Meat characteristics of Qinghai yak and semi-wild yak

Six domestic yaks aged 6 years, comprising three culling male and three culling female yaks, from the Qinghai Lake area and three male semi-wild yaks aged 6 months from Datong Yak Farm were used to detect the levels of amino acids, mineral elements, residual heavy metals and pesticides in yak meat. The results showed that there was little difference in amino acid levels for different types of yak by age and sex. The meat of the adult male yak was 7.35 mg/kg higher in calcium (P < 0.05) and 124 mg/kg higher in phosphorus (P < 0.01) than that of the adult female yak. There was an obvious difference in zinc content, and there was also a significant difference for copper and sulfur between adult male and female yaks (P < 0.01). Iron was 8.85 mg/kg higher in semi-wild yaks than in domestic yaks, but there were no differences for other minerals. The levels of residual heavy metals and residual pesticides were well within those allowed by the National Standard of China. Furthermore, the data showed that introducing wild yak's blood did not result in a quality change in the domestic yak meat. Yak meat from Qinghai Plateau has the characteristics of being non-polluted and rich in amino acids in comparison with local yellow cattle meat.

Suitability of extractants for predicting available sulfur in natural grassland in the Inner Mongolia steppe of China

It was the objective of this study to compare the suitability of different extractants for predicting the availability of sulfur (S) in natural grassland in a sulfur response trial on three different soil types in the Inner Mongolia steppe of China. For soil analysis, seven different extractants have been employed. The inorganic SO4-S concentration was determined by ion chromatography. Additionally, in the Ca(H-2-PO4)(2) extract the total soluble S was determined employing turbidimetry. Weak salt solutions (0.15% CaCl2, Ca(H2PO4)(2), and KH2PO4) extracted similar amounts Of SO4-S. Extraction with 0.025 M KCl provided the lowest SO4-S values. Deionized water dissolved significantly more SO4-S in the control plots than most weak salt extractants. The concentration of soluble organic S decreased in the control plots after 100 days of plant growth, indicating that the organic S pool contributed significantly to the S nutrition of the forage crops. Significant relationships among the SO4-S in the soil determined in different extracts and crop yield, sulfur content in the forage, and total sulfur uptake were only found for the Ca(H2PO4)(2) extract. In general, the correlation coefficients proved to be unsatisfactory for field experimentation.

Digestibility, nutrient balance and urinary purine derivative excretion in dry yak cows fed oat hay at different levels of intake

A feeding trial A as conducted at the farm of Qinghai Academy of Animal and Veterinary Science, Xining, China during 1996 - 1997 with three dry yak cows (initial body weight 163 - 197 kg, age 5 - 6 years) by using 3 x 3 Latin Square Design to determine the effect of levels of feed intake on digestion, nitrogen balance and purine derivative excretion in urine of yak cows. The animals were fed oat hay (nitrogen 13.5 g/kg dry matter (DM), metabolisable energy 8.3 MJ/kg DM), i.e., 0.3, 0.6 and 0.9 of voluntary intake (VI). Each intake treatment lasted for 17 days and the samples (feeds, faeces and urine) were collected during last 7 days of each period. The results indicate that digestibility of dietary DM, OM, NDF and ash declined when intake levels increased from 0.3 to 0.9 VI [DM, from 66.1% to 59.1% (P < 0.05); OM, from 68.1% to 59.9% (P < 0.05); NDF, from 62.1% to 54.3% (P < 0.05); and ash, from 33.9% to 11.8% (P < 0.05)]. Around 0.10 g N/kg W-0.75 was deficient daily in yak cows at 0.3 VI, and positive N balances were observed at 0.6 and 0.9 VI. Intake levels significantly (P < 0.05) affected total PD excretion in yak urine. The proportion of allantoin increased (P < 0.05) and uric acid decreased (P < 0.05) as intake level of feed increased. (C) 2004 Elsevier B.V. All rights reserved.