饲料养分的绝大部分是碳水化合物和蛋白质,其营养价值的准确评定及其在瘤胃内代谢规律的精细化研究对发展反刍动物的精细饲养具有重要意义,目前在国际上受到广泛关注和应用的美国康奈尔净碳水化合物和蛋白质体系(Cornell Net Carbohydrate and Protein System,CNCPS)是一种反刍动物饲料营养价值评定的重要方法,但在国内实际生产中尚未广泛应用。本文系统地概述了CNCPS中碳水化合物和蛋白质各组分的划分及其变化,并通过列举常用饲料各组分的含量和变化范围及计算公式等,全面揭示了不同类型饲料中碳水化合物及蛋白质组分的含量特性及其差异的原因,以及瘤胃降解速率(Kd)及食糜流通速率(Kp)的变化规律;同时比较了CNCPS与传统饲料养分划分体系的联系与区别。
[Objective] The paper was to precisely predict nutrient requirements and optimize ration formula, and explore the inherent feature of ration optimization of dairy cow. [Method] Based on cornell net carbohydrate and protein system （CNCPS） with integrating dynamic prediction models on main nutrient requirements of dairy cattle recommended by NRC （2001） and the CNCPS parameter database accumu- lated by Chinese feed database, the ration nutrient requirement dynamic calculation and total mixed ration （TMR） formula optimizing system for Holstein dairy cow was developed using FOXPRO database system and parametric linear programming algo- rithm. [Result] By optimizing a specific cow ration and analyzing its completed nutri- ents, the results showed that this system could entirely consider a lots of nutrient balances, such as concentrate fraction and forage fraction balance, rumen degrad- able protein and rumen undergradable protein balance, crude protein and lactation net energy balance, fibrous substances （ADF, NDF） and non-fiber carbohydrates （NFC） balance, calcium and phosphate balance, electrolytes balance and trace ele- ment balance etc., and could also calculate intestinal amino acid flow in terms of different models. [Conclusion] By using dynamic mathematical equations and comput- erized program, it can be realized for the ration formula design of lactating cow with all-round interoperable but mutual-constraining each other among ration nutrients.
