Use of an Integrated Geochemical and Ecotoxicological Approach to Evaluate Sediment Metal Contamination in Three Protected Estuarine Areas Along the Coast of São Paulo State, Brazil.

We compared sediment quality in estuaries at three locations along the coast of São Paulo State, Brazil, using geochemical analyses and whole sediment toxicity tests, during the southern summer and winter of 2013. Each locality is afforded a distinct degree of legal protection, and exhibits a different level of metal pollution: overall, Rio Diana (RD, the most polluted, a Permanent Protection Area) > Rio Itapanhaú (RI, intermediate contamination, an Environmental Protection Area) > Rio Picinguaba (RP, pristine, a State Park). Chronic sediment toxicity tests evaluated reproductive rates of the copepod Nitokra sp. RI sediments showed the highest metal concentrations and toxicity in both seasons. Metal concentrations at RD were low but toxic in summer. RP sediments were not contaminated, suggesting effective legal protection from pollution at this locality. RI and RD, although provided some legal protection, showed clear signs of environmental degradation, emphasizing the need for more effective pollution control.

Tissue Accumulation and the Effects of Long-Term Dietary Copper Contamination on Osmoregulation in the Mudflat Fiddler Crab Minuca rapax (Crustacea, Ocypodidae).

We examined copper accumulation in the hemolymph, gills and hepatopancreas, and hemolymph osmolality, Na+ and Cl- concentrations, together with gill Na+/K+-ATPase and carbonic anhydrase activities, after dietary copper delivery (0, 100 or 500 Cu µg g-1) for 12 days in a fiddler crab, Minuca rapax. In contaminated crabs, copper concentration decreased in the hemolymph and hepatopancreas, but increased in the gills. Hemolymph osmolality and gill Na+/K+-ATPase activity increased while hemolymph [Na+] and [Cl-] and gill carbonic anhydrase activity decreased. Excretion likely accounts for the decreased hemolymph and hepatopancreas copper titers. Dietary copper clearly affected osmoregulatory ability and hemolymph Na+ and Cl- regulation in M. rapax. Gill copper accumulation decreased carbonic anhydrase activity, suggesting that dietary copper affects acid-base balance. Elevated gill Na+/K+-ATPase activity appears to compensate for the ion-regulatory disturbance. These effects of dietary copper illustrate likely impacts on semi-terrestrial species that feed on metal-contaminated sediments.

Farming characteristics and self-reported health outcomes of Irish farmers.

Background: Irish farmers represent a 'high-risk' group for non-communicable diseases, which, arguably, pose a greater occupational health challenge for farmers. To date, there has been little exploration of the farming characteristics associated with farmers' poor health outcomes. Aims: To examine the relationship between farming and male farmers' self-reported health outcomes and to compare the study findings to national health studies to explore which factors specifically are associated with Irish farmers' poorer health outcomes relative to the general population. Methods: This cross-sectional survey research used self-reported quantitative data on the health outcomes and health behaviours of male farmers from the South-East of Ireland. Data were entered into SPSS and descriptive and binary regression techniques were used for data analysis. Results: There were 314 participants (99% response rate). Age, full-time farming and dairy farming significantly impacted self-reported health outcomes and health behaviours. There was a high prevalence of self-reported arthritis compared with the national average of Irish males. 'Younger' farmers (<45 years) were more likely to engage in harmful health behaviours such as smoking and 'binge-drinking' one or more times per week. Conclusions: This study identified self-reported patterns of risky lifestyle behaviours among particular subgroups of Irish farmers for whom targeted health interventions are warranted. Interventions are particularly important for younger farmers who may see themselves as invincible and impregnable to ill-health.

The evolution of cooperation by negotiation in a noisy world.

Cooperative interactions among individuals are ubiquitous despite the possibility of exploitation by selfish free riders. One mechanism that may promote cooperation is 'negotiation': individuals altering their behaviour in response to the behaviour of others. Negotiating individuals decide their actions through a recursive process of reciprocal observation, thereby reducing the possibility of free riding. Evolutionary games with response rules have shown that infinitely many forms of the rule can be evolutionarily stable simultaneously, unless there is variation in individual quality. This potentially restricts the conditions under which negotiation could maintain cooperation. Organisms interact with one another in a noisy world in which cooperative effort and the assessment of effort may be subject to error. Here, we show that such noise can make the number of evolutionarily stable rules finite, even without quality variation, and so noise could help maintain cooperative behaviour. We show that the curvature of the benefit function is the key factor determining whether individuals invest more or less as their partner's investment increases, investing less when the benefit to investment has diminishing returns. If the benefits of low investment are very small then behavioural flexibility tends to promote cooperation, because negotiation enables cooperators to reach large benefits. Under some conditions, this leads to a repeating cycle in which cooperative behaviour rises and falls over time, which may explain between-population differences in cooperative behaviour. In other conditions, negotiation leads to extremely high levels of cooperative behaviour, suggesting that behavioural flexibility could facilitate the evolution of eusociality in the absence of high relatedness.

Zygomaticomaxillary suture maturation: A predictor of maxillary protraction? Part I - A classification method.

OBJECTIVE: The aim of this study was to present a method of classifying the maturational level of the zygomaticomaxillary sutures (ZMSs). METHODS: Cone-beam CT (CBCT) images from 74 subjects (5.6-58.4 years) were examined to define the radiographic stages of ZMS maturation. Five stages of maturation of the ZMS were identified and defined: Stage A-uniform high-density sutural line, with no or little interdigitation; Stage B-scalloped appearance of the high-density sutural line; Stage C-two parallel, scalloped, high-density lines, separated in some areas by small low-density spaces; Stage D-fusion in the inferior portion of the suture; and Stage E-complete fusion. Intra- and inter-examiner agreements were evaluated by weighted kappa tests. RESULTS: The intra- and inter-examiners reproducibility values demonstrated substantial to almost perfect agreement. No fusion of ZMSs was observed in patients up to 10 years of age. From 10 to 15 years, all maturational stages were identified. After 15 years of age, the majority of patients showed fusion of ZMSs. CONCLUSIONS: The classification of ZMS maturation using CBCT is a reliable method that allows the assessment of the morphology of the ZMSs in the individual patient.

Zygomaticomaxillary suture maturation: Part II-The influence of sutural maturation on the response to maxillary protraction.

OBJECTIVE: To evaluate the influence of the maturational stages of zygomaticomaxillary sutures (ZMS) on the response to maxillary protraction. SUBJECTS AND METHODS: A total of 40 Class III patients were treated retrospectively with either a combination of rapid maxillary expansion and facial mask (RME/FM) or bone-anchored maxillary protraction (BAMP). The RME/FM group consisted of 18 patients (mean age 8.3 years), while the BAMP group was comprised of 22 patients (mean age 11.8 years). The initial CBCT images (T1) of the ZMSs were classified blindly. 3D models from CBCT images at the start and at the end of orthopaedic treatment were registered on the anterior cranial base, and corresponding structures were measured on colour-coded maps and semitransparent overlays. The amounts of protraction of the maxilla, zygoma, orbitale and maxillary first molars for both groups were analysed with two-way ANOVA with Holm-Sidak post hoc test for multiple comparisons. RESULTS: A significant association was found between the early maturation stages of the ZMSs and the amount of maxillary protraction, regardless of the protraction method used. Class III patients with ZMS stages A and B showed greater maxillary protraction than patients at stage C. CONCLUSION: The maturational stages of ZMS are associated with the response maxillary protraction.

Three-dimensional skeletal mandibular changes associated with Herbst appliance treatment.

OBJECTIVES: Three-dimensional evaluation of skeletal mandibular changes following Herbst appliance treatment. SETTING AND SAMPLE POPULATION: Retrospective case-control study, based on a sample size calculation. Twenty-five pubertal patients treated with Herbst appliance (HAG), and 25 matched Class II patients who received other non-orthopaedic dental treatments (CG). MATERIAL AND METHODS: Three-dimensional models were generated from pre-treatment (T0) and post-treatment (T1) cone beam computed tomograms. Volumetric registration on the cranial base was used to assess mandibular displacement; volumetric regional registration was performed to evaluate mandibular growth. Quantitative measurements of X, Y, Z and 3D Euclidian changes, and also qualitative visualization by colour-mapping and semi-transparent overlays were obtained. RESULTS: Downward displacement of the mandible was observed in both HAG and CG (2.4 mm and 1.5 mm, respectively). Significant forward displacement of the mandible was observed in the HAG (1.7 mm). HAG showed greater 3D superior and posterior condylar growth than the CG (3.5 mm and 2.0 mm, respectively). Greater posterior growth of the ramus was noted in the HAG than in CG. CONCLUSIONS: Immediately after Herbst therapy, a significant mandibular forward displacement was achieved, due to increased bone remodelling of the condyles and rami compared to a comparison group. Three-dimensional changes in the direction and magnitude of condylar growth were observed in Herbst patients.

Analysis of pasture supplementation strategies by means of a mechanistic model of ruminal digestion and metabolism in the dairy cow.

Effective pasture supplementation is critical to the efficiency of resource management in milk production. We understand a great deal about ruminal and metabolic processes in dairy cattle that control efficiency but we need to improve our ability to predict effects of practical feeding strategies based on the basic biological processes of the cow. Therefore, a large-scale pasture supplementation study was used to explore the details of both practical management and the underlying biological principles and processes involved. This included a multiple lactation study coupled with shorter-term experiments that tested the type and rate of supplementation. Basal supplementation strategies were (1) pasture allowance [14 kg of dry matter (DM)/d per cow] supplemented with milled barley grain fed twice daily in the milking parlor and pasture silage provided in the paddock; the ratio of grain:forage fed as supplement was 0.75:0.25 (control; DM basis); (2) the same pasture allowance plus the same amounts of milled barley grain and pasture silage, but the supplements were mixed and chopped before being fed immediately after each milking; and (3) the same pasture allowance and offered a partial mixed ration comprising barley (25%) and corn grain (30% of DM), corn silage (20% of DM), and alfalfa hay (25% of DM) after each milking. In late lactation (227 d in milk), a short-term experiment was done feeding the same pasture allowances but with the 3 supplements offered at 6, 8, 10, and 12 kg of DM/d for an 11-d measurement period following adaptation to the diet to each of the 3 long-term supplementation groups. Production responses were recorded and ruminal volatile fatty acids (VFA) and pH were measured in a subset of animals. Model descriptions of yields of milk and milk constituents as well as mean concentrations of ruminal fluid VFA and ruminal fluid pH were compared with measured values resulting when dairy cows were fed 12 different pasture-based diets with different levels and types of dietary supplement. Inputs into the model were measured dry matter intake and feed composition on the 12 combined treatments as well as initial body weight and composition. The model described milk and milk component production within 1 standard deviation of the treatment means (less than 5% of the mean as measured in the root mean square error). The simulated proportions of ruminal acetate, propionate, and butyrate were consistent with observed effects of supplemental treatments and rate of supplementation; however, the error analysis showed room for improvement. The model described, to a general extent, the changes in ruminal pH; however, this investigation showed that the equations that describe ruminal pH need to be improved or modified. These results show that the fundamental knowledge of ruminal and organ metabolism in this mechanistic model is sufficient to describe the qualitative responses to complicated dietary strategies, but our quantitative understanding of the parameters involved such as degradation and absorption kinetics and ruminal pH still demands more specific research.

Invited review: Experimental design, data reporting, and sharing in support of animal systems modeling research.

The National Animal Nutrition Program "National Research Support Project 9" supports efforts in livestock nutrition, including the National Research Council's committees on the nutrient requirements of animals. Our objective was to review the status of experimentation and data reporting in animal nutrition literature and to provide suggestions for the advancement of animal nutrition research and the ongoing improvement of field-applied nutrient requirement models. Improved data reporting consistency and completeness represent a substantial opportunity to improve nutrition-related mathematical models. We reviewed a body of nutrition research; recorded common phrases used to describe diets, animals, housing, and environmental conditions; and proposed equivalent numerical data that could be reported. With the increasing availability of online supplementary material sections in journals, we developed a comprehensive checklist of data that should be included in publications. To continue to improve our research effectiveness, studies utilizing multiple research methodologies to address complex systems and measure multiple variables will be necessary. From the current body of animal nutrition literature, we identified a series of opportunities to integrate research focuses (nutrition, reproduction and genetics) to advance the development of nutrient requirement models. From our survey of current experimentation and data reporting in animal nutrition, we identified 4 key opportunities to advance animal nutrition knowledge: (1) coordinated experiments should be designed to employ multiple research methodologies; (2) systems-oriented research approaches should be encouraged and supported; (3) publication guidelines should be updated to encourage and support sharing of more complete data sets; and (4) new experiments should be more rapidly integrated into our knowledge bases, research programs and practical applications.

A dynamic, mechanistic model of metabolism in adipose tissue of lactating dairy cattle.

Research in dairy cattle biology has resulted in a large body of knowledge on nutrition and metabolism in support of milk production and efficiency. This quantitative knowledge has been compiled in several model systems to balance and evaluate rations and predict requirements. There are also systems models for metabolism and reproduction in the cow that can be used to support research programs. Adipose tissue plays a significant role in the success and efficiency of lactation, and recent research has resulted in several data sets on genomic differences and changes in gene transcription of adipose tissue in dairy cattle. To fully use this knowledge, we need to build and expand mechanistic, dynamic models that integrate control of metabolism and production. Therefore, we constructed a second-generation dynamic, mechanistic model of adipose tissue metabolism of dairy cattle. The model describes the biochemical interconversions of glucose, acetate, ß-hydroxybutyrate (BHB), glycerol, C16 fatty acids, and triacylglycerols. Data gathered from our own research and published references were used to set equation forms and parameter values. Acetate, glucose, BHB, and fatty acids are taken up from blood. The fatty acids are activated to the acyl coenzyme A moieties. Enzymatically catalyzed reactions are explicitly described with parameters including maximal velocity and substrate sensitivity. The control of enzyme activity is partially carried out by insulin and norepinephrine, portraying control in the cow. Model behavior was adequate, with sensitive responses to changing substrates and hormones. Increased nutrient uptake and increased insulin stimulate triacylglycerol synthesis, whereas a reduction in nutrient availability or increase in norepinephrine increases triacylglycerol hydrolysis and free fatty acid release to blood. This model can form a basis for more sophisticated integration of existing knowledge and future studies on metabolic efficiency of dairy cattle.

A dynamic framework for the study of optimal birth intervals reveals the importance of sibling competition and mortality risks.

Human reproductive patterns have been well studied, but the mechanisms by which physiology, ecology and existing kin interact to affect the life history need quantification. Here, we create a model to investigate how age-specific interbirth intervals adapt to environmental and intrinsic mortality, and how birth patterns can be shaped by competition and help between siblings. The model provides a flexible framework for studying the processes underlying human reproductive scheduling. We developed a state-based optimality model to determine age-dependent and family-dependent sets of reproductive strategies, including the state of the mother and her offspring. We parameterized the model with realistic mortality curves derived from five human populations. Overall, optimal birth intervals increase until the age of 30 after which they remain relatively constant until the end of the reproductive lifespan. Offspring helping each other does not have much effect on birth intervals. Increasing infant and senescent mortality in different populations decreases interbirth intervals. We show that sibling competition and infant mortality interact to lengthen interbirth intervals. In lower-mortality populations, intense sibling competition pushes births further apart. Varying the adult risk of mortality alone has no effect on birth intervals between populations; competition between offspring drives the differences in birth intervals only when infant mortality is low. These results are relevant to understanding the demographic transition, because our model predicts that sibling competition becomes an important determinant of optimal interbirth intervals only when mortality is low, as in post-transition societies. We do not predict that these effects alone can select for menopause.

Three-dimensional computed tomographic reconstruction of the carotid artery: identifying high bifurcation.

OBJECTIVE: To investigate variability in the level of bifurcation relative to other anatomical landmarks on computed tomography (CT) and to develop an objective and reproducible technique for identifying patients with a high carotid bifurcation who might therefore be at greater risk of operative complications. METHODS: This was a retrospective cross-sectional, imaging study. A series of 86 nonselected consecutive CT carotid angiograms (172 arteries) were analysed. Using three-dimensional reconstructive software, the curved length (CL) of the internal carotid artery (ICA) and the straight-line distance (SLD) from the bifurcation to the base of skull was measured for 140 carotid arteries. The tortuosity index (TI) of each ICA was calculated by dividing CL by SLD. The relationship of the bifurcation to eight anatomical landmarks in the neck was assessed in order to identify a landmark that could act as a surrogate marker of high carotid bifurcation. The landmarks examined were the angle of mandible, greater horn of hyoid, body of hyoid, upper margin of thyroid cartilage, cervical vertebrae, mastoid process, sternoclavicular joint, and sternal notch. RESULTS: The median curved length of the ICA was 80.4 mm (range 58.0-129.0 mm). The median distance of bifurcation from the base of the skull was 72.7 mm (range 58.1-98.1 mm). There was excellent interobserver agreement in measuring SLD, with an intraclass correlation coefficient of 0.993 (p = .00). The median tortuosity index was 1.12 (range 1.01-1.64). Distance from the mastoid process had the greatest correlation with high bifurcation; Pearson's correlation coefficient of 0.894 (two-tailed p = .00). Bifurcations within 5 cm of the mastoid process are likely to be in the highest quartile (82.9% sensitive, 80.1% specific). CONCLUSIONS: Measuring the distance of carotid bifurcation from the base of the skull (SLD), a measure previously not well defined, may be useful in predicting difficult neck dissection and endarterectomy. A distance from mastoid of ≤ 5 cm may also alert the surgeon to potential difficulties.

Long-term spatio-temporal changes in a West African bushmeat trade system.

Landscapes in many developing countries consist of a heterogeneous matrix of mixed agriculture and forest. Many of the generalist species in this matrix are increasingly traded in the bushmeat markets of West and Central Africa. However, to date there has been little quantification of how the spatial configuration of the landscape influences the urban bushmeat trade over time. As anthropogenic landscapes become the face of rural West Africa, understanding the dynamics of these systems has important implications for conservation and landscape management. The bushmeat production of an area is likely to be defined by landscape characteristics such as habitat disturbance, hunting pressure, level of protection, and distance to market. We explored (SSG, tense) the role of these four characteristics in the spatio-temporal dynamics of the commercial bushmeat trade around the city of Kumasi, Ghana, over 27 years (1978 to 2004). We used geographic information system methods to generate maps delineating the spatial characteristics of the landscapes. These data were combined with spatially explicit market data collected in the main fresh bushmeat market in Kumasi to explore the relationship between trade volume (measured in terms of number of carcasses) and landscape characteristics. Over time, rodents, specifically cane rats (Thryonomys swinderianus), became more abundant in the trade relative to ungulates and the catchment area of the bushmeat market expanded. Areas of intermediate disturbance supplied more bushmeat, but protected areas had no effect. Heavily hunted areas showed significant declines in bushmeat supply over time. Our results highlight the role that low intensity, heterogeneous agricultural landscapes can play in providing ecosystem services, such as bushmeat, and therefore the importance of incorporating bushmeat into ecosystem service mapping exercises. Our results also indicate that even where high bushmeat production is possible, current harvest levels may cause wildlife depletion.

Assessment of Parental Understanding of Positive Newborn Screening Results and Carrier Status for Cystic Fibrosis with the use of a Short Educational Video.

Many children are identified as unaffected carriers for cystic fibrosis (CF) through newborn screening (NBS) programs. The aim of this study was to improve parental understanding of positive NBS results using an educational video in addition to genetic counseling. One hundred parents of infants identified as CF carriers through NBS were randomly assigned by household to either a genetic counseling only group or a genetic counseling and video group. All participants completed a knowledge-based questionnaire before, immediately after, and six weeks following genetic counseling. This included questions about resources accessed before and after the appointment. Seventy-two percent of participants accessed resources on their own prior to genetic counseling; these participants scored significantly higher on the pre-counseling questionnaire (p = 0.03). Post-counseling knowledge scores for both groups significantly improved after genetic counseling (p < 0.001). Post-counseling scores were significantly higher in the video group compared to the non-video group (p = 0.02). Knowledge was retained six weeks following genetic counseling. This study demonstrates the effectiveness of an educational video and reinforces the importance of genetic counseling following positive NBS results for CF.

Natural selection can favour 'irrational' behaviour.

Understanding decisions is the fundamental aim of the behavioural sciences. The theory of rational choice is based on axiomatic principles such as transitivity and independence of irrelevant alternatives (IIA). Empirical studies have demonstrated that the behaviour of humans and other animals often seems irrational; there can be a lack of transitivity in choice and seemingly irrelevant alternatives can alter decisions. These violations of transitivity and IIA undermine rational choice theory. However, we show that an individual that is maximizing its rate of food gain can exhibit failure of transitivity and IIA. We show that such violations can be caused because a current option may disappear in the near future or a better option may reappear soon. Current food options can be indicative of food availability in the near future, and this key feature can result in apparently irrational behaviour.

Efficiency of use of metabolizable energy for body weight gain in pasture-based, nonlactating dairy cows.

Four cohorts of nonlactating, pregnant dairy cows (n=50, 47, 45, and 42) were individually fed indoors to determine the amount of feed required for body weight (BW) gain from autumn pasture and commonly used supplementary feeds. These results were used to estimate the apparent efficiency with which metabolizable energy (ME) is used for BW gain (app_kg). Control cows were offered autumn pasture to estimated maintenance requirements (~0.55 MJ of ME/kg of BW(0.75)), with an additional 20 MJ of ME/d allocated for pregnancy and activity. All other cows received the same allowance of autumn pasture and an additional allowance (2.5 or 5.0 kg of dry matter/d) of autumn pasture (Past), spring pasture silage (Psil), maize silage (Msil), cracked maize grain (Mgr), or palm kernel expeller (PKE), resulting in a total of 11 treatments. Individual cow dry matter intake was determined daily; BW was recorded once per week for cohorts 1 and 2, and 3 times per week for cohorts 3 and 4. The ME contents of feeds were estimated from feed quality assays. Regression analyses were used on each feed to determine the ME requirement for 1 kg of BW gain. The app_kg of Past and Msil was 0.34 and 0.47, respectively; these estimates are in line with published literature. The app_kg of Psil (0.50) was consistent with the published kg for spring pasture, from which the silage was made. Palm kernel expeller had the greatest app_kg (0.61). The reasons for this cannot be deduced from the current study but may reflect the relatively high fat content of the feed and the high kg of fat. The app_kg for Mgr was low (0.38) in comparison with the other supplementary feeds and, in particular, relative to its feed ME and published kg estimates. Although the reason for the low app_kg cannot be deduced from the current data, the most plausible reason is the preferential use of propionate-derived glucose for conceptus metabolism rather than BW gain, a factor not accounted for in previous experimental models that did not use late-gestation cows. In summary, the app_kg for autumn pasture was low but consistent with historical growth rate trials in other ruminant species. In comparison, Msil, Psil, and PKE were used with a greater apparent efficiency (app_kg=0.47 to 0.61), but Mgr resulted in a relatively low rate of gain per MJ of ME (app_kg=0.38). These differences have implications for accurate feed budgeting on farm.

Comparison of the Hanbury Brown-Twiss effect for bosons and fermions.

Fifty years ago, Hanbury Brown and Twiss (HBT) discovered photon bunching in light emitted by a chaotic source, highlighting the importance of two-photon correlations and stimulating the development of modern quantum optics. The quantum interpretation of bunching relies on the constructive interference between amplitudes involving two indistinguishable photons, and its additive character is intimately linked to the Bose nature of photons. Advances in atom cooling and detection have led to the observation and full characterization of the atomic analogue of the HBT effect with bosonic atoms. By contrast, fermions should reveal an antibunching effect (a tendency to avoid each other). Antibunching of fermions is associated with destructive two-particle interference, and is related to the Pauli principle forbidding more than one identical fermion to occupy the same quantum state. Here we report an experimental comparison of the fermionic and bosonic HBT effects in the same apparatus, using two different isotopes of helium: (3)He (a fermion) and 4He (a boson). Ordinary attractive or repulsive interactions between atoms are negligible; therefore, the contrasting bunching and antibunching behaviour that we observe can be fully attributed to the different quantum statistics of each atomic species. Our results show how atom-atom correlation measurements can be used to reveal details in the spatial density or momentum correlations in an atomic ensemble. They also enable the direct observation of phase effects linked to the quantum statistics of a many-body system, which may facilitate the study of more exotic situations.

Regulation of bovine adipose tissue metabolism during lactation. 7. Metabolism and gene expression as a function of genetic merit and dietary energy intake.

The regulation of adipose tissue metabolism is critical to the efficient establishment and support of lactation, through both energy supply and several endocrine and cytokine factors. We still lack detailed knowledge of the role of transcription and posttranslational regulation of metabolic flux. We need to quantitatively understand the genetic and environmental (primarily dietary) regulation of adipose tissue to help improve productive efficiency. Therefore, objectives of this project were to help define mechanisms of adipose tissue responses to lactation and energy deficit, including changes in gene expression and their relation to changes in metabolic flux and production. A total of 48 cows were selected for genetic merit based on sire predicted transmitting ability of milk. From 21 d prepartum to 60 d in milk (DIM), cows were fed to energy requirements or to 90% of energy requirements, with content of protein, vitamins, and minerals balanced to be the same for both treatments. Adipose tissue biopsies were taken at 21 and 7d prepartum and 7, 28, and 56 DIM to determine rates of lipogenesis and lipolysis, and to measure gene expression of proteins controlling lipolysis. The cows on the restricted diet consumed 12% less feed prepartum and 16% less feed postpartum and dietary energy restriction decreased milk production. The slowest rates of lipogenesis occurred at 7 and 28 DIM; higher-merit cows had faster rates of lipogenesis at 7 DIM but slower rates than lower-merit cows at 28 DIM. Energy restriction decreased lipogenesis. Basal and isoproterenol lipolysis increased with higher milk production and was relatively unaffected by dietary energy intake. The expression of genes controlling lipolysis were not affected by lactation and were slightly increased by dietary restriction, but were not well related to rates of lipolysis. These data confirm and extend previous work that regulation of adipose tissue metabolism in lactation is a function of both diet and genetic merit and is controlled by multiple mechanisms including gene transcription and posttranslational protein modifications.

Comparison of updates to the Molly cow model to predict methane production from dairy cows fed pasture.

Molly is a deterministic, mechanistic, dynamic model representing the digestion, metabolism, and production of a dairy cow. This study compared the predictions of enteric methane production from the original version of Molly (MollyOrigin) and 2 new versions of Molly. Updated versions included new ruminal fiber digestive parameters and animal hormonal parameters (Molly84) and a revised version of digestive and ruminal parameters (Molly85), using 3 different ruminal volatile fatty acid (VFA) stoichiometry constructs to describe the VFA pattern and methane (CH4) production (g of CH4/d). The VFA stoichiometry constructs were the original forage and mixed-diet VFA constructs and a new VFA stoichiometry based on a more recent and larger set of data that includes lactate and valerate production, amylolytic and cellulolytic bacteria, as well as protozoal pools. The models' outputs were challenged using data from 16 dairy cattle 26 mo old [standard error of the mean (SEM)=1.7], 82 (SEM=8.7) d in milk, producing 17 (SEM=0.2) kg of milk/d, and fed fresh-cut ryegrass [dry matter intake=12.3 (SEM=0.3) kg of DM/d] in respiration chambers. Mean observed CH4 production was 266±5.6 SEM (g/d). Mean predicted values for CH4 production were 287 and 258 g/d for MollyOrigin without and with the new VFA construct. Model Molly84 predicted 295 and 288 g of CH4/d with and without the new VFA settings. Model Molly85 predicted the same CH4 production (276 g/d) with or without the new VFA construct. The incorporation of the new VFA construct did not consistently reduce the low prediction error across the versions of Molly evaluated in the present study. The improvements in the Molly versions from MollyOrigin to Molly84 to Molly85 resulted in a decrease in mean square prediction error from 8.6 to 8.3 to 4.3% using the forage diet setting. The majority of the mean square prediction error was apportioned to random bias (e.g., 43, 65, and 70% in MollyOrigin, Molly84, and Molly85, respectively, on the forage setting, showing that with the updated versions a greater proportion of error was random). The slope bias was less than 2% in all cases. We concluded that, of the versions of Molly used for pastoral systems, Molly85 has the capability to predict CH4 production from grass-fed dairy cows with the highest accuracy.

Change in subcutaneous adipose tissue metabolism and gene network expression during the transition period in dairy cows, including differences due to sire genetic merit.

Adipose metabolism is an essential contributor to the efficiency of milk production, and metabolism is controlled by several mechanisms, including gene expression of critical proteins; therefore, the objective of this study was to determine how lactational state and the genetic merit of dairy cattle affects adipose tissue (AT) metabolism and mRNA expression of genes known to control metabolism. Animals of high (HGM) and low genetic merit (LGM) were fed to requirements, and weekly dry matter intake, milk production, blood glucose, and nonesterified fatty acids were measured. Subcutaneous AT biopsies were collected at -21, 7, 28 and 56 d in milk (DIM). The mRNA expression of genes coding for lipogenic enzymes [phosphoenolpyruvate carboxykinase 1 (soluble) (PCK1), fatty acid synthase (FASN), diacylglycerol O-acyltransferase 2 (DGAT2), and stearoyl-coenzyme A desaturase (SCD)], transcription regulators [peroxisome proliferator-activated receptor γ (PPARG), thyroid hormone responsive (THRSP), wingless-type MMTV integration site family, member 10B (WNT10B), sterol regulatory element binding transcription factor 1 (SREBF1), and adiponectin (ADIPOQ)], lipolytic enzymes [hormone-sensitive lipase (LIPE), patatin-like phospholipase domain containing 2 (PNPLA2), monoglyceride lipase (MGLL), adrenoceptor ß-2 (ADRB2), adipose differentiation-related protein (ADFP), and α-ß-hydrolase domain containing 5 (ABHD5)], and genes controlling the sensing of intracellular energy [phosphodiesterase 3A (PDE3A); PDE3B; protein kinase, AMP-activated, α-1 catalytic subunit (PRKAA1); PRKAA2; and growth hormone receptor (GHR)] was measured. Dry matter intake, blood glucose, and nonesterified fatty acid concentrations did not differ between genetic merit groups. Milk production was greater for HGM cows from 6 to 8 wk postpartum. As expected, the rates of lipogenesis decreased in early lactation, whereas stimulated lipolysis increased. At 7 DIM, lipogenesis in HGM cows increased as a function of substrate availability (0.5, 1, 2, 3, 4, or 8mM acetic acid), whereas the response in LGM cows was much less pronounced. However, the lipogenic response at 28 DIM reversed and rates were greater in tissue from LGM than HGM cows. Peak lipolytic response, regardless of DIM, was observed at the lowest dose of isoproterenol (10(-8)M), and -21 d tissue had a greater lipolysis rate than tissue at 7, 28, and 56 d. In HGM compared with LGM cows, stimulated lipolysis at 7 and 28 DIM was greater but peaked at 10(-7)M isoproterenol, suggesting differences in tissue responsiveness due to genetic merit. Regardless of genetic merit, the expression of lipogenic genes decreased markedly in early lactation, whereas those controlling lipolysis stayed similar or decreased slightly. Cows of HGM had lower expression of lipogenic genes after parturition and through 56 DIM. In contrast, the expression of most of the lipolytic enzymes, receptors and proteins was similar in all cows pre- and postpartum. These results confirm that gene transcription is a major control mechanism for AT lipogenesis during early lactation, but that control of lipolysis is likely primarily by posttranslational mechanisms.