The sheep is one of the mammals. She has periodic sexual activity, like all sheep. She can therefore only have one litter of lambs per year.
But, how does the reproduction cycle of the sheep, from mating with the ram to the birth of lambs and ewe lambs? We will explain everything to you…
Draw me a sheep
First of all, it is essential to understand who is who, because several names designate the same animal. A reminder is therefore in order:
- Sheep is a generic term designating the species which includes ewes, rams and lambs: a sheep can therefore be male or female
- Ewe means the female sheep
- Aries refers to the male sheep that is not castrated and capable of procreating
- Lamb means the male baby sheep, and lamb means the female baby sheep
Sheep is a ruminant mammal, and more precisely a sheep belonging to the bovidae family. It is a domestic animal that has been bred since Antiquity all over the world. Today there are more than a billion sheep across the globe. It is appreciated by man for its milk, its wool, its meat and its skin which is made into leather called sheepskin.
But, back to our sheep and the reproductive cycle of this sheep, now well known to breeders.
Puberty and reproductive age of the ewe
The puberty, or age of sexual maturity, is usually reached in ewes within 6 to 8 months. As for the ram, sexual maturity is reached a little earlier, between 4 and 6 months. Depending on the breeds of sheep being kept, it may take longer, up to 12 months.
However, if the ewe can be bred for reproduction as soon as she has reached puberty, she is only 60 to 70% of her adult weight. For this reason, the majority of breeders wait until the ewes reach the age of one year to start reproduction.
From the age of 12 months, the ewe is fully developed. Not only are the risks associated with early pregnancies removed, but she is also able to give birth to stronger and bigger lambs.
Seasonality of reproduction
Sheep, like all sheep, have a reproductive period marked by sexual seasonality. We are talking about photoperiodism, which defines the relationship between the length of day and night.
Thus, the French ewes have an active sexual season in decreasing days, that is to say from the end of the summer (month of August) until the end of the autumn (December). This period of natural reproduction allows the birth of lambs during the spring, a period when the climate is milder and food more abundant.
Of course, a sheep living near the equator will have a less marked reproductive seasonality. In addition, some breeds are less affected than others by photoperiodism, especially under intensive breeding conditions.
The ewe’s sexual cycle
In the sexual season, the ewes have a regular menstrual cycle of 16 to 17 days. During this phase, a distinction is made between the estrus period or follicular phase of 3 days and the luteal phase period of 14 days.
Theestrus corresponds to the heat of the ewe, the external signs appearing only in the presence of the male. The ewe then gives off a characteristic odor easily recognizable for the ram, it presents a slightly swollen vulva and wags its tail frequently.
Ovulation takes place 18 to 36 hours after the onset of heat. If the female is fertilized and gestating during the luteal phase, the cyclic corpus luteum becomes a gestating corpus luteum. Otherwise, the corpus luteum degenerates and a new menstrual cycle begins.
Mating between the sheep and the ram
In the presence of natural reproduction and without human intervention, rams compete to establish their position as dominant male. During the rut, they can become aggressive towards their master, even if they have a gentle character outside this period.
In practice, the breeders put the ewes in the presence of a single ram. The latter can cover around thirty sheep on his own when he is young, and nearly forty if he is experienced. The protrusion recurs several times to ensure a sufficient number of sperm.
The month of October is frequently chosen for the mating period, so that the lambs are born at spring, In April and May. The ram then has a characteristic behavior: it sniffs the anogenital parts of the female then rolls up its upper lip while raising its head to indicate to the female that it is ready to mate with her. The female then stops and the male protrudes her.
Pregnancy and farrowing in the ewe
The gestation period is relatively long and hard 145 to 152 days, or about 5 months. At the end of this period, she is ready for farrowing, also called lambing.
Lambing is preceded by warning signs ten days earlier. Among the latter, we note a vulva and lips which relax and become congested, udders developed and hard to the touch from which a little colostrum sometimes escapes. Finally, when giving birth is near, the ewe naturally places itself away from the flock.
Lambing begins and is divided into three successive work phases:
- Contractions and dilation of the cervix: this stage lasts 3 to 4 hours, sometimes longer and is accompanied by restlessness of the sheep which bleats frequently
- Expulsion of the lamb (s): this stage lasts an hour on average, but may be longer when a first farrowing or in the presence of several lambs, the lamb (s) are expelled front legs first, followed by the head and the rest of the body
- Delivery: this last step occurs 2 to 3 hours after the birth of the lamb (s), it consists of the expulsion of the placenta between each birth
The breeders are generally present to supervise the good progress of the lambing. This goes well and does not require outside help in 95% of cases. For the remaining 5% of cases, the breeder or the veterinarian can help with the repositioning of the lambs and their extraction, in order to save the ewe and its babies.
The first hours of life of the lamb
A scope usually includes one to two lambs, more rarely three. From birth, the ewe adopts maternal behavior. She actively licks her lamb (s) to stimulate them, smell marks and dry them.
The little ones stand up quickly, within minutes of birth, and no later than one hour. They are then able to feed and suck immediately in order to receive colostrum, which is essential for their survival.
If they are rejected by their mothers or fail to suckle, lambs need human help. Either they are taken to the breasts and everything is back to normal, or they are bottle-fed. Giving them to another sheep is tricky because they have an exclusive relationship with their lambs.