【作者】 张鹏；

【导师】 苏鹏程；

【作者基本信息】 山东农业大学 ， 动物营养与饲料科学， 2012， 硕士

【摘要】 国内外许多研究表明日粮添加生物素能改善奶牛的肢蹄状况,但是对于奶牛生物素适宜添加量,研究未取得一致的结果。本研究期望通过对山东省奶牛肢蹄病影响因素的调查、体外发酵实验及添加不同梯度生物素区组实验的方法,确定山东省规模化牛场泌乳奶牛的生物素适宜添加量,为我国奶牛生物素营养标准的制定,提供一定理论依据。试验一、奶牛肢蹄病发病率影响因素的研究2010年5月至2011年2月间,对山东省26个奶牛场进行随机调查,调研采用查阅档案和实地评分的方法进行。调研指标包括奶牛平均产奶量,TMR的饲喂,苜蓿饲喂,地面平整度,地面硬度,地面泥泞度,修蹄,药浴,精粗比等。利用调研所得上述9个影响因素数据,进行肢蹄病发病率影响的线性回归分析。结果表明：地面平整度,泥泞度,苜蓿的饲喂对肢蹄病发病率有显著影响作用(P<0.05),其它因素对肢蹄病发病率影响作用不显著(P>0.05)。肢蹄病发病率与牛场地面平整度、泥泞度和苜蓿的饲喂存在以下线性关系：y=18.56774-3.25685a-2.74194b-3.65887c,其中y为肢蹄病发病率大小(%),a代表地面平整度,b代表地面泥泞度,c代表牛场苜蓿饲喂。试验二、不同精粗比和粗饲料类型对发酵液生物素合成影响的研究采用体外发酵法,研究不同精粗比(4：6,5：5,6：4)和粗饲料类型(黄贮,青贮,苜蓿)的发酵底物对发酵液内pH值、生物素浓度等指标的影响。结果表明,不同精粗比发酵底物对发酵混合物pH值和生物素浓度没有显著影响(P>0.05)。添加粗饲料为苜蓿的底物在体外发酵10h时,发酵液混合物生物素浓度明显(P<0.05)高于其它两组。试验三、泌乳奶牛生物素适宜添加量的研究选择60头泌乳期中国荷斯坦奶牛,随机分为A、B、C和D四个组,每组15头,采用区组试验设计,四个试验组分别添加10、20、30和40mg/d的生物素,研究生物素梯度对奶牛生产性能,血液生化指标和奶牛肢蹄硬度的影响。研究结果表明：日粮中生物素梯度的增大降低了乳蛋白率,试验四组中B组,C组和D组(3.26%、3.14%、3.27%)跟A组(3.64%)比较显著降低(P<0.05)；B组,C组和D组(P<0.05)血浆中生物素浓度分别为2.12ng/ml、2.24ng/ml和2.35ng/ml,显著高于A组1.57ng/ml;B组和D组(P<0.05)奶牛血糖(Glu)含量分别为3.40mmol/L和3.28mmol/L,显著提高了奶牛血糖含量；肢蹄状况与蹄壳硬度有密切关系,两者呈显著性负相关(γ<0,P<0.05)；在饲喂试验225天时B组和C组奶牛肢蹄硬度明显高于A组(P<0.05),饲喂试验300天时B组奶牛肢蹄硬度明显高于A组(P<0.05),B组、C组和D组奶牛肢蹄硬度差异不显著(P>0.05)。研究表明：在本试验条件下,维持泌乳奶牛肢蹄健康的适宜生物素添加量为每头奶牛20mg/d左右。更多还原

【Abstract】 Many studies indicate that dietary biotin supplementation can improve cow limb hoof disease. However, there are no consistent results about the appropriate addition amount of biotin. The factors influencing cow limp hoof disease in Shandong Province was surveyed, in vitro fermentation was preformed, different biotin level was added to the cow diet using the block experiment design. The results will provide the appropriate amount of biotin in diet in early lactation cows in large-scale cattle industries in Shandong province and pave the theory basis on the nutritional standard of biotin in cows. Test one:the study of the factors influencing the disease of cow’s limb hoof diseaseDuring May2010to February2011, a survey of randomly selected26dairy farms in Shandong province was conducted, and files and the field score method were used. Research indice include the average milk yield, the disease rate of the limb hoof incidence, surface hardness surface smoothness, the muddy degree of the ground, whether feeding TMR diet, whether feding alfalfa on crude material, repairing hoof, whether building a special pool bath, the ratio of concentrate to roughage on diets. A linear regression analysis was performed to investigate the factors influence the incidence rate of limb hoof disease. The results showed that surface smoothness, muddy degree, and alfalfa feeding significantly affect the limb hoof disease morbidity(P<0.05), however the other factors (milk yield, TMR, the hardness of the ground, repairing hoof, bath, the ratio of concentrate to roughage) did not significantly affect the limb hoof disease morbidity (P>0.05). There were linear relationship between Limb hoof disease incidence and farm ground evenness, muddy degree and alfalfa feeding. The linear regression equation was y=18.56774-3.25685a-2.74194b-3.65887c, where y represents limp hoof disease incidence (%), a represents the degree of the ground roughness, b represents the muddy of the ground, C represents Alfalfa feeding.Test two:the study of influence of different ratio of concentrate to roughage and forage type on biotin synthesis in fermentation liquidThe effects of different ratio of concentrate to roughage (4:6,5:5,6:4) and forage type (yellow storage, silage, alfalfa) fermentation substrate cultivation ruminal fermentation liquid on the pH value and biotin concentration was observed. The results showed that different ratio of concentrate to roughage fermentation substrate did not affect significantly the pH value and biotin concentration in fermentation mixture (P>0.05). After10hour of fermentation, the biotin concentration in fermentation liquid mixture was significantly higher in alfalfa substrate than that other two groups (P<0.05).. Test three:appropriate addition amount of biotin on lactating dairy cowsSixty Holstein cows were randomly selected and divided into4groups (15in each group) to study the effects of production performance,10,20,30and40mg/d biotin were added in each group, respectively. Blood parameters, hardness of cow limbs and hoof in each group were recorded. The results showed that:the dietary biotin reduced with the increasing of percentage of milk protein.. The percentage of milk protein in group A (3.64%) was significantly higher than that in group B, C and D(3.26%,3.14%,3.27%). plasma biotin concentrations were2.12ng/ml,2.24ng/ml and2.35ng/ml in B group, C group and D group, respectively (P<0.05), which is significantly higher than that in A group of1.57ng/ml, The blood glucose (Glu) levels were3.40mmol/L and3.28mmol/L in B group and D group, respectively and significantly improved cow blood sugar content (P<0.05). There was native relationship between limb hoof situation and hoof shell hardness (γ<0, P<0.05), Cow limb hoof hardness degree was higher in group B and C than that in group A(P<0.05) on225days of age. Cow limb hoof hardness degree in B group was higher than that in group A (P<0.05), the hardness degree in B group, C group and D group was not significant (P<0.05).In conclusion, feeding alfalfa can improve the biotin concentration in the fermentation mixture, which may be associated with the factors that can reduce limb hoof disease. To improve the health of the cow limbs and hoof, the optimum additive amount of biotin was20mg/d or so in Holstein lactating cows.更多还原