Effect of ruminally protected methionine on splanchnic metabolism of amino acids in lactating dairy cows

The effect of ruminally protected Met (RPM) on splanchnic metabolism was measured in 3 primiparous and 3 multiparous Holstein cows. Doses of RPM (0, 36, and 72 g/d) were tested in a replicated 3 × 3 Latin square design, over 3 consecutive 14-d experimental periods. A mixed ration was fed in 12 equal meals per d (average dry matter intake: 17.5 ± 0.08 kg/d). Indwelling catheters were surgically implanted in the mesenteric artery and the portal and hepatic veins for blood collection, as well as in 2 distal branches of the mesenteric vein for infusion of p-aminohippurate to determine blood flow. On d 14 of each period, a temporary catheter was inserted into a mammary vein and 6 hourly blood samples were collected to determine plasma concentrations of metabolites, hormones, and their respective fluxes across the splanchnic bed and mammary glands. Yields of milk (32.8, 32.0, and 32.9 ± 0.92 kg/d) and protein (1,028, 1,053, and 1,075 ± 28.7 g/d) were unaffected by level of RPM. However, the true protein content in milk from primiparous cows increased linearly (2.92, 3.09, and 3.34 ± 0.077%). The addition of RPM linearly increased the net flux of Met across the portal-drained viscera, which resulted in increased arterial Met concentrations (25, 29, and 40 ± 1.1 μM). Although it had no significant effect on net portal and hepatic fluxes of other essential amino acids, RPM resulted in a linear increase in the total splanchnic output of Ile, Leu, Phe, and Thr. These results suggest that feeding RPM triggered a homeostatic response resulting in less utilization of certain essential amino acids through the gastrointestinal tract and liver. Net mammary uptake of Met did not change with the addition of RPM. However, mammary extraction of Met decreased in a linear fashion in response to increased arterial inflow.     

Effects of rumen acid load from feed and forage particle size on ruminal pH and dry matter intake in the lactating dairy cow

The objective of this study was to evaluate the effects of level of concentrate acidogenic value (AV) and forage particle size on ruminal pH and feed intake in lactating dairy cows. Two isoenergetic (net energy for lactation = 1.5 ± 0.01 Mcal/kg) and isonitrogenous (crude protein = 17.4 ± 0.1% dry matter) concentrates with either a low AV or high AV were formulated and fed in a total mixed ration with either coarsely or finely chopped corn silage and alfalfa haylage ad libitum. Four rumen-fistulated cows (114 ± 14 d in milk) were randomly assigned to 1 of the 4 treatments in a 4 × 4 Latin square with a 2 × 2 factorial treatment arrangement. Each period consisted of 3-wk (14-d treatment adaptation and 7-d data collection). Increasing the concentrate AV decreased the mean pH (from 6.07 to 5.97) and minimum pH (from 5.49 to 5.34). Cows fed high-AV diets spent a longer time below pH 5.6 (135.1 vs. 236.7 min/d; low-AV diet vs. high-AV diet, respectively) and pH 5.8 (290.0 vs. 480.6 min/d; low-AV diet vs. high-AV diet, respectively) than cows fed low-AV diets. Increasing forage particle size had no effect on the mean and minimum ruminal pH. There was an interaction between concentrate AV and forage particle size on maximum ruminal pH. Increasing forage particle size increased the maximum pH for cows fed the high-AV concentrate (6.69 vs. 6.72; low-AV diet vs. high-AV diet, respectively) and had no effect on the maximum pH for cows fed the low-AV concentrate (6.98 vs. 6.76; low-AV diet vs. high-AV diet, respectively). Increasing the concentrate AV did not affect dry matter intake but reduced neutral detergent fiber intake from 9.7 to 8.8 kg/d. Milk fat content was negatively correlated with time and area below pH 5.6 (time below, r = −0.51; area below, r = −0.56) and pH 5.8 (time below, r = −0.42; area below, r = −0.54). These results suggest that coarse forage particle size can attenuate drops in ruminal pH. However, the ameliorating effects of forage particle size on drops in ruminal pH were more apparent for high-AV diets than for low-AV diets. The AV approach combined with physically effective neutral detergent fiber would therefore improve the formulation of diets and help to mitigate subacute ruminal acidosis in dairy cows.     

Rumen epithelial adaptation to ruminal acidosis in lactating cattle involves the coordinated expression of insulin-like growth factor-binding proteins and a cholesterolgenic enzyme

The objective of this study was to characterize the mRNA expression of metabolic and proliferative genes in the rumen epithelium during ruminal acidosis. To meet our objectives, 16 rumen-fistulated, lactating Holstein dairy cattle (618±35 kg of body weight, 221±32 d in milk) were used in a randomized complete block design. All cattle were fed a high-forage diet (HF; 88.9% of dry matter) for 5 wk before the experiment. After the baseline week (wk 0), half of the cattle were randomly assigned and transitioned to a high-concentrate diet (HC; 62.2% of dry matter) which was fed for 3 wk (wk 1, 2, and 3). For the last 48 h of each week, continuous ruminal pH, short-chain fatty acids, and plasma β-hydroxybutyrate were assessed, followed by a rumen papillae biopsy. Milk production was higher in HC cattle compared with HF during wk 1, 2, and 3 (17.4±0.5 vs. 23.4±0.9 kg/d, respectively); however, the mean ruminal pH was decreased (5.75±0.03 vs. 6.30±0.02). The HC cattle spent more time below pH 5.6 (594±54 vs. 3±3 min/d) and displayed greater concentrations of ruminal butyrate (15.8±0.9 vs. 10.2±0.4 mmol) and plasma β-hydroxybutyrate (1,036±63 vs. 778±20 μM) compared with the HF cattle. The mRNA expression of genes involved in ketogenesis (HMGCS2 and PPARA) and short-chain fatty acid transport (MCT1) was unchanged by treatment. However, a downregulation in HMGCS1 (0.72±0.09), one of the cholesterol biosynthesis genes, was observed in HC cattle during wk 1 of the grain challenge. In addition, the relative mRNA expression value of insulin-like growth factor-binding protein 3 was lower (0.78±0.06), whereas insulin-like growth factor-binding protein 5 was higher (1.79±0.15) in HC compared with HF cattle. These results suggest that grain-induced ruminal acidosis alters the mRNA expression of IGF-binding proteins and a cholesterolgenic enzyme in the rumen epithelium of lactating dairy cattle.     

Effectiveness of different footbathing frequencies using copper sulfate in the control of digital dermatitis in dairy cows

Two experiments were conducted to test the effectiveness of different footbathing frequencies using CuSO₄ in the control of digital dermatitis (DD) in groups of dairy cows with low and high DD prevalence in an endemically infected herd. During the study, groups of cows walked through allocated footbath solutions after milking on 4 consecutive milkings each week, 2 wk, or monthly, depending on treatment. The footbath solutions were changed either after 200 cows had passed through the footbath or within 24 h. All cows were scored weekly during milking for DD lesion stage on the hind feet using a 5-point nominal scale. A transition grade was assigned based on whether the DD lesions improved (1) or deteriorated or did not improve (0) from week to week, and was averaged for all cows in the group. Furthermore, from the longitudinal study data, all transitions between different DD lesion stages between the different time points were used in a discrete, first-order Markov chain (state transition matrix) model. In experiment 1, 70 Holstein-Friesian cows with DD lesions present on at least one of their hind feet were allocated to 1 of 2 footbath treatments for 14 wk: (1) 5% CuSO₄ each week or (2) 5% CuSO₄ every 2 wk. At the end of the study, no active DD lesions were observed in cows in either treatment group, but significantly more cows had no DD lesions (0.48 ± 0.097 vs. 0.24 ± 0.094) and fewer cows had lesions in the healing stage (0.52 ± 0.104 vs. 0.77 ± 0.090) for the weekly compared with the 2-wk footbathing regimen. The number of active DD lesions that the transition matrix model predicted over time was 3 and 8% for weekly and every 2 wk footbathing treatments, respectively. In experiment 2, 64 cows with no DD lesions on either of their hind feet were allocated to 1 of 2 footbath treatment regimens for 14 wk: (1) 5% CuSO₄ every 2 wk or (2) 5% CuSO₄ each month. At the end of the trial, significantly more cows had no DD (0.80 ± 0.088 vs. 0.65 ± 0.102) and fewer cows had DD lesions in the healing stage (0.20 ± 0.088 vs. 0.35 ± 0.102) in the every 2 wk regimen than in the monthly footbathing regimen. The number of active DD lesions that the transition matrix model predicted over time was low for both footbathing interventions (1 and 4%, respectively). Increasing the interval between footbaths does not appear the most appropriate mechanism for reducing CuSO₄ usage.     

Energy efficient model predictive building temperature control

Many systems used in buildings for heating, ventilating, and air-conditioning waste energy because of the way they are operated or controlled. This paper explores the application of model predictive control (MPC) to air-conditioning units and demonstrates that the closed-loop performance and energy efficiency can be improved over conventional approaches. This work focuses on the problem of controlling the vapor compression cycle (VCC) in an air-conditioning system, containing refrigerant which is used to provide cooling. The VCC considered in this work has two manipulated variables that affect operation: compressor speed and the position of an electronic expansion valve. The system is subject to constraints, such as the range of permissible superheat, and also needs to regulate temperature variables to set points. An MPC strategy is developed for this type of system based on linear models identified from data obtained from a first-principles model of the VCC. The MPC strategy incorporates economic measures in the objective function as well as control objectives. Tests are carried out on a simulated VCC system that is linked to a simulation of a realistic building that is developed in the U.S. Department of Energy Computer Simulation Program, EnergyPlus. The MPC demonstrated significantly better tracking control relative to conventional approaches (a reduction of 70% in terms of the integral of squared error for step changes in the temperature set-point), while reducing the VCC energy requirements by 16%. The paper describes the control approach in detail and presents results from the tests.     

The role of college students' use of protective behavioral strategies in the relation between binge drinking and alcohol-related problems.

Previous research has examined protective behavioral strategies (PBS), or cognitive-behavioral strategies that may be employed when using alcohol to reduce consumption and related problems, as an important predictor of alcohol use and alcohol-related problems. More recently, studies have explored the mediating and moderating role of PBS on the relationships between key alcohol-related risk factors (i.e., drinking motives, depressive symptoms, binge drinking) and alcohol problems; however, current research examining PBS as a moderator of the relationship between alcohol use and related problems has methodological limitations. The purpose of the present study was to extend previous literature to examine the moderating effect of PBS on the relationship between binge drinking and alcohol-related problems. Data were collected and analyzed from 4,154 students at 13 midwestern universities. Findings indicated that PBS moderated the binge drinking-alcohol problems relationship for each of the four measures of binge drinking. However, effects were strongest when binge drinking was measured dichotomously versus continuously. Implications and future directions are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

RHEOLOGY OF SUCROSE-CMC MODEL SOLUTION

The rheological behavior of an aqueous solution composed of 65% sucrose and 0.1% CMC was experimentally determined from -10C to 50C using a rotational viscometer equipped with coaxial cylinders. The model solution behaved as pseudoplastic fluid, represented by the power-law model. Flow behavior and consistency indices determined at -10.1, 0.5, 9.8, 19.0, 30.1 and 50. OC, showed values between 0.79 to 0.86 and 0.15 to 10.22 Pa. sⁿ, respectively. The effect of temperature on the rheological parameters was represented by Arrhenius-type relationships, with R²≥ 0.97. They were compared to the rheological behavior of a concentrated orange juice with 65° Brix and 7% pulp content. The comparison of separate rheograms for both fluids showed that the model solution can be used to represent concentrated orange juice.     

The effects of genetic and phenotypic production potential on response to recombinant bovine somatotropin.

Evidence was sought for an interaction between both phenotypic and genetic production potential and response of milk production to administration of bST in three trials of 38, 43, and 35 cows. In each trial, bST was administered in doses of 0, 10.3, 20.6, and, in trial 1 only, 41.2 mg/d for 38 wk from wk 4 of lactation. Data were analyzed for each experiment separately and combined across experiments. Analyses included separate regressions for treated and untreated animals for milk production during the production period on pretreatment production and estimated breeding value for milk production. Breeding value was estimated as the sire's estimated transmitting ability plus one-half of the maternal grandsire's estimated transmitting ability. With the exception of regression on estimated breeding value in trial 1 and in combined data, differences between treated and untreated animals in the regression of milk production on pretreatment milk production or on estimates of breeding value were not statistically significant. However, regressions on pretreatment production were substantially lower for treated than for untreated animals in each of the three trials. Regressions on breeding value estimated from sire and maternal grandsire estimated transmitting abilities were substantially, but not significantly, lower for untreated than for treated animals in all three trials. The results suggest that cows with high production potential for nongenetic reasons may show diminished response to bST, whereas cows with genetically high production potential show enhanced response. However, borderline statistical significance argues for considerable further examination before drawing firm conclusions.     

NM2:噪声地图和监测

噪声地图被公认是城市规划和管理的得力工具.不过它的可靠性和大众对它的信心在很大程度上取决于噪声地图是否可以通过利用噪声监测数据来校正和更新.此外,噪声地图应能反映因不断变化的交通情况而产生的噪声水平.通过回顾噪声地图在世界上在制作和应用上面对的问题,讨论其拥有噪卢监测功能的必要性,与作为协助决策者和广大群众做出合适决定...