巴林右旗干草原主要牧草的营养成分季节动态与饱和链烷烃组成结构的研究

通过测定10种牧草5月至翌年1月的7种常规营养成分含量及其中8种牧草7和10月的8种饱和链烷烃浓度,对巴林右旗典型干草原的主要牧草的营养成分季节变化规律和同一季节饱和链烷烃组成差异进行了研究。结果表明,多数草样的粗蛋白含量5月到翌年1月逐季显著降低(P<0.05),Ca含量10月最高(P<0.01),总磷(TP)含量5月最高(P<0.01),中性洗涤纤维与酸性洗涤纤维含量极显著正相关(P<0.01),Ca与TP含量极显著负相关(P<0.01);7、10月,多数草样的C₂₉、C₃₁饱和链烷烃浓度极显著(P<0.01)高于其余的6种饱和链烷烃,其饱和链烷烃组成结构的主成分值Z₁、Z₂的差异显著(P<0.05)。上述研究表明,巴林右旗干草原的主要牧草的蛋白质逐季减少且钙磷含量彼此反向变化,需对家畜及时补饲,其饱和链烷烃组成差异明显,通过链烷烃技术估测放牧家畜采食结构可行。

The seasonal nutritional dynamics of major forages composition of the steppe of Bahrain Right Banner and its forming structure of the saturated chain alkane research

Seven conventional nutrient analyses were conducted monthly for 10 forage species in the typical steppe grassland of Bahrain Right Banner from May to the following January, and concentrations of 8 saturated chain alkane compounds from eight of the forage species were measured in July and October, to study the seasonal changes in grassland feed quality. It was found that across the May-January period studied, crude protein (CP) content decreased significantly (P<0.05) quarter by quarter, in most of the species measured. The calcium content peaked (P<0.01) in October, and total P (TP) content was highest (P<0.01) in May. The acid detergent fiber (ADF) content was highly correlated with the neutral detergent fiber content (NDF) (P<0.01), while Ca content displayed an extremely negative correlation with TP content (P<0.01). In July and October, the concentrations of C₂₉ and C₃₁ saturated chain alkanes were much higher (P<0.01) in most grass samples, than the other six saturated chain alkanes measured. On principal component analysis of the data, Z₁ and Z₂ which were the principal component scores reflecting the saturated chain alkane composition were significantly different (P<0.05). For the major forage species in the steppe grassland of Bahrain Right Banner, the above data showed that supplementary feeding would be required by livestock as the CP decreased in late season, seasonal trends in herbage calcium and phosphorus contents were opposite, and the nutritional value of herbage for grazing livestock could also be estimated by the paraffin determinations as the contents of the various saturated chain alkanes in these forages showed seasonal variation parallel to that of the nutritional parameters.