| This paper studied the problem of the low reproductive performance in modern dairy industry, we added different concentration of biotin to the daily ration for the first calving cows and then we selected the best dosage of biotin after making analysis of the reproductive performance index about estrus rate, fertilization rate, conception rate, parturition rate, calving interval and the postpartum estrus time. We also studied the influence of the biotin on ovaries’ function and we added biotin in different estrus stages of the experimental cows to test the change laws of the reproductive hormone, so we could illuminate the biotin’s function of the reproductive performance from the internal secretion mechanism. Meanwhile, this paper also studied the influence of the biotin of different concentration on cow’s follicle development. The results of the study are as follows: 1.The experiment studied the influence of adding biotin of different concentration into cows’ daily ration on estrus and conception.The result indicated that the estrus rate of the group which was added 20 mg·d-1(69.44%)、30 mg·d-1(70.43%) and 40 mg·d-1(68.80%)biotin was much(P<0.05) higher than the 10 mg·d-1 group(62.86%)and control group(55.24%), and the 10 mg·d-1 group(62.86%) was much(P<0.05)higher than the control group(55.24%), while there was slight(P>0.05)difference between 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 groups. The gross conception rate of groups added 20 mg·d-1(90.67%)、30 mg·d-1(91.36%)and 40 mg·d-1(89.53%)was much(P<0.01) higher than the 10 mg·d-1 group(84.85%)and the control group, the gross conception rate of the group added 10 mg·d-1 was higher than the control group, but not evident, and the 30 mg·d-1 group was slightly higher than 20 mg·d-1 and 40 mg·d-1 group, but the difference between the 3 groups was not evident(P>0.05) as well. The result of study indicated it was much better to add the biotin of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 to the daily ration than other two groups of 0 mg·d-1 and 10 mg·d-1. So we advise that the addictive amount should be between 20 mg·d-1~30 mg·d-1. 2. The influence of biotin of different concentration on cows’ calving rateThe result indicated that: the calving rate of 20 mg·d-1(82.67%)、30 mg·d-1(86.42%)and 40 mg·d-1(83.72%)groups was much higher(P<0.01)than the control group(70.69%),and also much higher(P<0.05)than 10 mg·d-(75.76%) group,the calving rate of 10 mg·d-1 was much higher(P<0.05)than the control group,and the calving rate of 30 mg·d-1 group is slightly higher than 20 mg·d-1 and 40 mg·d-1 group,but the difference between the 3 groups was not evident(P>0.05)。The result of study indicated that different concentration of biotin had evident influence on cows’ calving rate, and the concentration of 30 mg·d-1 was the biggest. 3. The influence of biotin of different concentration on cows’ parturition rateThe result indicated that:the parturition of 20 mg·d-1( 378.23±12.82)、 30 mg·d-1(375.71±10.95) and 40 mg·d-1(379.17±9.81)groups was much(P<0.01)lower the control group(396.34±14.50),and much(P<0.05)lower than the group of 10 mg·d-1(385.80±10.76),and the group of 10 mg·d-1(385.80±10.76)was much(P<0.05)lower than the control group,the group of 30 mg·d-1(375.71±10.95)was slighter lower than the group of 20 mg·d-1(378.23±12.82)and 40 mg·d-1(379.17±9.81),but the difference between the 3 groups was not evident(P>0.05)。 The result of the study indicated that adding biotin could evidently shorten the parturition interval. The biotin of different concentration had evident influence on cows’ parturition rate and the concentration of 30 mg·d-1 was the best. 4. The influence of biotin of different concentration on cows’ postpartum estrus timeThe result indicated that: the estrus rate of the cows after 30 days’ parturition in 20 mg·d-1(78.67%)、30 mg·d-1(80.25%)and 40 mg·d-1(79.07%) groups was much(P<0.01)higher than the control group(51.72%),and also much(P<0.05)higher than 10 mg·d-1(69.70%)group,the group of 10 mg·d-1 was much higher(P<0.05)than the control group,but the groups of 20 mg·d-1、30 mg·d-1 and 40 mg.d-1 were not much different(P>0.05)。The average days of the cows from parturition to first fertilization in groups of 20 mg·d-1(63.37±10.96)、30 mg·d-1(61.97±8.91)与 40 mg·d-1(62.65±9.0) was much(P<0.05)lower than the 10 mg·d-1 groups(69.76±11.23)and the control group(72.19±14.79),though the group of 10 mg·d-1 was lower than the control,but it was not evident(P>0.05),and the difference of the groups of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 were not evident(P>0.05)。The result of the study indicated that adding biotin could evidently improve the cows’ postpartum estrus rate and shorten the time of postpartum estrus and fertilization, the biotin of different concentration had evident influence on the cows’ postpartum estrus rate and fertilization time, and the concentration of 30 mg·d-1 was the best. 5. The influence of biotin of different concentration on the estradiol’s level in different time of the cows’ estrus periodAt the 3rd day of the cows’ estrus period, the content of estradiol in cows’ blood plasma in the groups of 20 mg·d-1(5.91±0.97pg/ml)、30 mg·d-1(5.95±0.83 pg/ml)and 40 mg·d-1(5.98±1.17 pg/ml) was much(P<0.05) higher the 10 mg·d-1(5.01±0.73 pg/ml)group and the control group(4.93±0.59 pg/ml),and the group of 10 mg·d-1 was higher than the control group,but not evident(P>0.05),and the difference of the 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 groups was also not evident(P>0.05)。At the 20 th day of the cows’ estrus period( 1 day before estrus),the content of estradiol in cows’ blood plasma in the groups of 20 mg·d-1(12.53±2.01 pg/ml)、30 mg·d-1(12.91±1.51 pg/ml) and 40 mg·d-1(12.57±1.13 pg/ml) was extremely much(P<0.01)higher than the control group(8.92±0.57 pg/ml),and much(P<0.05) higher than the group of 10 mg·d-1(10.55±1.72 pg/ml),the group of 10 mg·d-1 was much(P<0.05)higher than the control group,and the difference among the groups of 20 mg·d-1、30 mg·d-1与 40 mg·d-1 was not evident(P>0.05)。The result of the study indicated that adding the biotin of 20 mg·d-1、30 mg·d-1and 40 mg·d-1 to the daily ration could evidently improve the elementary level and the peak value of the estradiol in blood plasma. 6. The influence of biotin of different concentration on the progesterone’s level in different time of the cows’ estrus periodAt the 1st day of the cows’ estrus period,the blood plasma progesterone in groups of 20 mg·d-1(0.33±0.04ng/ml)、30 mg·d-1(0.35±0.06 mg/ml) and 40 mg·d-1(0.34±0.07 mg/ml) was extremely much(P<0.01)much higher than the control group(0.27±0.04 mg/ml),and much(P<0.05)than the group of 10 mg·d-1(0.27±0.03 mg/ml),the group of 10 mg·d-1 was much(P<0.05) than the control group,and the difference among the groups of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 was not evident(P>0.05)。At the 14 th day of the cows’ estrus period, he blood plasma progesterone in groups of 20 mg·d-1(7.43±0.81 mg/ml)、30 mg·d-1(7.51±0.74 mg/ml)与 40 mg·d-1(7.52±0.73 mg/ml)was extremely much(P<0.01)higher than the control group(6.57±0.35 mg/ml),and much(P<0.05)higher than the group of 10 mg·d-1(6.91±0.79 mg/ml),the group of 10 mg·d-1 was much(P<0.05)higher than the control group, and the difference among the groups of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 was not evident(P>0.05)。The result of the study indicated that adding the biotin of 20 mg·d-1、30 mg·d-1and 40 mg·d-1 to the daily ration could evidently improve the elementary level and the peak value of the blood plasma progesterone. 7. The influence of biotin of different concentration on the growth of the cows’ ovaries and follicleThrough the statistic and analysis of the ovary’s growth. The result indicted that: the average amount of follicle in the groups of 20 mg·d-1(7.69±1.98)、30 mg·d-1(7.84±1.35)and 40 mg·d-1(7.82±3.54)was extremely much(P<0.01)higher than the control group(3.45±1.77),and much(P<0.05)higher than the group of 10 mg·d-1(5.38±2.01),the average amount of follicle in the groups of 10 mg·d-1 was(P<0.05)higher than the control group, and the difference among the groups of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 was not evident(P>0.05). the average amount of the small follicle in the groups of 20 mg·d-1(13.13±5.84)、30 mg·d-1(13.36±3.98)and 40 mg·d-1(12.94±6.87)was much(P<0.05)lower than the group of 10 mg·d-1(16.67±7.32) and the control group(17.97±7.91),the average amount of the small follicle in the control was higher than the group of 10 mg·d-1,but not evident(P>0.05), and the difference among the groups of 20 mg·d-1、30 mg·d-1 and 40 mg·d-1 was not evident(P>0.05)。The total amount of the average follicle was not evident(P>0.05)either。The result of the study indicted that the medium follicle in the cow’s ovaries in the groups of adding biotin by 20 mg·d-1、30 mg·d-1and 40 mg·d-1 to the daily ration was much higher than the other two groups, because the oocyte conception rate from the medium ovaries was higher than those from small and big ovaries. Therefore, in order to improve the cows’ reproductive performance, adding 20 mg·d-1~30 mg·d-1 biotin is the best choice. |
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