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Weaning and transport represent a high stress time for calves. Preconditioning (PC) by weaning before the transport separate these stressors. The stressors generate oxidative stress, which can be reduced by mineral and vitamin supplementation (MVS) with an antioxidant capacity. Our objective was to evaluate the effect of PC and MVS on performance of steers. The experiment used a 2 × 2 factorial arrangement design, considering a 26-d PC treatment from weaning to transport to the feedlot (day 0), and injectable MVS on days −45, −26, and 0. The MVS consisted of Cu, Zn, Mn, Se, vitamin E (0.2, 0.8, 0.2, 0.1, and 1 mg/kg body weight [ BW ], respectively), and vitamin A (1,190 IU/kg). Sixty Angus-crossbred steers (186.4 ± 27.6 kg) were randomly assigned to the four treatments (MVS+PC ; N + PC ; MVS + N ; N + N ; n = 15 per treatment). BW was recorded on days −45, −26, 0, 8, 15, and 29. On day 0, an additional BW was taken 30 min after the 5-h transportation (day 0.5). Between days 0 and 29, dry matter intake (DMI) and average daily gain (ADG) to DMI ratio (G:F) were measured. Between days −26 and 29 plasma concentrations of glucose, nonesterified fatty acids (NEFA), cortisol, insulin, total antioxidant status (TAS), and thiobarbituric acid-reactive substances were evaluated. Data were analyzed using the MIXED procedure of SAS with repeated measures, using treatment, time, and treatment × time as fixed effects and steer as a random effect. Between days −26 and 0, there was an interaction of MVS × PC (P ˂ 0.01) for ADG. From days −26 to 0, N+N and N+PC had the greatest and lesser ADG, respectively. On day 0.5, no-PC steers tended to lose BW, whereas the PC steers tended to gain BW (P = 0.09). In the period days 0 to 8, there were no differences (P ≥ 0.27) in DMI, but the PC steers had greater G:F and ADG (P < 0.01) compared with no-PC steers. Plasma NEFA concentration on day 0 was affected by MVS × PC (P < 0.01) because MVS decreased plasma NEFA concentration in no-PC steers, but it increased in the PC steers. Plasma concentrations of glucose, insulin, and cortisol did not differ among treatments (P ≥ 0.23). There was an MVS × PC interaction (P = 0.09) for TAS on day 0; N+N had the greatest TAS concentrations and MVS+N had the lowest TAS concentrations. In conclusion, a 26-d PC decreased steers BW compared with no-PC steers. The BW loss during PC was not recovered 29 d after feedlot entry. Despite this BW loss, MVS treatment decreased BW loss in the steers allocated to PC treatment on the day of transport. [ABSTRACT FROM AUTHOR]

Background: Ruminants play a great role in sustainable livestock since they transform pastures, silage, and crop residues into high-quality human food (i.e. milk and beef). Animals with better ability to convert food into animal protein, measured as a trait called feed efficiency (FE), also produce less manure and greenhouse gas per kilogram of produced meat. Thus, the identification of high feed efficiency cattle is important for sustainable nutritional management. Our aim was to evaluate the potential of serum metabolites to identify FE of beef cattle before they enter the feedlot. Results: A total of 3598 and 4210 m/z features was detected in negative and positive ionization modes via liquid chromatography-mass spectrometry. A single feature was different between high and low FE groups. Network analysis (WGCNA) yielded the detection of 19 and 20 network modules of highly correlated features in negative and positive mode respectively, and 1 module of each acquisition mode was associated with RFI (r = 0.55, P < 0.05). Pathway enrichment analysis (Mummichog) yielded the Retinol metabolism pathway associated with feed efficiency in beef cattle in our conditions. Conclusion: Altogether, these findings demonstrate the existence of a serum-based metabolomic signature associated with feed efficiency in beef cattle before they enter the feedlot. We are now working to validate the use of metabolites for identification of feed efficient animals for sustainable nutritional management. [ABSTRACT FROM AUTHOR]

In a previous study using a microRNA (miRNA/miR) microarray assay, we demonstrated that miR‑133b‑5p was upregulated in response to hypoxic preconditioning (HPC). The present study was designed to investigate the role of the miR‑133b‑5p in HPC‑induced cardioprotection and the underlying mechanisms involving caspase‑8 and caspase‑3 apoptotic signaling. Adult rats were subjected to myocardial ischemia/reperfusion (I/R) injury with or without ischemic preconditioning (IPC), and the level of miR‑133b‑5p in myocardium was measured. Neonatal rat cardiomyocytes were isolated and subjected to hypoxia/reoxygenation (H/R) injury, with or without HPC. miR‑133b‑5p antagomir was transfected into the cardiomyocytes to observe whether it could block HPC‑induced cardioprotection. Cellular injury was evaluated by detecting cell viability, lactate dehydrogenase (LDH) activity and apoptotic rate. Reverse transcription‑quantitative polymerase chain reaction was used to measure the level of miR‑133b‑5p. The activation of caspase‑8 and caspase‑3 were measured by western blot analysis to detect the cleaved fragments as well as a colorimetric assay. Following myocardial I/R injury, the expression of miR‑133b‑5p was decreased in myocardium, while this decrease was restored by IPC. HPC protected neonatal rat cardiomyocytes against H/R injury by increasing cell viability, while reducing LDH release and cell apoptosis. These protective effects were coupled with the upregulation of miR‑133b‑5p. However, the knockdown of miR‑133b‑5p in the cardiomyocytes blocked HPC‑mediated cardioprotection as reflected by the aggravation of cell injury and apoptosis. HPC upregulated miR‑133b‑5p level was markedly suppressed by the antagomir. In addition, the cleavage and activities of caspase‑8 and caspase‑3 were inhibited by HPC while reversed by knockdown of miR‑133b‑5p. Upregulation of miR‑133b‑5p contributes to HPC‑mediated cardioprotection in cardiomyocytes, and the mechanism may be associated with inhibition of caspase‑8 and caspase‑3 apoptotic signaling. [ABSTRACT FROM AUTHOR]

Ischemia-reperfusion (IR) injury is central to the pathology of major cardiovascular diseases, such as stroke and myocardial infarction. IR injury is mediated by several factors including the elevated production of reactive oxygen species (ROS), which occurs particularly at reperfusion. The mitochondrial respiratory chain and NADPH oxidases of the NOX family are major sources of ROS in cardiomyocytes. The first part of this review discusses recent findings and controversies on the mechanisms of superoxide production by the mitochondrial electron transport chain during IR injury, as well as the contribution of the NOX isoforms expressed in cardiomyocytes, NOX1, NOX2 and NOX4, to this damage. It then focuses on the effects of ROS on the opening of the mitochondrial permeability transition pore (mPTP), an inner membrane non-selective pore that causes irreversible damage to the heart. The second part analyzes the redox mechanisms of cardiomyocyte mitochondrial protection; specifically, the activation of the hypoxia-inducible factor (HIF) pathway and the antioxidant transcription factor Nrf2, which are both regulated by the cellular redox state. Redox mechanisms involved in ischemic preconditioning, one of the most effective ways of protecting the heart against IR injury, are also reviewed. Interestingly, several of these protective pathways converge on the inhibition of mPTP opening during reperfusion. Finally, the clinical and translational implications of these cardioprotective mechanisms are discussed. [ABSTRACT FROM AUTHOR]

he aim of this study was to answer the question whether models for genetic evaluations of longevity should include a correction for age at first calving (AFC). For this purpose, phenotypic and genetic relationships between AFC, its component traits age at first insemination (AFI) and interval from first to last insemination (FLI), and survival of different periods of the first lactation (S1: 0 to 49 d, S2: 50 to 249 d, S3: 250 d to second calving) were investigated. Data of 721,919 German Holstein heifers, being inseminated for the first time during the years from 2003 to 2012, were used for the analyses. Phenotypic correlations of AFI, FLI, and AFC to S1 to S3 were negative. Mean estimated heritabilities were 0.239 (AFI), 0.007 (FLI), and 0.103 (AFC) and 0.023 (S1), 0.016 (S2), and 0.028 (S3) on the observed scale. The genetic correlation between AFI and FLI was close to zero. Genetic correlations between AFI and the survival traits were −0.08 (S1), −0.02 (S2), and −0.10 (S3); those between FLI and the survival traits were −0.14 (S1), −0.20 (S2), and −0.44 (S3); and those between AFC and the survival traits were −0.09 (S1), −0.06 (S2), and −0.20 (S3). Some of these genetic correlations were different from zero, which suggests that correcting for AFC in genetic evaluations for longevity in dairy cows might remove functional genetic variance and should be reconsidered. [ABSTRACT FROM AUTHOR]

Morbidity, mortality, and antimicrobial use and resistance are major concerns in the rearing of male dairy calves, so information to support disease prevention is important. The objective of this cross-sectional study was to describe management practices associated with the care of male calves during their first days of life on Canadian dairy farms. A survey was completed by dairy producers across Canada between March 1 and April 30, 2015. The survey included 192 questions covering producer background, farm characteristics, biosecurity practices, disease prevalence, calf health, animal welfare, lameness, milking hygiene, reproduction, and Internet and social media use. A total of 1,025 surveys were completed online, by telephone, or by mail, representing 9% of all dairy farms in Canada. Five percent of respondents (n = 49) answered that they had euthanized at least 1 male calf at birth in the previous year, and blunt force trauma was commonly used in these cases. The majority of respondents always fed colostrum to male calves; however, 9% (n = 80) did not always feed colostrum. Almost 40% (n = 418) of respondents reported always dipping the navels of male calves, 12% (n = 123) vaccinated male calves, and 17% (n = 180) did not provide the same quantity of feed to male calves as heifer calves. The care of male calves differed greatly depending on the geographical region of the respondents. However, some regional effects may be confounded by economic conditions and the logistics of marketing male dairy calves in different parts of the country. Herd size was another important variable in many aspects of the management of male calves on dairy farms. Larger herd sizes were more likely to use an appropriate method of euthanasia at birth but were less likely to always feed colostrum to their male calves or feed them the same as female calves. Familiarity with the Code of Practice for the Care and Handling of Dairy Cattle (National Farm Animal Care Council) by respondents was associated with better care of male calves on dairy farms. The results of this survey suggest that the treatment of male dairy calves on Canadian dairy farms varies and that there are opportunities to improve the health management of male calves on the farms of origin. [ABSTRACT FROM AUTHOR]

Bathymetric data reveal abundant submarine landslides along the deformation front of the northern Cascadia margin that might have significant tsunami potential. Radiocarbon age dating showed that slope failures are early to mid-Holocene. The aim of this study is the analysis of slope stability to investigate possible trigger mechanisms using the factor of safety analysis technique on two prominent frontal ridges. First-order values for the earthquake shaking required to generate instability are derived. These are compared to estimated ground accelerations for large ( M=5 to 8) crustal earthquakes to giant ( M=8 to 9) megathrust events. The results suggest that estimated earthquake accelerations are insufficient to destabilize the slopes, unless the normal sediment frictional resistance is significantly reduced by, for example, excess pore pressure. Elevated pore pressure (overpressure ratio of 0.4) should significantly lower the threshold for earthquake shaking, so that a medium-sized M=5 earthquake at 10 km distance may trigger submarine landslides. Preconditioning of the slopes must be limited primarily to the mid- to early Holocene as slope failures are constrained to this period. The most likely causes for excess pore pressures include rapid sedimentation at the time of glacial retreat, sediment tectonic deformation, and gas hydrate dissociation as result of ocean warming and sea level rise. No slope failures comparable in size and volume have occurred since that time. Megathrust earthquakes have occurred frequently since the most recent failures in the mid-Holocene, which emphasizes the importance of preconditioning for submarine slope stability. [ABSTRACT FROM AUTHOR]

This study evaluated growth and measurements of innate and humoral immunity of preconditioning beef heifers supplemented with wet brewers grains (WBG) at 2 supplementation rates and frequencies. At 14 d after weaning (d 0), Angus heifers (n = 36; 213 ± 2 kg BW and 254 ± 7 d of age) were stratified by BW and age and randomly assigned to 1 of 12 drylot pens (3 heifers/pen). Treatments were randomly assigned to pens, in a 2 × 2 factorial design, and consisted of heifers provided ground tall fescue hay ad libitum (55% TDN and 12% CP of DM) and supplemented with WBG (75% TDN and 36% CP of DM) either daily (7X) or 3 times weekly (3X; Monday, Wednesday, and Friday) at 0.5 or 1.0% of BW (DM basis) for 42 d. Heifers were vaccinated against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV), Mannheimia haemolytica, and Clostridium on d 14 and 28. Individual BW was measured before feeding on d 0 and 42 following 12 h of feed and water withdrawal. Blood samples were collected via jugular venipuncture 4 h after WBG supplementation on d 14, 15, 16, 17, 21, 28, 29, 30, 31, 35, and 42. Heifers fed WBG 3X had less hay DMI (2.6 ± 0.16 vs. 3.2 ± 0.16 kg/d; P < 0.0001) but greater total DMI (5.6 ± 0.16 vs. 3.8 ± 0.16 kg/d; P < 0.0001) than 7X heifers on days that all heifers received WBG supplementation. However, overall hay and total DMI was not affected (P = 0.40) by supplementation frequency. Therefore, ADG, BW, and G:F from d 0 to 42 did not differ among treatments (P ≥ 0.29). Plasma concentrations of haptoglobin on d 15 and cortisol on d 14 were greater for 3X heifers vs. 7X heifers (P ≤ 0.04). Heifers fed WBG at 0.5% of BW tended to have greater plasma cortisol concentrations on d 15, 17, and 35 (P ≤ 0.09) than heifers fed at 1.0% of BW. Serum BVDV-1a titers were greater (P = 0.04) for 7X heifers vs. 3X heifers on d 42 (4.2 ± 0.28 vs. 3.3 ± 0.28 log2), whereas serum titers against BVDV- 2 and IBR were greater for heifers fed WBG at 1.0% of BW vs. heifers fed WBG at 0.5% of BW (7.6 vs. 6.7 and 3.3 vs. 2.8 ± 0.19 log2, respectively). In summary, decreasing WBG supplementation frequency (7 vs. 3 times weekly) or rate (1.0 vs. 0.5% of BW) for recently weaned beef heifers did not affect growth but decreased vaccine-induced antibody production against pathogens associated with bovine respiratory disease during a 42-d preconditioning period. [ABSTRACT FROM AUTHOR]

In vivo during the day, intervertebral discs are loaded mainly in compression causing fluid and height losses that are subsequently fully recovered overnight due to fluid inflow under smaller compression. However, in vitro , fluid flow through the endplates, in particular fluid imbibition, is hampered possibly by blood clots formed post mortem. Despite earlier in vitro studies, it remains yet unclear if and how fluid flow conditions in vitro could properly emulate those in vivo . Effects of various preload magnitudes (no preload, 0.06 and 0.28 MPa) and disc-bone preparation conditions ( e.g ., w/o bony endplates) on disc height and nucleus pressure were investigated using 54 bovine specimens. Changes in specimen height and pressure at different nucleus locations were used as surrogate measures to assess the fluid content and flow within the discs. Under all investigated preparation conditions and preload magnitudes, no significant pressure recovery could be obtained during low loading phases, even without bony endplates. On the contrary, partial to full displacement recovery were reached in particular under 0.28 MPa preload. Results highlight the significant role of disc preload magnitude in disc height recovery during low loading periods. Attention should hence be given in future studies to the proper selection of preload magnitude and duration as well as the animal models used if in vivo response is intended to be replicated. Findings also indicate that flushing the endplates or injection of bone cement respectively neither facilitates nor impedes fluid flow into or out of the disc to a noticeable degree in this bovine disc model. [ABSTRACT FROM AUTHOR]

We evaluated the effects of frequency of energy supplementation on growth and measurements of innate and humoral immune responses of preconditioning beef steers following vaccination. Angus steers (n = 24; 221 ± 6.3 kg; 177 ± 4 d of age) were weaned on d -7 and kept in a single drylot pen with free access to tall fescue hay and concentrate DMI at 0.5% of BW (50:50 mix of soyhulls and corn gluten pellets; DM basis) from d -7 to 0. On d 0, steers were stratified by BW and age and randomly assigned to 1 of 8 feedlot pens (3 steers/pen). Treatments were randomly assigned to pens (4 pens/treatment) and consisted of steers provided daily free access to ground tall fescue hay and similar weekly concentrate DMI (1% of BW times 7 d), which was divided and offered either daily (S7) or 3 times weekly (S3; Monday, Wednesday, and Friday) from d 0 to 42. Individual BW was measured before feeding on d 0 and 42, after 12 h of feed and water withdrawal. Steers were vaccinated against infectious bovine rhinotracheitis, bovine viral diarrhea virus (BVDV), Mannheimia haemolytica, and clostridium on d 7 and 21. Blood samples were collected from the jugular vein on d -7 and 4 h after concentrate supplementation on d 0, 7, 8, 9, 10, 14, 21, 22, 23, 24, 28, 35, and 42. Steers offered concentrate daily had greater (P = 0.02) BW on d 42, overall ADG, and total DMI, but similar (P = 0.14) G:F, than S3 steers. On days that S7 and S3 steers were offered concentrate, total DMI was greater and hay DMI was less for S3 vs. S7 steers (P = 0.05). On days that only S7 steers were supplemented, hay DMI was greater, but total DMI was less for S3 vs. S7 steers (P = 0.05). Mean CP and NEg intake were greater (P = 0.03) for S7 vs. S3 steers. Plasma cortisol concentrations on d 7 and 28, and mean plasma haptoglobin concentrations, but not liver mRNA expression of haptoglobin (P = 0.75), were greater for S3 vs. S7 steers (P = 0.03). Plasma IGF-1 concentrations on d 0 and urea nitrogen on d 1 and 3, relative to vaccination, were greater for S7 vs. S3 steers (P = 0.008). Positive seroconversion to BVDV-1b on d 42 and mean serum BVDV-1b titers were greater for S7 vs. S3 steers (P = 0.05). In summary, decreasing the frequency of concentrate supplementation from daily to three times weekly, during a 42-d preconditioning period, decreased growth performance, increased plasma concentrations of haptoglobin and cortisol, and decreased vaccine-induced antibody production against BVDV-1b of beef steers. [ABSTRACT FROM AUTHOR]

Calf (Bos taurus) depredation by the federally endangered Florida panther (Puma concolor coryi) on ranches in southwest Florida is an important issue because ranches represent mixed landscapes that provide habitat critical to panther recovery. The objectives of this study were to (1) quantify calf depredation by panthers on two ranches in southwest Florida, and (2) develop a habitat suitability model to evaluate the quality of panther hunting habitat on ranchlands, assess whether the model could predict predation risk to calves, and discuss its potential to be incorporated into an incentive-based compensation program. We ear-tagged 409 calves with VHF transmitters on two ranches during 2011–2013 to document calf mortality. We developed a model to evaluate the quality of panther hunting habitat on private lands in southwest Florida using environmental variables obtained from the Florida Natural Areas Inventory (FNAI) Cooperative Landcover Database and nocturnal GPS locations of panthers provided by the Florida Fish and Wildlife Conservation Commission (FWC). We then tested whether the model could predict the location of calf depredation sites. Tagged calf loss to panthers varied between the two ranches (0.5%/yr to 5.3%/yr) and may have been influenced by the amount of panther hunting habitat on each ranch as the ranch that experienced higher depredation rates contained a significantly higher probability of panther presence. Depredation sites of tagged calves had a significantly greater probability of panther presence than depredation sites of untagged calves that were found by ranchers in open pastures. This suggests that there may be more calves killed in high risk environments than are being found and reported by ranchers and that panthers can hunt effectively in open environments. It also suggests that the model may provide a means for evaluating the quality of panther hunting habitat and the corresponding risk of depredation to livestock across the landscape. We suggest that our approach could be applied to prioritize and categorize private lands for participation in a Payment for Ecosystem Services program that compensates landowners for livestock loss and incentivizes conserving high quality habitat for large carnivores where livestock depredation is a concern. [ABSTRACT FROM AUTHOR]

We evaluated the effects of MP supply on growth performance before and after preconditioning and measurements of innate and humoral immune response of beef steers following vaccination. Angus steers (n = 36; BW = 231 ± 21 kg; age = 184 ± 18 d) were weaned on d -6, stratified by BW and age on d 0, and randomly assigned to 1 of 18 drylot pens (2 steers/pen). Treatments were assigned to pens (6 pens/ treatment) and consisted of corn silage-based diets formulated to provide 85%, 100%, or 115% of the daily MP requirements of a beef steer gaining 1.1 kg/d from d 0 to 42. Steers were vaccinated against infectious bovine rhinotracheitis virus, bovine viral diarrhea (BVDV) types 1 and 2 viruses, Mannheimia haemolytica, and clostridium on d 14 and 28. Blood samples were collected on d 0, 14, 15, 17, 21, 28, 29, 30, 35, and 42. Body weight did not differ (P = 0.17) among treatments from d 0 to 28. On d 42, 115% MP steers were heaviest, 100% MP steers were intermediate, and 85% MP steers were lightest (P = 0.05; 297, 290, and 278 ± 7 kg, respectively). Overall, ADG and G:F did not differ (P = 0.13) between 100% and 115% MP steers and were least (P < 0.01) for 85% MP steers (1.2, 1.4, and 0.8 ± 0.07 kg/d and 0.23, 0.24, and 0.19 ± 0.008, respectively). Plasma haptoglobin (Hp) concentrations did not differ among treatments (P = 0.46), whereas plasma ceruloplasmin (Cp) concentrations were greatest (P = 0.04) for 85% MP steers, intermediate for 100% MP steers, and least for 115% MP steers on d 30, 35, and 42. Plasma cortisol concentrations were greater (P = 0.03) for 85% vs. 100% and 115% MP steers on d 14 and 28. Liver mRNA expression of Cp and Hp and muscle mRNA expression of m-calpain, mammalian target of rapamycin, and ubiquitin did not differ among treatments (P = 0.17). Serum neutralization titers to BVDV-1b titers were greater (P = 0.02) for 115% vs. 85% and 100% MP steers on d 42 (5.8, 3.0, and 3.7 ± 0.60 log2, respectively), whereas mean serum M. haemolytica leukotoxin titers were greater for 85% vs. 100% and 115% MP steers (3.1, 2.4, and 2.5 ± 0.21 log2, respectively). Preconditioning MP supply did not affect (P = 0.26) subsequent finishing growth performance and carcass characteristics. Thus, increasing MP supply from 85% to 115% of daily requirement of preconditioning beef steers had variable results on innate and humoral immune response and enhanced growth performance during a 42-d preconditioning period without affecting carcass characteristics at slaughter. [ABSTRACT FROM AUTHOR]

Sixty non-pregnant, non-lactating double-muscled Belgian Blue (DMBB) cows were used to estimate the energy required to maintain body weight (BW). They were fed one of three energy levels for 112 or 140 days, corresponding to approximately 100%, 80% or 70% of their total energy requirements. The relationship between daily energy intake and BW and daily BW change was developed using regression analysis. Maintenance energy requirements were estimated from the regression equation by setting BW gain to zero. Metabolizable and net energy for maintenance amounted to 0.569 ± 0.001 and 0.332 ± 0.001 MJ per kg BW0.75/d, respectively. Maintenance energy requirements were not dependent on energy level (p > 0.10). Parity affected maintenance energy requirements (p < 0.001), although the small numerical differences between parities may hardly be nutritionally relevant. Maintenance energy requirements of DMBB beef cows were close to the mean energy requirements of other beef genotypes reported in the literature. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the effects of preconditioning on the deformation response of planar tissues measured by inflation tests. The inflation response of test specimens, including the bovine cornea, bovine and porcine sclera, and human skin, exhibited a negligible evolving deformation response when subjected to repeated pressure loading with recovery periods between cycles. Tissues obtained complete recovery to the reference state, and strain contours across the entire specimen were nearly identical at the maximum pressure of each load cycle. This repeatability was obtained regardless of strain history. These results suggest that negligible permanent change was induced in the microstructure by inflation testing. Additionally, we present data illustrating that a lack of a recovery period can result in an evolving deformation response to repeated loading that is commonly attributed to preconditioning. These results suggest that the commonly observed effects of preconditioning may be avoided by experimental design for planar tissues characterized by long collagen fibers arranged in the plane of the tissue. Specifically, if the test is designed to fully fix the specimen boundary during loading, adequate recovery periods are allowed after each load cycle, and loads are limited to avoid damage, preconditioning effects may be avoided for planar tissues. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated that ischemic preconditioning prevents reperfusion-induced endothelial dysfunction. However, the question of the influence of preconditioning on the occurrence of the no-reflow phenomenon remains open. The receptor mechanisms of the cardioprotective and vasoprotective effects of preconditioning are different. The ability of preconditioning to prevent reperfusion-induced endothelial dysfunction is associated with activation of bradykinin B 2 receptors and is independent of stimulation of adenosine receptors. The vasoprotective effect of preconditioning is mediated by mechanisms associated with activation of protein kinase C, NO synthase, and cyclooxygenase, the opening of mitochondrial KATP channels, and increases in the antioxidant defense of the heart. Delayed preconditioning also has an endothelium-protecting effect. Triggers for these effects are NO •, O 2•, and peroxynitrite, and endothelial NO synthase may be the end effector is. [ABSTRACT FROM AUTHOR]

Human safety can be compromised by the response of beef cows to handling or when defending their calf. However, little is known about how precalving temperament, postcalving defensiveness, and maternal care are related. The impacts of cow temperament on calf neonatal vigor and ADG are also unknown. Data were collected on 2 farms (Farm 1, n = 143, 1 parity; Farm 2, n = 237,2 parities). Temperament was recorded before calving when restrained in a crush (crush score), on exit from the crush (flight speed), and when isolated with a handler. Defensiveness was recorded within 4 d after calving during handling of the calf Maternal interactions with the calf and calf vigor were recorded for 3 h after calving (Farm 1 only) and ADG was measured over 7 mo. Crush score and flight speed were repeatable within a parity (range in repeatability 0.33 to 0.49; P < 0.001). Crush score (0.50; P < 0.001) and defensiveness (up to 0.71; P < 0.001) were repeatable across parities. Temperament and defensiveness were unrelated on Farm 1 ; on Farm 2 a fearful crush score was associated with heightened defensiveness as measured by vigorous movement during calf handling (P < 0.001). Temperament and defensiveness were unrelated to calving ease or the amount of maternal behavior shown to the calf. At Farm 1, cows that exited the crash quickly had calves with a lighter birth weight (P = 0.023) and those that were agitated when isolated had calves with a decreased ADG (P=0.017). Defensiveness was unrelated to ADG and neither temperament nor defensiveness affected calf vigor. Cow precalving temperament and postcalving defensiveness are repeatable but appear to be independent traits, neither of which is related to maternal interactions with the neonatal calf. Reducing precalving fearfulness should not affect postcalving behavior and changing postcalving defensiveness should not affect other maternal care traits. Fearful cows may produce calves with decreased birth weight and ADG, which, if confirmed, suggests that cow fearfulness may have wider economic implications than previously realized. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an essential micronutrient in cattle, and Se-deficiency can affect morbidity and mortality. Calves may have greater Se requirements during periods of stress, such as during the transitional period between weaning and movement to a feedlot. Previously, we showed that feeding Se-fertilized forage increases whole-blood (WB) Se concentrations in mature beef cows. Our current objective was to test whether feeding Se-fertilized forage increases WB-Se concentrations and performance in weaned beef calves. Recently weaned beef calves (n = 60) were blocked by body weight, randomly assigned to 4 groups, and fed an alfalfa hay based diet for 7 wk, which was harvested from fields fertilized with sodium-selenate at a rate of 0, 22.5, 45.0, or 89.9 g Se/ha. Blood samples were collected weekly and analyzed for WB-Se concentrations. Body weight and health status of calves were monitored during the 7-wk feeding trial. Increasing application rates of Se fertilizer resulted in increased alfalfa hay Se content for that cutting of alfalfa (0.07, 0.95, 1.55, 3.26 mg Se/kg dry matter for Se application rates of 0, 22.5, 45.0, or 89.9 g Se/ha, respectively). Feeding Se-fertilized alfalfa hay during the 7-wk preconditioning period increased WB-Se concentrations (PLinear<0.001) and body weights (PLinear = 0.002) depending upon the Se-application rate. Based upon our results we suggest that soil-Se fertilization is a potential management tool to improve Se-status and performance in weaned calves in areas with low soil-Se concentrations. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to compare ruminal, physiological, and performance responses of forage-fed cattle consuming grain-based supplements without (NF) or with the inclusion (10%; DM basis) of a rumen-protected PUFA (PF) or SFA source (SF). Supplements were offered and consumed at 0.6% of BW/animal daily (DM basis). In Exp. 1, DMI and ruminal in situ forage degradability were evaluated in 3 Angus × Hereford cows fitted with ruminal cannulas and allocated to a 3 x 3 Latin square design. Within each experimental period, hay was offered in amounts to ensure ad libitum access from d 1 to 13, DMI was recorded from d 8 to 13, and cows were limited to receive 90% of their average hay DMI (d 1 to 13) from d 14 to d 21. On d 16, polyester bags containing 4 g of ground hay (DM basis) were incubated within the rumen of each cow for 0, 4, 8, 12, 24, 36, 48, 72, and 96 h. Hay and total DMI were reduced (P < 0.05) in PF cows compared with SF and NF cows. No treatment effects were detected (P > 0.48) for ruminal disappearance rate and effective ruminal degradability of hay DM and NDF. In Exp. 2, preconditioning DMI, ADG, carcass traits, and plasma concentrations of cortisol, FA, acute-phase proteins, and pro-inflammatory cytokines were assessed in 72 Angus × Hereford steers receiving supplement treatments during a 28-d preconditioning period. All steers were transported to a commercial growing lot after preconditioning (d 1), and later moved to an adjacent commercial finishing yard (d 144) where they remained until slaughter. No treatment effects were detected (P = 0.52) for preconditioning ADG and G:F, but DMI tended (P = 0.09) to be reduced in PF steers compared with NF and SF. Plasma PUFA concentrations were greater in PF steers compared with NF and SF (P = 0.01). Following transportation, concentration of tumor necrosis factor-a increased for NF, did not change for SF, but decreased for PF steers (treatment × day interaction, P < 0.01). Steers fed PF had greater (P = 0.02) ADG compared with NF steers during the growing phase. Carcass yield grade and marbling were greater (P < 0.05) for PF compared with NF steers. In conclusion, PUFA supplementation did not impact ruminal forage degradability, but impaired DMI in beef cows. Further, PUFA supplementation to steers during preconditioning reduced plasma concentrations of TNF-a following transportation, and benefited growing lot ADG and carcass marbling. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess changes in exit velocity (EV) of Brahman calves from 21 d of age (DOA) to 56 d postweaning (231.30 ± 1.23 DOA). Spring-born calves (n = 308) from 2006 to 2008 were sired by 18 bulls. Exit velocity (m/s) was determined as the rate of speed of a calf traversing 1.83 m after being released from a working chute. Temperament score was determined as the average of EV and pen score 28 d before and at weaning (2006: 173 ± 2 DOA; 2007: 174 ± 2 DOA; 2008: 163 ± 2 DOA). Pen score was determined by separating calves into groups of 3 to 5 animals and scoring their reactivity to a human observer on a scale of 1 (calm, docile, approachable) to 5 (aggressive, volatile, crazy). The number of calves that switched temperament group was determined by ranking calves based on their EV at 21 to 24 DOA, 90 DOA, weaning, and at 56 d postweaning. The GLIMMIX procedure of SAS was used to analyze EV with DOA, birth year and sex as fixed effects, and sire and calf nested within sire included as random effects. Temperament classification (calm, intermediate, temperamental) was modeled as a fixed effect, and the linear regression of traits on DOA investigated. Spearman rank order correlations were determined between EV at 21 to 24 DOA, 90 DOA, weaning, and 56 d postweaning and correlations decreased as the number of days between EV measurements increased. Differences in EV were observed between the 2006 (2.23 ± 0.057 m/s) compared with the 2007 (1.90 ± 0.059 m/s) and 2008 (1.83 ± 0.057 m/s) calves (P < 0.001), but the 2007 and the 2008 calves did not differ (P = 0.75). The random effect of sire approached significance (P = 0.07) and accounted for some of the variation observed. Exit velocity increased as days of age increased (P < 0.001). Exit velocity of temperamental calves increased at a faster rate with age (P < 0.001; estimate of slope = 0.005 ± 0.0004 m/s daily) compared with intermediate (slope = 0.003 ± 0.0005 m/s daily; P < 0.001) and calm calves (slope = 0.0007 ± 0.0005 m/s daily; P < 0.001). Exit velocity is a useful and viable indicator of temperament classification. Results suggest that temperamental calves increase their EV at a faster rate and may be identified before weaning, which may enhance the ability of producers to select against temperamental animals. [ABSTRACT FROM AUTHOR]

One hundred thirty-eight Angus cross yearling steers (initial BW 390 ± 0.5 kg) were allotted by BW to a 3 × 2 factorial arrangement of 6 treatments (4 pens per treatment) to determine the effect of wet distillers grains (WDG) concentration (0, 20, 40% of dietary DM) in low-forage (12% hay) and high-forage (50% hay) diets on growth performance and marbling. Steers were implanted on d 0 with Component TE-S (VetLife, Overland Park, KS) and were slaughtered in 3 groups when final BW averaged 578 kg. Steers fed a low-forage diet gained BW faster (P < 0.001) than did steers fed a high-forage diet; the amount of WDG fed did not affect (P = 0.25) daily BW gain. Hot carcass weight and dressing percentage were greater (P < 0.001) for steers fed low-forage diets than for steers fed high-forage diets. Dressing percentage increased (P = 0.08) as WDG concentration increased. Longissimus muscle area (P = 0.08) and yield grade (P < 0.01) were greater for steers fed low-forage diets compared with steers fed high-forage diets. Longissimus muscle area (P = 0.02) and yield grade (P = 0.03) increased as WDG concentration increased. An interaction occurred for marbling (P < 0.01), fat thickness (P = 0.08), and PUFA content (P < 0.01). In steers fed low-forage diets, marbling score (325, 306, 265) and fat thickness (1.22, 1.07, 1.07 cm) decreased with WDG inclusion rates of 0, 20, and 40%, respectively, but in steers fed high-forage diets, marbling score (249, 282, 262) and fat thickness (0.89, 0.97, 0.81 cm) increased from the 0 to 20% inclusion rate and then decreased from the 20 to 40% inclusion rate. The inclusion of 0, 20, or 40% WDG increased PUFA content of beef from steers fed low-forage diets (6.9, 9.3, 10.6 g/100 g) but decreased PUFA content of beef from the 0 to 20% inclusion rate and then increased PUFA content of beef from the 20 to 40% inclusion rate in steers fed high-forage diets (8.5, 5.9, 7.8 g/100 g). In conclusion, when fed to a common BW end point, concentration of WDG in feedlot diets alters lean and adipose tissue deposition in beef cattle. [ABSTRACT FROM AUTHOR]

Three calf starter concentrates containing Maize, Oats and Maize + Oats as a source of energy having 20% crude protein and 80% total digestible nutrients were formulated and fed to three groups of young calves A, B & C, respectively for a period of 90 days. The daily consumption of milk was 3.30, 3.70 and 3.32 litres while daily intake for starter ration and berseem hay was 0.410 & 1.80; 0.320 & 2.25 and 0.372 & 2.00 kg in groups A, B and C, respectively. The feed efficiency for milk was 5.66, 9.44 and 6.99 for concentrates 0.703, 0.816 and 0.783 and for berseem hay 3.09, 5.74 and 4.21 in respective groups. The daily weight gain was 0.583, 0.392 and 0.475 kg in groups A, B and C, respectively. The results revealed that the animals fed on starter ration containing maize as energy source gained 18.57 % and 13.71% more weight and showed better feed efficiency as compared to the calves reared on starter concentrates having Oats or Maize + Oats as a source of energy. [ABSTRACT FROM AUTHOR]

The present study was conducted on fourteen winter born buffalo calves to establish the developmental changes in various energy substrates and their relation to delayed colostrum intake. Blood samples were collected from these calves at 1, 2, 4, 8 and 24h after birth and subsequently once on day 7, 15, 30, 45, 60 and 90 and were analyzed for glucose, fructose, lactate, pyruvate and alkaline phosphatase. Colostrum was fed to these calves 8h after birth. Fructose was found to be an important energy source at birth (37.90±3.50 mg%) and its level registered a continuous fall on first day (P<0.01). The levels were not influenced by colostrum intake. Afterwards, the concentration ranged between 3.25±0.34 to 4.64±0.18 mg percent. Glucose, after an initial increase, (P<0.01) receded till 8h. Following colostrum feeding, the level again increased, eventually reaching to 98.04±7.72 mg% at 24h. Thereafter, the values exhibited fluctuations and ranged between 72.04 ±7.36 to 81.54±7.33 mg% (p>0.01). Lactic acid remained high for first 24h. The variations were not significant at different hours of sampling. Pyruvic acid was low at birth (2.20± 0.06 mg%). It increased significantly for first 8h, declining after feed intake to 2.74±0.19 mg% at 24h and hence, suggested that pyruvate as a substrate was important for neonate calf immediately after birth. Lactate and pyruvate though declined subsequently, but did not present appreciable change with advancing age. Alkaline Phosphatase registered a significant increase after colostrum feeding. The pattern of change of these metabolites, thus cleared indicated the enhanced metabolic rate in response to high-energy demands of neonate calves after birth at low ambient temperatures. Both age and nutrient intake played an important role in attaining homeostasis for several hours of life. [ABSTRACT FROM AUTHOR]

The observation and measurements of 118 buffaloes of Murrah, Nili-Ravi and local breeds maintained by the farmers at three villages viz Goharni, Badheo and Bhainswal of district M. Nagar (U.P.) India for a period of two months i.e. from 1st July to 31st Aug. 2005 were taken. Four observations on each milking trait were taken continuously on each buffalo. Least squares technique was used to study the effect of breeds, parity, stage of lactation, shape of teats, let down with or without calf, method of milking, fodder feeding concentrate feeding and shift of milking. Out of 118 buffaloes under investigation 51 buffaloes were Murrah or Murrah type, 20 Nili-Ravi and 47 were non descript. The overall least squares means for milk let down time, actual milking time, milk yield per milking and milk flow rate were found as 154.99±5.56 seconds, 289.85±12.20 seconds, 2994.35±106.52 gms and 10.50±0.29 gms/second, respectively. The milk let down time was influenced significantly (P<0.01) by breed, parity order, stage of lactation, let down with or without calf and significantly (P<0.05) by time of fodder feeding. The actual milking time was affected significantly (P<0.01) by parity order, stage of lactation, method of milking, time of fodder feeding and trend of concentrate feeding. The milk yield per milking on test day was affected significantly by parity, stage of lactation, shape of teats and method of milking. The milk flow rate was influenced significantly (P<0.01) by breed, parity order, stage of lactation, time of fodder feeding and trend of concentrate feeding. The milk yield per milking was found to have positive and moderate correlation with milk flow rate. It means milk flow rate can be used in evaluating the buffalo for milk production specially in rural, where complete milking of animal is not possible and milk recording is not practiced. [ABSTRACT FROM AUTHOR]

The aim of this paper was to estimate the genetic relationships among calving ease (CE), calf survival (CS), and gestation length (GL) to assess the possibility of including this information in beef cattle breeding programs. A total of 35,395 field records were available for CE, 30,684 for GL, and 36,132 for CS from the Asturiana de los Valles beef cattle breed. The 3 traits were analyzed as traits of the calf fitting a multivariate linear mixed model. Estimates of heritability (±SE) for the direct genetic effects (CEd, GLd, and CSd) were 0.325 ± 0.022, 0.331 ± 0.026, and 0.226 ± 0.018, respectively, whereas the estimates for maternal genetic effects (CErn, GLm, and CSm) were 0.066 ± 0.018, 0.066 ± 0.017, and 0.034 ± 0.011. The estimates for the ratio of permanent environmental variance to phenotypic variance were CEc 0.090 ± 0.011, GLc 0.066 ± 0.011, and CSc 0.024 ± 0.007. Genetic correlations between direct, maternal genetic, or permanent environmental effects involving CE and CL were, in general, positive and moderate, whereas those involving CE and CS were high. All were significant except for the pair CEm-GLm (0.277 ± 0.172). Correlations between GL and CS were nonsignificant. Genetic correlations for CEd-CEm, GLd-GLm, and CSd-CSm were negative and high, ranging from -0.461 ± 0.120 for GLd-GLm to -0.821 ± 0.145 for CSd-CSm. The genetic correlations for CEd-CSm and for CSd-CEm were negative, significant, and high, whereas that for GLd-CEm was moderate (-0.323 ± 0.124) and that for GLd-CSm was nonsignificant. The genetic correlations for GLm with the direct effects of the other traits were non-significant. Strong selection for CE will result in a significant correlated response in CS. Therefore, CE can be considered an early indicator of CS performance. The benefit of using CL as a correlated trait in a genetic evaluation with CE and CS seems limited. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to examine the influence of endogenous cannabinoids on neuroprotection of the spinal cord afforded by limb remote ischemic preconditioning. Methods: In experiment 1 (RIPC group), 3 cycles of limb remote ischemic preconditioning within different episodes (2, 3, or 5 minutes) were induced before spinal cord ischemia in rats (N = 5, n = 8). In experiment 2, animals were pretreated intravenously by the vehicles, cannabinoid 1 (AM251, 1 mg/kg) or cannaboid 2 (AM630, 1 mg/kg) receptor antagonist 15 minutes before remote ischemic preconditioning, or else they were subjected to a sham operation. Thirty minutes after the pretreatment, spinal cord ischemia was induced (N = 8, n = 8). In experiment 3, the arachidonylethanolamide and 2-arachidonoylglycerol contents in the spinal cord after remote ischemic preconditioning and spinal cord ischemia were detected in rats (N = 2, n = 12). Spinal cord ischemia was induced by 12 minutes of thoracic aorta occlusion in rats. Neurologic function was assessed 24 and 48 hours after reperfusion. Histopathologic examination was performed and the number of normal neurons in anterior spinal cord were counted. Results: In experiment 1, 3 cycles of limb remote ischemic preconditioning (3 minutes of ischemia/3 minutes of reperfusion) induced ischemic tolerance on the spinal cords of the rats. The RIPC group showed a significant reduction in motor deficit index (P < .01) as well as an increase in the number of normal neurons (P < .01). In experiment 2, the cannabinoid 1 receptor antagonist AM251 pretreatment abolished the protective effects of remote preconditioning. In experiment 3, arachidonylethanolamide content in spinal cord was elevated by remote ischemic preconditioning in rats. Conclusion: These results indicated that endogenous cannabinoids, through acting on cannabinoid 1 receptors, were involved in the neuroprotective phenomenon on spinal cords of limb remote ischemic preconditioning. [Copyright &y& Elsevier]

Increasingly available information is illustrating the value of management on feeder cattle prices. Information from more than 2,000 lots was collected from a single market facility in western Wisconsin from 2004 through 2006 to examine factors affecting feeder cattle prices. Factors such as weight, breed, haircoat color, sex, lot size, and management practices commonly associated with preconditioning programs are found to affect feeder cattle prices in a market where dairy calves are predominate. This information provides support for implementation of a statewide preconditioning program. [ABSTRACT FROM AUTHOR]

Abstract: This experiment was designed to study the effects of avoiding calf contact and genotype on the metabolic, behavioural and reproductive traits of beef cows during lactation. Fifty-two multiparous cows, 25 Parda de Montaña (PA) and 27 Pirenaica (PI), fed at maintenance were assigned from the day after calving to twice-daily nursing (2× 30-min sessions at 0800 and 1600h) either with fence contact with their calves (partial contact, PC) or without visual, tactile and olfactory contact (non-contact, NC) between suckling periods. Blood samples were collected to analyse metabolites (triglycerides, cholesterol, non-esterified fatty acids (NEFA), β-hydroxybutyrate and urea) and progesterone at different intervals. Cow–calf behaviour was monitored on weeks 4, 9 and 15 of lactation. Cow activity at oestrus was recorded through collars. Cows from both treatments and breeds showed similar live-weight gains during the first three months post-partum (P >0.10). Milk yield and calf gains were not affected by treatment (P >0.10) but they were greater in PA than in PI (P <0.05). Plasma triglycerides and urea in the cows were not affected either by calf contact, breed or week post-partum (P >0.10). Plasma cholesterol increased from week 6 post-partum onwards in PA cows (P <0.05) while this rise was delayed to week 7 of lactation in PI breed (P <0.05). Plasma NEFA was greater in blood from PC–PA cows than in the rest of groups (P <0.05), and these metabolites were greater on week 1 and lower on week 11 than in rest of samplings (P <0.05). Plasma β-hydroxybutyrate was not affected by either calf contact or breed (P >0.10), but it was greatest on weeks 1–3 than in the rest of lactation (P <0.05). Cows with PC calves took less time to first contact after they entered the barn than their NC counterparts (P <0.05). Dams from both contact treatments nursed their offspring and remained in close proximity for similar time within suckling periods (P >0.10). PA cows devoted more time than PI ones to lick their young (P <0.001). There were no differences throughout lactation in any of the studied maternal behaviours (P >0.10). Calf contact and breed did not affect the interval to first post-partum ovulation or oestrus in these cows (P >0.10). Under twice-daily nursing conditions, the limitation of visual, tactile and olfactory contact with calves did not trigger different maternal or reproductive traits in these breeds but only a slightly higher mobilisation of body fat substrates in Parda de Montaña compared to Pirenaica. [Copyright &y& Elsevier]

The article presents a study on the effectiveness of gamma-aminobutyric acid (GABA) administration on the growth rate of Japanese Black calves fed with the use of automatic milk feeder. The Japanese Black cattle is a popular beef breed in Japan and considered weak against other breed. Accordingly, GABA is a neurotransmitter in the nervous system that has been linked in regulating endocrine functions. The study aims to know the efficacy of GABA preparations as a supplement milk to ameliorate the health and growth rate of group-housed Japanese Black calves. The result showed that calves given with GABA preparation tends to need less medication than those in the control group. The study suggests that perhaps GABA have etiotropic effects in calves fed with an automatic milk feeder.

Effects of ractopamine hydrochloride (RAC) supplementation on growth performance and carcass characteristics of feedlot steers differing in biological type were investigated using British, Continental crossbred, and Brahman crossbred calf-fed steers (n = 420). Steers of each type were weighed at reimplantation [British, mean BW = 375 kg (SD = 38 kg); Continental crossbred, mean BW = 379 kg (SD = 42 kg); Brahman crossbred, mean BW = 340 (SD = 32 kg)] and sorted into 7 BW blocks, each block consisting of 2 pens (10 steers per pen) per type. Pens within a block × type subclass were randomly assigned to RAC treatments (0 or 200 mg·steer-1·d-1 fed during the final 28 d of the finishing period). The type × RAC interaction did not affect (P > 0.05) any of the traits evaluated in this study. Feeding RAC improved (P = 0.001) ADG (1.50 vs. 1.73 ± 0.09 kg) and G:F (0.145 vs. 0.170 ± 0.005), but did not affect (P = 0.48) DMI of steers. Dressing percentage, adjusted fat thickness, KPH percentage, and yield grade were not affected by RAC supplementation. Carcasses of steers fed RAC had heavier (P = 0.01) HCW (359 vs. 365 ± 4.9 kg), larger (P = 0.046) LM areas (81.7 vs. 84.0 ± 1.1 cm²), and tended (P = 0.07) to have lower mean marbling scores (487 vs. 477 ± 5.2; Slight = 400, Small = 500) than did carcasses of control steers. Among the 3 biological types, Brahman crossbred steers had the lowest DMI and produced the lightest-weight carcasses that had the lowest mean marbling score (P < 0.05). Compared with Continental crossbred and Brahman crossbred steers, British steers produced carcasses with the greatest (P = 0.001) mean marbling scores. Continental crossbred steers had the heaviest BW and greatest dressing percentages and produced the heaviest carcasses with the largest LM areas (P < 0.05) compared with British and Brahman crossbred steers. In the present study, 28 d of supplementation with RAC at a dosage rate of 200 mg·steer-1·d-1 elicited consistent responses in growth performance and carcass traits among 3 diverse biological cattle types. [ABSTRACT FROM AUTHOR]

One hundred six female Holstein calves [body weight (BW) = 41.5 ± 0.37 kg and 11.2 ± 0.3 d old] were used to evaluate the effects of physical form of a starter on animal performance and starter intake. Calves were randomly allocated to 2 treatments consisting of either a multiparticle or a pelleted starter. Both starters had exactly the same ingredient and nutrient composition but differed in their physical form. Calves received 4 L/d of the same milk replacer at a 150 g/kg dilution rate in 2 offers of 2 L each until they consumed an average of 300 g/d of starter (as fed) for 2 consecutive days; then the dilution rate was decreased to 120 g/kg until the age of 49 d when milk replacer was limited to 1 daily dose of 2 L until 57 d of age. Calves were kept in individual hutches for at least 1 wk after weaning. Body weight was measured at the beginning of the study and at 49 and 64 d of age. The median perimeters for the multiparticle and pelleted starters were 0.61 ± 0.016 and 2.71 ± 0.082 cm, respectively. Overall starter consumption was greater in calves receiving the multiparticle starter (944.8 ± 30.01 g/d) than in those receiving the pelleted starter (863.9 ± 32.04 g/d). There were no differences in the total milk replacer intake between the 2 treatments. Calf BW when leaving the individual hutches at the end of the study was similar between both treatments. Consequently, feed conversion efficiency was greater in calves consuming the pelleted than the multiparticle starter up to 64 d of age, mainly due to the greater conversion efficiency obtained with the pelleted than with the multiparticle starter after the preweaning period. It is concluded that pelleted starters may result in lower dry feed consumption compared with multiparticle starters, but because final BW was similar in both treatments, feed efficiency of calves consuming pelleted starters may be greater than that of calves consuming multiparticle starters. Therefore, when feeding a starter with similar nutrient composition to the one used in this study, there seems to be an economic advantage associated with feeding the starter in a pelleted form compared with a multiparticle form. [ABSTRACT FROM AUTHOR]

Three rumen-fistulated Jersey steers were gradually adapted to a wheat-barley concentrate over a 4-wk period. Adaptation steps consisted of four 1-wk periods during which steers were fed diets with forage-to-concentrate (F:C) ratios of 100:0, 79:21, 59:41, and 39:61. The forage consisted of chopped hay (CH), and the concentrate consisted of pelleted concentrate containing 50% ground wheat and 50% ground barley. Steers were fed the all-forage diet ad libitum during wk 1. Feed offered in wk 2 to 4 was kept constant at the ad libitum intake during wk 1. On 2 d that were set 3 d apart during wk 5, subacute ruminal acidosis (SARA) was induced in the steers by feeding a diet with an F:C ratio of 24:76 by offering them 0.9 kg of CH at 0900 h followed by 2 meals of 3.0 kg each of wheat-barley pellets (WBP) at 1100 h and 1300 h and 0.9 kg of CH at 1700 h, to depress rumen pH for at least 3 h/d below 5.6. The average concentrate inclusion for the SARA induction diet was 76 ± 10% DM. During stepwise adaptation, time with pH below 5.6 increased to an average of 121 min/d when the steers were consuming a diet containing 61%, DM as WBP. Dietary inclusion of WBP at the rate of 76% DM induced SARA because the steers spent an average of 219 min/d with pH below 5.6. The free ruminal lipopolysaccharide (LPS) concentration increased from 6,310 endotoxin units (EU)/mL with the all-forage diet to 18,197 EU/mL with the 61% concentrate diet. The ruminal LPS concentration increased to 26,915 EU/mL when SARA was induced. Serum haptoglobin increased from 0.53 mg/mL when steers were on the all-forage diet to 1.90 mg/mL with the 61% concentrate diet and were not increased further by inducing SARA. The serum amyloid-A concentration was not affected by increasing dietary concentrate during stepwise adaptation to the concentrate, but increased from 71 to 163 µg/mL when SARA was induced. A gradual increase in dietary concentrate so that the F:C ratio decreased to 39:61 resulted in increased ruminal LPS concentrations. Subsequent induction of SARA further increased ruminal LPS and activated an inflammatory response. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize genetic, environmental, and economic factors related to the incidence of bovine respiratory disease (BRD) in feedlot calves. Records from 18,112 calves representing 9 breeds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and 3 composite types (MARC I, MARC II, and MARC III) over a 15-yr period (1987 to 2001) were evaluated. Disease incidence was observed and recorded by station veterinary and technical staff. The incidence of BRD varied across years, with the annual observed incidence ranging from 5 to 44%. From 1987 to 1992, the annual average incidence generally exceeded 20%. However, in later years the annual incidence did not exceed 14%. The epidemiological pattern indicated that BRD infection increased dramatically after 5 d on feed and remained high until approximately 80 d on feed. Previous BRD infection during the preweaning period did not influence subsequent BRD infection in the feedlot. Steers were more likely to become sick with BRD than heifers; castration before entry in the feedlot may be a predisposing cause. Few significant differences among breeds were detected for BRD incidence. Adjusted solutions from mixed model analyses indicated that Herefords were generally more susceptible to BRD infection (P < 0.05) than MARC I and III composite types. Composite breed types had similar susceptibility compared with other purebred breeds. Mortality associated with BRD was greatest in Red Poll calves (9%) compared with the average over all breeds (4%). Estimates of heritability for resistance to BRD ranged from 0.04 to 0.08 + 0.01. When the observed heritability was transformed to an underlying continuous scale, the estimate increased to 0.18. Selection for resistance to BRD could be effective if phenotypes for BRD resistance were known. Thus, development of an inexpensive and humane method of challenging animals with BRD to determine resistance would be an important step in reducing the incidence of BRD. This study also demonstrated that producer-collected field data could be used for selection against this disease. The economic loss associated with lower gains and treatment costs for BRD infection in a 1,000-cattle feedlot was estimated as $13.90 per animal, not including labor and associated handling costs. [ABSTRACT FROM AUTHOR]

Three conditioned lever-press suppression experiments with rats investigated the interaction between overshadowing and outcome-alone exposure effects. Experiment 1 found in first-order conditioning that combined overshadowing and outcome-preexposure treatments attenuate the response deficit produced by either treatment alone. Experiments 2 and 3 investigated the interaction between overshadowing and outcome pre- and postexposure effects in sensory preconditioning, varying retention intervals to engage recency and primacy effects with respect to treatment order. Contrary to when a solitary cue is conditioned, responding to a cue conditioned in compound appeared positively correlated with the context's associative status. These findings suggested that some of the basic laws of learning applicable to cues conditioned alone do not similarly apply to a component of a compound cue. [ABSTRACT FROM AUTHOR]

The effects of weaning and transport on fecal shedding of Escherichia coli and on E. coli O157:H7 were investigated using 80 Angus and 94 Charolais range steer calves blocked by breed and assigned to four treatments. The calves were or were not preconditioned before transport on commercial cattle liner to the feedlot via long (15 h) or short (3 h) hauling duration, yielding preconditioned long haul (P-L; n = 44), preconditioned short haul (P-S; n = 44), nonpreconditioned long haul (NP-L; n = 43), and nonpreconditioned short haul (NP-S; n = 43). Preconditioned calves were vaccinated and weaned 29 and 13 days, respectively, before transport. Nonpreconditioned calves were weaned 1 day before long or short hauling, penned for 24 h and hauled again for 2 h, and vaccinated on arrival at the feedlot. Fecal samples were collected from calves while on pasture, at weaning, at loading for transport, on arrival at the feedlot, twice in the first week, and on days 7, 14, 21, and 28 for enumeration of total E. coli (biotype 1) and detection of E. coli O157:H7. No calves were positive for E. coli O157:H7 before transport. Following transport, more (P < 0.005) NP-L calves (6 of 43) tested positive for E. coli O157:H7 than did P-L (1 of 44), NP-S (1 of 43), or P-S (0 of 44) calves, and on days 0, 1, 7, and 21, their levels of shedding of E. coli were higher (P < 0.005). The calves' susceptibility to infection from the environment (possibly the holding facilities or feedlot pens) was likely elevated by the stresses of weaning, transport, and relocation. Lack of preconditioning and long periods of transport (NP-L) increased fecal shedding of E. coli and E. coli O157:H7. Preconditioning may serve to reduce E. coli O157:H7 shedding by range calves on arrival at the feedlot. [ABSTRACT FROM AUTHOR]

Articular Cartilage is a load bearing tissue whose microarchitecture, electrochemical composition, and fluid interactions afford it unique mechanical properties. It consists of an extracellular matrix (ECM) interspersed with a sparse population of chondrocytes, varying in density by depth. The structure and mechanical properties of this highly specialized tissue also vary depending on depth from the articular surface; with three specialized zones, each with unique material properties. Typically this tissue is mechanically modeled as a biphasic material, consisting of a solid phase and a fluid phase, which can redistribute itself under loading, altering hydrostatic pressure within the material. Thus, articular cartilage exhibits a time-dependent viscoelastic behavior when subjected to constant loading or deformation, and will reach an equilibrium via stress relaxation and creep behavior. The objective of this study was to test a custom designed confined compression chamber. We characterize the ability of the test chamber to generate curves capable of quantifying the stress relaxation level and equilibrium state in bovine articular cartilage, and to show the preliminary results of a comparison between the equilibrium aggregate modulus (HA) obtained from pre- conditioned and non-conditioned tissues. Using fresh bovine articular cartilage samples, stress relaxation tests were conducted in compression, obtaining equilibrium stress and HA through a linear relation between the initial strain and the equilibrium stress. The test specimens were divided into two groups, one with a pre-conditioning load and the other without. The tests resulted in equilibrium stresses of 0.015 ± 0.0067 MPa for the non-conditioned and 0.067 ± 0.012 MPA for the pre-conditioned, and HA values of 0.205 ± 0.100 MPa for the unconditioned group and 0.878 ± 0.160 MPa in the pre-conditioned group. Our confined compression chamber successfully produced the stress relaxation curve characterizing the mechanical behavior of articular cartilage, defining both the equilibrium stress and HA. Our results suggest that pre-conditioning correlates with a higher equilibrium stress and aggregate modulus based on the fact that pre-loading the specimens reduces the effects of viscoelasticity. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies about the animal nutrition of ruminants presented at the March 2001 conference of American Society of Animal Science Midwestern Section. `Self-fed Wheat Middlings in Backgrounding Diets for Beef Heifers,' by T. Gilbery et al.; `Response of Feedlot Steers to Diets Containing Bloodmeal and Choice White Grease,' by J.W. Lehmkuhler et al.; `Phosphorus Requirements of Finishing Steer Calves,' by G. E. Erickson et al.

The present work is devoted to a class of preconditioners based on the augmented matrix approach considered earlier by two of the present authors. It presents some generalizations of the subspace-correction schemes studied earlier and gives a brief comparison of the developed technique with a somewhat similar "deflation" algorithm. The developed preconditioners are able to improve significantly an eigenvalue distribution of certain severely ill-conditioned algebraic systems by using properly chosen projection matrices, which correct the low-frequency components in the spectrum. One of the main advantages of the proposed approach is the possibility of using inexact solvers within the projectors. Another attractive feature of the developed method is that it can be easily combined with other preconditioners, for instance, those which correct the high-frequency eigenmodes. [ABSTRACT FROM AUTHOR]

Evaluates the effects of three weaning ages on steer performance and carcass traits and on cow performance. Effect of weaning age on calf performance; Carcass evaluation; Effects of three weaning ages on carcass quality.

Evaluates the heat tolerance of purebred Hereford and Brahman steers and crossbred steers when exposed to high ambient temperature and relative humidity under controlled conditions. Data on the mean ambient dry bulb temperature in experiment two; Parameters identified in experiment one in purebred and crossbred Hereford and Brahman; Implications of the study.

The application of some recently proposed algebraic multilevel methods for the solution of two-dimensional finite element problems on nonuniform meshes is studied. The locally refined meshes are created by the newest vertex mesh refinement method. After the introduction of this refinement technique it is shown that, by combining levels of refinement, a preconditioner of optimal order can be constructed for the case of local refinement along a line. Its relative condition number is accurately estimated. Numerical tests demonstrating the performance of the proposed preconditioners will be reported in a forthcoming paper. [ABSTRACT FROM AUTHOR]

The article looks at a study which compare breed for growth traits adjusted for within-breed genetic trend using expected progeny differences. It mentions evaluation of sire in beef cattle is currently based on information primarily taken on purebred progeny and information required to select sires from multiple breeds for use in crossbreeding. It also mentions three-breed-cross calf data was augmented with either the continuous effect of the total maternal weaning weight (MAT).

Clinical scoring systems have been proposed for respiratory disease diagnosis in calves, including the Wisconsin (WI) system (McGuirk in 2008) which uses five clinical signs, each partitioned into four levels of severity. Recently, we developed the California (CA) bovine respiratory disease (BRD) scoring system requiring less calf handling and consisting of six clinical signs, each classified as normal or abnormal. The objective of this study was to estimate the on-farm agreement between the WI and the CA scoring systems. A total of 100 calves were enrolled on a CA dairy and assessed for BRD case status using the two scoring systems simultaneously. The Kappa coefficient of agreement between these two systems was estimated to be 0.85, which indicated excellent agreement beyond chance. The simpler design and reduced calf handling required by the CA BRD scoring system may make it advantageous for on-farm use. [ABSTRACT FROM AUTHOR]

Buffalos have become an economically viable source of protein due to their adaptability, precocity and longevity. Knowledge about the behavior of this species contributes to its welfare and good performance in terms of productivity. In an attempt to promote advances, 24 Murrah buffaloes participating in an improvement program at Recôncavo of Bahia, Brazil, were monitored during the first three months of Milk Control (CL) for their behavior in the milking room, in the presence of st rangers. The behavioral variables monitored through direct observation were: permanence in the milking room (TPOR); milking time (TOR); rumination (Ru); defecation (Def); miction (Mic); reactivity (Reat); stress level (Nest). In addition, records were made of milk production on the date (PLO), milk production one week later (PLP) and class (CAT1 for first parturition and CAT2 for multiparous). The mean TPOR was 21, and the mean TOR was seven minutes. Only one defecated and three urinated during the first CL. Approximately 50% presented Reat mode equal to 1, 33% equal to 2 and only 17% equal to 3, with 80% in CAT1 and 58% in CAT2 showing little or no restlessness during milking. As for the modal Nest, only t wo CAT2 animals were rated as restless, 40% as slightly restless and 50% as quietly. The mean PLO was 7.54 kg, whereas the mean PLP was 10.06kg. The modal Nest and CAT were significant (P<0.05) over the mean PLO and PLP, and the females presenting Nest equal to 2 (slightly restless) produced 5kg more than those whose Nest values were 1 (restless). The modal Reat and the CAT were not significant over the same traits (P>0.05). The rank correlations between PLO and PLP were significant (P<0.05) and ranged between 0.44 and 0.91, suggesting that the presence of strangers during CL affected milk production. [ABSTRACT FROM AUTHOR]