| Twenty-eight Angus crossed beef cattle(Angus×Native cattle) with the age of 12 months and weight of 145 kg(P>0.05),were selected and randomly divided into 4 groups(n=7) according to a single factorial design,fed with different supplementary levels(0,0.5,1.0,1.5 kg/herd·d),to study the effects of supplementary level on performance,biochemical indexes of blood and carcass characteristic and meat quality of grazing beef cattle in southern part,the results showed as follows:(1) Growth performance:After feeding 180 days,with the supplementary level increased,the average final weight of 4 groups cattle had significant difference(P< 0.05),total weight gain and average daily gain(ADG) were significantly different(P <0.01),with the level 3 was the highest and control group was the lowest.The body size indexes increased with the supplementary level.And economic profit of supplement for fattening was distinct.(2) Biochemical indexes of blood:Determination of blood index,all the biochemical indexes of blood were fluctuated within the normal range.Red blood cell (RBC),hemoglobin(Hb) and Glucose(GLU) increased as the supplementary level increased,in favor of providing and transferring oxygen within body and organ.There was no significant difference in 4 groups cattle of serum urea nitrogen(SUN),glutamic oxaolacetic transaminase(GOT),alkaline phosphatase(AKP),total protein(TP) and albumin(Alb)(P>0.05).Supplement was good for improving the inner circumstance of cattle body and enhancing productive performance.(3) Carcass characteristic and meat quality:The dressing percentage in control group and three supplementary groups cattle were 46.47%,50.56%,52.31%,53.95% respectively,and supplementary groups were higher than control group(P<0.05).The meat percentage in 4 groups cattle were 36.74%,41.16%,43.28%,44.93%respectively, and supplementary groups were significantly higher than control group(P<0.01). Increasing supplementary level could improve rib muscle area,marbling grade and decreased drip water loss significantly(P<0.05),while there was no significant difference on meat color,fat color,rate cooked,pH and dry matter(DM),organic matter(OM) and calcium(Ca) of the dorsal muscle in 4 groups cattle(P>0.05),while supplementary level had significant difference on ether extracts(EE)(P<0.05).(4) According to the results of this trial,based on the supplementary level of 0～1.5 kg/herd·d(NEmf:6.56～6.68 MJ/kg,CP:12.46～14.05%),incresing supplementary level could improve the productive performance and economic benefit of crossed beef cattle.So,the proper level of supplement for Angus crossed cattle with age of one year old would be higher than 1.5 kg/herd·d under grazing condition in the southern part. |
