Effects of feeding different levels of concentrate on growth and carcass characteristics in younger Japanese Black cattle

The effects of a higher concentrate feed during the raising period on the growth and carcass of Japanese Black cattle being fattened at a younger age were investigated using three pairs of artificially bred identical twins and three pairs of full‐sibs. The animals were fed the concentrate at 2.4%/day (2.4% group) and 1.2%/day (1.2% group) comparative bodyweight (BW) during the raising period. The BW and subcutaneous fat thickness were measured every month using ultrasonic equipment. The animals were slaughtered at the age of 24 months. The BW of the 2.4% group from the age of 6–10 months appeared to be higher than that of the 1.2% group (P < 0.1). The subcutaneous fat of the 2.4% group from the age of 7–11 months was thicker than that of the 1.2% group (P < 0.1). After those ages, the BW and subcutaneous fat of the two groups did not differ and there was no difference in the carcass characteristics between the two groups. Using a higher concentrate feed during the raising period for younger fattening of Japanese Black cattle influenced growth from the late half of the raising period to the early part of the fattening period.     

杂交野猪适宜日粮磷水平与钙磷比例的研究

选用纯种野公猪与杜洛克母猪的杂交后代含50%野猪血缘的42日龄杂交野猪36头,随机分成9组,试验为双因子3水平(3×3)析因安排分组,完全随机区组设计,每个因子3个水平,共9个处理。结果显示,不同磷水平与钙磷比例对各处理组的平均日耗料量、平均日增重、料重比差异均不显著(P>0.05)。不同钙磷比例水平下对血清钙的影响差异极显著(P<0.01),日粮磷和钙磷比例互作效应对血清钙影响差异极显著(P<0.01)。不同日粮钙磷比例对血清磷水平差异显著(P<0.05),日粮磷和钙磷比例互作效应对血清磷影响显著(P<0.05);0.4%的日粮磷水平与0.6%的磷水平对血清AKP活性影响差异极显著(P<0.01)。     

牦牛奶渣乳酸菌对虉草青贮品质的影响

为评价牦牛奶渣乳酸茵对藕草青贮饲料发酵品质和化学成分的影响,试验设置对照组（CK）和3个不同乳酸茵含量处理组（Nzl：0．1ml·kg-1FM;NZ2：0．3ml·kg-1FM;NZ3：0．5ml·kg—FM）,青贮60d后检测发酵品质和化学成分。试验表明：不同添加剂比例对藕草青贮饲料影响不同;NZ1和NZ3处理能够显著降低祷草青贮饲料的pH（P〈0．05）,具有较高的乳酸和乙酸含量（P〈0．05）,NZ3处理的中性、酸性洗涤纤维含量显著降低（P〈0．05）,说明牦牛奶渣乳酸茵可以改蒿草青贮饲料的发酵品质;随着添加浓度的增加赫草青贮饲料的可溶性碳水化合物和粗蛋白具有显著增加趋势,中、酸性洗涤纤维具有降低趋势,说明牦牛奶渣乳酸菌能够改籍草青贮饲料的营养价值;牦牛奶渣乳酸茵的最适添加量为0．5ml·kg-1FM。     

Pharmacodynamics of amoxicillin against Mannheimia haemolytica and Pasteurella multocida and pharmacokinetic/pharmacodynamic (PK/PD) correlation in sheep

Silicone-made tissue cages were implanted in sheep. Blood serum (SBS) and tissue cage fluid (TCF) samples were collected after amoxicillin intravenous and intramuscular administrations, at the dose of 15 mg/kg. Amoxicillin pharmacodynamics were studied in an artificial culture medium, SBS and TCF with use of a Mannheimia haemolytica and a Pasteurella multocida strain. A concentration-independent antimicrobial activity of amoxicillin was confirmed for levels higher than 0.79–1.75 × MIC. This result favored the use of the percentage of the 24 h dosing interval during which drug levels remain above MIC as the appropriate pharmacokinetic/pharmacodynamic index. The subsequent correlation revealed that intravenous administration could be considered effective against “deep” infections caused by bacteria with MICs < 1 μg/mL or “shallow” infections caused by bacteria with MICs < 0.1 μg/mL. Intramuscular administration could be safely considered effective against both “deep” and “shallow” infections when the MICs of the targeted pathogens are lower than 1 μg/mL.     

复种饲料油菜对麦茬耕层土壤酶活性的影响

采用大田试验方法,研究了不同种植密度与施氮量条件下,复种饲料油菜对麦茬耕层(0~15 cm)土壤酶活性的影响。结果表明,麦收后复种饲料油菜能显著或极显著地提高土壤过氧化氢酶(CAT)、酸性磷酸酶(APHA)、纤维素酶(CEL)和脲酶(URA)的活性,与休闲熟化地(CK)比较,最大提高幅度分别为32.15%,35.61%,78.66%和127.36%。土壤酶活性的变化与复种饲料油菜的播种量和施氮量有关,随播种量的增加土壤CAT、CEL和URA活性表现为逐渐递增态势,而土壤APHA表现为先增后减,播种量为11.5 kg/hm2时,APHA活性可达0.7888mg/g。在油菜生长的苗期,土壤APHA、CEL和URA随施氮量的增加而增加,土壤CAT则随施氮量的增加先增后降,呈单峰曲线;在生长后期(收获期),低氮量有利于土壤APHA活性的增加,中氮量有利于土壤CAT和CEL活性的增加,高氮量有利于URA活性的增加。     

添食色素对家蚕茧质影响的研究

家蚕是一种产业化生产的经济昆虫 ,家蚕彩色茧的开发与产业化利用 ,有望为丝绸业带来新的绿色活力.本实验采用色素添食法生产彩色茧 ,研究了添食色素对结茧率和全茧量、茧层量、茧层率的影响.结果发现 :添食红色素对结茧率和茧质无显著影响 ,添食橙色2号色素其茧质成绩有所提高.     

温度和盐分胁迫对野大麦种子萌发的影响

采用2种温度(恒温和变温)、5种盐分类型(NaCl、KCl、MgCl2、Na2SO4、MgSO4)、5种盐分浓度(0、100、200、300、400 mmol/L)研究了温度和盐分对野大麦Hordeum brevisubulatum种子萌发的影响.结果表明,同一盐分胁迫时,变温和恒温处理的野大麦种子初始萌芽率(解除盐分胁迫前的萌芽率)、恢复萌芽率(解除盐分胁迫后的萌芽率)、总萌芽率差异显著,变温有利于野大麦种子萌发.在同一温度和盐分类型处理下,野大麦种子初始萌芽率和总萌芽率随着盐分浓度的增大显著降低.不同盐分类型对野大麦种子的初始萌芽率、恢复萌芽率、总萌芽率差异显著.3种氯化盐对野大麦种子萌发的抑制作用大小依次为NaCl＞KCl＞MgCl2.氯化盐对野大麦种子萌发的抑制作用大于硫酸盐.方差分析结果表明,温度和盐分类型两者之间的交互作用对总萌芽率的差异不显著,而其他两者或三者的交互作用对初始萌芽率、恢复萌芽率、总萌芽率差异显著.     

A spline polynomial model to describe serum IGF-I concentration from birth to slaughter in calves: effects of weaning age,pre-weaning concentrate feeding and breed

The statistical analysis of hormones sampled throughout the production cycle is complicated because factors such as age and weight at the measuring date interfere. Spline curves constructed from pieces of low-degree, random-effects polynomials could be used for a more accurate analysis of data. Concentration of insulin-like growth factor-1 (IGF-1), weight gain, and concentrate intake of Parda de Montaña (PM) (n = 27) and Pirenaica calves (n = 14) were modeled with a spline model according to age at weaning, pre-weaning concentrate feeding, and breed. At birth, calves were randomly assigned to early weaning (EW) at 90 d or traditional weaning (TW) at 150 d. During lactation, half of PM calves received concentrates (S), whereas the remainder received no concentrates (NS). After weaning, calves received concentrates on an ad libitum basis until they reached a weight of 450 kg. The spline model had better likelihood than a polynomial of 6 degrees or a split-plot model. Serum IGF-1 concentration was greatly affected by age at weaning and pre-weaning concentrate feeding, but not by breed. In NS calves, IGF-1 concentration was greater in EW than in TW calves from 120 to 300 d, irrespective of breed. During lactation, S calves had greater IGF-1 concentration than NS calves. After weaning, EWNS calves reached the IGF-1 concentration of EWS calves after 4 mo on concentrates, whereas TWNS calves attained IGF-1 concentration of TWS calves after only 2 mo, because of their increased concentrate intake relative to TWS calves. Concentration of IGF-1 was positively correlated with the immediate weight gains and intake, but it was not a good predictor of performance in the long term.     

苜蓿和沙打旺苗期需水及其根冠比

研究苜蓿和沙打旺苗期水分利用与根冠比例。结果表明,沙打旺叶片对土壤水分的瞬时利用效率均高于苜蓿。沙打旺地下部与地上部生物量比和根长/株高比在不同水分条件下亦高于苜蓿,尤其在低水分时。在高水分下苜蓿单位水分消耗所形成的生物量较多,随着土壤含水量的降低而大幅度减少。苜蓿具有较高的蒸腾速率和较快的根系生长速率,因而造成土壤水分的过快消耗。总之,高水分生长条件易于苜蓿生产效率的发挥,但沙打旺对土壤水分环境变化的稳定性较强。结合多年的研究成果和黄土丘陵区的实际情况,提出在不同立地条件下,沙打旺可以种植在该地区的坡地,而苜蓿则应在水分条件相对较好的川地种植。     

蛋氨酸硒对肉用仙居鸡生长性能、硒存留率和胴体特性的影响

采用饲养试验、代谢试验、屠宰测定等方法 ,研究在基础日粮中添加不同剂量蛋氨酸硒对肉用仙居鸡生长性能和胴体特性的影响。结果表明 ,在基础日粮中分别添加 0 .1,0 .15 ,0 .2和 0 .2 5mg/kgSe水平的蛋氨酸硒比对照组 (添加 0 .15mg/kgSe水平的亚硒酸钠 )体增重分别增加了 9.5 4 % ,12 .30 % ,9.0 7%和 8.0 4 % (P <0 .0 5 ) ;饲料转化率分别提高了 7.35 % ,9.4 5 % ,9.19%和 8.4 0 % (P <0 .0 5 ) ;硒存留率分别提高 2 9.92 % ,2 6 .4 2 % ,19.88%和 19.6 4 %(P <0 .0 5 ) ;蛋氨酸硒对鸡的胴体特性无显著影响