T. Boland, M. McCann, and J. P. Fontenot Estimation of Forage Intake by Steers Grazing Three Fescue Types and Determination of Alkaloids in Ruminal Fluid and Forage Professional Animal Scientist, December 1, 2008; 24(6): 578 - 587. [Abstract] [PDF]
|
|
|
|
|
|
P. A. Beck, S. A. Gunter, K. S. Lusby, C. P. West, K. B. Watkins, and D. S. Hubbell III Animal performance and economic comparison of novel and toxic endophyte tall fescues to cool-season annuals J Anim Sci, August 1, 2008; 86(8): 2043 - 2055. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. K. McClanahan, G. E. Aiken, and C. T. Dougherty Case Study: Influence of Rough Hair Coats and Steroid Implants on the Performance and Physiology of Steers Grazing Endophyte-Infected Tall Fescue in the Summer Professional Animal Scientist, June 1, 2008; 24(3): 269 - 276. [Abstract] [PDF]
|
|
|
|
 |
|
 R. Flores, W. K. Coblentz, R. K. Ogden, K. P. Coffey, M. L. Looper, C. P. West, and C. F. Rosenkrans Jr. Effects of Fescue Type and Sampling Date on the Nitrogen Disappearance Kinetics of Autumn-Stockpiled Tall Fescue J Dairy Sci, April 1, 2008; 91(4): 1597 - 1606. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. C. Burke, G. Scaglia, K. E. Saker, D. J. Blodgett, and W. S. Swecker Jr Influence of endophyte consumption and heat stress on intravaginal temperatures, plasma lipid oxidation, blood selenium, and glutathione redox of mononuclear cells in heifers grazing tall fescue J Anim Sci, November 1, 2007; 85(11): 2932 - 2940. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Flores, W. K. Coblentz, R. K. Ogden, K. P. Coffey, M. L. Looper, C. P. West, and C. F. Rosenkrans Jr Effects of Fescue Type and Sampling Date on the Ruminal Disappearance Kinetics of Autumn-Stockpiled Tall Fescue J Dairy Sci, June 1, 2007; 90(6): 2883 - 2896. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. D. Jensen, L. Mikkelsen, and N. Roulund Variation in Genetic Markers and Ergovaline Production in Endophyte (Neotyphodium)-Infected Fescue Species Collected in Italy, Spain, and Denmark Crop Sci., January 22, 2007; 47(1): 139 - 147. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. A. Hopkins and M. W. Alison Stand Persistence and Animal Performance for Tall Fescue Endophyte Combinations in the South Central USA Agron. J., August 3, 2006; 98(5): 1221 - 1226. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Burns, D. S. Fisher, and G. E. Rottinghaus Grazing Influences on Mass, Nutritive Value, and Persistence of Stockpiled Jesup Tall Fescue without and with Novel and Wild-Type Fungal Endophytes Crop Sci., July 25, 2006; 46(5): 1898 - 1912. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. K. Coblentz, K. P. Coffey, T. F. Smith, D. S. Hubbell III, D. A. Scarbrough, J. B. Humphry, B. C. McGinley, J. E. Turner, J. A. Jennings, C. P. West, et al. Using Orchardgrass and Endophyte-Free Fescue Versus Endophyte-Infected Fescue Overseeded on Bermudagrass for Cow Herds: II. Four-Year Summary of Cow-Calf Performance Crop Sci., July 25, 2006; 46(5): 1929 - 1938. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. Richards, R. B. Pugh, and J. C. Waller Influence of soybean hull supplementation on rumen fermentation and digestibility in steers consuming freshly clipped, endophyte-infected tall fescue J Anim Sci, March 1, 2006; 84(3): 678 - 685. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Zhang, M. A. R. Mian, and J. H. Bouton Recent Molecular and Genomic Studies on Stress Tolerance of Forage and Turf Grasses Crop Sci., February 1, 2006; 46(2): 497 - 511. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. K. Matthews, M. H. Poore, G. B. Huntington, and J. T. Green Intake, digestion, and N metabolism in steers fed endophyte-free, ergot alkaloid-producing endophyte-infected, or nonergot alkaloid-producing endophyte-infected fescue hay J Anim Sci, May 1, 2005; 83(5): 1179 - 1185. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. E. Realini, S. K. Duckett, N. S. Hill, C. S. Hoveland, B. G. Lyon, J. R. Sackmann, and M. H. Gillis Effect of endophyte type on carcass traits, meat quality, and fatty acid composition of beef cattle grazing tall fescue J Anim Sci, February 1, 2005; 83(2): 430 - 439. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. H. Watson, M. A. McCann, J. A. Parish, C. S. Hoveland, F. N. Thompson, and J. H. Bouton Productivity of cow-calf pairs grazing tall fescue pastures infected with either the wild-type endophyte or a nonergot alkaloid-producing endophyte strain, AR542 J Anim Sci, November 1, 2004; 82(11): 3388 - 3393. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Nihsen, E. L. Piper, C. P. West, R. J. Crawford Jr., T. M. Denard, Z. B. Johnson, C. A. Roberts, D. A. Spiers, and C. F. Rosenkrans Jr. Growth rate and physiology of steers grazing tall fescue inoculated with novel endophytes J Anim Sci, March 1, 2004; 82(3): 878 - 883. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
