Study On Feeding Evaluationg Of Forage-Type Total Mixed Rations

The domestic mutton industry is still in the tradition feeding mode. In other words, several kinds of forage feeding separately not only has the lower utilization rate of forage grass, serious waste, higher costs, but also has the lower marketing rate of fattened stock, longer feeding cycle, and poorer mutton quality. The pelleted forage-type total mixed ration is the effective way to improve this current situation. The forage-type total mixed ration is still the perspective study in domestic. This paper creatively introduced the forage graded index (GI) and Multiple-factors associative effects index (MFAEI) theory, use the enriched forage resources which is abundance in source and lower in price in agricultural areas, develop the special total mixed ration of lamb fattening which is orientate by forage. On the basis of forage nutritional evaluation, combining the nutritional requirements of lamb fattening, adopting the method combined with digestion in vitro, animal breeding test and slaughtering test ,research the optimal formula of forage-type total mixed ration in lamb fattening, fill in gaps in technology and theory method of special total mixed ration in lamb fattening. Firstly, evaluating the quality of four kinds of forage using GI . On this basis, make the scientific matching by four kinds of forage GI.Then select four groups of mixed forage which is preferable through fermentation in vitro index and the associative effects index; and match up it with different proportional concentrate , on the principle of the maximum associative effects of total mixed ration, determine the optimal formula of forage-type total mixed ration in lamb fattening through digestion in vitro. And produce pelleted total mixed ration according to this formula. Research the economic benefits and index such as lamb fattening performance and meat quality systematically. Ultimately determining the optimal techniques of forage-type total mixed ration in lamb fattening. Provide the theoretical basis for the production practice. The main results are as follows:1. This study evaluate the nutritional quality of four kinds of forage by GI. Referring to the classification standards of legumes and gramineous forages which is formulated by the United States. It is concluded that Medicago sativa is 14.92, its nutritional value belongs to level 2 medium leguminous forage; Tomato pomace is 6.44, its nutritional value equivalent to level 2 lower legume; Corn stover is 3.35, wheat straw is 1.65, both of their nutritional value belong to the lower germanous forage. Among them the GI value of ADL as the fiber index is more accurate to the classification of forage quality.2. According to four different formulations of forage, it exists obviously positive correlation between the GI value of mixed forage (X) and organic matter digestion rate in vitro (Y). The regression equation is Y = 1.579 X + 20.61 (R2 = 0.6778, P < 0.0001, N = 18). The mixed forage which is optimization by GI can increase the product quantity and utilization rate of total volatile fatty acids especially the propionic acid content. And it can reduce the usage of concentrate effectively. At the same time it has a significant effect (P < 0.05) on many aspects such as offsetting unbalanced supply of low-quality nutrients of forage, improving the nutrition potential and utilization of forage, optimizing the growth environment of ruminal microbes and increasing the protein synthesis quantity of microbial. According to the comprehensively evaluate of GI, cost and indexes of fermentation in vitro, we can choose four better formula,that is alfalfa/tomato pomace /corn stover: 30/10/60, alfalfa/corn stover: 50/50, alfalfa/tomato pomace/ wheat straw: 30/20/50, alfalfa/ wheat straw: 60/40.3.Through the comparison of each digestion in vitro index and multiple associative effects value, the optimal supply concentrate quantity of high GI group that alfalfa /corn stover and alfalfa / wheat straw is 20%; And the optimal supply concentrate quantity of low GI group that alfalfa/tomato pomace /corn stover and alfalfa/tomato pomace /wheat straw is 30%.4.The fattening effect of four optimized groups are generally no significant difference (P>0.05). But they are significant difference (P<0.05)comparing with control group. The conversion rate of total mixed ration after optimizing is higher than those in control group.In terms of meat quality ,they are slightly better than control group in the content of necessary amino acids, fleshy amino acid , fresh and tender, but the difference is not significant (P>0.05).5.The ration cost of all the four optimized groups is significantly lower than the control group. The cost of increasing weight per kilograme reduced by 3.57 Yuan at least . In addition, high GI groups can achieve good economic benefit without increase too much concentrate. Although the low GI groups forage cost of increasing weight per kilograme is higher, the daily gain and forage conversion rate is also better. The difference of four groups profit is not significant, but all of them are higher than control group.It highlights the importance of improve forage quality, reduce concentrate quantity, increase the forage utilization rate, and optimal the forage association by GI.