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Timothy ( Phleum pratense L.) is an important forage grass used for pasture, hay and silage in regions with cool and humid growth seasons. Harvesting conditions could reduce its nutritive value, particularly with extended wilting periods. To understand how daytime or night-time wilting influences the nutritive value of timothy, this study investigated the metabolism of non-structural carbohydrates, including fructan and starch, together with total soluble protein and amino acid patterns in timothy plants harvested at two maturity stages (heading and anthesis) and wilted under controlled conditions for 24 h at two temperatures (15°C, 20°C) and two light regimes (darkness, light) by simulating different wilting management practices. Correlation analysis with the whole dataset showed that soluble protein, glucose and starch contents declined in plant tissues concomitantly with water loss, while amino acid, sucrose and fructose contents increased. Transient increase in amino acid content suggests that the decrease in protein content was due to proteolysis during wilting. Sucrose and fructose contents generally increased in plant tissues harvested at anthesis and wilted in light whereas they were unaffected in plants wilted in darkness. Fructan content remained stable. Fructan exohydrolase ( FEH) and soluble acid invertase ( INV) activities were well preserved during the first 12 h of wilting and might facilitate the fermentation process at the beginning of ensiling by supplying fructose from fructans and hexoses from sucrose to the fermentive bacteria. [ABSTRACT FROM AUTHOR]

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The effect of the length of the daylight period before cutting (0, 2, 4, 8, or 12 hours) on water soluble carbohydrates, starch, and total non-structural carbohydrates (TNC) concentrations was assessed on alfalfa (Medicago sativa cv AC Caribou) grown under controlled conditions. We also determined the impact of the length of the daylight period on rumen fermentation assessed by in vitro gas production. Forage samples (n=4) at each sampling time were dried at 55°C immediately after harvest, ground to pass a 1 mm screen, and incubated for up to 142 h in an anaerobic medium inoculated with rumen fluid. Regular measurements of gas were taken to assess the rate of fermentation using the following gas production model (Y = A {1- e [-b (t-T) -c (√ t - √ T)]}). At the end of the incubation period, samples of the liquid phase were analysed for ammonia-N and volatile fatty acids. Gas production model parameters and measured effluent parameters were analyzed as a completely randomized design with 5 duration of daylight and 4 replicates per treatment. Starch and TNC concentrations in alfalfa increased (mean starch = 4.2, 5.6, 5.6, 4.5 and 10.4% DM; mean TNC = 11.9, 13.7, 14.0, 12.9 and 18.5% DM; P < 0.001) with the length of the daylight period. Rumen fermentation also increased (P < 0.01) with the length of the daylight period before cutting as shown by parameters (half-life; mean = 10.09, 10.61, 10.56, 10.24, 11.32 h and maximum values; mean = 231.5, 236.3, 236.9, 230.7, 248.9 ml) describing cumulated gas production curves. Propionate concentrations in the liquid phase increased linearly (mean = 11.8, 11.6, 12.8, 13.6, 14.6 mmol/L; P = 0.01) with a longer daylight period. Increasing the daylight period up to 12 h before cutting favoured the accumulation of starch and TNC in alfalfa and had a positive effect on rumen fermentation. [ABSTRACT FROM AUTHOR]

Forages cut at sundown usually contain a greater concentration of nonstructural carbohydrates (NSC) than those cut at sunrise. Maceration can speed up the rate of moisture loss of cut forage during field drying and reduce NSC utilization by plant cells. We aimed to evaluate the effects of cutting time and forage maceration on feed preference, apparent total tract digestibility of nutrients, and N balance in growing steers. A mixed sward of birdsfoot trefoil and timothy grass was divided into two halves, with the first half cut at sundown (1800 h) after a sunny day and the second half at sunrise (0600 h) the next day. Approximately 50% of the sundown- and sunrise-cut herbage were macerated. Forages were harvested as hay resulting in four treatments: 1) sunrise-cut hay (AM); 2) AM plus maceration (AM-M); 3) sundown-cut hay (PM); and 4) PM plus maceration (PM-M). Hays were offered as the sole feed source to four crossbred steers (296.1 ± 7.25 kg) according to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 21 d with 14 d for diet adaptation and 7 d for collection. Hays cut at sundown had 15% greater NSC than those cut at sunrise. A cutting time by maceration interaction was found ( P < 0.05) for intake and apparent digestibility of crude protein (CP), indicating that these two variables decreased more when maceration was applied to sundown- versus sunrise-cut hays. Similarly, interaction effects were observed ( P < 0.05) for total digestible nutrients and digestible energy, showing that maceration decreased the energetic value of sundown-cut hays but did not change that of sunrise-cut hays. Steers fed hays cut at sundown had decreased urinary N excretion and improved retained N ( P < 0.05), whereas N retention was reduced by maceration ( P < 0.05). In addition, six crossbred steers were used to assess feed preference, 2 wk before (period 1) and 1 wk after (period 2) the digestibility trial. Animals were randomly assigned to receive a sequence of the four hays combined in pairs. The intake rate was greater for sundown- than sunrise-cut hays, and it was decreased by maceration. Steers showed the greatest preference for PM hay, while AM-M was the most rejected. In conclusion, shifting forage cutting from sunrise to sundown increased hay NSC concentration, which resulted in improved N utilization and preference. Forage maceration during field drying decreased CP concentration and N retention in beef steers under the conditions of our study., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Objective: To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from 5 to 25 °C on corn silage which was previously fermented at ambient or low temperature., Methods: Whole-plant corn silage was fermented in vacuum bag mini-silos at either 10 or 20 °C for two months and stored at 5 °C for two months. The mini-silos were then subjected to additional incubation from 5 to 25 °C in 5 °C increments. Bacterial and fungal diversity was assessed by PCR-DGGE profiling and biochemical analysis from mini-silos collected at each temperature., Results: A temperature of 10 °C during fermentation restricted silage fermentation compared to fermentation temperature of 20 °C. As storage temperature increased from 5 to 25 °C, little changes occurred in silages fermented at 20 °C, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a fairly high number of enterobacteria and yeasts (4-5 log10 CFU g FM-1) were detected at 15 °C and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at 10 °C, no significant changes were observed in most silage characteristics when temperature was increased from 5 to 20 °C. However, above 20 °C, silage fermentation resumed as observed from the significantly increased number of LAB colonies, acetic acid content, and the rapid decline in pH and WSC concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from 20 to 25 °C., Conclusion: Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at 20 °C indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

Timothy (Phleum pratense L.) is an important grass forage used for pasture, hay, and silage in regions with cool and humid growth seasons. One of the factors affecting the nutritive value of this grass is the concentration of non-structural carbohydrates (NSC), mainly represented by fructans. NSC concentration depends on multiple factors, making it hardly predictable. To provide a better understanding of NSC metabolism in timothy, the effects of maturity stage and nitrogen (N) fertilization level on biomass, NSC and N-compound concentrations were investigated in the tissues used for forage (leaf blades and stems surrounded by leaf sheaths) of hydroponically grown plants. Moreover, activities and relative expression level of enzymes involved in fructan metabolism were measured in the same tissues. Forage biomass was not altered by the fertilization level but was strongly modified by the stage of development. It increased from vegetative to heading stages while leaf-to-stem biomass ratio decreased. Total NSC concentration, which was not altered by N fertilization level, increased between heading and anthesis due to an accumulation of fructans in leaf blades. Fructan metabolizing enzyme activities (fructosyltransferase-FT and fructan exohydrolase-FEH) were not or only slightly altered by both maturity stage and N fertilization level. Conversely, the relative transcript levels of genes coding for enzymes involved in fructan metabolism were modified by N supply (PpFT1 and Pp6-FEH1) or maturity stage (PpFT2). The relative transcript level of PpFT1 was the highest in low N plants while that of Pp6-FEH1 was the highest in high N plants. Morevoer, transcript level of PpFT1 was negatively correlated with nitrate concentration while that of PpFT2 was positively correlated with sucrose concentration. This distinct regulation of the two genes coding for 6-sucrose:fructan fructosyltransferase (6-SFT) may allow a fine adequation of C allocation towards fructan synthesis in response to carbon and N availability. Contrary to fructans, starch content increased in low N plants, suggesting different regulatory mechanisms and/or sensitivity of starch and fructan metabolism in relation to the N status., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

A PCR-denaturing gradient gel electrophoresis (DGGE) method was used to examine on-farm sources of Clostridium cluster I strains in four dairy farms over 2 years. Conventional microbiological analysis was used in parallel to monitor size of clostridial populations present in various components of the milk production chain (soil, forage, grass silage, maize silage, dry hay, and raw milk). PCR amplification with Clostridium cluster I-specific 16S rRNA gene primers followed by DGGE separation yielded a total of 47 operational taxonomic units (OTUs), which varied greatly with respect to frequency of occurrence. Some OTUs were found only in forage, and forage profiles differed according to farm location (southern or northern Québec). More clostridial contamination was found in maize silage than in grass silage. Milk represented a potential environment for certain OTUs. No OTU was milk specific, indicating that OTUs originated from other environments. Most (83%) of the OTUs detected in raw milk were also found in grass or maize silage. Milk DGGE profiles differed according to farm and sampling year and fit into two distinct categories. One milk profile category was characterized by the presence of a few dominant OTUs, the presence of which appeared to be more related to farm management than to feed contamination. OTUs were more varied in the second profile category. The identities of certain OTUs frequently found in milk were resolved by cloning and sequencing. Clostridium disporicum was identified as an important member of clostridial populations transmitted to milk. Clostridium tyrobutyricum was consistently found in milk and was widespread in the other farm environments examined.

Intramuscular EMG of the lateral pterygoid muscles (LPM), surface EMG of the temporalis and masseter muscles and force measurements of the temporomandibular joint (TMJ) were synchronously used to investigate the biomechanical role of the two heads of the LPM in relation to internal derangement (ID) of the TMJ. EMG and kinetic analysis of five static conditions (resting, protraction, opening, molar and incisor clenching) and three maximum isometric masticatory forces (opening, molar and incisor clenching) were done to compare forces and muscular activity between TMJ ID and control subjects. The analysis of variance results of the integrated linear envelope (LE) EMG showed no significant differences between the two groups for the masseter and temporalis muscles. Therefore, there is no apparent reason to believe that these muscles are hyperactive in TMJ ID. The integrated LE EMG of the SLP was significantly lower in the TMJ group during molar clenching (104 microV + 60.0 over 159 microV + 68.8 for a p = .020). The superior head of the lateral pterygoid muscle (SLP) seemed to have lost its diskal stabilizing function. The integrated LE EMG signals of the ILP were significantly higher in the TMJ ID group during rest, resisted protraction and incisor clenching (p = .029, p = .046, p = .031 respectively). The ILP muscle has probably adapted to control the inner joint instability while continuing its own actions. The ILP muscle seemed to have lost its functional specificity. The results of the isometric forces showed that TMJ ID subjects exhibited significantly lower molar bite forces (297.1N over 419N, p = .042) confirming that they have less muscle strength and tissue tolerance than subjects with healthy masticatory muscle systems. A neuromuscular adaptation could be occurring in the TMJ ID masticatory system affecting muscular actions and forces.