The rational division of male and female is a crucial link for the breeding farm to improve its economic efficiency. There are too many cocks in the flock, eating much, fighting each other and interfering with breeding. The fertilization rate of the eggs is not necessarily high. If the cock is too small, the feed can be saved, but the cock can hardly afford the task of mating with each hen. Because of the large number of chickens, the fertilization rate of eggs is also low. Therefore, in the case of large groups of free mating, maintaining a reasonable ratio of male and female is a problem worthy of attention.
It is now generally accepted that ratio of male to female is 1:12-15, that is, for every 120 to 150 hens in the flock, 10 cocks are placed, and the ratio of male to female of medium-sized laying hens is 1:10-12, ie every 100-120. Only 10 cocks were placed in the hen to ensure satisfactory fertilization rates. Under the condition of cage breeding and artificial insemination, the breeding burden for each rooster is 35-40 hens, ensuring that the fertilization rate of the breeding eggs is above 90%. The above-mentioned ratio of male to female refers to large groups. If the number of cock is too small, although the fertility rate can be guaranteed, it is difficult to guarantee germplasm. The same chicken species, the number of chicken farms is not large, there are not many breeder cockerels, and the breeder chickens will be produced in the future. The quality is certainly not as good as the breeder farm with a large number of chickens.
In order to ensure that chicken breeds should have a level of production performance, it is recommended that small-scale breeder flocks be raised and that they should raise more male cocks. In order to prevent cockroaches, the same group of cocks should be changed together in accordance with a reasonable proportion of parents. Or withdraw together, can not be mixed. Although the number of matings per hen to a hen was reported to be 20 to 30 times per day, it was observed as 0 to 41 times. However, according to our observations on the bred population of Qingdao Airlines, the average time from one day to the next day is 5.8 to 7.7 times per day, ranging from 2 to 12 times. During the afternoon, the frequency of feeding and management of the eighth-chapter breeder chickens accounted for 73.7% of the total number of matings at 3-7 o'clock in the afternoon, and it was concentrated at 5-7 o'clock, accounting for 47.4% of the day.
According to observations, chickens were busy in the early morning and they began to enter the nest to produce eggs. They did not love to mate and even ignored the cocks. After 3:00 pm, most hens had already finished laying eggs and began to accept cock mating. Two hours before sunset, the hens all went to the sports field. The sex activities of the male and female chickens were very strong. Some hens even took the initiative to attract males to mate.
A total of 7 cocks were co-provided within 5 to 6 hours of this time, and 4 hens were assigned from 5:50 to 5:57 with a minimum interval of 1 minute. This phenomenon of natural mating of roosters is also consistent with the conclusion that the optimal timing of insemination after artificial insemination is after 3 pm.
Vitamins are a kind of trace organic substances that humans and animals must obtain from food in order to maintain normal physiological functions. They play an important role in the growth, metabolism, and development of the human body. In the body, this kind of substance can neither be a raw material for body tissue nor a source of energy, but a kind of regulating substance, which plays an important role in material metabolism.
From the point of view of chemical structure, various vitamins are very different or even unrelated. Therefore, vitamins are usually classified according to their physical properties. They can be divided into fat-soluble vitamins (such as vitamin A, D, E, K, etc.) and water-soluble vitamins ( Such as vitamin C, vitamin B1, B2, B6, B12, pantothenic acid, PP, biotin, folic acid, choline, etc.). Water-soluble vitamins are easily soluble in water but not soluble in organic solvents. They are stored in the body after absorption. Excessive amounts are mostly eliminated in the urine; fat-soluble vitamins are easily soluble in organic solvents but not in water. They can be absorbed by the body with fat and stored in the body, and the excretion rate is not high.
From the perspective of obtaining methods, vitamins can be divided into natural products and chemical synthetic products. Because natural vitamins are limited by raw materials and extraction technology, their yields are low, and their prices are high. Therefore, chemical synthesis takes the lead, accounting for about 80% of the total vitamin output. Among the various segments of the vitamin industry, vitamin B, vitamin E, vitamin C and vitamin A have the largest market shares, 33%, 30%, 21% and 13% respectively. Other vitamins have a smaller market share, accounting for only 3%.
Vitamin C,vitamin b3,vitamin raw material
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