Search

Grazing and subsequent finishing performance of steers (Bos taurus) grazed on a wheat (Triticum aestivum L.)-crabgrass [Digitaria ciliaris (Retz) Koel.] system were evaluated in 1999, 2000, and 2001 to compare interseeding lespedeza (Lespedeza stipulacea Maxim.) with an additional application of N fertilizer. Hard red winter wheat was no-till seeded in fall 1998, 1999, and 2000 in pastures previously seeded to ‘Red River’ crabgrass. In early spring 1999, 2000, and 2001, additional crabgrass seed was broadcast over all pastures, and Korean lespedeza was no-till seeded in 4 pastures. All pastures received similar applications of fertilizer; however, 3 pastures not seeded with lespedeza received an additional 56 kg of N/ha in mid July. Wheat grazing was initiated in mid to late March of each year. Following wheat graze-out, cattle remained on the pastures and grazed crabgrass from mid May until early September. Legume cover, forage DM production, grazing steer performance, and subsequent finishing performance were measured. Available forage DM and grazing BW gains were similar (P > 0.05) between pastures fertilized with additional N and those interseeded with lespedeza. Although there were no treatment differences (P > 0.05), there were significant (P 0.05) when pastures in a wheat-crab-grass grazing system were interseeded with lespedeza or fertilized with additional N. However, there were significant (P

Shrink is a normal occurrence in cattle that affects both the seller and buyer; a few hours to over 30 d are required to replenish this lost BW. The primary factor affecting shrink is the length of time of feed and water withdrawal; rate of shrink averages ca. 1%/h during the initial 3 to 4 h, but decreases to as low as 0.1%/h after 10 h or more. Shrink is not only loss of gut fill but actual tissue loss, which can exceed 60% of the total BW loss. This amount is greater when ambient temperatures are high. Many other factors also affect the amount of shrink cattle incur. Shrink may be increased by up to 2 percentage units when environmental conditions are stressful, such as during periods of high ambient temperature, transport (compared with holding in a drylot), or during extra or rough handling. Preconditioning calves or feeding specific types of diets prior to shrink have not affected shrink conclusively. Allowing calves to consume feed or forage immediately before deprivation reduced the amount of shrink by up to 2.9 percentage units, and feeding ionophores reduced shrink by 0.2 to 1.5 percentage units. Electrolyte supplementation may also reduce shrink, but much more research is needed to determine which electrolyte or combination of electrolytes is needed, at what levels they are needed, and when is the optimal time to supplement with higher levels of electrolytes to have the greatest impact on reduction of shrink and stress.

Eight paired comparisons conducted at three field sites with 1059 newly-received lightweight stocker calves were used to determine the effect of free-choice cooked molasses tubs designed for receiving cattle on 28-day receiving period performance, percentage of cattle treated for respiratory disease, and death loss. At all sites, cattle received similar management with the exception that cooked molasses tubs were added to half of the pens immediately following initial processing. Weight gains were similar (P=0.36) for cattle with or without access to tubs (43 and 38 lb, respectively). The addition of tubs also did not affect the number of cattle treated (P=0.48) or percent death loss (P=0.61); however, there was a numerical decrease in death loss for cattle with access to tubs (2.7 vs 1.8%). Tub consumption (0.245 lb/day) based on beginning and ending weights of the tubs, was below the desired level of 0.5 lb/day. Low tub consumption may have compromised any potential for improved performance or overall health response for cattle offered free access to cooked molasses tubs.

Two experiments were conducted to determine the effects of Mg-mica supplementation on grazing and feedlot performance of stocker steers. In Exp. 1, eight groups of six steers were fed a basal diet of 80% ground grain sorghum, 15% corn silage, and 5% control protein supplement (DM basis) or a supplement containing Mg-mica (9% of supplement; 4.5 mg/kg diet DM) for 141 d. Marbling scores tended (P 0.10) higher marbling scores, and a higher percentage of carcasses grading USDA Choice than steers fed the control supplement during the pasture phase. Therefore, adding Mg-mica to pasture supplements or feedlot diets appears to have no impact on grazing or feedlot performance, but may improve carcass quality.

Two studies having 4 × 4 Latin square designs were conducted to quantify the effect of different gathering times on weight of steers grazing smooth bromegrass pastures. Initial and final weights were measured following a 16-h removal from feed and water. An intensive weighing period followed 3 to 4 d after the initial shrunk weight in which all steers were weighed either at grazing initiation (T0; 0700 h in Exp. 1 and 0615 h in Exp. 2) and 1 (T1), 2 (T2), or 3 (T3) h later on 4 separate d with a 2- to 3-d interval between weighings. In Exp. 1 (September 24 to October 7, 1992), 37 steers were allotted into four replicates. Steers gathered at T3 weighed 7 kg more (P

An injection of tilmicosin phosphate (Micotil®) at arrival reduced mortality and morbidity (P

An experiment was conducted to evaluate the effects of supplemental Aspergillus oryzae fermentation extract (AO) on intake, gain, temperature, and serum prolactin levels of steers fed seed screenings with and without Acremonium coenophialum. Sixty-four Angus and Angus × Hereford crossbred steers were allotted randomly by weight into one of 16 groups and fed an A. coenophialum-free hay basal diet offered for ad libitum consumption. Groups were assigned randomly to one of four treatments in a 2 × 2 factorial arrangement Treatments consisted of 2.0 kg/d seed screenings from either bromegrass (B) or A. coenophialum-infected fescue (F; 677 μg/kg ergovaline). Within each screenings type, 0.9 kg/d of a soybean hull-mineral supplement was offered either with 2 g per head per d AO or no AO (C) for 90 d beginning on June 30. Steers fed B gained 15.6 kg more (P

Three studies were conducted to look at the effects of four trace mineral elements on gain and health of lightweight, long-hauled (24 h on truck) calves. In trial 1, copper sulfate (982 mg), zinc oxide (833 mg), and vitamin E (400 IU) applied in a drench at arrival resulted in a trend toward reducing the number of pulls (calves removed from pen and doctored for sickness) through 29 to 56 d. A copper sulfate, zinc oxide, and vitamin E drench had no effect on gain through 56 d. In trial 2, daily gains, percentage pulls, and medications per animal did not differ (P

Four trials were conducted to determine the effect of different implants on steers and heifers grazing native grass pastures for different lengths of time. In addition, two groups of steers were followed through a feeding period to determine if previous implanting had a residual effect on gain. The implanted (Ralgrofi, Ralgrofi Magnum , Synovex Sfi) steers gained faster than the controls; however, no differences in gain occurr ed among implants. In the finishing group that went on grass at 687 lb, implants had no ef fect on subsequent feedlot gain. In the second group (on grass at 569 lb and grazing for 80 days), controls gained faster in the feedlot than those that ha d been implanted on grass, resulting in essentially equal weights for all treatments. Among the heifer groups, no differences occurred in pasture gains. Genetic differences in cattle, length o f grazing, and other factors may change implant results.

Two hundred eighty-eight newly weaned beef steers were used to evaluate effects of dietary Zn source and level and supplemental Cu Lys on performance and health during receiving and growing and finishing periods. Eight dietary treatments were applied in a 4 x 2 factorial arrangement during the 28-d receiving period (three pens per treatment) and included: Basal, 65% concentrate diet supplemented (DM basis) with 30 mg/kg of Zn (from ZnO) and 3.25 mg/kg ofCu (from CuO); Basal + 5 mg/kg of supplemental Cu from Cu Lys; Low Zn Met, Basal + 35 mg/kg of supplemental Zn from Zn Met; Low Zn Met + 5 mg/kg of supplemental Cu from Cu Lys; High ZnSO4, Basal + 70 mg/kg of supplemental Zn from ZnSO4; High ZnSO4 + 5 mg/kg of supplemental Cu from Cu Lys; High Zn Met, Basal + 70 mg/kg of supplemental Zn from Zn Met; and High ZnMet + 5 mg/kg of supplemental Cu from Cu Lys. At the conclusion of the 28-d receiving period, Cu Lys supplementation was discontinued, and steers remained in their assigned pens, resulting in a total of six pens per each of the four Zn source-level treatments. Over a subsequent 21-d period, steers were stepped up to a 90% concentrate diet, which was fed for a 161-d finishing period. Neither Zn source-level nor Cu Lys supplementation affected performance or morbidity from bovine respiratory disease during the 28-d receiving period. Percentage of morbid steers during both the receiving and step-up periods was decreased (P

A study was conducted to determine effects of feeding diets high in deep-stacked or composted broiler litter compared with diets differing in forage quality on feed intake, digestibility, and live weight gain in growing cattle. Holstein heifers (158 ± 7.4 kg initial BW) were fed .5% of their BW of bermudagrass hay, 1% of their BW of ground corn, and ad libitum quantities of bermudagrass hay (Control), alfalfa hay (ALF), or deep-stacked or composted broiler litter (D-L and C-L, respectively) in an 84-d experiment. Stacked and composted litters were 27 and 32% ash, 3.8 and 7.8% N, 58 and 36% NDF (DM basis), and 25 and 29% ADF N (total N basis), respectively. Total DM intake was similar among treatments (5.9, 6.3, 5.8, and 6.0 kg/d for Control, ALF, D-L, and C-L, respectively); OM digestibility ranked (P Control (67%) > D-L (52%) > C-L (44%); and digestible OM intake was 3.65, 4.59, 2.49, and 1.99 kg/d (SE = .378) for Control, ALF, D-L, and C-L, respectively. Live weight gain was greatest (P

Bermudagrass [Cynodon dactylon (L.) Pers.] is productive in summer but is dormant for much of the year. The grazing season for bermudagrass pastures can be lengthened by fall interseeding of rye (Secale cereale L.). In trial 1, performance of Stocker cattle (222 kg average BW) grazing monocultured rye (MR) followed by bermudagrass (MB) in separate pastures was compared with that of cattle grazing interseeded rye-bermudagrass pastures (IRB). Spring forage production and 1989 carrying capacity were greater (P .10)between systems. Summer bermudagrass gain and grazing days from the two systems varied by year. Overall gain per hectare of land grazed and animal grazing days per hectare were greater (P 2.0, indicating a greater efficiency for interseeding. In trial 2, ruminally fistulated heifers (395 kg average BW) were used to estimate forage intake and nutritional components from the two types of rye pastures. Dietary forage from MR was higher (P ≤ .01) in neutraldetergent fiber, ADF, and in vitro organic matter digestion (IVOMD, 48 h) and lower (P .10) between MR and IRB dietary forage. Heifers grazing MR had higher (P

Whole plant corn silage was ensiled for 0, 2, 6, 14, 30, and 50 d in triplicate plastic silo bags, with or without addition of a commercial cellulase and xylanase enzyme mixture (230 mL/ton). After each fermentation period, silage was removed and analyzed for DM, pH, water soluble carbohydrates (WSC), Total N, ADF, NDF, and lactic acid. Samples from 50 d silage bags were analyzed for in situ DM and NDF disappearance. Aerobic stability of silage was recorded upon opening 30 d silage bags. No differences were noted for pH, DM, or ammonia (percentage of total N). The WSC content (DM basis) was higher (P < .05) at 6 d for enzyme-treated silage (4.27 vs 3.91%). Increases in lactic acid levels for treated silage were noted after 2 d of fermentation, however this was significant only at 30 d (P < .10). Reductions in ADF and NDF concentrations were significant at 50 d for enzyme-treated silage (P < .10). No differences were observed for in situ disappearance of DM. After 48 h of ruminal incubation, control silage had higher NDF disappearance. Following 3 d of silage exposure to air, temperature of enzyme-treated silage rose dramatically and declined to temperatures similar to the control at 5 d. Although silage was lower in ADF and NDF after 50 d of fermentation, these data suggest that an application of a commercial enzyme mixture to corn silage did not appreciably change silage fermentation or composition.

To assess incidence of elevated body temperature expressed by stocker cattle marketed in central Kentucky at different times of the year, rectal body temperature data were collected during a 9-mo period on 11,084 stocker cattle varying in genetic type, sex, weight, and hair-shedding condition. If rectal body temperature was > 39.4 °C, body temperature was considered to be elevated and recorded as 1; otherwise, 0 was recorded. Incidence (0,1) of elevated body temperature data were analyzed assuming a mathematical model that included effects for calf genetic type [Britishsired (BS), Continental-sired (CS), Holstein-sired (HS)], sex [bull (B), steer (S), heifer (H)], month, week/month, hair shedding condition [slick-shed (SS), partial-shed (PS), nonshed (NS), average weight of group [136 to 181, 182 to 226, 227 to 271, 272 to 317 kg] and appropriate two-way interactions between these effects. Specific comparisons involving calf genetic type, sex, and hair-shedding condition indicated that incidence of elevated body temperature was: 1) similar for HS and (BS + CS)/2 cattle; 2) 5.2% greater (P < .01) for BS than for CS cattle; 3) 12.1% less (P < .01) for SS than for (PS + NS)/2 cattle; 4) 12.3% less (P < .01) for PS than for NS cattle; 5) similar for Hand (B + S)/2 cattle and; 6) 10.9% higher (P < .01) for B than for S cattle. Also, incidence of elevated body temperature differed depending upon weight and month when cattle were marketed.

Ninety medium-framed crossbred steers (245 kg) were used in a 205-d feeding trial to evaluate the influence of 4, 8, and 12% supplemental fat (tallow soap stock) on feedlot growth performance. Increasing level of fat supplementation depressed ADG ( P P P P m was 1.00 with 4% supplemental fat and declined ( P m of tallow soap stock declined in a near rectilinear fashion from 5.65 Mcal/kg at the 4% level of supplementation to 2.85 Mcal/kg at the 12% level of supplementation. Six Holstein steers (296 kg) with T cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on digestive function. Ruminal digestion of OM ( P P P .10) postruminal digestion of OM, ADF, starch, and N. Postruminal digestion of lipid decreased ( P P

Summary Little information has been published concerning the effects of endophyte-infected tall fescue consumption on performance of young growing horses. Therefore, this study evaluated exercise performance and growth by yearlings fed endophyte-infected fescue. Twelve Quarter Horse yearlings (12-16 months of age) were blocked by age and sex and randomly assigned to one of three groups. Group I received native prairie hay (P), Group II received endophyte-free fescue hay (EF) and, Group III received endophyte infected fescue hay (EI). Rectal temperatures were monitored daily and growth parameters (weight, hip and wither heights, and body fat) were measured at the start of the study (d 0) and every 2 weeks throughout the 106 d study. Additionally, blood samples were collected on d 0 and every 28 d for the duration of the study to monitor blood concentrations of calcium, phosphorus, prolactin (PRL), thyroxine (T 4 ), and triiodothyronine (T 3 ). Horses were exercised twice a week for 10-30 min. Respiration, heart rate, and rectal temperature were measured at the start and 5, 30, and 60 min postexercise. Growth parameters and daily rectal temperatures were not different (P >.05) among grdups. No differences (P >.05) occurred among groups in concentrations of serum calcium, phosphorus, PRL, T 3 , and T 4 . Respiration rates were lower (P

A 4-yr study was conducted to evaluate grazing pressure and stand persistence of endophyte-free Kentucky-31 fescue (EFF) pastures. Forage systems were: 1) continuous grazing to an estimated height of 7.6 to 10.2 cm (CONTSH), 2) continuous grazing to an estimated height of 15.2 to 20.3 cm (CONTT), 3) rotational grazing to an estimated height of 7.6 to 10.2 cm (ROTSH), 4) rotational grazing to an estimated height of 15.2 to 20.3 cm (ROTT), and 5) rye with fescue continuously grazed until rye was utilized to a height of

Volatile prices and cattle performance contribute to variability in cattle feeding profit and cost of gain. This study investigated the relative impacts of prices and animal performance on variability in cost of gain and profit for three placement weight categories using closeout data on 6,696 pens of steers placed on feed from January 1980 to May 1991 in two western Kansas feedyards. Fed cattle price and feeder steer price explained 70 to 80% of steer feeding profit risk. Corn price accounted for 6 to 16% of profit variability and animal performance explained 5 to 10%. Corn price explained 58 to 67% of cost of gain variance, feed conversion accounted for 23 to 33%, and average daily gain was responsible for approximately 3% of the variability in cost of gain. Results indicate that cattle feeders should consider these factors when developing budgets, calculating break-evens, or considering placing cattle on feed.

Cow-calf performance on endophyte ( Acremonium coenphialum )-free fescue (EFF) and endophyte-infected fescue (EIF) were evaluated. Four groups of 15 cows each (60 total) were used and allotted to groups on the basis of breed (Hereford and Angus), age, weight, and body condition. Pregnancy rate, cow and calf weights, milk production, milk-fat, lactose, protein and solids-non-fat were measured. Cows grazing EFF had a higher ( P P P

Three experiments were conducted to evaluate the effects of endophyte level, ladino clover interseeding, grazing management or supplemental antibiotics on stocker cattle performance and the amount and diurnal distribution of grazing time by stocker cattle on tall fescue ( Festuca arundinacea Schreb.) pastures. Grazing time was measured during 7-day periods by fitting 12 steers per experiment with vibracorders that recorded grazing time. In Experiment 1, 40 crossbred steers ( Bos taurus ) grazed eight 2.02 ha tall fescue pastures from 9 April to 4 November. Six of the pastures were of ‘Kentucky 31' tall fescue, two pastures simply infected (IF; 65% of the plants infected) with the endophytic fungus Acremonium coenophialum , two uninfected (NIF) and two infected and overseeded with ‘Regal' ladino clover ( Trifolium repens L.; IFL). The other two pastures were of ‘Missouri 96' (MO96; non-infected) tall fescue. Steers grazing NIF gained 50 and 59 kg more ( P P P In Experiment 2, 48 stocker steers were allotted to 2.02 ha IF (70% of the plants infected) or IFL pastures and managed by either allowing them continuous access to their respective pastures or rotating them through 0.2 ha strips at 1–4 day intervals from 21 April to 4 November. Cattle allowed continuous access to IFL pastures gained more ( P P In Experiment 3, consumption of 357 mg day −1 of oxytetracycline in a mineral mixture did not alter grazing time or performance by stocker heifers grazing IF (70% of the plants infected) from 18 June to 8 October. Interseeding ladino clover into high-endophyte fescue pastures or replacing them with endophyte-free fescue may be viable management options for increasing cattle gains. Total grazing time may not be related to the performance of cattle allotted to endophyte-infected tall fescue pastures, but those cattle may graze more after dark than cattle allotted to endophyte-free fescue.

In 29 trials over 10 yr, 6614 head of cattle (heifers: 11 trials, 2862 head; steers: 18 trials, 3752 head) were used to determine the effect of starting BW on gain while grazing native grass pastures. The heifers grazed for an average of 81 d (range, 70 to 93 d), and steers grazed for an average of 86 d (range, 75 to 99 d) from April to July. Average stocking rate was one animal per 0.81 ha (0.65 animal unit month/0.27 ha). The cattle were sorted by starting BW into five groups as follows: below 181 kg, 182 to 227 kg, 228 to 272 kg, 273 to 318 kg, and above 319 kg. In three additional trials, 602 yearling heifers were sorted by starting BW, as described previously, and assigned a body condition score from 1 (thinnest) to 5 (fattest). A separate grazing trial was conducted in which 158 yearling steers were compared with 103 steer calves. The yearlings were springborn and wintered on wheat pasture; the calves were fall-born. Heifers between 182 and 227 kg gained more BW (P

A total of 2,269 mixed-breed steers (256 kg) grazed burned (April), native-grass pastures for nine grazing seasons from 1990 to 1998. Steers were allotted randomly to graze for either 1/2 season (short season [SS]) from late April to July 15 (an average of 81 d, at one steer per 0.81 ha), or for 3/4 season [intermediate season (IMS)] from late April to August 15 (an average of 112 d, at one steer per 1.21 ha). The grass species composition was measured in yr 1, 4, and 8 of the study. The economics of steers grazing the two systems were determined by stocker and feeder cattle prices at Dodge City, adjusted to southeast Kansas. The steers grazing SS gained more per day (1.26 vs 1.13 kg, P 0.10) between systems for big bluestem, little bluestem, switch-grass, Indiangrass, and total perennial grass. However, percentage basal cover of perennial grass increased more for SS (P

Three stocker cattle field studies were conducted comparing a traditional 4to 5-week drylot receiving program with injectable antibiotics administered on a pull-and-treat basis versus a pasture-based conditioning program using an initial metaphylaxis with Micotil followed by immediately placing cattle on grass. Although daily gains were similar (P=.80) for both receiving programs during the first 28 days, pasture conditioning reduced the number of cattle treated and increased (P

Steers grazing high- and low-endophyte-infected tall fescue pastures were either not implanted or implanted with 36 or 72 mg of zeranol. Zeranol had a greater effect on improving gains of steers grazing high-endophyte tall fescue pastures than on those grazing low-endophyte pastures. Steers implanted with zeranol had lower (P

Three experiments were conducted to evaluate performance and fecal nematode egg counts in grazing stocker cattle receiving morantel tartrate (MT) in two continuously administered forms. In Exp. 1, 80 crossbred steers either received no anthelmintic (C) or were dewormed at the initiation of a 140-d bermudagrass grazing study with either levamisole injection (L) or MT in a sustained-release trilaminate (MSRT). Anthelmintics did not affect performance parameters, but fecal nematode egg counts were lowest from L, intermediate from MSRT, and highest from C at the end of the study. In Exp. 2, 60 crossbred steers grazing fall-regrowth smooth bromegrass were offered a mineral mixture of trace-mineralized salt and dicalcium phosphate (3:1 ratio) with 0 or 10% dried molasses and 0 or 5.58 mg/g MT. Steer gains were similar (P>.10) across treatments, but fecal egg counts were reduced (P

The feeding of antibiotics or ionophores in free-choice mineral mixtures was evaluated in four studies with stockers (heifers and steers) grazing native range. In trial 1, heifers with access to lasalocid in a free-choice mineral mixture consumed more mineral ( P P P >.05) in daily gain and in ruminal propionic acid. Both groups gained more ( P P P

A study was conducted to evaluate the feeding of rumen-protected lysine methionine (Smartamine ML®, RPLM) to long-hauled calves during the receiving period. The calves (initial weight =133 kg) were fed 10 g of RPLM/d. Difference in gain occurred during the first 28 d, but the RPLM group gained faster (P

Crossbred steers (266 kg avg BW) were allotted to groups and provided either a control mineral mixture or one containing 2.5% zinc methionine while grazing late-spring burned native grass pastures in early summer to determine whether zinc methionine would reduce the incidence of footrot. Four pastures were provided per treatment per year, and the treatments were rotated in each year of a 3-yr study. The steers were weighed individually in early morning at the start of the trial in April and again at the end in late July or early August. The pastures were grazed an average of 93 d. The mineral mixtures were fed in open wooden boxes, and intake was recorded weekly. The steers were checked once each week for signs of footrot. The steers receiving zinc methionine gained faster (1.27 vs 1.23 kg; P < .06) and had a lower incidence of footrot (2.45 vs 5.38%; P < .06) than the control group. However, the difference in gain between steers with footrot and nonaffected steers did not account for the total difference in gain. Zinc methionine at 2.5% of the mineral mixture improved steer gains and reduced the incidences of footrot.

Tarentaise heifers fitted with a rumen cannula (539 ± 7.5 and 487 ± 15.7 kg avg initial BW in Exp. 1 and 2, respectively) were used in two Latin square metabolism experiments having 2 x 2 factorial treatment arrangements to determine the effects of supplementation with Aspergillus oryzae fermentation extract (AO) or laidlomycin propionate (LP) on intake, digestion, and digestive characteristics of Neotyphodium coenophialum-infected (IF) or uninfected (FF) tall fescue (Festuca arundinacea) hay diets consumed ad libitum. Heifers were housed in individual stanchions in a metabolism facility with ambient temperatures controlled to range between 26.7 and 32.2°C daily. Total feces and urine were collected for 5 d following a 21-d dietary adaptation period. In situ DM and NDF disappearance and ruminal fermentation characteristics were also determined. In Exp. 1, DMI was 24% greater (P < 0.01) by heifers offered FF than by those offered IF (6.7 vs 5.4 kg/d). Heifers fed 2 g/d AO tended (P = 0.09) to consume 4% more DM than those fed a diet without AO. Degradable DM and NDF fractions of IF were greater (P < 0.01) than those of FF, but AO supplementation did not affect situ disappearance (P ≥ 0.42). In Exp. 2, DMI was 18.9% greater (P < 0.01) by heifers offered FF than by those offered IF (6.6 vs 5.5 kg/d). Heifers fed LP (50 mg/d) consumed 10.6% less (P< 0.05) DM than those not fed LP (5.7 vs 6/5 kg/d). Digestibility of NDF tended to be greater (P = 0.08) and digestibility of ADF was greater (P < 0.05) from FF than from IF. Conversely, apparent N absorption (%) was greater (P < 0.05) from IF than from FF. Heifers fed LP had lower (P < 0.05) ADF digestibility than those not fed LP. In situ degradable DM and NDF fractions were greater (P < 0.01) from IF than from FF. Diets supplemented with LP had higher (P < 0.01) indigestible DM and NDF fractions than those without LP. Propionic acid and total VFA concentrations were greater (P < 0.05) from heifers offered FF than from those offered IF and from heifers fed LP than from those not fed LP. Therefore, it appears the major effect of N. coenophialum was a reduction in forage intake and total-tract fiber digestibility in certain situations. Response to the feed additives was similar whether heifers were offered IF or FF and no evidence was apparent that either additive would improve performance substantially by animals consuming low-quality fescue hay diets.

Heifers developed on high-endophyte, tall fescue gained half as much weight (56 vs 117 lb; P

Spring-born, suckling beef calves were offered a limited creep feed of either protein, energy, or energy plus lasalocid from August 15 to October 15 in a 3-yr study. Creep feeding improved daily gain (P < .01) over calves in the control group, but there were no differences in gain among calves fed the three creep rations. Consumption was slightly less for the protein feed resulting in an improved feed efficiency for the protein compared to the energy (P < .01). Creep feeding improved (P < .01) preweaning and 53-d postweaning gains with no differences in gains due to type of creep feed.

Two studies were conducted to determine the effect of feed additives on the transit shrink of yearling cattle. In Trial I, 146 mixed-breed heifers were offered a mineral mixture containing either Terramycin® or Bovatec®, or without additive while grazing native grass pastures. Shrinkage after 300 miles in transit was lower (P .05). The small shrinkage differences observed in these two trials would not justify changes in the weighing practices of feeder cattle.

Summary An analysis of more than 1400 pens of cattle marketed during 1990 examined the influence of several cattle traits and marketing factors on fed cattle prices. Cattle quality grade had an important impact on packer bids and feedyard asking prices. However, both feedyard asking and packer purchase prices reflected less than 25%, on average, of estimated wholesale value differentials. Other factors, including estimated dressing percentage, finish uniformity, cattle weight, number of head purchased, presence of heiferettes, and cattle type had significant price impacts. Feedyards generally received what they asked for cattle; 65% of the pens sold for their asking prices. Price signals for differences in cattle "quality" are not fully transmitted to cattle feeders.

Eighty mixed breed steers (avg. wt. 560 lb.) were used to evaluate the effect on grazing gain and subsequent feedlot performance of different management options for steers earlyintensively grazing Acremonium coenophialuminfected tall fescue pastures. Steers were allotted to pastures of infected fescue pastures or infected fescue overseeded with ladino clover and received no supplement or were offered grain sorghum at .25% of their body weight. Neither supplementation nor overseeding affected grazing or feedlot performance. However, grain supplementation on overseeded pastures reduced subsequent feedlot feed efficiency (P

Two studies were conducted to determine the effect of long-acting penicillin and/or levamisole injected at arrival or levamisole injected on day 1 and/or day 7 on the health and gain of newly received, highly stressed, light weight calves. Levamisole injected at arrival reduced (P

Factors affecting western Kansas fed cattle prices during May through November 1990 were investigated. In particular, the impact of changes in captive cattle supplies on cash prices was examined. The term captive cattle supplies refers to cattle procured by a packer well in advance of slaughter. Captive supplies take one of three forms: 1) packer-owned cattle, 2) cattle procured on forward contracts, and 3) cattle procured under formula price (or marketing) agreements. Captive supplies were defined as cattle procured under forward contracts or formula price agreements, because data on packer-owned cattle were unavailable. Over the May through November 1990 period as a whole, the presence of captive cattle supplies was associated with an average reduction in western Kansas cash market transaction prices of about $0.15/cwt.

Four ruminally fistulated, nonpregnant, nonlactating heifers (515 +/- 7.9 kg) were offered chopped (10-cm screen size) prairie hay for ad libitum consumption with 1.8 kg/d of supplements to provide 0, 45, 113, or 181 g/d of magnesium-mica (MM) in a 4 x 4 Latin square design experiment. Heifers were adapted to diets for 7 d in drylot followed by a 19-d confinement period in individual stalls within a metabolism facility. Total feces and urine were collected for 5 d, daily intake and water consumption were monitored for 16 d, and in situ disappearance of fiber (prairie hay) and CP (soybean meal) were determined during the confinement period. Ruminal samples for fermentation product analyses were collected at feeding and every 2 h thereafter for 12 h on d 18, and rumens were evacuated at 1100 on d 19 to determine rumen fill. Cubic responses (P < .05) to MM level were observed for DM, OM, NDF, and ADF digestion and were characterized by a tendency for improved digestion with 45 g/d compared with the control diet, followed by a suppressive effect on digestion with 113 g/d, then little effect with 181 g/d MM. In situ NDF disappearance at 72 and 96 h tended (P < . 10) to be influenced quadratically by level of MM, but MM level had no apparent effect on ruminal fill and passage rate, ciliated protozoa counts, in situ rate of disappearance of fiber or CP, or nitrogen balance. Therefore, feeding MM at low levels to heifers consuming a prairie hay diet with a 20% CP supplement seemed to be beneficial for feed digestion with no measurable negative impact on intake or ruminal protein or fiber digestion.

Two experiments were conducted to compare the effects of a progesterone-estradiol implant (PEI) with no implant (NI) and 20 g of copper oxide needles (CuON) with no CuON on grazing, subsequent feedlot performance, and selected serum constituents of steers. In Exp. 1, 114 Limousin crossbred yearling steers (317 kg average initial BW) were stocked continuously on Acremonium coenophialum-infected tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) pastures (C) or were rotated to bermuda grass (Cynodon dactylon [L.] Pers.) during summer months (R) of two consecutive years. Implant and copper treatments were applied within pasture. Blood samples were collected four times during each grazing season. Continuously stocked steers had greater (P less than .05) grazing gain, less (P less than .10) feedlot gain, and heavier (P less than .05) carcass weights than R steers did. Implanted steers had greater (P less than .05) pasture but lesser (P less than .05) feedlot gains than did NI steers. Prolactin concentrations were greater (P less than .05) from R than from C steers in late summer 1988. Ceruloplasmin was greater (P less than .01) with CuON than without on the last three and last two sampling dates in 1988 and 1989, respectively. In Exp. 2, blood samples were collected twice from 40 mixed-breed steers (283 kg average initial BW) receiving the same implant and copper treatments as in Exp. 1 and grazing infected fescue for one season. Serum ceruloplasmin and copper concentrations were increased (P less than .01) by CuON, but other measurements did not differ among treatments. Summer grazing of bermuda grass increased serum copper, ceruloplasmin, and prolactin but decreased grazing performance. Implanting increased grazing performance. Copper oxide needles increased serum ceruloplasmin and copper concentrations but did not affect steer performance.

Quality factors affecting fed cattle prices were examined during a six-month period in southwestern Kansas. Transaction prices were significantly affected by the percentage of cattle expected to grade choice times the choice-to-select carcass price spread, finish uniformity, average weight, dressing percentage, breed, number of cattle purchased by a single packer on a given day, the packer, the feedyard, the day-of-the-week the cattle were sold, and the number of bids received. Asking prices were significantly affected by many of the same factors. Asking and transaction prices reflected approximately 25 percent of the packer value differentials for expected carcass quality grades.