The objective of this study was to evaluate the effects of adding experimental formulations of exogenous protease enzymes on the fermentation and nutritive value of whole-plant corn ensiled in laboratory silos. Chopped and processed whole-plant corn (36.8% DM) was ensiled without enzymes or treated with 1 of 2 experimental proteases (E85 or E86; AB Vista, Wiltshire, UK) at 20 or 2,000 mg/kg (wet-weight basis). Forages were packed in vacuumed and heat-sealed bags and ensiled for 45 and 150 d at 23±1°C. When compared with untreated silage, addition of proteases and length of ensiling time had no effect on silage pH or concentration of crude protein. The results were similar for the concentrations of acid detergent fiber, neutral detergent fiber, and starch, although protease × time interactions were observed for these components, which were biologically minor. When compared with untreated silages, only treatment with the 2,000-mg/kg application amount of E 0425 resulted in lower neutral detergent fiber after 45 d of ensiling. Proteases did not affect NDF digestibility after 150 d of ensiling when compared with untreated silage. Similarly, treatment with enzymes did not affect the concentrations of lactic and acetic acids or ethanol when compared with untreated silage. Concentrations of NH(3)-N and soluble protein (% of crude protein) increased with storage time compared with concentrations at harvest and were greater for the 2,000-mg/kg doses of proteases when compared with untreated silage at both 45 and 150 d. In vitro ruminal digestibility of starch after 7 h of incubation was 66.3% for freshly chopped corn plants. After 45 d of ensiling, starch digestion was greater for E 0430 applied at the 2,000-mg/kg dose (80.6%) than in all other treatments, with the exception that it was similar to the 2,000-mg/kg dose of E85. After 150 d of ensiling, the 20-mg/kg dose of E 0425 (81.9%), the 2,000-mg/kg dose of E 0425 (82.9%), and the 2,000-mg/kg dose of E 0430 (88.6%) had greater starch digestibility than untreated silage (74.0%). To the best of our knowledge, this is the first study to show that addition of exogenous proteases added to corn forage at the time of harvest can increase in vitro ruminal starch digestibility during silage fermentation. Data suggests that adding exogenous sources of protease enzymes at ensiling may be a method to obtain a high degree of ruminal starch digestibility in corn silage that would normally require longer periods of time to obtain from prolonged storage.

20Substrate quality impacts the rate of microbial decomposition of soil organic 21 matter (OM), with higher quality substrates leading to faster rates of decomposition. 22

A recent study reported a 0.4 percentage unit increase in milk fat of lactating dairy cattle when dietary K was increased from 1.2 to 2% with potassium carbonate. Because milk fat yield has been associated with ruminal production of certain conjugated linoleic acid (CLA) isomers, 2 studies were conducted to determine if increasing potassium carbonate in the rumen would alter patterns of fermentation and biohydrogenation. In experiment 1, 5 dual-flow continuous fermenters were injected just before each feeding with a 10% (wt/wt) stock potassium carbonate solution to provide the equivalent of 1.1 (K1), 2.2 (K2), and 3.3 (K3) % of diet dry matter (DM) as added K. One of the remaining fermenters received no K (K0) and the last fermenter (NaOH) was injected with adequate NaOH stock solution (10%, wt/wt) to match the pH observed for the K3 treatment. For experiment 2, 6 dual-flow continuous fermenters were used to evaluate 6 treatments arranged in a 2 × 3 factorial to examine 2 levels of soybean oil (0 and 3.64% of diet DM) and added K at 0, 1.6, and 3.3% of diet DM. In both experiments, fermenters were fed 55 to 57 g of DM/d of a typical dairy diet consisting of 1:1 forage (10% alfalfa hay and 90% corn silage) to concentrate mix in 2 equal portions at 0800 and 1630 h, and fed the respective diets for 10-d periods. Potassium carbonate addition increased pH in both experiments. Acetate:propionate ratio and pH in experiment 1 increased linearly for K0 to K3. Acetate:propionate ratio was lower for NaOH compared with K3 but the pH was the same. The trans-11 18:1 and cis-9,trans-11 CLA production rates (mg/d) increased linearly from K0 to K3, but K3 and NaOH did not differ. Production of trans-10 18:1 decreased and that of trans-10,cis-12 tended to decrease from K0 to K3, but production of trans-10,cis-12 CLA remained high for NaOH. Addition of K to the cultures in experiment 2 decreased propionate and increased acetate and acetate:propionate ratio for the 0% fat diet but not for the 3.64% fat diet. Addition of K increased stearic acid and cis-9,trans-11 CLA but decreased daily production of trans-10 C18:1 and trans-10,cis-12 CLA. The results indicate that increasing potassium carbonate in the diet shifts both fermentation and biohydrogenation pathways toward higher milk fat percentage in dairy cows, but the effects are only explained in part by elevation of pH.

The variable start and duration of the Grey seal breeding season makes the estimation of total pup production from a single census very difficult. Classifying the count into morphological age classes enables the form and timing of the birth rate curve and estimates of pup mortality rates to be elucidated. A simulation technique is described which enables the duration of each morphological stage to be determined from a series of such classified counts taken over one season. A further statistical technique uses these estimates to calculate the mean timing and duration of the breeding season from a single classified count taken from similar populations in subsequent years. This information allows total pup production to be calculated for any appropriate breeding colony. Some guidance is given as to the optimal timing of that single census which would yield the best estimate of production, although the precise date is not critical to the success of the technique. Results from single census estimates obtained in this way are compared with known production data from more detailed surveys for a number of different colonies.

This study presents high-quality draft genome assemblies of six bacterial strains isolated from the roots of wheat grown in soil contaminated with cadmium. The results of this study will help to elucidate at the molecular level how heavy metals affect interactions between beneficial rhizobacteria and crop plants.