Cow penning is actually a popular name circulating in the folk, in fact, its written name is called cow estrus. The time after the cow has finished laying the calf, that is, the time of postpartum estrus, is related to the environment, nutritional status and physical recovery of the cow, so only a general time can be given.
Usually, the normal time spent on the barn after the cow has laid the calf is 63 days, and the range is about 40 to 110 days. Because the cow is very weak after the calf is laid, and it is also responsible for feeding the calf, there will be a considerable number of individuals who do not have estrus or have late estrus. If the nutrition of postpartum cows is fundamental, there will even be a phenomenon of mating in heat in the second year.
The above-mentioned cows after the calves after the normal playing time is not empty, the author's family has previously raised soil breeding cattle, Simmental beef cattle, Qinchuan cattle and other breeds, through careful observation of their estrus cycle, only to reach the above more scientific conclusions.
The estrus cycle refers to the fact that the sexual activity of the cow has a certain periodicity. It is generally believed that the average estrus cycle of adult cows is 21 days, ranging from 18 to 25 days; the average estrous cycle of breeding cows is 20 days, ranging from 18 to 24 days. Farmers divide the estrus cycle of cows into four parts: estrus duration, late estrus, recess, and pre-estrus.
1. The duration of estrus refers to the period from the beginning of estrus to the end of estrus in cows, which is about 18 hours, usually within 6 to 36 hours.
2. The performance of the cow in the late stage of estrus is very quiet, and the best breeding time has passed this period, which lasts for about 3 to 4 days.
3. Cows in the recessive period return to normal mental state, and the secretion of progesterone gradually decreases, lasting about 12 to 15 days.
4. The estrogen content of cows in the pre-estrus period increases, and preparations are made for the next estrus mating, which lasts for about 1 to 3 days.
When we understand this, we will infer the normal time of the cow after the calf is laid. For example, if a cow has just given birth to a calf, it will wait for 18 to 25 days at the earliest to be in heat. However, because the postpartum cow is very weak, it is very likely to be postponed until after the next estrus period, that is, after 36 to 50 days. Take an average of 43 days, which is about the earliest time after the cow has finished laying the calf. However, due to the influence of various factors, the penning time of postpartum cows is generally delayed, so the average penning time of 63 days is given.
Under normal circumstances, cows are in heat all year round, but due to different climatic influences and different nutritional levels, cow estrus rarely occurs in the cold winter in the northern region of China. The peak season of cow estrus is mostly concentrated in spring and autumn, especially in autumn from August to October, which is the "golden peak season" for cow estrus breeding.
Cows in heat will appear to be agitated, often making rapid mooing sounds, congestion and swelling of the external genitalia, frequent urination of the forked hind legs, and reduced or stopped rumination. At this time, the estrus cow will actively accept the climbing behavior of the breeding bull or other cattle, and will remain standing still, and will also raise its tail to meet it.