荷斯坦母牛血钾浓度的影响因素分析

Analysis on Influencing Factors of Blood Potassium in Holstein Cows

【目的】研究奶牛血钾浓度的影响因素。【方法】采用手持血钾仪在夏季和秋季分别测定北京地区222头和67头荷斯坦泌乳牛的血钾浓度,利用固定模型分析环境温湿度指数(Temperature and humidity index,THI)、直肠温度、胎次、泌乳阶段、血液类型和挤奶前后对血钾浓度的影响。【结果】手持血钾仪所测血钾浓度在正常范围内,荷斯坦牛泌乳牛血钾浓度为2.31~5.13 mmol/L;THI>72时的血钾浓度显著(P<0.05)高于THI<72时的血钾浓度;不同THI条件下,直肠温度对血钾浓度的影响程度不同,THI为55~60和77~78时,直肠温度每升高1℃血钾浓度分别上升0.7和0.32 mmol/L,THI为72~76和79~88时直肠温度与血钾浓度无回归关系(P>0.05);静脉血钾浓度(4.01±0.05)mmol/L极显著(P<0.01)高于动脉血钾浓度(3.81±0.05)mmol/L;奶牛挤奶后血钾浓度(4.06±0.05)mmol/L极显著(P<0.01)高于挤奶前血钾浓度(3.76±0.04)mmol/L;胎次和泌乳阶段对血钾浓度无显著(P>0.05)影响,但随着泌乳天数的增加血钾浓度有逐渐降低的趋势。【结论】手持血钾仪可以快速、准确地测定奶牛的血钾浓度;THI对血钾浓度有显著影响,THI的升高会引起血钾浓度的变化;挤奶和血液类型对血钾浓度有较大影响,研究血钾浓度时应注意排除这两项因素的影响,血钾浓度可作为判断奶牛健康状态的指标。

【Objective】This study was objectiveto explore the factors affecting blood potassium concentration(BPC)of dairy cows.【Method】The BPCwas measured from 222 milking cows in summer and 67 milking cows in autumn in Beijingby a hand-held blood potassium meter. The effects of temperature humidity index(THI),rectal temperature(RT),parity,milk stage,blood type and milkingstatuson BPC were analyzedusing a fixed model.【Result】The resultsshowed that the BPC measured by hand-held blood potassium meter were in the normal range,the BPC was 2.31~5.13 mmol/L. The BPC when THI>72 was significantly higher than that when THI<72(P<0.05). The effect of RT on BPCwas different under different THI range. When THI is between 55~60 and 77~78,BPC increased by 0.7 mmol/L and 0.32 mmol/L for every 1℃ increasein RT,respectively. There was no regression relationship between RT and BPC when THI were 72~76 and 79~88(P>0.05).Venous BPC(4.01±0.05)mmol/L was significantly higher than arterial BPC(3.81±0.05)mmol/L(P<0.01).The BPC after milking(4.06±0.05)mmol/L was significantly higher than that before milking(3.76±0.04)mmol/L(P<0.01). The influence of parity and milk stage on BPC was not significant(P>0.05),whilewith the increase of day in milk,the BPC showed a decreasing trend.【Conclusion】The hand-held blood potassium meter can quickly and accurately determine the BPC indairy cows. THI has a significant effect on BPC,and the increase of THI will cause the increase or decrease of BPC. Milking status and blood type have great influence on BPC,which should beexcludedwhen it is analyzed.