Dose selection of selamectin for efficacy against adult fleas (Ctenocephalides felis felis) on dogs and cats

Selamectin, a novel avermectin, was evaluated in two controlled studies (one in Beagles, one in domestic shorthaired cats) to determine an appropriate topical dose for efficacy against adult Ctenocephalides felis felis (C. felis) fleas on dogs and cats for 1 month. For each study, animals were allocated randomly to four treatments. One treatment consisted of the inert formulation ingredients (vehicle) administered as a negative control, and the other three treatments consisted of a single topical dosage of 3, 6, or 9mgkg(-1) of selamectin. In each study, selamectin was administered as a topical dose applied to the skin in a single spot at the base of the neck in front of the scapulae. Dogs and cats were infested with 100 viable unfed C. felis (50 males and 50 females) on days 4, 11, 18, and 27. Seventy-two hours (+/-2h) after each infestation, on days 7, 14, 21, and 30, a comb count to determine the number of viable fleas present on each animal was performed. Efficacy of selamectin on day 30 was used to select an appropriate dose. For dogs and cats, percentage reductions in geometric mean flea comb counts for the three selamectin treatments ranged from 94. 6 to 100% on days 7, 14, and 21, compared with the negative-control treatment. On day 30, reductions in flea comb counts were 81.5, 94.7, and 90.8% for dogs, and 79.8, 98.0, and 96.2% for cats treated with selamectin at 3, 6, or 9mgkg(-1), respectively. For day 30 flea comb counts for dogs and cats, analysis of variance showed that the three selamectin treatments resulted in significantly (P< or =0.05) lower counts than did the negative-control treatment. For dogs and cats, geometric mean flea counts for selamectin administered at a dosage of 3mgkg(-1) were significantly (P< or =0.05) higher than those for the 6 and 9mgkg(-1) treatment dosages combined. There were no significant differences in flea counts between the 6 and 9mgkg(-1) treatments. This analysis was confirmed by linear-plateau modeling. Thus, the optimal dose of selamectin for efficacy against adult fleas for both dogs and cats, as estimated by the turning point (plateau) in the dose response curve, was 6mgkg(-1).     

提高种猪群体生产力的对策

1母猪方面 1．1保持合理的母猪群体年龄结构母猪群内年龄结构 主要依据母猪的利用年限而定。一般猪种的母猪繁殖高峰为第3—8胎，第9胎及9胎以后产仔数逐胎减少，仔猪存活率也逐胎下降。据此，母猪的利用年限限定为4—5岁，每年更新20％。25％，各年龄的母猪大体上均占20％-25％，对生产力较高的母猪可适当延长年限，对生产力很低的母猪可早期淘汰。     

母乳途径间接补硒的可行性及增强仔猪免疫机能的初步探讨

以某正常生产的集约化猪场为试验场所,在满足生长需要的全价配合饲粮（含硒量０．３１ｍｇ／ｋｇ）基础上,给哺乳母猪饲粮添加不同剂量的无结晶水亚硒酸钠（０．７５,１．０,１．５ｍｇ／ｋｇ）,检测断奶仔猪的血硒含量、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性等生化指标并综合分析,结果仔猪血硒含量与哺乳母猪饲粮亚硒酸钠的添加量相对应,试验２组（１ｍｇ／ｋｇ组）仔猪的ＧＳＨ－Ｐｘ活性、红细胞、嗜中性白细胞、单核细胞和Ｔ淋巴细胞含量均显著增加,说明母乳途径间接补硒能提高仔猪的生理免疫机能。     

凉山圆根在昭觉地区的品比试验研究

对4个圆根品种在昭觉地区进行了品比试验，通过对物候期、生产性能及单株性状等指标的测定，以选出生产性能高、遗传稳定的凉山圆根地方品种。结果表明，四开、烂坝、打洛圆根的生产性能及单株性状明显优于对照品种百肯芜菁，特别是四开圆根品种值得推广。     

腾冲县扑灭中缅边境重大森林火灾

2月18日,中缅边境腾冲段发生由缅方烧入的森林火灾。接到报告后,腾冲县立即启动应急预案,组织军警民火速扑救。党中央、国务院和云南省委、省政府及国家森林防火指挥部高