Study On Growth And Fasting Metabolism Of Grassland Red Cattle

In order to improve continuously and enhance production performance and implement the standardized feeding of science, study on the characteristics of gas metabolism of Grassland Red cow on five different body weight stages (78.63±0.55kg,168.17±12.41kg,213.73±18.45kg,310.73±9.44kg,394.83±45.40kg) with the large open-circuit respiration chamber system, to measure methane emissisions at the same times, the purpose is to provide scientific basis for the further improvement of raising standards and nutritional requirements and to strengthen measures of methane emissions reduction.Determination indicators include:Oxygen concentration, carbon dioxide concentration, methane concentration of respiration chamber and outside the respiration chamber; respiratory quotient, oxygen consumption, cabon dioxide emissions, methane emissions; feed, fecal samples and urine samples protein content and energy content.The results showed:(1) The results of growth metabolism:the amount of oxygen consumption, carbon dioxide emissions and heat production were increased with body weight increase, there were significant differences between period one, two, three, four (p<0.05). there was no significant difference between period four and five (p>0.05). However, according to metabolic body weight. The amount of oxygen consumption of different stages were17.49±0.06、10.61±1.36、15.53±0.93、24.57±2.04、27.10±2.97L/W0.75·d. there were no significant differences between period one, two. three, five(p>0.05). Period four were significantly higher than period one. two. three, five (p<0.05); Carbon dioxide emissions of different stages were13.98±0.01、8.74±0.92、12.96±0.92、20.04±1.09、22.89±2.67L/W0.75·d, there were significant differences between period one, two. three. four (p<0.05), there was no significant difference between period three and five (p>0.05); Heat production of different stages were352.56±1.01、213.47±26.39、312.89±19.53、492.47±38.06、546.98±60.90kJ/W0.75·d, there was no significant difference between period one and two (p>0.05). there was no significant difference between period three and five (p>0.05). Period four was significantly higher than period one, two, three, five (p<0.05).(2) The results of fasting metabolism test:the amount of oxygen consumption, carbon dioxide emissions, heat production were increased with body weight gain. However, according to metabolic body weight, the amount of oxygen consumption of different stages were7.77±0.45、7.31±0.33、7.06±1.35、7.09±1.30L/W0.75·d; carbon dioxide emissions of different stages were4.12±0.13、3.81±0.26、4.97±0.96、5.09±0.91L/W075·d; heat production of different stages were146.27±7.85、137.41±6.46、139.01±26.65、140.02±25.40kJ/W0.75·d; In terms of the amount of oxygen consumption and carbon dioxide emissions and heat production, there was no significant difference between different stages (p>0.05).(3) The results of methane metabolism:Methane emissions were increased with metabolic body weight gain, methane emissions of different stages were5.76±0.00、29.28±5.45、67.20±7.25、133.92±11.25、196.80±29.13L/d, there were significant differences between period one, two, three, four (p<0.05), there was no significant difference between period four and five (p>0.05); However, according to metabolic body weight, methane emissions were increased with hunger strike metabolic weight, methane emissions of different stages were0.22±0.00、0.63±0.12、1.20±0.07、1.80±0.12、2.27±0.27L/W0.75·d. there was no significant difference between the periods (p>0.05). Methane emissions were rapidly increased after feed intake, methane emissions were reached peak after1.5to2hours and decreased after the peak maintain two hours. DM intakes, CP intakes, GE intakes and methane emissions were positively correlated. CH4-E/GE (%) of two, three, four, five period of this experiment were:3.23%,4.36%,6.22%,6.15%.Conclusion:Gas exchange indicators of Grassland Red Cattle are in line with the growth and development law of cow. reliable data can be used as a follow-up study basis. There are great relationships between methane emissions and animal body weight, dry matter intake, which can be used as the basis for the estimation of methane emissions.