A recent assessment of the elemental composition of New Zealand pastures in relation to meeting the dietary requirements of grazing livestock
A recent assessment of the elemental composition of New Zealand pastures in relation to meeting the dietary requirements of grazing livestock
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DOI：
10.2527/jas.2013-6847
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发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Grace, N. D.
中科院分区：
文献类型：
--
作者：
Knowles, S. O.;Grace, N. D.
了解牧场饲养的好处和局限性是可持续放牧系统的基础，可持续放牧系统可以从反刍动物中生产牛奶和肉类。我们评估了从2001年至2006年从新西兰各地独立收集的1,106个牧场样本的矿物成分。大约一半是在2002年和2003年提交的，87%来自北岛。大部分牧草来自以黑麦草和三叶草为主的草地。Ca、Co、Cu、Fe、K、Mg、Mn、Mo、Na、P、S、Se或Zn的浓度通过硝酸消化，随后通过电感耦合等离子体发射光谱法或原子吸收光谱法来测量。常量元素的中位浓度为Ca 5.5，K 33，Mg 2.2，Na 2.0，P 4.0，S 3.6 g/kg DM，微量元素的中位浓度为Co 0.10，Cu 8.4，Fe 131，Mn 74，Mo 0.66，Se 0.050，Zn 43 mg/kg DM。浓度的频率直方图显示，分布范围从接近正态分布到底部重偏态分布，具有高值的长尾。在大多数牧场中，植物良好生长所需的矿物质浓度足够。例外是P;只有74%的牧场含有推荐的3.5 mg P/kg DM。牧场调查的结果进行了比较，牛和羊的饮食摄入量的要求。对于7种元素，>95%的牧场含有足够高的浓度，以满足未补充动物的需要。三是硒的膳食需求，这是满足只有76%的牧场，羊的钴的需求满足只有54%的牧场，和铜，钠，磷的需求，牛满足25，78，和87%的牧场，分别。磷分析是一个重要的工具，用于确定膳食不足以及不利的矿物质平衡，其中相互作用可能导致缺乏，如铜x钼和镁x钾。还需要监测动物的营养状况，以管理与围产期Ca和Mg通量相关的复杂代谢紊乱。这项研究是30年来唯一一项对新西兰牧场矿物质成分进行大规模评估的研究，也是第一项包括全方位微量元素的研究。了解不太可能满足某些元素营养需求的牧场比例有助于确定放牧牲畜系统的风险区域，并估计如果目前的补充做法不到位，矿物质缺乏症可能有多普遍。
An understanding of the benefits and limitations of pasture feeding underpins sustainable grazing systems that produce milk and meat from ruminant livestock. We evaluated the mineral composition of 1,106 pasture samples collected independently from locations across New Zealand from 2001 to 2006. About half were submitted during 2002 and 2003, and 87% came from the North Island. Most herbage was from ryegrass and clover-dominated swards. The concentrations of Ca, Co, Cu, Fe, K, Mg, Mn, Mo, Na, P, S, Se, or Zn were measured by nitric acid digestion followed by inductively coupled plasma optical emission spectroscopy or atomic absorption spectroscopy. Median concentrations for the macro elements were Ca 5.5, K 33, Mg 2.2, Na 2.0, P 4.0, and S 3.6 g/kg DM and for the trace elements were Co 0.10, Cu 8.4, Fe 131, Mn 74, Mo 0.66, Se 0.050, and Zn 43 mg/kg DM. Frequency histograms of concentrations revealed distributions ranging from near-normal to bottom-heavy skew with a long tail of high values. The minerals required for good plant growth were found at adequate concentrations in the majority of pastures. The exception was P; only 74% of pastures contained the recommended 3.5 mg P/kg DM. Results of the pasture survey were compared to the dietary intake requirements of cattle and sheep. For 7 elements, >95% of the pastures contained sufficiently high concentrations to meet the needs of unsupplemented animals. Exceptions were the Se dietary requirement, which was met by only 76% of pastures, the Co requirement of sheep met by only 54% of pastures, and the Cu, Na, and P requirements of cattle met by 25, 78, and 87% of pastures, respectively. Pasture analysis is an essential tool for identifying dietary insufficiency as well as unfavorable mineral balances where interactions could induce a deficiency, such as Cu x Mo and Mg x K. Monitoring of animals' nutritional status is also required to manage complex metabolic disorders related to peripartum flux of Ca and Mg. This study is the only large scale assessment of the mineral composition of New Zealand pastures to be published in 30 yr and the first to include a full range of trace elements. Knowing the proportion of pastures that are unlikely to meet nutritional requirements for some elements helps to define the risk areas for grazing livestock systems and provides an estimate of how prevalent mineral deficiencies might be if current practices of supplementation were not in place.