| 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. |
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