Comparative Studies On Performance Of Grassland Red Cattle And Crossbred F₁ Of Grassland Red Cattle And Limousin

The research attempted to compare the differences in growth performance, carcasscharacteristics, meat quality, and serum biochemical parameters in Grassland Red Cattle andcrossbred F₁ of Grassland Red Cattle and Limousin fed with identical and different nutritionallevels diets, to find out the differences of performance in Grassland Red Cattle and crossbredF₁ of Grassland Red Cattle and Limousin, to approach the effects of different nutritional levelson their performance, and to reveal the relationships between the activity of serum enzymesand performance.Grassland Red Cattle(n=18) and crossbred F₁ of Grassland Red Cattle and Limousin(n=22) were used in the experiment, their average age was 11 months. The experiment wasconsisted of fattening test and slaughtering test, The fattening test were divided into twostages. There were 215 days in the earlier stage and 83 days in the later stage. In the laterstage, Grassland Red Cattle and crossbred F₁ of Grassland Red Cattle and Limousin weredivided into two groups respectively, were fed with two nutritional levels diets.Average daily gains, body size, body weight, the traits of slaughter, meat quality andserum biochemical parameters were measured. All parameters of meat quality were measuredwith longissimus muscle of back. Some correlation analysis were made for finishingperformance and serum biochemical parameters. The results were follows:1. Crossbred F₁ of Grassland Red Cattle and Limousin were obviously higher than GrasslandRed Cattle in average daily gains, body size, body weight, feed conversion ratio, livingweight, carcass weight, net meat weight, dressing percentage, meat percentage (P＜0.05).2. The concentration of GH and AKP in serum in crossbred F₁ of Grassland Red Cattle andLimousin were higher than Grassland Red Cattle (P＜0.05). But the concentration ofglucose, the activity of LDH and Amy were lower than Grassland Red Cattle (P＜0.05).3. The beef of Grassland Red Cattle and crossbred F₁ of Grassland Red Cattle and Limousinwas high-quailty in pH, tenderness, water holding capacity, meat color, fatty color etc. But thediameter of muscle fiber in Grassland Red Cattle were bigger than crossbred F₁ of GrasslandRed Cattle and Limousin (P＜0.05). The meat color was deeper than crossbred F₁ of GrasslandRed Cattle and Limousin (P＜0.05). The content of intramuscular fat was higer than crossbredF₁ of Grassland Red Cattle and Limousin. The marble texture and water holding capacity were better than crossbred F₁ of Grassland Red Cattle and Limousin.4. Effects of different nutrient levels on growth performance were significant. High nutrientlevel diet was beneficial to crossbred F₁ of Grassland Red Cattle and Limousin, but GrasslandRed Cattle grew well fed with middle nutrient level diet. Therefore, designing nutrient levelof diet should be accord with the different nutrient requirement of cattle.5. Meat quality of Grassland Red Cattle and crossbred F₁ of Grassland Red Cattle andLimousin was influenced by different nutrient levels diet. The content of intramuscular fat wasimproved by high nutrient level diet, and marble texture and tendness was improvedaccompanyly. High nutrient level diet also improved the content of total amino acid, essentialamino acid, palatable amino acid in crossbred F₁ of Grassland Red Cattle and Limousin(P＜0.05).6. Growth performance, carcass characteristics, meat quality correlated with the activity ofGOT,GPT,AKP,LDH,Amy and the concentration of GH in Grassland Red Cattle. Themultiple regression equation between activity of enzyme and the dressing percentage inGrassland Red Cattle: Y=56.895-0.0119x₁+0.05207x₂+0.01839x₃-0.0387x₄-0.0011x₅(x₁,x₂,x₃,x₄,x₅ reprsented the enzymatic activity of GPT,GOT,AKP,Amy,LDHrespectively)On the whole, Effects of hereditary factor, nutrient level and their interaction onperformance in Grassland Red Cattle and crossbred F₁ of Grassland Red Cattle and Limousinwere significant. We should decide the nutrient level of diet and slaughtering age according tothe different nutrient requirement and regularity of growth and development, then meatproduction and quality will be improved.