Effect Of Roughage Combinations On N, P Emission And Study On Farmland Carrying Capacity Of Dairy Cow

This paper was conducted to investigate the response to the production performance,nutrient apparent digestibility, nitrogen and phosphorus metabolism, blood serumbiochemical parameters and economic benefits of dairy cows fed basal diets withdifferent whole corn silage: alfalfa hey ratios from the view of planting-breedingfarm.The ability of corn farmland and alfalfa farmland carrying manure nitrogen andphosphorus of dairy cows in the sandy loam soil of the Yellow River Beach wasdiscussed in the way of farmland nutrient balance base on agro-animalhusbandry dairy farm; And then, the carrying capacity of corn and alfalfafarmland was calculated in nitrogen or phosphorus standard. The experiment wasdivided into two parts:Exp.1The trial was set up as a3×3Latin square design, with three treats and threeperiods, involving9lactating Holstein cow milked20kg to25kg, fed diet Ⅰincluding whole corn silage27kg and alfalfa hay4kg（27M4A）, dietⅡincludingwhole corn silage21kg and6kg alfalfa hay（21M6A）, diet Ⅲ including whole cornsilage15kg and alfalfa hay8kg （15M8A） respectively. The level of crude proteinin mixed diet of ⅠⅡ Ⅲ was14.45%、14.97%、15.46%, the concentrate: roughageratio of all the mixed diet is40:60based on DM, the level of phosphorus in all themixed diet was0.35%. The trail lasted61days, every period had21days. Thepre-trial period was from1st day to14th day, and the trial period was from15th to21st day. All the results as follows.The different diet treatments had no significant influence on the dry matter intake,but the dry matter intake showed an increased trend with the rise of alfalfa hay ratio ofroughage. The DM intake of group Ⅲ increasedby9.49%than group Ⅰ. Thedifferent diet treatments had no significant influence on4%standard milk productionand the conversion ratio of feed to milk. The milk yield in group Ⅱincreased by0.75kg/d than group Ⅰ, and the conversion ratio in group Ⅱ was better than others. The test treatment had no significant effect on DHI, milk protein yieldand solids-not-fat yield showed a trend of rise with increased alfalfa hay, milk fatyield in group Ⅱwas2.5%higher than other two groups.The apparent digestibility of crude protein in group Ⅰ, Ⅱ, and Ⅲwas75.79%,75.98%,78.25%, respectively. The apparent crude protein digestibility in group Ⅲincreased by3.25%（P<0.05）. The test treatment had no significant effect on theapparent digestibility of NDF, ADF and phosphorus, but the apparent digestibility ofphosphorus reduced with the increase of the proportion of alfalfa hay.The CP level of diet could significantly increase nitrogen intake nitrogen intakein group Ⅲ, increased by19.5%than groupⅠ（P=0.003）, The test treatments had nosignificant effect on manure nitrogen and milk nitrogen, but manure and milk nitrogenin group Ⅱ was higher than other groups. The CP level of diet could significantlyincrease urine nitrogen and excretion nitrogen, but urine nitrogen and excretionnitrogen in group Ⅲ significantly increased by29.0%（P<0.05）and21.0%（P<0.05）than group Ⅰ, respectively. N retention could increase with the rise of crude protein（P>0.05）.The test treatments had no significant effect on the nitrogen apparentdigestibility（P>0.05）. Milk urine nitrogen in group Ⅱ, and Ⅲ increased by16.21%（P<0.05）and22.61%（P=0.007）than in group Ⅰ, respectively.The test treatments had no significant effect on phosphorus intake, manurephosphorus, milk phosphorus, the ratio of manure phosphorus: phosphorus intake, theratio of milk phosphorus: phosphorus intake and phosphorus retention （P>0.05）, andphosphorus intake, manure phosphorus, milk phosphorus and the ratio of manurephosphorus: phosphorus intake showed elevated trend with the rise of proportion ofalfalfa hay. However, the ratio of milk phosphorus: phosphorus intake in group Ⅱwas higher than other groups.The test treatments had effect on blood urea nitrogen significantly, and bloodurea nitrogen in group Ⅲ was higher significantly than group Ⅰ（P<0.05）. Totalprotein, albumin, blood glucose, carbon dioxide combining power, ALT and bloodphosphorus showed an increased trend with the rise of proportion of alfalfa hay（P>0.05）.From the view of the conversion ratio of feed to milk and economic profits, theratio of whole corn silages: alfalfa hay in group Ⅱ was better than other groups.Exp.2Based on the planting-breeding dairy farm,1hm~2corn and alfalfa farmland could theoretically match2.54and1.54cows（20-25kg/d milk yield）in the sandyloam soil of the Yellow River Beach, respectively.