Study On The Effects Of Additives On Growth, Meat Production And Meat Quality Of Fattening Cattle

Three experiments were conducted in this paper. Experiment I is the effect of two additives on liveweight gain and slaughter of fattening cattle. In experiment II, the contents of intramuscular fat (IMF),intramuscular collagen (IMC), muscle glycolytic potential (GP) and color (Mb) were determined inlongissimus dorsi (LD), semimembranosus (SM) and semitendinosus (ST). In experiment III, The contentsof intramuscular fat (IMF), intramuscular collagen (IMC), muscle glycolytic potential (GP) were alsodeterminedinlongissimusdorsi(LD)fromXinjiangbrownbullsandHolsteinbulls.In Experiment I, forty-five Xinjiang brown bulls were selected and randomly divided into threegroups (15 bulls in each group) and were fattened for 90 days. Bulls in trial group1 and 2 supplementedwith additive No.1 and No.2 respectively. The results indicated that difference in the average daily weightgain of bulls was not significant between three groups from 1 to 60 days. But from 61 to 90 days, group 2was extremely significant compared with the control. There were no significant among three groups in thewhole trial. The slaughter trial showed that the neat percentage and the meat-bone ratio in group1 and 2werehigherthanthecontrolgroupwithincrementsof7.87%,33.44%and2.02%,24.69%,respectivelyIn Experiment II, LD, SM, STwere removed fromthe left side of the carcass in each groups and thecontents of IMF, IMC, GPand Mb were determined in the three muscles. The results showed that the IMFin LD was28.12mg/g in thecontrolgroupand thatin Group1andGroup2 was57.01mg/g and 40.26 mg/grespectively. The IMF in SM and ST of Group1and Group 2 were 40.49mg/g, 64.8 mg/g and 22.93 mg/g,38.93 mg/g, with increments of 48.32%, 123.97% and -16.01%, 35.64% than the control group,respectively. Additive level affected the IMC. Compared with the control group, the contents of IMC ingroup1 and group 2 were higher in the LD and the ST, but lower in the SM. Compared with the controlgroup,theGPingroup1andgroup2werehigherintheSTandSM,butlowerintheLD.In Experiment III, he contents of IMF, IMC, and GPwere also determined in longissimus dorsi (LD)from 4 Xinjiang brown bulls and 12 Holstein bulls aged 1.5-2 year-old. The results showed that the IMFand IMC in theXinjiangBrown bullsare higherthan those in the Holstein beef,butthe GPwaslowerthantheXinjiangBrownbeef.