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1.
This study investigated the effects of low potassium diets with different levels of Ca compared to two diets low in dietary cation–anion difference (DCAD) fed prepartum as a strategy to prevent hypocalcemia on sorting behaviour, total tract digestibility, oxidative status and energy and protein metabolism of transition cows. Forty-eight pregnant dairy cows were assigned to 4 treatment groups: Low Ca, low K (LCLK), High Ca, low K (HCLK), Supplementation with anionic mineral mixture (AMS) supplementation with SoyChlor (CAS). After parturition, all animals were fed a standard postpartum diet. Data were collected until 21 DIM. Prepartum urinary pH was significantly reduced by the low DCAD diets, while postpartum Ca homeostasis was affected by the HCLK ration. Feeding AMS induced sorting against particles <1.18 mm in favour of particles >19 mm prepartum. In contrast, cows fed CAS showed an increase in selective consumption of fine particles and sorted against longer particles similar to the HCLK and LCLK groups. Postpartum sorting activity was not affected by the dietary treatments. After calving, apparent digestibility of NDF was significantly reduced in the HCLK group. Prepartum, we observed effects on serum concentrations of non-esterified fatty acids were higher and insulin sensitivity was lower in the AMS group. Blood urea nitrogen (BUN) was decreased in cows fed the CAS ration. Postpartum, we found serum protein to be decreased with the low DCAD diets while BUN was decreased in the CAS group. The low DCAD rations increased prepartum serum malondialdehyde concentrations, while postpartum total antioxidant capacity was lower in the HCLK and the AMS group. From these data, we conclude that AMS decreased prepartum intake due to compromised palatability. Intermediate protein metabolism was affected by the low DCAD diets, while parameters of oxidative stress were probably affected by acid–base balance and Ca homeostasis.  相似文献   
2.
Two studies were conducted to determine whether a bacterial direct-fed microbial (DFM) alone or with yeast could minimize the risk of acidosis and improve feed utilization in feedlot cattle receiving high-concentrate diets. Eight ruminally cannulated steers, previously adapted to a high-concentrate diet, were used in crossover designs to study the effects of DFM on feed intake, ruminal pH, ruminal fermentation, blood characteristics, site and extent of digestion, and microbial protein synthesis. Steers were provided ad libitum access to a diet containing steam-rolled barley, barley silage, and a protein-mineral supplement (87, 8, and 5% on a DM basis, respectively). In Exp. 1, treatments were control vs. the lactic-acid producing bacterium Enterococcus faecium EF212 (EF; 6 x 10(9) cfu/d). In Exp. 2, treatments were control vs EF (6 x 10(9) cfu/d) and yeast (Saccharomyces cerevisiae; 6 x 10(9) cfu/d). Supplementing feedlot cattle diets with EF in Exp. 1 increased (P < 0.05) propionate and (P < 0.05) decreased butyrate concentrations, decreased the nadir of ruminal pH (P < 0.05), enhanced the flow of feed N (P < 0.10) to the duodenum but reduced that of microbial N (P < 0.10), reduced (P < 0.10) intestinal digestion of NDF, and increased (P < 0.10) fecal coliform numbers. Other than the increase in propionate concentrations that signify an increase in energy precursors for growth, the other metabolic changes were generally considered to be undesirable. In Exp. 2, providing EF together with yeast abolished most of these undesirable effects. Combining EF with yeast increased the DM digestion of corn grain incubated in sacco, but there were no effects on altering the site or extent of nutrient digestion. The diets used in this study were highly fermentable, and the incidence of subclinical ruminal acidosis, defined as steers with ruminal pH below 5.5 for prolonged periods of time, was high. Supplementing the diet with EF, with or without yeast, had limited effects on reducing ruminal acidosis. It seems that cattle adapted to high-grain diets are able to maintain relatively high feed intake and high fiber digestion despite low ruminal pH. The Enterococcus faecium bacterium and yeast used in this study were of limited value for feedlot cattle already adapted to high-grain diets.  相似文献   
3.
This study investigates the effects of feeding diet based on untreated (UT) or ensiled alkali‐treated (ET) barley straw with either urea or casein supplementation, on feed intake, digestibility, ruminal pH, water intake and faecal and urinary characteristics. Four sheep fitted with ruminal cannulas were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Barley straw was treated by the dry (spraying) method in pH adjusted of hydrogen peroxide (pH 11.5), ensiled for 6 weeks and included at 65% of the diet dry matter (DM). The results showed that straw pH reduced from 11.58 to 8.60 after 6 weeks of ensilage. The ET diet increased average DM digestibility and intake by 19% and 43% respectively. Total water intake was similar across treatments, while the water/DM intake ratio was 23% higher with the UT diet than with the ET one. Ruminal (6.73 vs. 6.84) and faecal (8.67 vs. 9.05) pH decreased but urinary pH (6.14 vs. 8.13) increased as a result of feeding animals on the ET diet compared with the UT diet. Compared with the UT diet, the ET one decreased faecal fibre (12%), moisture (32%) and water holding capacity, while it increased faecal ash (10%) and density (20%). The volume of urine excreted by the sheep fed with the ET diet increased by 67%, but their urine specific gravity (SG) decreased. No significant effects were observed for the dietary N supplementation and interactions between straw type × N supplementation with regard to any of the measured characteristics except for DM intake, which reduced due to the casein supplementation in the ET diet. These results indicate that the alkali treatment and ensilage of barley straw increased digestibility, intake, faecal consistency and urinary pH and dilution but decreased straw alkalinity as well as ruminal and faecal pH.  相似文献   
4.
Sulphur‐containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous.  相似文献   
5.

Context

We develop a modelling concept that updates knowledge and beliefs about future climate changes, to model a decision-maker’s choice of forest management alternatives, the outcomes of which depend on the climate condition.

Aims

Applying Bayes’ updating, we show that while the true climate trajectory is initially unknown, it will eventually be revealed as novel information become available. How fast the decision-maker will form firm beliefs about future climate depends on the divergence among climate trajectories, the long-term speed of change, and the short-term climate variability.

Methods

We simplify climate change outcomes to three possible trajectories of low, medium and high changes. We solve a hypothetical decision-making problem of tree species choice aiming at maximising the land expectation value (LEV) and based on the updated beliefs at each time step.

Results

The economic value of an adaptive approach would be positive and higher than a non-adaptive approach if a large change in climate state occurs and may influence forest decisions.

Conclusion

Updating knowledge to handle climate change uncertainty is a valuable addition to the study of adaptive forest management in general and the analysis of forest decision-making, in particular for irreversible or costly decisions of long-term impact.  相似文献   
6.
The antifungal activity of twelve monoterpenes, camphene, (R)-camphor, (R)-carvone, 1,8-cineole, cuminaldehyde, (S)-fenchone, geraniol, (S)-limonene, (R)-linalool, (1R,2S,5R)-menthol, myrcene and thymol was evaluated against four plant pathogenic fungi Rhizoctonia solani, Fusarium oxysporum, Penecillium digitatum and Asperigallus niger by using mycelial growth inhibitory technique. (S)-limonene and thymol were examined for their inhibitory effects on pectin methyl esterase (PME), cellulase and polyphenol oxidase (PPO) of tested fungi. Thymol was the most potent antifungal compound against the four test fungi with EC50 values of 33.50, 50.35, 20.14 and 23.80 mg/L on R. solani, F. oxysporum, P. digitatum and A. niger, respectively. The antifungal activity of thymol was comparable to a reference fungicide, carbendazim. (S)-limonene and 1,8-cineole exhibited pronounced antifungal activity against the four tested fungi. The most effective antifungal compounds thymol and (S)-limonene showed strong inhibitory effect on the activity of PME and cellulase but revealed no inhibitory effect on PPO. The results showed that PME was more sensitive than cellulase to thymol and (S)-limonene. This is the first report on the inhibitory effects of monoterpenes thymol and (S)-limonene on PME, cellulase and PPO. The results indicated that monoterpenes may cause their antifungal activity by inhibiting PME and cellulase. The strong antifungal activity of thymol, (S)-limonene and 1,8-cineole reported in this study indicated that these compounds have a potential to be used as fungicides.  相似文献   
7.
Safflower seed has the highest concentration of linoleic acid among 80 oilseeds but little information exists on the effective use of SS for lactation cows. It was hypothesised that a diet supplemented with an Iranian SS variety (IL-111) in combination with fish oil (FO) would result in higher concentrations of trans-18:1 (including vaccenic acid) and conjugated linoleic acids in milk fat than feeding an unsupplemented control diet. Our objective was to determine the effects of feeding diets containing: (i) Control: (C); (ii) 25 g of roasted SS IL-111 (RSS); (iii) 20 g FO and (iv) 25 g RSS + 10 g FO (RSS + FO) per kilogram of dietary DM on feed intake, ruminal fermentation, milk production and fatty acid profile. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design study. The experiment had four periods of 21 days. Milk Fat percentage was lower (p < 0.01) with FO supplementation and averaged 19.0 and 21.5 g/kg milk with FO and RSS + FO compared with 30.3 and 32.5 g/kg with C and RSS. Feed intake also was lower (p < 0.01) with FO vs. C (23.1 vs. 24.5 kg/day) but feeding RSS resulted in greater feed intake compared with other treatments (26 kg/day). Despite lower feed intake with FO, milk production did not change from controls but feeding RSS + FO resulted in greater milk yield than controls (42.6 vs. 39.3 kg/day). Ruminal pH was greater (p < 0.01) in cows fed FO than other treatments. Supplemental FO alone or in combination with RSS resulted in dramatic increases (p < 0.01) in c9,t11-18:2 in milk fat (12.7 and 13.2 g/day vs. 5.8 and 7.02 with C and RSS). It was surprising to note that 25 g/kg RSS can improve feed intake.  相似文献   
8.
9.

• Context  

This review paper provides an overview of approaches to which we may resort for handling the complex decision problems involving uncertainty and risk that climate change implies for forest managers. Modelling approaches that could support adaptive management strategies seem to be called for, not only as climate change denotes increased economic uncertainty but also because new and more reliable information becomes available as time passes and climate changes.  相似文献   
10.
This study aimed to investigate the role of epithelial cells in regulating innate immunity in bovine oviduct epithelial cell (BOEC) culture. We studied the effect of Escherichia coli lipopolysaccharide (LPS) and its interaction with ovarian steroids, estradiol (E2) and progesterone (P4), and luteinizing hormone (LH) at concentrations observed during the preovulatory period on immune responses in BOEC culture. Immunohistochemistry of oviduct tissue showed intensive expression of Toll-like receptor-4 (TLR-4) and TLR-2 in epithelial cells. A dose of 10 ng/ml LPS stimulated TLR-4, cyclooxygenase-2 (COX-2), nuclear factor kappa B inhibitor A (NFKBIA), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) expression, indicating an early pro-inflammatory response. A dose of 100 ng/ml LPS did not induce expression of these genes but stimulated TLR-2, IL-10,IL-4 and microsomal prostaglandin E synthase-1 (mPGES-1) expression and PGE2 secretion, indicating an anti-inflammatory response. Ovarian steroids and LH completely block LPS (10 ng/ml)-induced TLR-4, IL-1β and TNF-α expression as well as LPS (100 ng/ml)-induced TLR-2 expression. Taken together, this study suggests the existence of an early signaling system to respond to infection in the BOEC. In addition, ovarian steroids and LH may play a critical role in inducing homeostasis and in controlling hyperactive pro-inflammatory responses detrimental to epithelial cells, sperm and the embryo.  相似文献   
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