| Com, chinensis, com silage, com stalks and alfalfa and alfalfa hay are used most commonly in dairy industry, evaluating the nutrition of this feed have direct effect to production practice.Its nutritional value and net energy value has a direct impact on the preparation of the energy level of diet can meet cows daily maintenance and production needs. Therefore, this experimental design three experiments to evaluate the nutritional value of roughage for dairy cattle, and dairy cow level and roughage combination of diet and energy of a single roughage. A separate experiment using the net energy value of the coarse material on the first few trials measured, Experimental measurement of the net value from the national collection of commonly used four different varieties of corn.Exp.1Nutrient component and metabolism of energy of4roughagesThe nutrient component of chinese wildrye, com silage, com stover and alfalfa hay was analyzed by commonly used chemical analysis methods. The results showed:the descending order of crude protein content was from alfalfa hay (17.72%) through chinese wildrye (8.57%) and corn silage (8.37%) to com stover (6.69%). All kinds of forages had lower ether extract, the EE content from higer to lower was that:chinese wildrye (2.73%), com silage (2.41%), alfalfa hay (1.47%) and com stover (0.94%). Com stover (68.09%) had highest neutral detergent fiber (NDF), and there were significant difference between corn stover and in turn reduced chinese wildrye (60.59%), com silage (53.16%) and alfalfa hay (46.97%). Acid detergent fiber (ADF) of com stover (36.72%) was highest in4forages, and there was signigicant difference between alfalfa hay (32.64%), but there was no difference beween the other forages. The feeding relative value (FRV) from high to low was alfalfa hay (125.71), com silage (109.39), chiese wildrye(95.12) and com stover(82.36).Digestion and metabolic and respiration calorimeter were carried out to test the digestible energy, metabolic energy, net energy and methane emission of chinese wildrye, com silage, com stover and alfalfa hay. The results showed that:gross energy level from high to low were chinese wildrye (18.90MJ/kg), com silage (18.00MJ/kg), alfalfa hay (17.79MJ/kg) and com stover (17.30MJ/kg).The digestible energy of alfalfa hay, com silage, chinese wildrye and com stover were2.58MJ/kg,2.38MJ/kg,2.39MJ/kg and2.22MJ/kg, respectively. The metabolic energy of alfalfa hay, com silage, chinese wildrye and corn stover were2.10MJ/kg,1.74MJ/kg,1.80MJ/kg and1.61MJ/kg, respectively. The net energy of alfalfa hay, com silage, chinese wildrye and com stover were1.33MJ/kg,1.21MJ/kg,1.22MJ/kg and1.13MJ/kg, respectively. Exp.2The effect of production level on metabolism of energy of4roughages.Digestion and metabolic and respiration calorimeter were carried out to investigate the effects of production level on digestible energy, metabolic energy, net energy and methane emission of ration and chinese wildrye in dairy cows. To evaluate the effect of production level on energy utilization of chinese wildrye, this experiment was conducted to study the effects of production level on the utilizing efficiency of energy by the indirect method (substitution method). The gross energy of chinese wildrye was18.90MJ/kg, energy contribution of chinese wildrye to dry cows, cows milking15kg/d, cows milking27kg/d were respectively showed that:digestible energy were9.98MJ/kg,9.64MJ/kg and9.38MJ/kg; metabolic energy were7.52MJ/kg,7.34MJ/kg and7.28MJ/kg, net energy were5.10MJ1/kg,4.91MJ/kg and4.76MJ/kg, there was significant difference among3production level (P<0.05). The results showed that:DM intake, gross energy intake, fecal enerty, urine energy, methane emission and the diet’s digestible energy and metabolic energy were significantly increased with the rise of the level of production (P<0.05). The ratio of the fecal energy to gross energy intake inreased with increased of production level (P<0.05). Cows on digestibility of dietary energy and metabolic efficiency decreases with increasing production levels. With the production level of L. chinensis net energy value of a downward trend, and the differences between the groups was significantly (P<0.05).Exp.3The effect of roughages combinations on metabolism of energy of4roughagesDigestion and metabolic and respiration calorimeter were carried out to investigate the effects of associated effect of roughages on digestible energy, metabolic energy, net energy and methane emission of ration and chinese wildrye in dairy cows. The results showed that:dry matter intake, gross intake and fecal energy, urine energy, methane energy, energy digestibility and metabolizability of the diets combined with various forages had no significant difference among the4groups (P>0.05). For the energy metabolic efficiency, the ratio of fecal energy, urine energy and the total of fecal and urine energy to the intaking gross energy were higher in the diet Ⅱ (alfalfa hay+chinese wildrye+corn silage+concentration) than those of the other diets (P<0.05) There was no difference for the ratio methane energy to the intaking gross energy among the4types of forages combination (P>0.05). Energy digestibility and metabolizability of diet Ⅱ was higher than the other3types (P<0.05).To evaluate the effect of roughages combinations on energy net of chinese wildrye, this experiment was conducted to study the effects of roughages combinations on the utilizing efficiency of energy by the indirect method (substitution method). The gross energy of chinese wildrye was18.90MJ/kg, the descending order of digestible energy of chinese wildrye to dairy cows were from diet Ⅱ (9.98MJ/kg) through diet III (9.37MJ/kg) and diet IV(9.37MJ/kg) to diet I (8.99MJ/kg)(P<0.05). There was a significant difference between diet Ⅱ and diet I. It had been found that the types of roughages combinations had significant influence on digestible energy and metabolic energy, in which the diet II was higher than that of diet Ⅰ (P<0.05). Exp.4Nutrient component and net energy of4kinds of different varieties of comThe nutrient component of4kinds of different varieties of com was analyzed by commonly used chemical analysis methods. The results showed:the descending order of crude protein content was from Hebei com (8.39%), Henan com (7.68%), Beijing com (7.65%) and Shandong com (8.64%); All kinds of forages had lower ether extract, the EE content from higer to lower was that: Hebei com (4.24%), the Henan com (3.68%)> Shandong com (3.67%)> Beijing com (3.60%). The NDF content of each group the difference was not significant (P>0.05).ADF content of Henan (3.51%), the Hebei com (3.49%) between the difference was not significant, but significantly higher than in Beijing (3.39%) and Shandong com (3.38%).Was no significant difference between Beijing and Shandong com.Determination of digestion and metabolism trials fecal France received four com digestible energy and net energy value.The results showed:gross energy level from high to low were Hebei com (23.9195MJ/kg),Beijing com (23.9232MJ/kg),Henan com (23.5034MJ/kg),Shandong com.(23.2728MJ/kg).The digestible energy of Hebei corn,Beijing com, Henan com, Shandong com were18.99MJ/kg,18.29MJ/kg,18.98MJ/kg,18.52MJ/kg. The net energy of Hebei corn,Beijing com, Henan com, Shandong com were10.05MJ’kg、9.66MJ/kg、10.04MJ/kg、9.79MJ/kg。... |
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