Inaugural ASAS–CAAV Asia Pacif ic Rim Conference Abstracts

Beef Species PostersUrinary purine derivative excretion as an index forT228T226estimating rumen microbial nitrogen yield of yak in the Qinghai-Tibetan.H. Wang 1,2 , R. Long* 1 , and X. Guo 1 , 1 International Centre for Tibetan PlateauEcosystem Management, Lanzhou University, P.R. China, 2 Tibetan Rangelandand Yak Research Institute, College of Pastoral Agriculture Science andTechnology, Lanzhou University, P.R. China.The rangeland of the Qinghai–Tibetan plateau is characterized by its highaltitude, low annual average temperature, and a short growing season. Yaks,having lived in such a harsh environment for several thousand years, seemto have developed some special physiological features for their survival.The objective of the present study was to develop equations based on purinederivative (PD) excretion for estimating rumen microbial protein production. Inthe fasting experiment, three 3-year-old castrated yaks were used. The resultsof a 6-day fasting trial showed that the daily endogenous urinary PD and Nexcretion was 134 μmol/kg BW 0.75 and 0.25 g/kg of BW 0.75 , respectively. Inthe feeding experiment, excretions of urinary PD linearly ascended with theincreasing of feeding level. The relationships between digestible OM intake(kg/d) and PD (mmol/d) was PD = 16.02 digestible OM intake + 1.27 (R 2 =0.75, P < 0.001). With the increase of infusion RNA level, excretion of urinaryallantoin, total PD, and the ratio of allantoin to PD linearly ascended. Therelationship between daily urinary PD excretion (Y, mmol/d) and exogenouspurine supply via abomasums infusion (X, mmol/d) was Y = 0.85 X + 33.02(R 2 = 0.96), suggesting that 85% of the supplied exogenous purine was excretedin the urine of yak. Based on the endogenous PD excretion obtained in thefasting trial, the relationship between daily urinary PD excretion (Y, mmol/d)and daily microbial purine supply (X, mmol/d) was Y = 0.85 X + 0.134 kg ofBW 0.75 for yak. According to above equation, microbial N (MN, g/d) productionfor yak can be calculated from the following equations: MN = (X × 70)/(0.83× 0.15 × 1,000) = 0.56 X, or MN = (X × 70)/(0.83 × 0.33 × 1,000) = 0.26 X. Inthese equations, digestibility of microbial purine was assumed to be 0.83 and Ncontent of purine was 70 mg/mmol. The ratio of purine N to total N in mixedrumen microbes was taken as 0.15 or 0.33 in greater or lesser dietary N level,respectively.Key Words: purine derivative, digestible organic intake, microbial nitrogenPreliminary study on the use of inhibin to improvethe water buffalo superovulation. G.-S. Qin 1,2 , D.-R. Li 4 , Y.-M. Wei 1,3 , Q.-Y.Jiang 1,4 , Y.-C. Qin 1,3 , K. A. Al 1 , B. Pan 1 , B.-J. Chen 1 , X.-B. Mao 1 , Z.-D. Shi 4 , andH.-S. Jiang* 1,3 , 1 College of Animal Science & Technology, Guangxi University,Nanning, China, 2 Guangxi Buffalo Research Institute,, Nanning, China,3Nanning Ovagene Biotechnology Co., Ltd, Nanning, China, 4 Departmentsof Animal Science, South China Agricultural University, Guangzhou, China.Seventeen female buffaloes with normal estrus cycle were randomly dividedinto 10 heads for the experimental group and 7 heads for the control. In theexperimental group 1 mg/head of the Recombinant porcine inhibin α subunitfusion protein was administrated as the first immunization. After 28 and 56 days,the immunization was strengthened by the dose of 0.5 mg/head. At the sametime, an adjuvant consisting to the mixture of mineral oil and physiologicalsaline was administrated to the control group. In both the experimentalgroup and the control, at the days 28 (first strengthened immunization) and56 (second strengthened immunization), the follicles size and number weremonitored and counted respectively by B-mode linear array ultrasound scanner.At eight days after the super ovulation the follicles and corpus luteum countwere performed by B-mode linear array ultrasound scanner and palpation. Theresults showed that, in the experimental group compared with the control onethe average follicles number enhanced (from 8.8 to 15.0) after strengtheningthe immunization, but the difference was not significant (P > 0.05). After thesuper ovulation, in the experimental group the mean number of the folliclesand corpus luteum and ovulation rate were 12.2‚±0.79, 9.0‚±1.06 and 73.77% respectively, compared to the control, the difference was significant (P