Effects Of Roughage On Production Performance In Quality Beef

Roughage in terms of quantity, type and quality is characteristic by numerous、miscellaneous、poor, which exist some.problems such as underutilization and low utilization efficiency in China. The research subject of this experiment is primary roughage(corn straw、hybrid giant napier、brewery mash) in South agricultural zone. We explore the influence of roughage on the performance of beef cattle production, which provide a theoretical basis for the rational application of roughage.Eighteen healthy, similar body weight,5-8months old, hybrid cattles (Red Angus×Simmental×Southern Sichuan) were selected in this test. Using the weight stage, Randomized trial design. Cattles were randomly divided into 3 groups, each group had 6 duplicates, recorded as groupⅠ, groupⅡand groupⅢ. The source of roughage were silage corn stalk, silage hybrid giant napier and silage brewer grain(content 87% brewer’s grain,10% straw and 3% corn flour), respectively. The test include the pre-test period (40 days) and formally test period (410 days), formally test period was divided into four stages, they were the stage of early-growing (90d), the stage of latter-growing (100d), the stage of early-fattening (90d) and the stage of latter-fattening (130d), respectively. The diets were total mixed ration at same level of energy and nitrogen, and the ratio of concentrate to roughage for each stage were 50:50,60:40,65:35 and 70:30, respectively. The cattles were tethered in individual mangeres, and conventional feeding and management method were adopted. Fattening performance, meat quality traits and economic indicators were determined. Results were as follows:(5) Different roughage had significant differeces on fattening performance. Firstly, the stage of. early-growing, the stage of latter-growing and the stage of early-fattening had no significant differeces on ADG(P>0.05),.ADG of groupⅠin the three stages were 0.76kg,0.82kg and 0.78kg, ADG of group II in the three stages were 0.67kg, 0.75kg and 0.66kg, ADG of groupⅢin the three stages were 0.77kg,0.75kg and 0.62kg. During latter-fattening stage, ADG of group I (0.54kg) was significant higher than groupⅡ(0.38kg) (P<0.05), and ADG of groupⅢwas 0.43kg. As to ADG during the whole formly test period, groupⅠ(0.72kg) was significant higher than groupⅡ(0.57kg) and groupⅢ(0.61kg). Finishing body weight had no significant differeces between the three groups (P>0.05), they were 446,4kg,398.8kg,414kg, respectively. Second, effect of various roughage on the body size in whole feeding time:groupⅠbody straight length (30.38cm)and chest measurement(53.8cm) significance raise (P< 0.05) groupⅡbody straight length(24.06cm)and chest measurement(45.36cm), groupIII body straight length and chest measurement was 25.66cm、51.17cm; groupⅠbody slanting length (31.00cm)and cannon circumference(2.92cm) significance raise (P< 0.05) groupIII body slanting length (36.35cm)and cannon circumference (1.57cm),groupⅡbody slanting length and cannon circumference was 28.04cm、2.18cm; height at withers increase and chest width increase had no significant differeces between the three groups (P>0.05), they were 25.58cm、19.04cm,23.02cm、15.60cm, 21.30cm、7.28cm, respectively. Third, finishing body measurement index:fattening index of group I and group 111(371.64、352.86)was significant higher than groupⅡ(329.78) (P<0.05);soma index of groupⅢ(137.79%)was significant higher than groupⅡ(132.18%)(P<0.05);meat index of groupc(3.72).was significant higher than groupⅡ(3.30) (P<0.05),and meat index of groupⅢwas 3.53; body length index and the circumference index had no significant differeces between the three groups (P>0.05).(6) Effect of roughage on feed intake and feed/gain ratio. Feed intake of roughage, concentrate, and total dry matter intake of group I were significant higher than groupⅡand groupⅢduring latter fattening stage (P<0.01), but had no significant effect during others stages (P>0.05);feed-weight ratio had no significant differeces between the three groups during the four stages (P>0.05).(7) Effect of roughage on slaughter performance and meat quality traits. First, slaughter performance:liveweight before slaughtering, carcass weight, meat weight, bone weight, high-grade meat weight and eye muscle area are the highest groupⅠ, followed by groupⅢ, worst groupⅡ; high quality meat weight, dressing percentage, fat mass, meat percentage and carcass meat production rates were the highest groupⅢ, followed by groupⅠ, worst groupⅡ;among of dressing percentage, lean percentage had significant differences(P<0.05).Second, meat quality traits:Meat color, fat color, marbling, shear force, drip loss, water loss rate, water-holding capacity, pH45m, and pH24h had no significant differences (P>0.05); Shear forces were up to the requirements of high-grade beef tenderness shear values (3.62kg), groupⅢminimum (3.10kg), followed by groupⅠ(3.53kg),the largest groupⅡ(3.60kg); three cattle marbling were up to the requirements of high-grade beef marbling level (≤2) in groupⅢ,but groupⅠand groupⅡwere not. Third, the marbling and IMF content keep consistent with histological physical according to the group that groupⅢis the highest level, followed by groupⅠ, and roupⅡwas the worst; the groupⅢ(33.08um) was lower than the groupⅠ(37.08um) (P<0.05),and the groupⅡwas the lowest (39.58um) in muscle fiber diameter (P<0.01).Fourth, roughage had no significant differences (P>0.05)in the total content of minerals, fatty acids and amino acid in beef cattle. But the indices of calcium, phosphorus, linoleic acid, arachidonic acid, EPA, tryptophan and threonine had varied significant differences(P<0.05、P<0.01).Fifth, roughages have significant influence on flavor components of beef cattle which content of cysteine in group I and groupⅡ(0.20%、0.21%) compared to groupⅢreached a significant level and content of inosinic acid in groupⅠ(1.72mg/g) compared to groupⅡ(1.52mg/g)reached a significant level and compared to groupⅢ(1.42mg/g)reaching a very significant level. But the chang trend of flavor precursor and the volatile flavor compound’s is inconsistent(8) Roughages have significant influence on economic benefit, which the group III achieved the highest gross profit (6124.52 yuan/head)followed by groupⅠ(4376.52 yuan/head) and groupⅡgross profit was the lowest (2925.11 yuan/head).This study reveal that firstly, Corn stalks, Pennisetum and brewer’s grains are economical roughage which are suitable for beef cattle production, but these roughages should be a reasonable combination and mixed with the high quality feed; Secondly, under the experimental conditions,hybrid cattles (Red Angus×Simmental×Southern Sichuan) can produce high-grade beef.