低能饲粮添加植酸酶对仔猪养分利用率、血清理化指标及生长性能的影响

选用24头长白×荣昌杂交仔猪进行2×2因子的代谢试验,试验设2个有效磷水平(0.36%和0.26%)、2个植酸酶添加水平(0、750FTU/kg),共4个处理组,每个处理组设6个重复仔猪起始均重16.9kg,饲粮DE12.8MJ/kg,试验期2周。结果表明:饲粮添加植酸酶,仔猪平均日增重(ADG)、增重/kgW0.75(GPW)、F/G、增重/代谢能(GPM)、蛋白质物质价值(BV)、净蛋白效率比(PER)、钙消化率(CD)、钙沉积率(CR)、磷消化率(PD)和磷沉积率(PR)分别提高10.6%、7.2%、7.9%、7.7%、11.6%、6.7%、4.3%、4.9%、19.6%(P<0.01)、21.3%(P<0.01),每千克增重的饲粮成本(CPG)降低6.6%;植酸酶对仔猪血清理化指标无显著影响,但血清磷浓度趋于升高,血清钙、血清尿素氮浓度趋于降低。降低饲粮有效磷,ADG、GPW、F/G、GPM、BV、PER、PD和PR分别降低3.8%、3.3%、3.2%、4.6%、9.6%、3.2%、7.7%、6.9%,CD、CR和CPG分别增加11.1%、11.6%、3.0%(P>0.05)。     

大豆黄酮对奶牛血清钙、磷及葡萄糖水平的影响

本研究选用40头胎次、产奶量、泌乳期相近的中国荷斯坦奶牛随机分成4组(n=10),试验组奶牛日粮中分别添加45、60和75mg/kg大豆黄酮,在试验前及试验开始后第10天、第20天和第30天颈静脉采血,测定4组奶牛血清钙、磷和葡萄糖水平。结果表明:与对照组相比较,试验1组中血清钙、磷和葡萄糖变化均不显著(P>0.05);试验2组仅血清钙在第30天时显著高于对照组(P<0.05);试验3组第10天和20天时血清钙水平显著高于对照组(P<0.05),第30天时血清钙水平极显著高于对照组(P<0.01),而血糖水平仅第30天显著高于对照组(P<0.05)。     

大白猪繁殖性状遗传参数估计及影响因素的效应分析

本研究对7 945窝大白母猪妊娠周期、总产仔数、产活仔数、健仔数、弱仔数、畸形数、死仔数、木乃伊及死胎数9个繁殖性状进行了最小二乘分析,分析了胎次、配种季节及妊娠周期分类对母猪繁殖性能的影响;并利用动物模型REML(约束最大似然)方法估计动物繁殖性状的遗传力及性状之间的遗传相关.结果表明,胎次对畸形数(P=0.2619)和木乃伊(P=0.4639)影响不显著(P >0.05),对其他7个繁殖性状影响极显著(P <0.01);配种季节对妊娠周期、产活仔数、弱仔数、木乃伊、死仔数及健仔数影响极显著(P <0.01),对畸形数(P=0.3993)影响不显著(P> 0.05),对总产仔数和死胎数影响显著(P <0.05).妊娠周期对木乃伊影响显著(P <0.05),对其他7个性状影响极显著(P <0.01).妊娠周期遗传力最高,为0.34,其他繁殖性状遗传力都低于0.2,为低遗传力性状.总产仔数与妊娠周期之间存在负遗传相关(r_g=-0.10),与产活仔数及健仔数之间存在较强的正遗传相关,遗传相关都超过0.80.妊娠周期与其他繁殖性状之间的遗传相关较小,最高的为妊娠周期与畸形数之间的遗传相关为-0.17.由此得出结论,妊娠周期属于中等遗传力性状,妊娠周期不仅受到胎次、季节等环境因素的影响,而且也受总产仔数等繁殖性状的影响,妊娠周期可作为养猪生产的间接指标.     

Genetic parameters for litter size,piglet growth and sow's early growth and body composition in the Chinese–European line Tai Zumu

Genetics of piglet growth in association with sow's early growth and body composition were estimated in the Tai Zumu line. Piglet and sow's litter growth traits were calculated from individual weights collected at birth and at 3 weeks of age. Sow's litter traits included the number of piglets born alive (NBA), the mean piglet weight (MW) and the standard deviation of weights within the litter (SDW). Sow's early growth was measured by the age at 100 kg (A₁₀₀), and body composition included backfat thickness (BF₁₀₀). A main objective of this study was to estimate separately the direct genetic effect (d) and the maternal genetic effect (m) on piglet weight and daily weight gain during lactation. Variance components were estimated using the restricted maximum likelihood methodology based on animal models. The heritability estimates were 0.19 for NBA, 0.15 and 0.26 for SDW and MW at 3 weeks and 0.42 and 0.70 for A₁₀₀ and BF₁₀₀. The NBA was almost independent from SDW. Conversely, the A₁₀₀ and BF₁₀₀ were correlated unfavourably with SDW (r_g<−0.24, SE<0.12). A stronger selection for litter size should have little effect on litter homogeneity in weights. Selection for lean growth rate tends to favour heterogeneity in weights. The direct effect on piglet weight at birth and daily weight gain accounted for 12% (h² (d) = 0.02) and 50% (h² (d) = 0.11) of the genetic variance, respectively. The association between d and m for piglet weight was not different from zero at birth (r_g = 0.19, SE = 0.27), but a strong antagonism between d and m for daily weight gain from birth to 3 weeks was found (r_g = −0.41, SE = 0.17). Substantial direct and maternal genetic effects influenced piglet growth until weaning in opposite way.     

亚麻籽对育肥期肉牛生长性能和血液指标的影响

[目的]研究在日粮中添加亚麻籽对肉牛生长性能和血液指标的影响。[方法]选择体重接近的西杂牛32头,采用单因素试验设计,随机分为4组,每组8头。[结果]表明:日粮中随着亚麻籽添加水平的提高,日增重由1.59kg/d提高到1.74kg/d,提高9.43%(P0.05);料重比由5.31降低到4.93,相对提高7.16%;粗脂肪的表观消化率显著提高(P0.05);血清中游离脂肪酸随着添加比例的提高而升高(P0.05),血清尿素氮、甘油三酯、胆固醇含量随添加水平的提高均有降低趋势。试验组经济收入分别比对组照多收入0.04元,1.41元,1.64元。[结论]①提高日粮中亚麻籽的水平可以显著提高肉牛的生长性能;②可以显著降低血清胆固醇和甘油三酯的含量。③从经济效益的角度和各种指标的综合分析来看,适宜的亚麻籽添加水平为10%～15%。     

日粮锰水平对辽宁绒山羊与蛋白质代谢相关的血液指标的影响

为了研究日粮中添加锰对辽宁绒山羊蛋白质代谢的影响,试验采用单因子完全随机试验设计,将24只辽宁绒山羊公羊随机平均分为Ⅰ、Ⅱ、Ⅲ组,分别饲喂锰含量为20,40,60 mg/kg的日粮,测定了血液中谷丙转氨酶、谷草转氨酶、总蛋白、尿素氮含量。结果表明:随着锰含量的增加,谷丙转氨酶活性和总蛋白含量显著提高(P<0.05),尿素氮含量显著降低(P<0.05),但谷草转氨酶活性未受显著影响(P>0.05)。综合分析认为,含锰60 mg/kg的日粮对促进辽宁绒山羊的蛋白质代谢较为适宜。     

饲粮中添加铬——烟酸复合物对肉鸭生产性能、胴体成分及血液生化指标的影响

选择1日龄樱桃谷母鸭240只 ,随机分为3组 ,每组5个重复 ,每个重复16只 ,饲养49天。在各组鸭的饲粮中分别添加0、100、200μm/kg铬量的铬—烟酸复合物 ,研究铬—烟酸复合物对肉鸭生产性能、胴体成分及血液生化指标的影响。试验结果显示 :(1)饲粮中添加铬 -烟酸复合物显著(P<0.01)提高肉鸭体重和日增重 ,显著(P<0.01)降低料肉比 ,对日采食量无影响(P>0.05) ;(2)添加铬 -烟酸复合物显著(P<0.05)提高肉鸭瘦肉率和胴体粗蛋白质含量 ,显著(P<0.05)降低肉鸭皮脂率和胴体粗脂肪含量 ;(3)添加铬 -烟酸复合物显著(P<0.01)降低肉鸭血清总脂、葡萄糖、总胆固醇、三酰甘油和尿素氮含量 ,显著(P<0.01)提高血清总蛋白含量。试验结果表明 :饲粮中添加200μm/kg铬量的铬 -烟酸复合物不仅可促进肉鸭生长、降低料肉比 ,而且可提高屠宰性能 ,改善胴体品质     

Stress parameters and immune response of layers under different cage floor and density conditions

The aim of the experiment was to investigate the effects of cage floor and cage density on stress parameters of laying hens. A total of 162 brown laying hens (Hyline Brown), aged 34 weeks, were used in the experiment. Compact-type battery cages, with three floors, were used. Hens were allocated as one, three or five hens in each of 18 cages to obtain three different cage density groups of 1968, 656 and 393.8 cm² floor area per hen, respectively. The same number of cages with different cage density were allocated to three different battery floors (first floor=top, second=middle, third=bottom) systematically. Values for body weight, mortality rate, egg weight, egg production, egg quality characteristics, egg yolk cholesterol content, the levels of blood plasma corticosterone, serum glucose, total cholesterol and triglycerides, the ratio of heterophils to lymphocytes (H-L ratio), antibody titers, claw length score, foot health score, plumage score and throat skin injuries were taken as indicators of stress. The values for egg weight (P<0.01) at the first floor were greater than the other floor levels. The group with five hens per cage had significantly lower mean estimates (P<0.01) than other groups with respects to body weight (P<0.001), egg production (P<0.001), egg weight (P<0.001) and plumage score (P<0.01), while significantly higher mean estimates for egg albumen index (P<0.01), Haugh unit (P<0.01), serum glucose (P<0.001), and H-L ratio (P<0.001). Serum cholesterol was higher in cages with one hen than that with five hens, whereas plasma corticosterone was lower. Antibody titers in cages with one hen was similar to that with three or five hens; however, those with three hens had higher titers than those with five hens. Values for egg breaking strength, yolk index, egg cholesterol content, and foot health score were not affected by cage density or floor. The results suggest that the allocation of three hens per cage had no measurable effect on health and welfare.     

Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)₂ in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH₃-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.     

蓝山灰鹅生态之研究

对湖南省蓝山县的地方良种灰鹅进行了研究,测定了体重、体尺、体温、脉搏、呼吸次数、血液学参数、产蛋性能、屠宰率、羽绒产量等。经对该县不同生态环境中的灰鹅进行比较,发现山区灰鹅在体形外貌、成年体尺、体重、体温、脉搏、呼吸及血液学指数等方面与平原地区灰鹅没有明显差异,但生长发育较慢(P<0.05)、开产迟(p<0.05)、产蛋率低,但羽绒产量和孵化率皆显著高于平原地区(P<0.01和P<0.05),母鹅利用年限也较长(P<0.05)。