| Alfalfa is a kind of high quality coarse fodder including rich crude protein, vitamin and mineral. It also includes 33% non protein N (free Amino Acid, peptide, catecholamine, purine and alkaloid) in nitrogen that can be utilized by ruminant. In order to determine appropriate mixed level of alfalfa hay in dairy cows in mid to late lactation dietary and its nutrition value for dairy cows in mid to late lactation, in the same time, provide scientific foundation of alfalfa hay of appliance and generalization in dairy cows, according to the same crude protein(CP) and net energy(NEL) concentration and similar nutrition level for lactation dietary, the experiment was conducted to study the influence of different mixed alfalfa hay in dairy cows in mid to late lactation dietary on production performance, nutrient apparent digestibility, blood parameters and economy benefit.Eight multiparous Holstein cows in mid lactation were blocked by milk yield (24.3 ± 2.9 )kg/d, parity (3.4±1.1), days in milk (148.5±14)d, similar body weight and heredity composing into two groups of four and randomly assigned to 4 X 4 Latin Square trial with four periods. Regarded 1 group as control group, fed with basal control diet. The last three groups were fed with three level alfalfa hay that were mixed in the three diets 3.5, 7.0,10.5kg respectively. The experiment was four periods. After finished every period, milk sample, blood sample and feces sample should be collected and measured. The main results were showed as follows: (1) Milk yield of the control group was 22.13 kg/d. Milk yield of the 3.5 kg group,7.0kg group and 10.5 kg group were 21.46 kg/d ,24.96kg/d and 24.45kg/d respectively. Milk yield of 7.0kg group was higher than control group and 3.5kg group (P<0.05) ,10.5 kg group was higher than 3.5kg group (P<0.05) .Milk yield of 3.5 kg, 7.0 kg, 10.5 kg group decreased3.03%,increased 12.79%, 10.48% respectively compared with control group. The difference of milk fat percentage, milk protein percentage and lactose were not significant among all the groups (P>0.05);But with the alfalfa hay level being enhanced, the milk fat percentage had increased in different extend. The milk fat percentage of the experimental groups increased 0.52%, 3.11%, 3.37% respectively compared with control group. DMI of the 7.0 kg group was higher than control group (P<0.05) and 3.5kg (P<0.01) .DMI of the control group and 10.5kg group were higher than 3.5kg group (P<0.05) .Somatic cell count(SCC) of the experimental groups were lower than control group.The difference of SCC was significant among all the experimental groups and control group (P<0.05). SCC of the 3.5 kg,7.0 kg,10.5 kg group decreased 12.89%(P<0.05), 14.44%(P<0.05), 17.05%(P<0.05)compared with controlgroup. The difference of somatic cell count(SCC) was not significant among all the experimental groups (P>0.05). (2) The difference of apparent digestibility of CP and ADF were not significant among all the groups (P>0.05) . The apparent digestibility of NDF of 7.0kg group was higher than control group (P<0.05), 3.5kg and 10.5kg group were higher than control group too, but the difference of the apparent digestibility of NDF was not significant (P>0.05) . The apparent digestibility of NDF of the experimental groups increased 4.37%, 9.22%, 6.95% respectively compared with control group. (3) Total protein(TP) of the 7.0 kg and 10.5 kg group was higher than control group (P<0.05). Total protein(TP) of the 10.5 kg group was higher than 3.5 kg group (P<0.05). Total protein(TP) of the 3.5 kg, 7.0 kg, 10.5 kg groups increased 1.19% (P>0.05), 6.40% (P<0.05), 7.29% (P<0.05) respectively compared with control group. The difference of blood urea nitrogen (BUN) , albumin(ALB), blood glucose(GLU), CO2 combining power (CO2-CP) and ALT were not significant among all the groups (P>0.05) . (4)Added profit of 3.5kg, 7.0kg,10.5kg group were 0.56,4.20,3.23yuanRMB/head/d.Considering all the above,7.0kg alfalfa supplementation was suggested. |
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