鸡脱羽的原因和防治策略

鸡的体躯表面覆盖着一层厚厚的羽毛,包括贴身的绒羽和表层的羽片,形成一层不流动的空气层,产生良好的隔热作用,有效地阻止体热的散发,因此可抵御较低的外界环境温度,且能够维持比外界环境高得多的体温.然而,在养鸡生产中,会经常遇到鸡发生脱羽的现象,导致生产性能或胴体品质下降,影响经济效益.造成鸡脱羽的原因很多,但归纳起来主要分为生理性脱羽和非生理性脱羽两方面.     

成林桑园地膜覆盖技术综合效果研究

近年来我们开展了成林桑园采用黑色农用塑料薄膜覆盖地表的试验,对桑园除草、肥力流失、害虫防治、用工情况、桑叶产量等实际效果进行了综合研究。结果表明桑园地膜覆盖后,全年可以免除人工或药剂除草、减少土壤肥力流失,桑瘿蚊为害率降低66．3％,桑园管理用工减少41．6％,节约生产     

食管插入胃黏膜覆盖法在食管贲门穿孔术中的应用

在治疗异物梗塞引起的犬食道穿孔或坏死的治疗方案中．仍首选手术治疗。回顾过去手术治疗主要施以食道切除术，采取断端吻合，食道双层单纯连续缝合即可，因食道愈合较困难，仍出现许多并发症状，如吻合口瘘，吻合口狭窄，返流性食道炎。这些症状都可导致犬只术后死亡，探索一种安全有效的手术治疗方案。是外科兽医共同研究的一个重要课题。笔者曾遇到一例犬食道贲门穿孔病例，采用食管插入胃黏膜覆盖法治疗获得成功，值得临床推广。现将手术治疗经过介绍如下。     

不同处理全棉籽对泌乳牛养分消化率和生产性能的影响

本试验采用交叉设计,选择年龄、胎次、泌乳量、泌乳日龄都较接近的12头荷斯坦奶牛,随机分为6组,每组2头,进行为期45天的饲养试验,研究不同处理的全棉籽替代等量精料对泌乳牛养分消化率和生产性能的影响.结果表明:用2kg不同处理的全棉籽(脱绒、带绒、带绒压扁)等量替代精料后,三个不同处理全棉籽对泌乳牛养分消化率和生产性能的影响差异均不显著(P＞0.05).从CF和NDF的消化率来看,压扁带绒棉籽组有降低CF和NDF消化率的趋势.     

河北省养羊业发展方向及对策

近一两年来．全省养羊业的饲养方式逐步完成了从放牧向放牧加舍饲和全舍饲的转变，随着养羊成本的增加，养羊效益下降；前几年进口种羊及当地种羊价格连年攀升的局面已不复存在．取而代之的是种羊市场的异常萧条，种羊甚至有行无市。养羊场（户），尤其是种羊场面对目前严峻的形势，不能被击跨．要保持清醒的头脑，认清养羊业的发展方向，及时正确决策，少走弯路。下面是笔者依据多年的经验，根据我国、我省养羊的发展状况，结合世界各国养羊业发展所走过的道路，以及我国肉羊生产的新形势．提出我省养羊业发展方向及对策。     

Whole Genome Methylation Variation Analysis of Longissimus Dorsi Between Tan Sheep and Hu Sheep

It aimed to identify the differential methylation region (DMR) and differential methylation gene (DMG) through the analysis of the genome-wide methylation difference of the longest muscle of the sheep's back of different breeds of sheep,and laid the foundation for the analysis of the differences in sheep skeletal muscle development.In this study,one-year-old sheep(Tan sheep and Hu sheep and Tan-Hu F2) were sanned by the whole genome bisulfite sequencing method(WGBS).The degree of methylation and differentially methylated region in the whole genome DNA of longissimus dorsi(LD) muscle were studied to explore the difference of DNA methylation in level in sheep.The results showed that the methylation (mC) rates of cytosine (C) were 3.55%,3.18% and 3.56% in Tan sheep,Hu sheep and Tan-Hu F2,respectively.A total of 97 731 DMRs and 10 784 related DMGs were detected.In CG,CHH and CHG sequences,the methylation levels of the three groups were not significantly different.419 GO terms and 20 related signal pathways were detected by GO and KEGG analysis,respectively,which were showed to be significantly enriched in cellular process,cell part,binding,long-term depression,and so on.Five candidate genes,ACTA2、ROCK1、CALD1、MYH3 and MYH10 were sreened out in muscle tissues.This study provided genome-wide methylation of pattern of three groups (Tan sheep and Hu sheep and Tan-Hu F2).The results provided reference information for the epigenetic study of Tan sheep and screened candidate genes related to muscle development and meat quality.     

Genome-wide Association Study on Alive Litter Size Trait in Bama Xiang Pigs

In order to identify the molecular markers related to alive litter size of Bama Xiang pigs,the genome-wide association study (GWAS) was used to map and screen the candidate genes affecting the alive litter size trait.Ear tissue samples of 297 Bama Xiang pigs with multiple parity records were collected,and DNA was extracted and genotyped by porcine 50K SNP beadchip.After quality control and genotype imputation,the alive litter size of Bama Xiang pigs were GWAS by Tassel.The results showed that the average number born alive per litter of Bama Xiang pigs increased gradually with the increasing of parity in the range of 1-9 parities.A total of 32 816 SNPs were obtained after quality control and filtration.8 SNPs related to alive litter size of Bama Xiang pigs were screened by genome-wide association analysis,which were significant at genome or chromosome level.Based on the enrichment analysis of the coding genes in the region between 500 kb upstream and downstream of the associated significant SNP loci,and the QTL regions and gene functions related to porcine reproductive traits,4 genes (CAPZB,MSH3,CITED2 and HSD17B7) were finally identified to be candidate genes related to alive litter size of Bama Xiang pigs.     

全株水稻粉对生长猪生长性能和血清生化指标的影响

将36头台系杜洛克生长猪随机分为2个处理组,即对照组和10%稻粉组,研究添加10%稻粉对生长猪生长和血液指标的影响。结果表明:日粮中添加10%的全株粉时,生长肥育猪日增重比对照组低了2.94%,日采食量比对照组低了1.13%(P>0.05),饲料转化率比对照组低了1.57%(P>0.05)。因此,生长肥育猪的生长性能没有受到显著影响,试验组血液指标与对照组之间也没有显著差异。     

夏季水分管理对梨橙果实发育和产量品质的影响

干旱缺水是导致果园低产、低效的主要原因之一。重庆三峡库区降水丰沛,但水资源在时空上分布很不均匀,许多坡地果园水源紧缺,季节性干旱十分突出。2002年7月至2006年1月,通过用叶片水分亏缺与果实膨大相关性的研究以及水分管理模式,对柑橘生长和发育的影响进行试验研究,总结出了一套适合坡地柑橘园的水分管理模式。     

螨危防治柑桔全爪螨药效试验

24%螨危悬浮剂系拜耳杭州作物科学有限公司生产的杀螨剂。为明确该药剂防治柑桔全爪螨的持效期、适宜剂量及对柑桔的安全性等,2005年5—7月我们在浙江省淳安县的柑桔园内进行了药效试验。现将结果报告如下。1材料与方法试验在浙江省淳安县千岛湖镇斋上村12年生宫川早熟温州蜜柑