A number Of Studies have reported performance by spring-calving cows grazing Neotyphodium-infected fescue [E+, Lolium arundinaceum (Schreb.) Darbysh.], but post-weaning calf performance from the majority of those Studies is limited. Furthermore, both pre- and post-weaning information pertaining to fall-calving cows and their calves grazing E+ is particularly limited. A 3-year study was initiated in April 2000 near Batesville, AR (USA) to investigate the impact of rotational management (twice monthly vs. twice weekly) program and weaning date [mid-April (EARLY) vs. early June (LATE)] on production of fall-calving cow-calf pairs grazing E+ overseeded with ladino (Trifolium repens L.), and red clover (Trifolium pretense L), lespedeza (Lespedeza stipulacea Maxim.), and crabgrass (Digitaria sanguinalis (L.) Scop.). A secondary objective of the study was to evaluate calf performance both at weaning and after weaning until either breeding of the heifers or slaughter of the steers. Calves weaned later had greater (P<0.05) actual weaning weights, but weaning date x year interactions were detected (P<0.05) for most measurements at weaning. Weight loss during a simulated transport and sale, as well as the days required to regain the lost weight were lower (P<0.05) by EARLY than by LATE in 2 of 3 years, and intake (kg DM/100 kg BW) was higher by EARLY than by LATE in 2 of 3 years. Antibody titers to infectious bovine rhinotracheitis and bovine virus diarrhea measured prior to vaccination and at weaning were greater (P<0.05) from EARLY than from LATE. Heifer weight at breeding was greater (P<0.05) from LATE than from EARLY in 1 year and numerically greater (P >= 0.11) from LATE in the other 2 years. Initial and final feedlot BW and gain did not differ (P >= 0.16) among previous treatments in 2 of 3 years. Therefore, carryover effects of weaning date or rotational grazing on calves previously grazing E+ tall fescue may be mitigated during a Subsequent backgrounding period Such that impacts on subsequent breeding or feedlot performance is minimized. (C) 2008 Elsevier B.V. All rights reserved.

A systems trial was designed to evaluate forage characteristics within mixed‐species pastures consisting of (i) endophyte‐infected tall fescue (Festuca arundinacea Schreb.; E+) mixed with common bermudagrass [Cynodon dactylon (L.) Pers.] and other forages; (ii) endophyte‐free tall fescue (E−) overseeded into dormant common bermudagrass; and (iii) orchardgrass (OG; Dactylis glomerata L.) established under the same conditions as E−. The E− and OG pastures were grazed with either twice weekly (2W) or twice monthly (2M) rotation schedules, but E+ was grazed only as 2M. Across 41 sampling dates (2000 through 2003) the mean forage mass across all forage systems was 3809 kg ha−1, and there was an interaction of forage system and sampling date (P = 0.001). In vitro dry matter disappearance (IVDMD) and crude protein (CP) varied (P < 0.0001) with sampling date in seasonal patterns that were generally predictable. Frequencies of tall fescue in E− and E+ pastures increased (P < 0.10) over years, reaching numerical maxima (61 to 72%) at the end of the trial. For OG, frequencies reached numerical maxima of 52 and 42% in 2W and 2M pastures, respectively, but then declined (P < 0.10) over time, ending at 39 and 24%, respectively. At the end of the trial, reinfection of OG pastures by rogue E+ plants reached a numerical maximum frequency of only 10%, and concentrations of total ergot alkaloids in tall fescue plants from E− pastures were only about 25% of those for E+ pastures, thereby suggesting that pasture toxicity can be reduced substantially for at least 5 yr using these alternative forage systems.

Sand and granite fines were compared as bedding in free stalls for lactating cows. Eighteen stalls were randomly bedded with sand or granite fines. Lactating cows [100 to 160; 31 to 90 d in milk (DIM)] had access to these stalls plus 142 other stalls bedded with sand. Experimental stalls were observed on 6 d (4 times/d) during the 27-d study. Using a logistic procedure, experimental stalls bedded with sand were 2.8 times more likely to be used than those bedded with granite fines (P<0.01). Stall usage was analyzed using a frequency procedure (P<0.001); cows were observed lying on sand 90% of the time and on granite fines 73% of the time. On d 24, hardness of the surface, measured at a pressure of 2 kg/cm2, was greater for granite fines (P<0.01). On d 0 and 1, Streptococci spp. counts in granite fines and sand did not differ; however, on d 7 and 11 after adding new materials, Streptococci spp. counts in granite fines were greater than in sand (bedding material × time of sampling interaction, P<0.05). Cows preferred sand to granite fines in free stalls, possibly because sand was the softer bedding surface. Streptococci spp. counts were less in stalls bedded with sand on d 7 and 11 after cows had used the bedding. Costs (without shipping) of sand were $0.096/d compared with $0.049/d for granite fines.

A grazing study was initiated in April 2000 and continued through three calving and weaning cycles (ending July 2003) to investigate the effects of rotational grazing management (twice monthly [2M] vs. twice weekly [2W]) and weaning date (mid-April [EARLY] vs. early June [LATE]) on production of fall-calving cow-calf pairs (495 +/- 9.6 kg initial BW) grazing Neotyphodium coenophialum-infected tall fescue (Festuca arundinacea Schreb.) overseeded with legumes and crabgrass. Secondary objectives of the experiment were to monitor differences in quantity and quality of available forage and to evaluate changes in forage species composition. Pastures were dominated by tall fescue throughout the study, and the proportion of basal cover was greater (P < 0.05) in 2M than in 2W pastures. The percentage of legumes was very low across all treatment combinations, but the percentage of crabgrass continued to increase (P < 0.05) linearly and quadratically across years for both summer and fall sampling periods, regardless of rotation or weaning program. In vitro DM disappearance and mineral concentrations varied minimally because of rotation frequency or weaning date. Rotation frequency did not substantially affect (P = 0.11 to 0.97) cow BW, hay offered, milk production, calving interval, calf birth weight, or actual or adjusted weaning weights; however, 2M cows had 0.3 units higher (P < 0.05) BCS at the time of breeding than 2W cows. Calves weaned late had greater (P < 0.05) actual weaning weight and weighed more (P < 0.05) on the LATE weaning date than on the EARLY weaning date, but 205-d adjusted weaning weights did not differ (P = 0.74) across weaning dates. Therefore, rotation frequency and/or weaning date had little effect on forage species composition or forage quality. In addition, the rapid rotation program offered little advantage with respect to animal performance, and weaning fall-born calves grazing endophyte-infected tall fescue pastures at approximately 189 d of age seemed to be detrimental to calf performance compared with delaying weaning until 243 d of age.

Spontaneous heating reduces forage quality and nutrient digestibility in stored alfalfa (Medicago sativa L.) and cool-season grasses. However, research describing the impact of spontaneous heating on disappearance kinetics of warm-season grasses is limited. Five crossbred ruminally cannulated steers were used in a randomized complete block design to determine the impact of spontaneous heating during the curing process on in situ disappearance kinetics of bermudagrass hay. Bermudagrass hays were baled at various moisture levels and bale densities that resulted in spontaneous heating that produced 5, 119, 201, 273, or 401 heating-degree days (HDD; >35°C) during a 60-day storage period. Hays were evaluated for rumen dry matter (DM), neutral-detergent fiber (NDF), N, and neutral-detergent insoluble nitrogen (NDIN) disappearance kinetics. The immediately soluble DM fraction and effective ruminal DM disappearance generally decreased (P<0.05) as HDD increased. The fraction of DM that disappeared at a measurable rate was lower (P<0.05) in 5 HDD hays and the disappearance rate of DM (Kd) was faster (P<0.05) from 5 and 119 HDD hays compared with forages subjected to higher HDD. The Kd for NDF was faster (P<0.05) from 5 and 119 HDD than from 201 and 273 HDD hays and effective NDF disappearance was higher (P<0.05) from 5 and 119 HDD than from higher HDD hays. The Kd for N was faster (P<0.05) from 5 HDD, and effective N disappearance was greater (P<0.05) from 5 and 119 HDD than from 201 or higher HDD. The Kd for NDIN was faster (P<0.05) from 5 and 119 HDD and effective NDIN disappearance was higher (P<0.05) from 5, 119, and 201 HDD than from higher HDD hays. Moderate levels of spontaneous heating have negative effects on rate and effective ruminal disappearance of both DM and N in bermudagrass hay, thereby reducing the digestibility of DM and protein from heated forages.

Nutrient composition and in situ dry matter (DM) and neutral detergent fiber (NDF) degradation of bermudagrass [Cynodon dactylon (L) Pers.] may vary with different management and environmental factors. This study evaluated nutritional value and in situ degradation characteristics of DM and NDF for bermudagrass, a perennial, warm-season grass. Bermudagrass growing on a poultry layer—litter—amended site was fertilized with ammonium nitrate at four rates (0, 56, 112, and 168kgNha−1) on 28 April and 19 July 2000, then harvested on 10 May and 18 August 2000. Five crossbred ruminally-cannulated steers (422±21.0kg body weight (BW)) were used in a randomized complete block design with a 2×4 (harvest date×N fertilization rate) factorial arrangement to determine in situ DM and NDF degradation kinetics. Quadratic relationships were detected between N fertilization rates and N concentration in the plant when harvested on 30 May (y=0.0001x2+0.009x+27; P<0.01; R2=0.99) and 18 August (y=−0.0001x2+0.060x+18; P<0.01; R2=0.99), and both the quadratic relationships and intercepts differed (P<0.05) between harvest dates. Concentrations of NDF decreased linearly (P=0.01) with increasing N fertilization rate on both harvest dates and the intercept was higher (P<0.05) on 18 August than on 30 May. Other fiber fraction concentrations did not differ (P>0.05) across N fertilization rates. The undegraded DM fraction (fraction C) declined (P<0.01) linearly and the potential extent and DM degradation rate (kd) increased (P<0.01) linearly with increasing N fertilization rate across harvest dates. Effective DM degradability increased linearly (P<0.01) on both dates as N fertilization rates increased, but the rate of increase on 30 May was 64% greater (P<0.05) than on 18 August. When averaged across N rates, the intercept for DM fraction A and the potential extent of DM degradation was greater (P<0.05) while that of DM fraction C and kd were smaller on 30 May than on 18 August. Effective NDF degradability and kd increased (P<0.01) with N fertilization rate, and the intercept for effective NDF degradability was higher (P<0.05) on 30 May than 18 August. Therefore, N fertilization improved quality of bermudagrass marginally by increasing plant N concentration and by improving the degradation rate and effective ruminal degradability of DM and NDF.

Limited information is available describing digestive kinetics of crude protein (CP) in stockpiled bermudagrass (Cynodon dactylon (L.) Pers.) during late fall and early winter. 'Greenfield' bermudagrass was stockpiled at two sites following summer hay or pasture management, and samples were taken at 4-week intervals under caged exclosures (UNGRAZED) and outside exclosures (GRAZED) between 17 October 1997 and 9 January 1998. Forage samples were subsequently incubated in situ in five ruminally cannulated, crossbred steers to determine effects of fall harvest date and previous summer management on in situ degradation kinetics of forage CP. At the hay site, concentrations of total plant CP declined (P<0.05) for UNGRAZED forages between 17 October (134.4 g kg(-1)) and 12 December (119.4 g ka(-1)), but concentrations of CP did not differ (P>0.05) on the 17 October and 9 January harvest dates. From the pasture site, concentrations of total CP for UNGRAZED forages did not change (P>0.05) throughout the trial. In situ degradation rates of CP from the hay site were not different (P>0.05) for UNGRAZED forages on 17 October and 9 January (overall mean=0.056 h(-1)) . The ruminal degradation of CP decreased (P<0.05) by 63 g kg(-1) CP between 14 November and 12 December, but did not change during the first and last sampling intervals. At the pasture site, rates of CP degradation increased (P<0.05) for UNGRAZED forages between 17 October (0.044 h(-1)) and 9 January (0.080 h(-1)) due to the presence of immature, winter annual weeds. Similarly, the ruminal degradation of CP increased (P<0.05) between 12 December (580 kg(-1)) and 9 January (624 g kg(-1)) in response to winter annual weed presence. Ruminal availability of CP in stockpiled bermudagrass decreases as the dormant forage ages, but may be adequate to meet the minimum CP requirements of dry, pregnant beef cows. (C) 2002 Elsevier Science B.V. All rights reserved.

Two trials were conducted to determine the effect of supplemental thiamin in a receiving ration on thiamin status, immune response and growth performance of stocker calves. In Experiment 1, 32 crossbred calves (211 +/- 3.2 kg) were weaned, blocked by weight and assigned randomly to one of the eight pens. Pens were then assigned randomly within block to treatment. Treatments were control (no supplemental thiamin) or 956 mg/d supplemental thiamin as thiamin mononitrate. Calves were kept in 0.45 ha mixed grass pastures and fed 1.82 kg/d of a corn and soybean meal supplement. Daily gains for the 28-d study (P<0.10) were decreased by supplemental thiamin. On d14, blood thiamin monophosphate (TMP; P<0.001) and thiamin pyrophosphate (TPP) concentrations (P<0.001) were greater for calves fed supplemental thiamin. In vivo cell-Mediated immunity, measured on d 27 by determining the response of calves to an intradermal injection of phytohemagglutinin (PHA) were not altered (P>0.10) by supplemental thiamin. In Experiment 2, 88 crossbred heifers (205 +/- 1.6 kg) were blocked by weight, assigned randomly to one of the 16 pens and then pens within a block were assigned randomly to treatments. Treatments were identical to Exp. 1. Heifers had ad libitum access to bermudagrass hay in this study. Average daily gain was not different between treatments (P>0.10) for the 42-d study. Supplemental thiamin did not improve ADG, antibody response, cell-mediated immune response or morbidity rates, but. did increase TPP and TMP concentrations in these studies.

Two experiments were conducted to test the effects of feeding broiler litter, either directly in the diet or indirectly through pasture-fertilization, to beef cattle on the incidence of Salmonella typhimurium (S) and Escherichia coli O157:H7 (EC) contamination of carcasses and ground beef. In Experiment 1, beef cows (n = 32) were allotted either ad libitum access to grass hay or a formulated diet (80% deep-stacked broiler litter and 20% corn). In Experiment 2, beef cows (n = 32) were assigned to graze on pastures fertilized with a commercial fertilizer or fresh broiler litter. Cows in Experiment 1 were harvested following a 56-d feeding period; whereas, cows in Experiment 2 were harvested after 5, 10, 20, and 40 d of grazing pastures. All samples of muscle, purge, and ground beef were culture-negative for S and EC, suggesting that beef cattle may consume properly handled deep-stacked broiler litter, or pastures fertilized with fresh litter, without increasing the likelihood of carcass/meat contamination with S and (or) EC.

Two experiments were conducted to determine the efficacy of mannan oligosaccharides (MOS) fed at two levels of Cu on growth and feed efficiency of weanling and growing-finishing pigs, as well as the effect on the immunocompetence of weanling pigs. In Exp. 1, 216 barrows (6 kg of BW and 18 d of age) were penned in groups of six (9 pens/treatment). Dietary treatments were arranged as a 2 x 2 factorial consisting of two levels of Cu (basal level or 175 ppm supplemental Cu) with and without MOS (0.2%). Diets were fed from d 0 to 38 after weaning. Blood samples were obtained to determine lymphocyte proliferation in vitro. From d 0 to 10, ADG, ADFI, and gain:feed (G:F) increased when MOS was added to diets containing the basal level of Cu, but decreased when MOS was added to diets containing 175 ppm supplemental Cu (interaction, P < 0.01, P < 0.10, and P < 0.05, respectively). Pigs fed diets containing 175 ppm Cu from d 10 to 24 and d 24 to 38 had greater (P < 0.05) ADG and ADFI than those fed the basal level of Cu regardless of MOS addition. Pigs fed diets containing MOS from d 24 to 38 had greater ADG (P < 0.05) and G:F (P < 0.10) than those fed diets devoid of MOS. Lymphocyte proliferation was not altered by dietary treatment. In Exp. 2, 144 pigs were divided into six pigs/pen (six pens/treatment). Dietary treatments were fed throughout the starter (20 to 32 kg BW), grower (32 to 68 kg BW), and finisher (68 to 106 kg BW) phases. Diets consisted of two levels of Cu (basal level or basal diet + 175 ppm in starter and grower diets and 125 ppm in finisher diets) with and without MOS (0.2% in starter, 0.1% in grower, and 0.05% in finisher). Pigs fed supplemental Cu had greater (P < 0.05) ADG and G:F during the starter and grower phases compared to pigs fed the basal level of Cu. During the finisher phase, ADG increased when pigs were fed MOS in diets containing the basal level of Cu, but decreased when MOS was added to diets supplemented with 125 ppm Cu (interaction, P < 0.05). Results from this study indicate the response of weanling pigs fed MOS in phase 1 varied with level of dietary Cu. However, in phase 2 and phase 3, diets containing either MOS or 175 ppm Cu resulted in improved performance. Pharmacological Cu addition improved gain and efficiency during the starter and grower phases in growing-finishing pigs, while ADG response to the addition of MOS during the finisher phase seems to be dependent upon the level of Cu supplementation.

Two experiments were conducted to determine the effect of an antioxidant (AGRADO®; Solutia Inc., St. Louis, MO) on the growth, gain to feed ratio, and health of receiving calves. In Experiment 1, 96 mixed breed heifer calves (206 ± 1.4 kg initial BW) were purchased at sale barns and delivered as a single group to the research facility near Fayetteville. All heifers were fed a total mixed diet containing 30% cottonseed hulls, 53% cracked corn, and 11% soybean meal for 42 d with either 0 or 150 mg AGRADO®/kg diet. Fewer (P<0.05) of the heifers fed supplemental AGRADO® were treated for respiratory disease (73% vs 83%), and medication cost was lower (P<0.05) for heifers fed supplemental AGRADO ($6.33 vs $9.49 per pen). Supplemental AGRADO® did not affect (P>0.10) ADG, daily feed intake, and gain to feed ratio. In Experiment 2, 86 bull and steer calves (237 ± 2.2 kg initial BW) were managed and fed as in Experiment 1 for a 41-d study. In this trial, supplemental AGRADO® had no significant effect on the number of sick calves or medication costs, but gain to feed ratio was improved (P<0.05) during the first 28 d of the trial. These results indicate that supplemental AGRADO® may improve the health or growth performance of newly received feedlot cattle.

Limited information is available that describes the disappearance kinetics of bermudagrass (Cynodon dactylon L. Pers.) during fall and early winter. Five ruminally cannulated, crossbred steers (387 +/- 18.3 kg) were used to determine the effects of calendar date and previous summer management on the in situ degradation kinetics of DM and NDF for forage clipped from stockpiled 'Greenfield' bermudagrass pastures. Forage was stockpiled at two sites following summer hay or pasture management, and samples were taken outside (GRAZED) and under caged exclosures (UNGRAZED) at 4-wk intervals beginning October 17, 1997, and ending January 9, 1998. No effort was made to remove or avoid contaminate species. Concentrations of NDF increased (P < 0.001) to a maximum for UNGRAZED forages at the hay site between October 17 and December 12, but sampling date had no effect (P = 0.627) on concentrations of NDF at the pasture site. Concentrations of ADF and lignin increased (P < or = 0.023) during at least one sampling interval in UNGRAZED forages at both sites. At the hay site, degradation rates of DM decreased (P < 0.001) by 0.013/h for UNGRAZED forage between October 17 and January 9, whereas the effective ruminal degradability of DM decreased (P < 0.001) by 33.5% during the same time period. Fractional degradation rates of NDF for UNGRAZED forages at the hay site decreased (P < 0.001) by 0.014/h between October 17 and November 14 but did not change (P > or = 0.077) throughout the remainder of the study. The effective ruminal degradability of NDF decreased (P < 0.001) by 33.8% between the first and last sampling date. At the pasture site, sampling date did not affect (P = 0.458) rates of DM degradation, but the effective degradability of DM for UNGRAZED forages decreased (P = 0.001) by 19.0% from October 17 to December 12. Rates of NDF degradation for UNGRAZED forages did not differ (P > or = 0.113) on the first three sampling dates, but the rate on January 9 was slower than that observed on October 17 (P = 0.025) and November 14 (P = 0.044). The effective degradability of NDF decreased (P < 0.001) by 19.2% between October 17 and December 12. These data indicate that stockpiled bermudagrass should be used during a limited window during the late fall; after this time, the nutritive value becomes very poor.

A 64-d grazing study was conducted with a 2 × 2 factorial arrangement of treatments to evaluate the impact of implant treatment on growth performance, hair score, and serum prolactin levels of steers grazing tall fescue with high (HE) or low (LE) levels of infection with the endophytic fungus Neotyphodium coenophialum. Mixed-breed steers (n = 130; 246 ± 3.5kg initial BW) were allocated randomly to one of three HE or one of four LE pastures beginning April 13. Within each replication, one-half of the steers were implanted (IMP) with trenbolone acetate (40 mg) and estradiol (8 mg), and one-half were not implanted (NI). No implant treatment × endophyte level interactions were detected (P>0.10). Steers grazing HE had lower (P<0.01) BW gain, inferior (P<0.05) hair scores, and lower (P<0.01) serum prolactin concentrations on d 64 than those steers grazing LE. Total BW gains were greater (P=0.01) from IMP steers than from NI steers, but serum prolactin concentrations and hair scores did not differ (P>0.10) between IMP and NI steers on either d 36 or 64. When tabulated across forage and implant treatments, correlations were negative between overall BW gains and hair scores measured on d 64 (r = 0.28; P<0.01), and positive between overall BW gains and serum prolactin levels measured on d 36 and 64 (r = 0.33 and 0.43, respectively; P<0.001). Therefore, fescue toxicity symptoms were manifested in HE steers, and implanting trenbolene acetate and estradiol improved grazing BW gain, but no endophyte level × implant interactions were detected.

The economic consequences of bovine respiratory disease (BRD) in weaned calves and stocker cattle are considerable in terms of loss from death, decreased growth performance, increased medication costs, and labor. It is a complex disease involving both viruses and bacteria. The inflammation that accompanies BRD can result in permanent lung damage. The goals of therapeutic treatment for BRD are to reduce or resolve the lung damage. It is often difficult to determine whether this has actually been accomplished. Treatment success is often evaluated by the abatement of clinical signs and reduction in body temperature. In some cases, subclinical inflammation may persist, resulting in permanent lung damage. Acute-phase proteins, such as α-glycoprotein (AGP) and haptoglobin (HPT), are elevated during acute or chronic periods of inflammation associated with infectious disease. The plasma concentration of these proteins can change up to 1,000-fold during disease episodes (Eckersall and Conner, 1988). Alsemgeest et al. (1994) reported on the value of measuring serum AGP and HPT in cattle to distinguish between acute, subacute and chronic inflammatory disease. They found that these values could be used to distinguish healthy animals from those with inflammation. Flunixin meglumine (Banamine, Schering-Plough Animal Health Corp., Union, NJ) is a nonsteroidal antiinflammatory drug (NSAID) that has been widely used as a therapeutic agent in horses (Bottoms et al., 1981). It has recently been approved for use in conjunction with antibiotics for the treatment of BRD. Its primary mode of action is to inhibit inflammatory mediators such as cyclo-oxygenase and prostaglandins (Anderson et al., 1990). The effect of flunixin meglumine on serum AGP and HPT has not been reported. The purpose of this study was to determine the potential value of serum AGP and HPT levels to assess the therapeutic effectiveness of treating BRD with antibiotics and flunixin meglumine.