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The insecticidal activity of parasiticide residues in dung of cattle treated with a sustained release eprinomectin formulation was examined, and an improved eprinomectin dung residue extraction method is presented. Emergent insect abundance and richness were significantly reduced in all post-treatment intervals (7, 14, 28, 56, 84, 112, and 140 d), relative to pre-treatment. Emergent insect diversity was reduced for between 84 and 112 d post-treatment. Collembola were not affected by residues. Chemical analyses subsequently documented residues of eprinomectin in dung of each collection period post-treatment at levels expected based on previously reported excretion profiles for this product. Cattle subcutaneously injected with this product excreted residues that reduced dung-breeding insect emergence for 5 mo post-treatment. The consequences of these long-term non-target effects to pasture ecosystems are not known.

Clinical signs of photosensitivity in cattle can occur sporadically and unpredictably. It is believed that cases of photosensitivity may be underreported, causing inaccurate and inflated reports of mortality. Additionally, because secondary photosensitization in grazing cattle occurs with liver damage or dysfunction, photosensitivity can have many potential or associated causes. This case links a previous occurrence of coccidiosis to an outbreak of photosensitivity in grazing Holstein steers. Grazing management staff first observed clinical signs of photosensitivity 17 days after an outbreak of coccidiosis and subsequent turnout to spring pastures. Clinical signs were observed in 25% of the population. The severity of photosensitivity was variable and ranged from blistered skin on the muzzle to sloughing of unpigmented epidermis and thinly haired regions. Severely affected cattle were removed from pasture, housed under shade, monitored for infection, and recovered without treatment. Mild cases remained on pasture and recovered without treatment. Photosensitivity did not reoccur in the cattle that remained on pasture or in mildly affected cattle returned to pasture. Photosensitivity did not appear to be associated with pasture weeds, a specific forage species, or variable or extreme weather conditions that could have resulted in mycotoxin production. The occurrence appears to have been a result of a previous and concurrent coccidiosis outbreak that caused secondary photosensitization through hepatic lipidosis caused by anorexia and dehydration associated with the severe coccidiosis. Although clinical signs appeared suddenly, cattle recovered quickly and without treatment.

Background Chronic, low-grade inflammation provides a link between normal ageing and the pathogenesis of age-related diseases. A series of in vitro tests confirmed the strong anti-inflammatory activities of known inhibitors of NF-κB activation (δ-tocotrienol, quercetin, riboflavin, (-) Corey lactone, amiloride, and dexamethasone). δ-Tocotrienol also suppresses β-hydroxy-β-methylglutaryl coenzyme A (HMG-CoA) reductase activity (the rate-limiting step in de novo cholesterol synthesis), and concomitantly lowers serum total and LDL cholesterol levels. We evaluated these compounds in an avian model anticipating that a dietary additive combining δ-tocotrienol with quercetin, riboflavin, (-) Corey lactone, amiloride, or dexamethasone would yield greater reductions in serum levels of total cholesterol, LDL-cholesterol and inflammatory markers (tumor necrosis factor-α [TNF-α], and nitric oxide [NO]), than that attained with the individual compounds. Results The present results showed that supplementation of control diets with all compounds tested except riboflavin, (-) Corey lactone, and dexamethasone produced small but significant reductions in body weight gains as compared to control. (-) Corey lactone and riboflavin did not significantly impact body weight gains. Dexamethasone significantly and markedly reduced weight gain (>75%) compared to control. The serum levels of TNF-α and NO were decreased 61% - 84% ( P < 0.001), and 14% - 67%, respectively, in chickens fed diets supplemented with δ-tocotrienol, quercetin, riboflavin, (-) Corey lactone, amiloride, or dexamethasone as compared to controls. Significant decreases in the levels of serum total and LDL-cholesterol were attained with δ-tocotrienol, quercetin, riboflavin and (-) Corey lactone (13% - 57%; P < 0.05), whereas, these levels were 2-fold higher in dexamethasone treated chickens as compared to controls. Parallel responses on hepatic lipid infiltration were confirmed by histological analyses. Treatments combining δ-tocotrienol with the other compounds yielded values that were lower than individual values attained with either δ-tocotrienol or the second compound. Exceptions were the significantly lower total and LDL cholesterol and triglyceride values attained with the δ-tocotrienol/(-) Corey lactone treatment and the significantly lower triglyceride value attained with the δ-tocotrienol/riboflavin treatment. δ-Tocotrienol attenuated the lipid-elevating impact of dexamethasone and potentiated the triglyceride lowering impact of riboflavin. Microarray analyses of liver samples identified 62 genes whose expressions were either up-regulated or down-regulated by all compounds suggesting common impact on serum TNF-α and NO levels. The microarray analyses further identified 41 genes whose expression was differentially impacted by the compounds shown to lower serum lipid levels and dexamethasone, associated with markedly elevated serum lipids. Conclusions This is the first report describing the anti-inflammatory effects of δ-tocotrienol, quercetin, riboflavin, (-) Corey lactone, amiloride, and dexamethasone on serum TNF-δ and NO levels. Serum TNF-δ levels were decreased by >60% by each of the experimental compounds. Additionally, all the treatments except with dexamethasone, resulted in lower serum total cholesterol, LDL-cholesterol and triglyceride levels. The impact of above mentioned compounds on the factors evaluated herein was increased when combined with δ-tocotrienol.

Abstract Cull dairy cows contribute almost 10% of national beef production in the United States. However, different factors throughout the life of dairy cows affect their weight and overall body condition as well as carcass traits, and consequently affect their market price. Therefore, the objectives of this study were: (1) to assess relationships between price ratio and carcass merit of cull dairy cows sold through several sites of an auction market and (2) to investigate the effect of animal life history events and live weight on sale barn price (BP) and price ratio (as a measure of relative price), as an indicator of carcass merit. Data from 4 dairy operations included 3,602 cull dairy cow records during the period of 2015 to 2019. Life history events data were collected from each dairy operation through Dairy Comp software; live weight and price were obtained periodically from the auction market, and the carcass data were provided by a local packing plant. Cow price in dollars per unit of live weight ($/cwt) and price ratio were the 2 outcome variables used in the analyses. Price ratio was created aiming to remove seasonality effects from BP (BP divided by the national average price for its respective month and year of sale). The association between price ratio and carcass merit traits was investigated using canonical correlation analysis, and the effect of life history events on both BP and price ratio was inferred using a multiple linear regression technique. More than 70% of the cows were culled in the first 3 lactations, with an average live weight of 701.5 kg, carcass weight of 325 kg, and dressing percentage of 46.3%. On average, cull cows were sold at $57.0/cwt during the period considered. The canonical correlation between price ratio and carcass merit traits was 0.76, indicating that price ratio reflected carcass merit of cull cows. Later lactations led to lower BP compared with cows culled during the first 2 lactations. Injury, and leg and feet problems negatively affected BP. Productive variables demonstrated that the greater milk production might lead to lower cow prices. A large variation between farms was also noted. In conclusion, price ratio was a good indicator of carcass merit of cull cows, and life history events significantly affected sale BP and carcass merit of cull cows sold through auction markets.

Core Ideas Bloat incidence was less when grass proportion was 40% or more of grass–alfalfa sward. Alfalfa masked differences among grasses in grazed forage amount and nutritive value. Holstein steer growth rate was highest when sward alfalfa proportions were greatest. Alfalfa–meadow fescue maintained the greatest alfalfa proportion after three seasons. This study compared forage productivity and animal performance in three alfalfa (Medicago sativa L.)–grass mixtures: alfalfa–meadow fescue [Schedonorus pratensis (Huds.) P. Beauv] (A–MF), alfalfa–orchardgrass (Dactylis glomerata L.) (A–OG), and alfalfa–tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] (A–TF). Mixtures were rotationally grazed with Holstein (Bos taurus, initial weight 242 kg, annually n = 180) steers from 2014 to 2016. Steer performance data from 2014 were excluded due to several incidences of bloat. Grass proportions increased over the 3‐yr study from 23% in 2014 to 40% in 2015 to 71% in 2016 (P < 0.01). Relationships (P < 0.001) between grass proportion and nutritive variables were detected with neutral detergent fiber (NDF) (R2 = 0.40) and NDF digestibility (R2 = 0.13) increasing with grass proportion, and crude protein (CP) decreasing (R2 = 0.29) with grass proportion. No relationship (P = 0.82) existed for in vitro true digestibility (IVTD). Grass proportions were lower, 60% grass, (P < 0.05) in A–MF pastures in 2016, compared to 77% for A–TF and A–OG causing higher average daily gain (ADG) for A–MF (P < 0.01) (0.81, 0.56, and 0.57 kg d−1 for A–MF, A–OG, and A–TF, respectively) and a tendency (P = 0.10) for greater gain per hectare for A–MF (P = 0.08) (994, 752, and 765 kg ha−1 for A–MF, A–TF, and A–OG, respectively). Cattle ADG was greatest when alfalfa sward proportions were high. By 2016, A–MF pastures had the highest alfalfa proportion, and therefore, the highest levels of ADG and gain per hectare.

The effect of dietary nitrate supplementation on rumen bacterial community composition was examined in beef steers fed either a nitrate-N diet or urea-N diet. An automated method of ribosomal intergenic spacer analysis was applied to solid and liquid fractions of ruminal contents to allow comparison of bacterial communities. Supplemental N source affected relative population size of four amplicon lengths (ALs) in the liquid fraction and three ALs in the solid fraction. Five ALs were more prevalent after adaptation to nitrate. Correspondence analysis indicated that feeding the steers the nitrate-N diet versus urea-N diet changed the bacterial community composition in the liquid but not in the solid fraction. This led to an investigation of the relative sizes of potential nitrate-reducing populations. Mannheimia succiniciproducens , Veillonella parvula , and Campylobacter fetus were obtained from nitrate enrichment culture and quantified by real-time PCR based on 16S rRNA sequence. Nitrate supplementation increased the percentage of C . fetus in the liquid and solid phases, and in solid phase, the percentage of M . succiniciproducens increased. No change in species prevalence was observed for V . parvula . However, even after adaptation to dietary nitrate, the relative population sizes for all three putative nitrate-reducing species were very low (<0.06 % of 16S rRNA gene copy number). The liquid-associated bacterial community composition changed due to nitrate supplementation, and at least part of this change reflects an increase in the species prevalence of C . fetus , a species which is not typically regarded as a ruminal inhabitant.

Little research has been conducted in the northern United States to evaluate meadow fescue [Schedonorus pratensis (Huds.) P. Beauv] or tall fescue [S. arundinaceus (Schreb.) Dumort] in pastures, and implications for animal performance. This research compared swards containing meadow fescue (MF) or tall fescue (TF) alone or co‐established with white clover (Trifolium repens L.). Pastures were rotationally grazed with crossbred beef steers (Bos taurus, initial weight 261 kg, n = 180) using a variable stocking rate to detect treatment differences. Sward white clover percentage decreased as the trial progressed (42, 25, and 12 for years 1, 2, and 3, respectively), coinciding with decreased steer performance. Swards containing TF had greater available forage (3200 vs. 2800 kg ha−1) and less in vitro true digestibility, neutral detergent fiber digestibility, and steer average daily gain (ADG) (0.84 vs. 0.98 kg d−1) (P < 0.05) than MF swards. Adding white clover to MF and TF swards improved forage quality, steer ADG (0.98 vs. 0.84 kg d−1), and animal gain per hectare (780 vs. 680 kg ha−1) (P < 0.05) vs. monoculture grass pastures. Steers on MF pastures had greater ADG than TF pastures, but because TF pastures had greater stocking rate, gain per hectare was not different for the two grasses (728 vs. 735 kg) (P > 0.05). These results demonstrate the superior forage quality and animal performance of MF pastures, the higher productivity of TF pastures, and the need for a productive, persistent legume in upper Midwest pastures.

Abstract Three alfalfa biotypes were chosen based on the presumption that they would be sources of alfalfa herbage that differed in lignin concentration and therefore cell wall digestibility. The hypothesis was that a lesser lignin concentration would result in greater alfalfa neutral detergent fiber (NDF) digestibility and greater beef steer growth performance. The three alfalfa biotypes were HarvXtra (Forage Genetics International), Hi-Gest 360 (Alforex Seeds), and a control alfalfa, LegenDairy XHD (Winfield Solutions LLC). High-moisture wrapped bales were prepared from second-harvest, d 30 crops. Digestibility of NDF was determined using in vitro incubations and a steer digestibility trial. Alfalfa baleage and trace mineral salt were fed to Angus steers (300 kg initial body weight, 4 pens/treatment) in an 83-day growing-phase trial. Alfalfa acid detergent lignin concentrations were 75.6, 71.8, and 63.0 g/kg dry matter (P = 0.34) for LegenDairy, Hi-Gest and HarvXtra, respectively. Based on in vitro total-tract NDF digestibility coefficients, HarvXtra tended (P ≥ 0.09) to have the highest NDF digestibility. Alfalfa biotype affected in vivo apparent total tract digestibility of NDF (P < 0.001) and there was a trend for an effect on acid detergent fiber digestibility (P = 0.051). Hi-Gest and HarvXtra had similar in vivo apparent NDF digestibilities, which were greater than for LegenDairy (P < 0.05). There was no alfalfa biotype effect on daily alfalfa dry matter intake (DMI; P = 0.51) or average daily gain (P = 0.25) by growing steers. The absence of an effect by the novel alfalfa biotypes on DMI by growing steers suggests that the compositional and digestibility differences of the novel alfalfa biotypes compared to LegenDairy were not sufficient to alleviate the limitation of physical fill (if evident) on DMI. If more disparity in cell wall composition and NDF digestibility were to exist between control and reduced-lignin biotypes, then perhaps an advantage in cattle growth performance for a reduced-lignin alfalfa biotype would be detectable.

Abstract Single-pass corn stover harvest is a method whereby combine harvester tailings consisting of cob, stalk, leaf, husk, and tassel fractions are collected and baled without coming into contact with soil. The objective was to feed beef steers diets that included a roughage component consisting of harvested corn residue in chopped form from conventional corn stover bales (CST) or single-pass bales (SPB) to assess intake selectivity of corn stover fractions and estimate net energy values of these corn stovers. Whole plant corn silage served as the control roughage in the control diet (CSIL). Steers (n = 90, 5 pens per treatment) were fed during Grow (84 d) and Finish (66 d) trials. Steers sorted through corn stover during both trials and consumed 52.5% of corn stover offered and 40% of cob offered. Intake of SPB cob was 2.6-fold and 3.3-fold greater than CST cob intake (P < 0.01) in Grow and Finish trials, respectively, indicating that when more cob was available, cattle consumed more. During the Grow trial, stover intake tended (P = 0.07) to be lower for SPB and diet dry matter intake (DMI) was less (P ≤ 0.05) for SPB, which may be due to the elevated cob intake by SPB steers. Across treatments, stover DMI was similar in the Grow (1.10 kg per steer per d) and Finish (1.11 kg per steer per d) trials. The proportion (65%) of Fines (<8 mm) consumed from the Grow diet (40% neutral detergent fiber, aNDF) was greater than the Finish diet (25% aNDF; 18% to 31%) and gleaning of concentrate feeds from orts seemed to be more extensive in the Grow diet. Steers consuming Finish diets containing SPB and CST had DMI that were 17% and 18%, respectively, greater (P ≤ 0.05) than CSIL, an indication of compensatory intake. The physical effectiveness factors for stovers fed in the Grow and Finish diets were 0.85 and 0.95, respectively. Estimates for net energy maintenance and net energy gain (NEg), respectively, using National Research Council methods from 2001 were as follows for consumed stovers: SPB (1.09 and 0.54 Mcal/kg) and CST (0.98 and 0.44 Mcal/kg) in the Grow trial, and SPB (0.96 and 0.42 Mcal/kg) and CST (0.95 and 0.40 Mcal/kg) in the Finish trial. Although SPB and CST differ in botanical fraction composition and net intakes of botanical fractions, their energetic contributions to steer performance were very similar. Steers fed the Finish diet (1.25 Mcal performance-adjusted NEg per kg) selected stover botanical components to achieve a diet composition of 25% aNDF.

Assessment of cattle performance on grazed kura clover (Trifolium ambiguum M. Bieb.) has not been reported in USA. This study was conducted to compare steer performance on kura clover–grass (KC–G) and red clover (T. pratense L.)–grass (RC–G) mixed pastures. Pastures were rotationally stocked with Holstein (Bos taurus) steers using a variable stocking rate. Animal performance and pasture composition were recorded from 1998 to 2000. The red clover was annually renewed in the RC–G pasture by frost seeding. The legume fraction accounted for at least 66% of the herbage mass every year in KC–G pasture while in RC–G pasture, it ranged from 33% in 1998 to 10% in 2000. Kura clover–grass pasture was lower in neutral detergent fiber and acid detergent fiber and higher in crude protein and in vitro true digestibility than the RC–G pasture. Herbage mass and carrying capacity were greater in KC–G than in RC–G pasture each grazing season. Average daily gain was higher every year for KC–G than for RC–G and averaged 1.21 and 0.99 kg, respectively. Beef gains on KC–G and RC–G were 1151 and 953 kg ha−1 in 1998, 882 and 628 kg ha−1 in 1999, and 1030 and 820 kg ha−1 in 2000, respectively. The greater gain per hectare on KC–G was attributed to the combination of its capacity to produce more forage and its superior nutritive value. Both are consequences of the ability of kura clover to maintain a high proportion of legume in the sward.