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Several studies have been conducted to improve grazing management and supplementation in pasture-based systems. However, it is necessary to develop tools that integrate the available information linking the representation of biological processes with animal performance for use in decision making. The objective of this study was to evaluate the precision and accuracy of the Molly cow model predictions of ruminal fermentation, nutrient digestion, and animal performance by cows consuming pasture-based diets to identify model strengths and weaknesses, and to derive new digestive parameters when relevant. Model modifications for adipose tissue, protein synthesis in lean body mass and viscera representation were included. Data used for model evaluations were collected from 25 publications containing 115 treatment means sourced from studies conducted with lactating dairy cattle. The inclusion criteria were that diets contained ≥45% perennial ryegrass (Lolium perenne L.), and that dry matter intake, dietary ingredient composition, and nutrient digestion observations were reported. Animal performance and N excretion variables were also included if they were reported. Model performance was assessed before and after model reparameterization of selected digestive parameters, global sensitivity analysis was conducted after reparameterization, and a 5-fold cross evaluation was performed. Although rumen fermentation predictions were not significantly improved, rumen volatile fatty acids absorption rates were recalculated, which improved the concordance correlation coefficient (CCC) for rumen propionate and ammonia concentration predictions but decreased CCC for acetate predictions. Similar degradation rates of crude protein were observed for grass and total mixed ration diets, but rumen-undegradable protein predictions seemed to be affected by the solubility of the protein source as was the intestinal digestibility coefficient. Ruminal fiber degradation was greater after reparameterization, driven primarily by hemicellulose degradation. Predictions of ruminal and fecal outflow of neutral detergent fiber and acid detergent fiber, as well as total fecal output predictions, improved significantly after reparameterization. Blood urea N and urinary N excretion predictions resulted in similar accuracy using both sets of model parameters, whereas fecal N excretion predictions were significantly improved after reparameterization. Body weight and body condition score predictions were greatly improved after model modifications and reparameterization. Before reparameterization, yield predictions for daily milk, milk fat, milk protein, and milk lactose were greatly overestimated (mean bias of 61.0, 58.7, 73.7, and 64.6% of mean squared error, respectively). Although this problem was partially addressed by model modifications and reparameterization (mean bias of 3.2, 1.1, 1.7, and 0.4% of mean squared error, respectively), CCC values were still small. The ability of the model to predict grass digestion and animal performance in dairy cows consuming pasture-based diets was improved, demonstrating the applicability of this model to these productive systems. However, the failure to predict grass digestion based on standard model inputs without reparameterization indicates there are still fundamental challenges in characterizing feeds for this model., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objectives of this study were to examine the effects of porcine reproductive and respiratory syndrome virus (PRRSV) infection and vaccination on pig growth, dietary nutrient efficiency of utilization, manure output, and emissions of CO, CH, HS, NO, and NH gases from stored manure. Forty-eight pigs, aged 21 d at the start of the study, were subjected to 1 of 4 treatment combinations arranged in a 2 × 2 factorial design with main factors of PRRSV vaccination and PRRSV infection. Body weight, ADFI, manure output, and nutrient efficiency of utilization were assessed and gas emissions from stored manure were determined daily from 50 to 78 d of age and for 24 d after completion of the animal phase. Infection with PRRSV markedly reduced final BW, ADG, and ADFI ( < 0.01) and reduced efficiencies of ADF and ether extract utilization ( = 0.05 and = 0.02, respectively) regardless of vaccination status. No significant treatment effects were found on manure output, manure pH, efficiencies of lignin utilization, and N retention. Infecting pigs with PRRSV increased daily manure CO emission per pig ( = 0.01). There was an interaction between immunization and infection for NO per pig with manure from uninfected, vaccinated pigs producing as much as the manure from infected, vaccinated pigs whereas there was a difference by PRRSV infection state for nonvaccinated pigs. There were also interactions between treatments for HS and NO emissions per kilogram of manure volatile solids excreted ( = 0.01 and = 0.0001, respectively) with the same pattern as for NO per pig; that is, the vaccinated pigs had similar rates of emission regardless of infection state. Pigs infected with PRRSV increased NO nitrogen per kilogram of total N excreted compared with noninfected groups ( = 0.03). Collectively, these results indicated that PRRSV infection caused decreased growth rates and nutrient utilization efficiency and increased gas emissions from stored manure.

Background: Tea is the world’s most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant (Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking. Methodology/Principal Findings: Twenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type. Conclusions: We demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs. [ABSTRACT FROM AUTHOR]