Evaluation of Awassi genotypes for improved milk production in Syria

A performance evaluation, conducted between 2003 and 2005, compared the milk production of three genotypes of Awassi ewes: Turkish (T), Syrian (S) and the F1-cross between the Turkish and Syrian ewes (TS), at the International Center for Agricultural Research in the Dry Areas (ICARDA) experimental farm in Tel Hadya (northern Syria). After weaning, which occurred at 56days, milk yield and milking length were measured weekly during the milking period (n = 381). Milk yield of TS and T ewes were 12% and 30% higher, respectively, than S ewes. Milk yield and milking length of TS ewes reflected additive inheritance and did not differ from the parental genotypes' average (p ≥ 0.199). Culling of low producing ewes in 2003 and 2004 also resulted in increased milk yield. Dams of all genotypes displayed similar weights at birth (p = 0.898) and weaning (p ≥ 0.677). The latter suggests dams of the different genotypes olerated equally the pre-weaning lactation load. Performance tended to improve as ewes aged, with milk yield and milking length peaking at 3years of age (p > 0.05). Ewe lambing weight, birth–weaning ewe weight decline, litter size, and litter weight weaned peaked at 4–5years of age (p ≤ 0.016). With the exception of birth–weaning ewe weight decline, year effects influenced the traits under study (p ≤ 0.035). Excluding litter size, the best performance was in 2005, followed by 2003 and 2004. Milk yield increased with litter size at weaning (b = 18.7; p = 0.024). The lambing–weaning ewe weight decline (3.6kg) and ewe productivity (0.46kg litter weaned weight per kg ewe weight) did not differ between genotypes (p ≥ 0.178). Average litter size was 1.15, with the TS ewes displaying the largest litter size (1.23; p = 0.026). Single lambs were 25% heavier than twins at birth averaging 4.73kg and 3.8kg, respectively. Male lambs were 4% heavier than female lambs at birth (p < 0.0001) and 9.3% heavier at weaning (p < 0.0001). Lamb birth weights, weaning weights and daily weight gains were similar for all genotypes (p ≥ 0.210). The average proportion of fat (5.95%), crude protein (5.19%) and solids non-fat (11.29%) in the milk varied across genotypes where S < TS < T (p ≤ 0.0037). F1 crosses with T increased the productivity of S ewes by 12.2%. It is noteworthy that this occurred under improved feeding and may not be recommended for other conditions. Culling low producing ewes led to a 12.8% increase in milk yield, which could translate into a substantial boost in revenue for farmers rearing traditional sheep flocks in milk producing areas.     

Effects of concentrate supplementation on carcass and meat quality attributes of feedlot finished Small East African goats

Effects of concentrate supplementation on carcass and meat quality of feedlot finished Small East African (SEA) goats were assessed using 23 animals (14.5 months old and 20.1 kg body weight). Goats were subjected to four levels of concentrate supplementation: ad libitum concentrate allowance (T100), 66% of ad libitum concentrate allowance (T66), 33% of ad libitum allowance (T33) and no concentrate (T0). All goats were slaughtered after 90 days of experimental period. The ad libitum concentrate intake attained by the goats was about 370 g DM/d. All concentrate-supplemented goats had similar (P > 0.05) total dry matter intake. T100 goats had 31 g and 14 g higher (P < 0.05) daily body weight gain than T33 and T66 goats, respectively. T100 and T66 goats were comparable in final live weight and empty body weight but both were heavier (P < 0.05) than that of T33 and T0 goats. Hot and cold carcass weights for both T100 and T66 goats were 3 kg heavier (P < 0.05) than that of T0 goats. Concentrate-supplemented goats had similar (P > 0.05) EUROP scores for carcass fatness. T100 and T66 goats had 6.5 and 3 units higher (P < 0.05) scores for conformation than T0 and T33 goats, respectively. Dressing percentage increased with levels of concentrate supplementation in a curvilinear fashion, with highest values in T66 goats. At 6 h post-mortem, muscle pH for concentrate-supplemented animals was significantly lower compared with T0 goats. Carcass fat content was 9% higher (P < 0.05) in concentrate-supplemented goats than in their contemporaries. No differences in cooking loss or shear force were observed among treatments, while these variables were affected by the type of muscle. It is concluded that feedlot finishing of SEA had limited effects on meat quality. Finishing SEA goats at 66% of their ad libitum concentrate intake, however, significantly improved weight gains and carcass fatness. Cost–benefit analyses are recommended before embarking on a large scale feedlot finishing of SEA goats.     

Effects of selenium yeast on rumen fermentation, lactation performance and feed digestibilities in lactating dairy cows

The objective was to evaluate the effects of selenium-yeast (SY) supplementation on rumen fermentation, lactation performance and feed digestibilities in dairy cows. Twenty-eight multiparous (2.5 ± 0.3 parity) Holstein dairy cows, averaging 625 ± 18.2 kg of BW, 63 ± 3.0 days in milk and average daily milk production of 26.2 ± 0.5 kg/cow were used in a replicated 4 × 4 Latin square experiment. Treatments were: control, LSY, MSY and HSY with 0, 150, 300 and 450 mg selenium yeast (Sel-Plex®, 1 g/kg selenium, produced from Saccharomyces cerevisiae CNCM I-3060) per kg of diet dry matter (DM), respectively. Experimental periods were 45 days with 30 days of adaptation and 15 days of sampling. Ruminal pH was lower for MSY than for control and was linearly (P = 0.03) decreased, whereas total VFA concentration was linearly and quadratically (P ≤ 0.01) increased with increasing SY supplementation, with the least for control, followed by LSY and HSY, and the highest for MSY. Ratio of acetate to propionate was lower for LSY, MSY and HSY than for control, and was linearly and quadratically (P ≤ 0.01) decreased as SY supplementation increased due to an increase in molar proportion of propionate. Ruminal ammonia N content was lower (P ≤ 0.01) for MSY and HSY than for control and was linearly decreased (P ≤ 0.01) with increasing SY supplementation. Dry matter intake, proportions and yields of milk fat, protein and lactose were not affected (P > 0.05). Milk yields and 4% FCM were higher (P ≤ 0.05) for LSY and MSY than for HSY and control. Milk selenium content was linearly and quadratically (P ≤ 0.01) increased as increasing SY supplementation, with the least for control, followed by LSY and MSY, and the highest for HSY. Digestibilities of DM, organic matter (OM), crude protein (CP), ether extract (EE), aNDF and ADF in the total tract were higher (P < 0.01) for LSY and MSY than for control and HSY. The results indicate that supplementation of diet with SY improved rumen fermentation, milk yields, milk selenium, and feed digestion. It was suggested that the SY stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum selenium-yeast dose was about 300 mg per kg diet DM.     

植酸酶替代产蛋鸡饲料中的磷酸氢钙的应用试验

利用植酸酶可以水解植物性饲料中植酸的原理,探讨在产蛋鸡饲料中添加商品植酸酶替代不同水平磷酸氢钙的效果.选用50～54周海兰褐产蛋鸡为试验对象,在每千克饲料申添加400 FYT植酸酶分别替代8 g、16 g的磷酸氢钙,观测植酸酶对产蛋鸡生产性能的影响.结果显示,用400 FYT植酸酶替代16 g磷酸氢钙可以保持产蛋鸡生产性能不变,而替代8 g磷酸氢钙可以提高产蛋鸡的生产性能,只日产量、产蛋率、料蛋比分别提高3.4%、3.6%、3.7%.因此,在产蛋鸡饲料中用400FYT植酸酶替代8 g磷酸氢钙可以提高产蛋鸡生产性能,同时也可以降低饲料配方中的总磷.     

酶解豆粕对肉鸡生产性能和养分消化率的影响

本试验旨在研究微生物蛋白酶水解豆粕对1～21日龄肉鸡生长性能和养分消化率的影响。选择1日龄科宝母雏336只,随机分为4组,即对照组、试验Ⅰ、Ⅱ和Ⅲ组。对照组为玉米—豆粕型基础日粮,试验Ⅰ、Ⅱ和Ⅲ组分别以5%、10%和15%酶解豆粕替代对照组中等量的普通豆粕。试验结果表明,与对照组相比,试验组显著提高了肉鸡采食量（12%～21%）和增重（8%～16%）(P<0.05),降低料重比（3%～7%）(P<0.05);试验组对干物质、粗蛋白质、能量、钙和磷的消化率也具有显著的提高作用(P<0.05);各试验组之间,生产性能和干物质、粗蛋白质、钙消化率差异显著(P<0.05),但能量和磷的消化率差异不显著(P>0.05)。因此,豆粕经酶解改善了其蛋白质的营养价值,肉仔鸡日粮添加酶解豆粕可以提高肉鸡的生长性能和养分消化率。     

饲养方式对卢氏绿壳蛋鸡屠体性状的影响

本研究选择笼养和放养条件下49周龄的卢氏绿壳蛋鸡各20只（公母各半）,测定了其屠体性状。结果表明,饲养方式对卢氏绿壳蛋鸡的活重、屠宰率、半净膛率、全净膛率、胸肌率、腿肌率、腹脂率、翅重、心脏重、肝脏重、脾重、肠重、胃重和生殖器官重的影响均差异不显著（P>0.05）。饲养方式对公鸡的各项指标影响差异不显著（P>0.05）,而对母鸡的头重、颈重、脚重影响很大（P<0.01）;相同饲养条件下公鸡的全净膛率、腹脂率、头重、脚重、颈重、翅重、心脏重和肠重极显著高于母鸡（P<0.01）,对肝脏重、脾脏重和胃重的影响差异不显著（P>0.05）;笼养时公鸡的活重、腿肌率和生殖器官重显著高于母鸡（P<0.05）,而对半净膛率和胸肌率的影响不显著（P>0.05）;放养时母鸡的生殖器官重极显著的高于母鸡（P<0.01）;不同饲养条件下,公鸡头重、颈重、肠重、生殖器官重与屠宰率相关性不显著（P>0.05）;母鸡脚重、翅重、肠重、脾脏重与屠宰率的相关性显著（P<0.05）。     

猪β-干扰素的研究进展

干扰素是由干扰素诱生剂诱导生物细胞所产生的一类高活性多功能的糖蛋白,干扰素自被发现以来,由于其广谱抗病毒、抗肿瘤活性及其强大的免疫调节作用而受到研究者们的重视。在其基因结构、作用机理及体外重组表达等方面都取得了巨大突破。作者综述了猪β-干扰素的基本特性、作用机理及其临床应用。     

纤维素酶在改善奶牛生产性能方面的应用进展

纤维素酶具有广泛的应用价值。近年来,纤维素酶逐渐被应用于奶牛生产中,并取得了很好的效果,它可有效提高奶牛产奶量,提高经济效益。本文综述了纤维素酶的分类、作用机理及国内外纤维素酶对奶牛生产性能方面的最新进展。     

木醋液对蛋鸡生产性能及蛋品质的影响

本研究旨在探讨木醋液对蛋鸡生产性能及蛋品质的影响。将192只219日龄海兰褐蛋鸡随机分成A、B、C、D 4组,分别饲喂添加0%、0.5%、0.75%、1.0%木醋液的饲料,日饲喂量为124 g。每组设3次重复,每重复16只,试验期80 d。结果表明,添加0.5%、0.75%木醋液处理组产蛋量、产蛋率、蛋白质及钙含量比对照组均有不同程度的提高,且胆固醇含量明显降低。添加1.0%木醋液处理组产蛋量、产蛋率比对照组有所下降。试验结果证实,蛋鸡饲料中添加适量木醋液具有提高蛋鸡生产性能及蛋品质的作用。     

一株芽孢杆菌的分离鉴定及相关特性的初步研究

为了获得适应当地环境的益生菌株,从当地土壤中分离得到一株芽孢杆菌,经鉴定为蜡样芽孢杆菌.经安全性试验及抗逆性试验,研究了其在不同pH值、不同温度下的生长情况,并进行了药敏试验.结果表明,该菌无毒性,具有抗逆性,最适pH值为6～8,最适宜温度为37℃,可作为益生菌进行微生态制剂方面的进一步研究.