奶牛碘缺乏症及其防治试验

对４２ 份奶牛饲料碘、６ 份饮水碘和１３８ 份血清蛋白结合碘（ＰＢＩ） 进行测试。临床检查８２３ 头奶牛， 选取２３２ 头， 每天日粮添加０－４１ ｍｇ／ｋｇ碘， 连续饲喂３００ ｄ ， 探讨奶牛碘缺乏及添加效应。结果表明： 奶牛日粮碘０－１４ ｍｇ／ｋｇ， 饮水碘７－７３ μｇ／Ｌ， 含碘量严重缺乏。奶牛血清ＰＢＩ测值有４２－９９ ％ 低于正常范围的下限２－４ μｇ／１００ｍＬ。进一步分析， 颌下水肿奶牛ＰＢＩ为２－１３８ μｇ／１００ ｍＬ（ ｎ ＝ ２１） ， 肉垂肿大奶牛ＰＢＩ为２－７９８ μｇ／１００ ｍＬ（ ｎ＝ １４） ， 流产奶牛ＰＢＩ为２－２１６ μｇ／１００ ｍＬ （ｎ ＝ １１） ， 产死胎、弱犊占１９－５６ ％ （６３／３１７） 的ＰＢＩ为１－６２６ μｇ／１００ ｍＬ （ ｎ ＝ ３１） ， 尿酮阳性奶牛ＰＢＩ为１－４７７ μｇ／１００ ｍＬ （ ｎ ＝ ３４） ， 尿酮阴性奶牛ＰＢＩ为２－１８ μｇ／１００ ｍＬ（ ｎ ＝ ２９） ， 两者差异极显著（ Ｐ＜ ０－０１） 。日粮添加碘使奶牛血清ＰＢＩ上升至５－５４４μｇ／１００ ｍＬ， 死胎率下降到６－７８ ％ （１２／１７７） ， 咽喉周围及垂肉粘液性水肿消失， 生产性能和繁殖性能均得到改善。

Study on Iodine Deficiency and Its Control in Dairy Cow

Iodine contents of 42 diets,6 drinking water,138 serum protein bind iodine(PBI)and 823 dairy cows were examined in 4 farms,and efficiency of supplemental iodine in diets with 0 41 mg/kg daily for 300 days in 232 dairy cows were observed,The results indicated that contents of iodine in diet of dairy cow was 0 14 mg/kg,7 73 μg/L in drinking water,which were severely deficient,42 99% of serum PBI in dairy cow was less than the minimum normal range 2 4 μg/100 mL.Further analyses showed that PBI of dairy cow with mandibular dropsy was 2 138 μg/100 mL( n=21 ),PBI with swollen wattle was 2 798 μg/100 mL( n=14 ),PBI with abortion was 2 216 μg/100 mL( n=11 ),PBI with still birth and weak calves,which were accounted for 19 56%(62/317) was 1 626 μg/100 mL( n=31 ).PBI with positive urinary ketone bodies was 1 47 μg/100 mL( n=34 ),PBI with negative urinary ketone bodies was 2 18 μg/100 mL( n=29 ),both of which were significantly different( P<0 01) .It was suggested that Ningxia dairy cows suffered from iodine deficiency.When iodine was supplemented to dairy cow,the serum PBI was increased to 5 54 μg/100 mL,the morbidity of still birth decreased to 6 78%(12/177),mandibular dropsy and swollen wattle disappeared and the reproduction were improved.