If you’re raising sheep, understanding the ewe’s gestation period is critical to successful lambing. Proper care during pregnancy is key to healthy lambs and a thriving flock.
So, what is the ewes gestation period? On average, ewes are pregnant for 144 to 151 days, which is about 21 weeks.
This article will guide you through the different stages of ewe gestation, focusing on nutritional requirements, potential health problems to watch out for, and what to do when it’s time to assist with lambing.
Understanding the Ewe’s Gestation Period
So, how long are ewes pregnant? Let’s take a closer look at the typical gestation period and what can affect it.
Duration and Variability
Generally speaking, a ewe’s gestation lasts for about 144 to 151 days, or roughly 21 weeks. However, that’s just an average. The actual length can vary depending on several factors, including:
- Breed
- Nutrition
- Age of the ewe
- Number of lambs she’s carrying
- Environmental temperature
Key Stages and Trimesters
Just like with human pregnancies, it can be helpful to think of a ewe’s gestation in terms of trimesters. This can help you manage her nutritional needs most effectively.
- Early gestation: The focus here is on maintaining the ewe’s body condition.
- Mid-gestation: Her nutritional needs will be moderate during this period.
- Late gestation: This is when nutritional demands really ramp up due to rapid fetal growth.
That last trimester is critical, as about 75% of the lamb(s)’ growth happens then. You may need to provide supplemental feeding to ensure the ewe is getting enough energy to support both herself and her growing offspring.
Hormonal changes during gestation
The hormones estrogen and progesterone are vital throughout a ewe’s pregnancy. Progesterone is essential for maintaining the uterine lining and preventing contractions that could lead to premature birth. Estrogen levels tend to increase near the end of pregnancy, preparing the ewe for labor and delivery.
The hormone cortisol plays a crucial role in initiating labor. The release of cortisol triggers a cascade of events that lead to lambing. Minimizing stress in late pregnancy can help maintain optimal cortisol levels and avoid complications.
Hormone imbalances can lead to complications. For example, if a ewe doesn’t produce enough progesterone, she could lose the embryo early in pregnancy.
Nutritional Management of the Pregnant Ewe
An expecting ewe needs the right nutrition to carry her lambs to term and deliver healthy offspring. Good nutrition supports the lambs’ growth in utero, ensures high-quality colostrum, and protects the ewe’s overall health.
Ewes’ appetites often drop off by 30% in the final trimester, so it’s important to monitor their food intake and offer supplemental feed if necessary.
Nutritional Requirements by Trimester
- First trimester: You’ll want to maintain the ewe’s body condition score (BCS) during the first trimester. Don’t overfeed or underfeed her at this stage.
- Second trimester: Nutritional needs are moderate during the second trimester. Make sure your ewes have access to good-quality pasture or hay.
- Third trimester: The third trimester is when nutritional demands go up, due to rapid fetal growth. Supplement your ewes’ diets with concentrates, silage, or high-quality hay.
Essential Nutrients for Pregnant Ewes
Pregnant ewes need to get enough of these nutrients to ensure a successful pregnancy:
- Energy: Adequate energy intake is essential for fetal growth and colostrum production.
- Protein: Protein is important for tissue development and high-quality colostrum.
- Minerals and Vitamins: Ewes need enough calcium, phosphorus, selenium, and vitamin E during pregnancy.
Common health problems during ewe gestation
Like any pregnancy, a ewe’s gestation can come with health challenges. Here are a couple of issues that can arise.
Ovine pregnancy toxemia (twin lamb disease)
Twin lamb disease tends to affect ewes that are carrying multiple lambs, especially in flocks that graze in low-lying areas. It’s usually caused by a lack of energy intake in late pregnancy, when the lambs are growing the most rapidly.
If a ewe has twin lamb disease, she may be lethargic, lose her appetite, and show neurological signs like unsteadiness or disorientation. In some cases, she may seem blind.
The best way to prevent twin lamb disease is to make sure the ewe is getting enough nutrition, particularly in the last trimester of her pregnancy.
Hypocalcemia (milk fever)
Milk fever is a calcium deficiency that can occur late in pregnancy or in early lactation. It’s often seen in older ewes or ewes that are carrying more than one lamb.
If a ewe has milk fever, she may have muscle tremors, weakness, and be unable to stand. Because she is unable to stand, she is sometimes referred to as a “downer ewe.”
To prevent milk fever, make sure ewes have enough calcium in their diet and avoid stressful situations as much as possible.
Other considerations
During the last four weeks of gestation, it’s a good idea to vaccinate ewes against common diseases. Talk to your veterinarian to make sure you’re using the right vaccination protocol for the diseases common in your area.
Also, you’ll want to have a parasite control program in place to keep internal and external parasites from harming the ewes.
Preparing for Lambing and Assisting the Ewe
As your ewe’s due date approaches, it’s important to be prepared to assist her, if necessary, during lambing. Here’s what to watch for and how to help.
Recognizing Signs of Impending Lambing
There are a few key signs that indicate your ewe is getting ready to lamb:
- Her udder will become enlarged and swollen (“bagging up”).
- The ligaments around her pelvis will relax (“springing”).
- She may isolate herself from the rest of the flock.
- She’ll exhibit restlessness and nesting behavior.
Preparing a Lambing Kit
Having a well-stocked lambing kit on hand will make the process smoother. Essential items include:
- Disposable obstetrical gloves
- Obstetrical lubricant
- Antiseptic solution (iodine) for navel dipping
- Towels for drying lambs
- Lambing cords or snares
Assisting with Lambing
Normal lambing proceeds in three stages: dilation of the cervix, expulsion of the lamb, and expulsion of the placenta. In a normal presentation, the lamb will be born forefeet first, which happens about 95% of the time.
Be prepared to recognize and correct abnormal presentations, such as breech (hind legs first) or when the head is turned back. An internal examination can help you determine the lamb’s position. If you’re unable to resolve the issue, seek veterinary assistance promptly. It’s better to be safe than sorry when it comes to the health of your ewe and her lambs.
In Closing
Understanding a ewe’s gestation period is essential for successful sheep farming. During this time, you’ll need to carefully manage her nutrition, health, and lambing assistance.
Keep in mind that several factors can influence gestation length and lambing outcomes, including the ewe’s breed, nutrition, age, the number of lambs she’s carrying, and the environmental conditions.
Be proactive in managing your ewes throughout their pregnancies. Talk with your veterinarian and other experienced sheep farmers for tips and advice on how to ensure the health and well-being of your flock.