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In order to meet the needs of accurate traceability of dose monitoring instruments in domestic medical, security inspection and other pulse radiation places, a 50-120 kV millisecond pulse X-ray reference radiation field that meets the requirements of norms and standards was established, based on the gate control technology, and its pulse width can be adjustable in the range of 1-6 300 ms. The pulse X-ray reference waveform was established by studying and testing the tube voltage stability, dose linearity, repeatability, pulse waveform and other key parameters of the radiation field, and the pulse dose rate was measured using a cylindrical ionization chamber with a sensitive volume of 30 cm3, and obtained the following research results: when the tube voltage was preset to 60 kV, the relative deviation of the intervened and non-intervened measuring tube voltage did not exceed ±1.5%; the minimum pulse width of the reference waveform pulse output was 20 ms, and a 95% uniform radiation field with a diameter of about 5.5 cm could be generated at 1 m. Moreover, the dose rate range of N series and RQR series radiation quality was extended to 0.002-10 mGy/s and 0.03-250 mGy/s, respectively, which can be used for the metrological traceability of protective instruments.

In order to accurately measure the environmental level dose rate, based on the G(E) function method and conversion of complete spectra without deconvolution method, the energy spectrum and dose rate of X/γ ray was measured for calculating spectrum-dose conversion coefficient. And finally the conversion of energy spectrum to dose rate is realized. The residual difference between the calculated dose rate by the energy spectrum-dose method and the measured dose rate value is approximately 0, which proves that the method is self-consistent. Experiments have been conducted in 137Cs and 60Co radiation fields, and the maximum relative error of dose rate is ±10%, which proves that the G(E) function method and Conversion of complete spectra without deconvolution method are feasible for energy spectrum-dose conversion.

Simple Summary: Slow-release urea can slow down the degradation rate of urea in the rumen, improving nitrogen utilization efficiency and promoting the growth of rumen microorganisms. However, different slow-release urea may have variance functions. This study used two kinds slow-release urea, polymer-coated urea and gelatinized starch urea, to evaluate the effects on Angus heifers. We found that polymer-coated urea was able to improve the feed efficiency of cattle, and it also increased the daily gain. In rumen, adding polymer-coated urea increased the content of volatile fatty acids like acetate and propionate. In addition, polymer-coated urea increased the relative abundance of some friendly bacteria in the rumen, like Paraprevotella. Thus, we believe that polymer-coated urea can improve the production performance of Angus heifers and bring about more economic benefits. This study investigated the effect of replacing part of the dietary soybean meal with either polymer-coated urea or gelatinized starch urea on the production performance, blood indexes, and ruminal fermentation of Angus heifers. A total of 210 purebred Angus cattle (BW = 314.26 kg) were divided into three groups: the no urea group (CON), the polymer-coated urea group (PCU), and the gelatinized starch urea group (GSU); 20 g/kg polymer-coated urea or 25 g/kg gelatinized starch urea was used to replace part of soybean meal in the concentrate feed, according to the principle of isometabolic energy and isonitrogenous. The result showed that the PCU group had higher ADG and ADF apparent digestibility, while it had a lower feed–weight ratio. On the 86th day, the serum albumin (ALB) content in the PCU group was significantly higher than that in the CON group. In rumen, compared with the CON group, the contents of acetic acid and total volatile fatty acid were significantly higher in the PCU group, whereas butyric acid and propionic acid were significantly higher in the PCU group and GSU group. Ruminal bacterial diversity analysis found that the abundance of Firmicutes was higher in the PCU group at the phylum level, and an inverse result was observed in Bacteroidetes. The abundance of Paraprevotella was higher in the PCU group, whereas higher abundance of Prevotella was found in the GSU group at the genus level. These results indicate that slow-release urea can replace part of soybean meal in the diet, and the amount of substitution in this trial had no diverse effect on the performance of Angus heifers. [ABSTRACT FROM AUTHOR]

Simple Summary: Lentinan is a polysaccharide extracted from mushrooms, which could have anti-inflammatory and antioxidant properties. It is widely used in human medicine while rarely in husbandry. Previous studies have shown that early-lactation cows suffer from a negative energy balance, which could lead to various inflammations. In this study, we aimed to investigate the effects of lentinan on immune ability in dairy cows. Some factors that are prone to causing inflammation in cows, such as IL-2, IL-8, and some liver injury markers, such as AST and ALT, were reduced after adding lentinan. In addition, metabolites revealed that lentinan upregulated some immune-beneficial metabolites in plasma, including some quinones and trehalose, which can promote anti-inflammatory and antioxidant effects. The findings provide a basis for the use of lentinan as a new type of cow additive. In this study, we investigated the effects of lentinan (LNT) on hematological parameters, immune indices, and metabolite levels in dairy cows. We randomly assigned forty Holstein cows to four treatment groups. The treatments consisted of 0, 5, 10, and 15 g/d of LNT. Compared with the control group, the addition of 10 g/d of LNT decreased the content of ALT and IL-8 but simultaneously increased the content of IL-4 in the cows' serum. Supplementation with 10 g/d of LNT decreased the levels of lymphocyte, RDW, ALT, AST, TC, IL-2, and IL-8, but, concurrently, in-creased the levels of granulocytes and IL-4 in their serum. In addition, supplementation with 15 g/d of LNT decreased the levels of RDW, TC, IL-2, and IL-8, but, at the same time, increased the levels of IL-4 and IgM in their serum. For the metabolomic analysis, cows fed with 0 and 10 g/d of LNT were selected. The results showed that 10 metabolites, including reduced nicotinamide riboside and trehalose, were upregulated in the 10 g/d group. These differential metabolites were enriched in tyrosine metabolism and trehalose degradation and altered two metabolic pathways of ubiquinone and other terpene quinone biosynthesis, as well as starch and sucrose metabolism. These findings provide evidence that LNT could be used to reduce the risk of inflammation in dairy cows. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effects of Bupleurum extract (BE) on the haematological profiles, the mineral and hormone levels of heat stressed dairy cows. Forty Holstein cows (75 ± 15 days in milk, 37.5 ± 1.8 kg of milk/d, and 1.7 ± 0.4 parity) with heat stress were randomly assigned to four treatments, which consisted of 0, 0.25, 0.5, or 1.0 g BE/kg DM (Dry Matter). Compared with the control group, cows that were fed 0.5 g/kg BE had a higher red blood cell count, haemoglobin, haematocrit, and white blood cell count. Compared with the control group, the supplementation of 0.25 and 0.5 g/kg BE decreased creatine kinase levels. Compared with the cows that were fed 0 or 1.0 g/kg BE, glutamic-oxaloacetic transaminase and alkaline phosphatase activities were lower in those given 0.5 g/kg BE, while serum glutamic-pyruvic transaminase was lower in those given 0.25 and 0.5 g/kg BE. Compared with the control group, the supplementation of 0.5 and 1.0 g/kg BE decreased sodium concentrations and increased potassium and calcium concentrations. In addition, the supplementation of 1.0 g/kg BE decreased phosphorus concentrations, while that of 0.5 g/kg BE increased chloride concentrations. As for hormone levels, triiodothyronine and prolactin levels increased in cows given 1.0 g/kg BE, while cortisol levels were lower in cows given 0.5 g/kg BE. Further, growth hormone levels were elevated in cows fed 0.25 g/kg BE. These findings suggest that supplemental BE at 0.5 g/kg could have positive effects on the blood metabolism of heat-stressed cows. Supplementation of 0.5 g/kg Bupleurum extract improved the haematological parameters of heat stressed dairy cows; Bupleurum extract can be used as a feed additive for cows. [ABSTRACT FROM AUTHOR]