Search

The experiment was to study the effect of calcium zinc mixture feed additives on production performance and milk quality of dairy cows. A total of 180 lactating period Holstein dairy cows with similar pens, parity and days of lactation were randomly divided into two groups, with 90 replicates in each group. The dairy cows in control group were fed with a full-mixed diet, and the dairy cows in test group were fed with a full-mixed diet + 500 mL/(head ·d) calcium and zinc mixture, for 3 d consecutive, then stopped for 4 d, lasted for 35 d. The results showed that compared with control group, the feed conversion rate of dairy cows in test group was increased by 2.18%. Milk yield of dairy cows in test group was increased by 0.35%, 11.31%, 2.89%, 3.10%, 1.83% and 3.84% on the 7th, 14th, 21th, 28th and 35th day and the whole process, respectively. Milk yield of dairy cows on the 14th day increased significantly. Milk fat percentage and milk protein of dairy cows in test group were slightly lower. Somatic cell number and persistence of dairy cows in test group were increased slightly. Urea nitrogen of dairy cows in test group was decreased slightly. The average economic benefit in each cow per day of dairy cows in test group was increased by 8.24%. The experiment indicates that adding calcium zinc mixture in total mixed diet has no significant effect on feed conversion rate, tends to improve milk yield in a certain stage, which has no significant effect on milk quality, can improve economic benefit. [ABSTRACT FROM AUTHOR]

The multi-wavelength and tunable Yb3+:Ca3Y2(BO3)4 solid-state lasers using topological insulator Bi2Te3 nanosheets as saturable absorber have been reported for the first time. A maximum output power of 161 mW with single pulse energy up to 1.09~\mu \textJ was achieved for the multi-wavelength condition. The corresponding shortest pulse duration and the largest repetition rate were 416 ns and 147.7 kHz, respectively. By further inserting an etalon to modulate the laser spectra, the $Q$ -switched laser could be continuously tuned from 1027.9 to 1040.3 nm with a tuning range of 12.4 nm. At a fixed pump power of 5.09 W, it got a maximum output power and shortest pulse width at 1035 nm. This letter suggests that a topological insulator exhibits outstanding wideband saturable absorption properties because of its unique band structure of narrow bulk state and gapless surface state. [ABSTRACT FROM PUBLISHER]