Finding best exotic breed proportion in crossbred lactating sheep kept under farmers’ conditions in Ethiopia determined by use of nested Legendre polynomials with limited data

ABSTRACT

The present study was conducted to estimate milk production performance and fit lactation curves for groups of ewes of Local and of Awassi crosses, with a variable blood level, reared under farmer’s environment. The Weigh-Suckle-Weigh method plus hand milking was used to estimate milk yield for ewes. A total of 466 observations from 115 ewes were used. Estimated least-squares adjusted means for the milk production over 120 days were 0.56?kg day^?1 (Local), 0.67 (<30% Awassi), 0.86 (30–50% Awassi), and 0.96 (>50% Awassi). Groups with 30–50% Awassi and >50% Awassi ewes produced significantly (p?<?0.05) more milk than Local ewes. Significant differences were observed between <30% Awassi and >50% Awassi crossbred groups. The best crosses (>50% Awassi) produced over 70% more milk than the local ewes which demonstrates the potential that exists in increasing milk production through the initiated crossbreeding programme with sheep in Ethiopia.     

人参提取液体外抑制IHNV作用效果研究

探究人参提取液体外抑制CCB细胞感染IHNV的能力,构建体外CCB细胞模型,运用RTCA技术和MTT法测得不同浓度人参提取液对IHNV抑制作用曲线,并从阻断病毒复制和杀灭病毒两方面讨论人参提取液作用效果。结果表明,4%人参提取液对IHNV具有明显抑制作用,能够在16 h内保护细胞不受IHNV病毒的侵染,其中2 h时对病毒灭活抑制率最高达到51.5%,1~12 h内对病毒复制有持续抑制作用。研究可为IHVN防治药物的研发提供新的思路及参考。     

小黑麦与黑麦花序结构和籽粒特性比较

植物的花序结构及其形态特征是影响种子生产性能的重要因素。对于禾本科植物而言,其花序大小、小穗数、小花数及小花的外稃、内稃和芒的性状特征直接影响种子形成和产量。本研究通过测定小黑麦品系C2、C35和黑麦品系C13、C33的花序结构特征,得到以下结果:小黑麦花序[(14.30±0.52) cm×(1.24±0.09) cm]明显大于黑麦[(13.20±0.35) cm×(0.82±0.02) cm],小黑麦花序长而粗,黑麦花序短而细;小黑麦花序的小穗数[(21.35±1.47)个]少于黑麦[(30.20±0.79)个];小黑麦每个小穗的小花数较多,为3~4朵,黑麦的小花数趋于稳定,每个小穗有2朵小花。从花序中部小穗的小花结构看,小黑麦下位护颖长[(1.27±0.11) cm]和宽[(0.26±0.03) cm]、上位护颖长[(1.30±0.09) cm]和宽[(0.23±0.04) cm]均显著大于黑麦下位护颖长[(1.04±0.05) cm]和宽[(0.08±0.01) cm]、上位护颖长[(0.94±0.10) cm]和宽[(0.06±0.01) cm];小黑麦中部小穗第1小花的外稃宽[(0.32±0.03) cm]、外稃高[(0.24±0.03) cm]和芒长[(8.35±0.51) cm]、第2小花的外稃宽[(0.35±0.04) cm]、外稃高[(0.25±0.05) cm]和芒长[(8.37±1.19) cm]极显著大于黑麦相应值[(0.26±0.01),(0.15±0.01),(5.50±0.19),(0.25±0.01),(0.17±0.01)和(5.18±0.23) cm];第1和第2小花的外稃长[(1.35±0.06),(1.37±0.06) cm]和内稃长[(0.84±0.04),(1.41±0.06) cm]均小于黑麦的外稃长[(1.49±0.05),(1.47±0.05) cm]和内稃长[(1.45±0.05),(1.47±0.04) cm]。小黑麦的穗粒数[(52.50±1.80)粒]显著低于黑麦[(58.50±2.50)粒] (P<0.05),但其穗粒重[(2.08±0.04) g]、粒重[(0.04±0.00) g]和籽粒宽[(3.04±0.32) mm]均极显著高于黑麦 (P<0.01),每个花序的籽粒不仅体积大,而且质量较重,其籽粒的生产性能高于黑麦。小黑麦籽粒呈椭圆形或长卵圆形,浅黄色,表皮皱缩,饱满度差;黑麦籽粒呈窄纺锤形,青灰色,表皮光滑,籽粒饱满。小黑麦和黑麦花序结构与籽粒性状的Pearson相关分析表明,小黑麦花序宽和花序基部小穗数与籽粒长显著正相关(P<0.05),花序长与籽粒宽极显著正相关(P<0.01),花序中部小穗的下、上位护颖宽分别与穗粒重和穗粒数极显著正相关(P<0.01);黑麦花序中部小穗第2小花的内稃长与籽粒长显著正相关(P<0.05),外稃高与穗粒数极显著负相关(P<0.01)。研究小黑麦和黑麦的花序结构和籽粒特征,对正确区分二者和了解其籽粒的生产性能具有重要意义,同时有利于小黑麦的示范推广。     

乙烯对匍匐翦股颖ISR抗病反应中AsA-GSH循环及胼胝质沉积的影响

以匍匐翦股颖品种“Penn-A4”为试验材料,侵染立枯丝核菌后,经丁二醇(BDO)诱导产生系统抗性(ISR),喷施不同浓度的乙烯合成抑制剂氯化钴(CoCl₂)和促进剂1-氨基环丙烷羧酸(ACC)后,检测抗坏血酸-谷胱甘肽(AsA-GSH)循环中抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量及相关酶活性的变化,并观察匍匐翦股颖ISR反应中胼胝质沉积的变化。结果表明,乙烯抑制剂处理下,匍匐翦股颖幼苗中AsA含量较低,抗坏血酸过氧化物酶(APX)活性下降,大量GSH被催化还原为氧化型谷胱甘肽(GSSG),GSSG大量积累,同时谷胱甘肽还原酶(GR)活性较低,GSSG经GR少量还原为GSH。乙烯促进剂处理下,AsA含量较高,APX活性升高,GSSG在高活性GR作用下催化还原为GSH,使得GSH大量积累。因此在匍匐翦股颖ISR抗病反应中,高浓度乙烯促进AsA和GSH的大量积累,它们不仅参与了活性氧的代谢平衡,同时也作为信号分子在ISR抗病反应中起着重要作用。匍匐翦股颖感染褐斑病后,胼胝质主要沉积在厚壁细胞、韧皮部、木质部和表皮组织,其中厚壁细胞胼胝质沉积最多,表皮组织沉积最少。此外,胼胝质沉积面积在不同乙烯信号分子处理间存在差异,但随着处理时间的延长差异不显著。一定浓度的乙烯对ISR反应中胼胝质的沉积具有一定的影响,随着处理时间的延长显著增加,在100 μmol·L^-1ACC处理5 d后,胼胝质沉积总面积仅为9.916 mm²,处理10 d后升至最高,为38.396 mm²,但在病害侵染后期,胼胝质数量减少,在100 μmol·L^-1ACC处理15 d后,胼胝质沉积总面积降至20.052 mm²,反映了乙烯信号分子对胼胝质沉积的影响是一种短期效应,短期内可提高匍匐翦股颖植株抗病性,具有信号分子的短时效特点。研究结果为探清匍匐翦股颖ISR抗病响应中ET信号分子如何调控抗病生理特性提供了理论基础。     

Equine pituitary pars intermedia dysfunction: current understanding and recommendations from the Australian and New Zealand Equine Endocrine Group

The purpose of this article is to provide a review of the current knowledge and opinions about the epidemiology, clinical findings (including sequelae), diagnosis, treatment and monitoring of equine pituitary pars intermedia dysfunction, particularly in the Australian context. This information and the recommendations provided will assist practitioners in making informed decisions regarding the diagnosis and management of this disorder.     

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.