Sheep & Goats
This is an excerpt of Dairy Goat and Sheep Operations in the Southeast Production Guide, ANR-2457.
General Small Ruminant Breeding
The profitability of goat and sheep operations is largely reliant on successful reproduction programs. The number of kids and lambs raised and weaned successfully ultimately determine the profitability of the operation.
Small ruminants are generally seasonal breeders, with the onset resulting from decreased daylight. Most breeding occurs in the late summer through early winter. In Alabama, the breeding season is from August through December.
It is possible to alter the breeding season by keeping the animals indoors and utilizing artificial lighting. Does have an estrus cycle of 18 to 22 days, and they display estrus for 24 to 48 hours. Ewes have an average cycle length of 17 days, with most being between 14 and 20 days. They display estrus for 24 to 36 hours. The gestation period is 5 months, and twins are common, though single and triplet births are not rare.
Common management practices in dairy operations have the doe/ ewe milking for 10 months following parturition. They are then held dry for 2 months prior to the next lactation.
Kids and lambs may enter into the breeding colony at 5 to 10 months of age, depending on breed, as long as they have reached approximately 60 to 70 percent of mature body weight and are in good condition. The most important aspect is the body weight with respect to breed. Breeding too early can negatively impact their reproductive lifespan and milk-producing abilities. Overfeeding to achieve a larger body weight earlier also has negative consequences to reproductive lifespan and milk-producing ability and should be avoided.
Bucklings and rams are generally fertile by 5 months of age or earlier. In some breeds, puberty is reached at a young age; it is therefore important to separate doe/ewe and buck/rams at an early age.
Nutritional inputs are both critical and manageable with regard to reproduction. The body condition of the doe/ewe greatly influences many reproductive aspects:
- puberty onset
- conception rate at first estrus
- time to return to cyclicity following parturition
- vigor of offspring
The goal should be for does and ewes to maintain good body condition throughout the breeding season. Poor nutrition during the late stages of development can have consequences on the subsequent milk production following parturition.
Estrus is the period of time when does and ewes are receptive to males. Estrus detection is important to facilitating hand or pen mating and identifying potential repeat breeders or noncyclers. Goats and sheep are seasonal polyestrus, meaning they cycle multiple times during the breeding season.
Heat detection can be achieved using a teaser buck, the herd sire, or by the producer. A teaser ram/buck is a surgically altered buck unable to successfully fertilize the females. Teasers are particularly attractive, as they can induce heat when introduced to females.
A producer that is well advised of the physical signs of estrus can also be an ideal detection method, as doing so provides direct management of the estrus female.
Note: Standing heat is not considered a reliable heat sign as it is in cattle, and estrus signs are less obvious in ewes.
Signs of a doe/ewe in heat include the following:
- paying attention to or seeking out the buck/ram
- decreased appetite
- increased restless behavior
- frequent urination
- increased vocalization
- mounting and/or allowing mounting with other females
- a swollen vulva with the presence of mucus (clear during early estrus, thicker and opaque later is estrus)
The presence of a male in a neighboring pen will stimulate more obvious signs of estrus. When a buck or ram is introduced to a group of females, he stimulates the onset of estrus. Even during the nonbreeding season, some females will display estrus and ovulate due to the male effect. The key to success with this system is housing the males and females apart prior to putting them together.
Estrus observation should be avoided at feeding or milking, as signs may not be as obvious. Detection should take place at least twice daily, separated by 12 hours. Estrus lasts from 12 to 48 hours, and ovulation occurs 24 to 36 hours after the onset of estrus.
Because goats and sheep are seasonal breeders, it can be advantageous to utilize reproductive technologies to ensure a year- round milk supply. If a natural breeding program is utilized, you may have little or no milk being produced during January and February.
It is critical to decide on a breeding system that fits your production plan. There are four main breeding systems commonly employed in the goat and sheep industry:
1. Hand mating. This method involves selecting the buck/ram for the doe/ewe and mating them. This method has the advantage of allowing the exact breeding date to be recorded. It is, however, quite labor intensive, requiring the manager to accurately identify the doe/ewe in heat and facilitate the mating.
2. Pen breeding. In pen breeding, the buck/ram is put in a pen of does/ewes to facilitate their mating. This method relies on the male to detect females in heat. It is significantly less labor intensive when compared to hand breeding. Pen breeding has the disadvantage of resulting in a less certain day of breeding record. Also, if more than one female comes into heat on the same day, the male may single out one female and miss the others. There may also be the requirement of follow-up pregnancy ultrasounds to determine the female’s due date. Additionally, the age of the male must be taken into account when determining breeding densities. A yearling male should be placed with 10 to 25 females, while a more mature male can be placed with 15 to 40 females.
3. Artificial insemination (AI). Artificial insemination offers the advantage of introducing superior genetics cost effectively. There are, however, a limited number of technicians with small ruminant AI experience; thus, the farm manager often must acquire this skill. AI also requires large investments of time in order to carefully and accurately detect estrus. It is suggested that producers start off with a manageable number of females and work toward whole-herd usage. Currently, the most reliable results in goats and sheep are obtained by inseminating transcervically with fresh semen.
4. Out-of-season breeding. Several methods have shown to be effective in breeding goats out of season. The most reliable, though costly, method involves using artificial lighting. Males and females must be housed separately indoors to allow control of light exposure. During the winter months, both are exposed to at least 20 hours of light for 60 days. When considering lighting, it is important that the light is bright at the eye level. Goats are then moved to natural lighting for 45 days, after which the buck is put with the does for breeding. This generally produces a single shortened estrus. It is important to keep the buck to doe ratio high, and pen breeding should be used. One buck per fifteen does provides ample time to ensure does are bred. If successful, 60 percent or more females should cycle out of season.
Of equal importance to reproduction are the bucks and rams. To ensure prevention of production losses due to infertility, a breeding soundness exam should be performed on the male 30 to 60 days prior to the breeding season. Evaluation should include a physical exam, reproductive tract exam, and semen analysis. Consult your veterinarian regarding the options for breeding soundness exams.
Pregnancy and Kidding
Pregnancy diagnosis in small ruminants should be done to ensure the breeding season is not missed. Gestation is 150 days, and the use of an ultrasound allows pregnancy diagnosis 32 days post-breeding. Otherwise, it is difficult to determine pregnancy until approaching parturition.
It is important to keep in mind that a positive pregnancy at 32 days post-breeding could still be lost, as small ruminants are more prone to abortion. The pregnant female should have a 45- to 60-day dry period prior to kidding. Additional observation as kidding and lambing approaches will aid in successful parturition. (See table 3 to help determine gestation.)
Lambing and kidding generally occurs between 147 to 155 days post-conception. Eight to 12 hours prior to birth, signs including udder development and loosening around the vulva will be observable. The doe/ewe will also lie down and stand up multiple times. Females should be given a clean, dry place to birth at this time.
Unless labor is prolonged, females should be largely left alone during parturition. Generally, parturition should be completed within 2 hours following the appearance of the water sac. Kids and lambs present head first, leading with the front feet. Posterior presentation (leading with the hind feet) can occur and result in more difficult birthing. If the doe or ewe appears to be having difficulty, call your veterinarian for assistance.
Table 3. Gestation for Kids and Lambs
Numbers based on a 148-day gestation period.
Source: Sheep Pocket Guide As-989, North Dakota Extension Service, Fargo, North Dakota
|Breeding Date||Lambing or Kidding Date|
|Aug 6 - Sep 5||Jan 1 - 31|
|Sep 6 - Oct 3||Feb 1 - 28|
|Oct 4 - Nov 3||Mar 1 - 31|
|Nov 4 - Dec 3||Apr 1 - 30|
|Dec 4 - Jan 3||May 1 - 31|
|Jan 4 - Feb 2||Jun 1 - 30|
|Feb 3 - Mar 5||Jul 1 - 31|
|Mar 6 - Apr 5||Aug 1 - 31|
|Apr 6 - May 5||Sep 1 - 30|
|May 6 - Jun 5||Oct 1 - 31|
|Jun 6 - Jul 5||Nov 1 - 30|
|Jul 6 - Aug 5||Dec 1 - 31|
Raising Kids and Lambs
Offspring should be on their feet and nursing a short time after birth. For dairy goats, it is important not to let the kids nurse directly (disease prevention) but instead to feed them heat-treated colostrum and then pasteurized milk.
Neonatal survival is greatly improved by ensuring a good amount of colostrum is consumed as soon as possible after birth. It is important that the kid/lamb receives a first feeding of colostrum within the first 8 hours following birth. In a dairy operation, the first and second milkings should not be placed in the tank, as they will contain colostrum, and should be used primarily to feed the kids/ lambs.
If offspring are raised with the mother, they will consume small amounts of milk multiple times a day. When utilizing does for milk production, weaned kids should be raised using a similar approach. Kids should be fed about four times per day for the first couple of days and then twice daily.
Natural weaning and milk weaning can occur at 6 to 8 weeks and should be based on the amount of grain/forage and water the kids are consuming. Offer grain from 2 weeks of age onward. Remember to separate males and females at an early age.
Abortion Causes and Prevention
Abortion in goats and sheep can be a common clinical problem. To determine and correct the cause, good reproductive records are invaluable. Signs that there might be an issue include a repeat breeding rate higher than 10 percent across the herd; does/ewes that do not birth on the correct date after having a positive pregnancy test; preterm fetus and/or placentas found; and kids/lambs born at term but are weak or stillborn.
Enzootic abortion, caused by chlamydial (goat and sheep) or campylobacter (sheep) infection, can lead to pregnancy loss. There are still many other infectious agents that can lead to abortions.
When dealing with abortion issues within a herd, diagnostic investigation is particularly important. Collecting expelled fetuses and placentas for diagnosis will help to ensure that the outbreak can be properly managed. Consult your veterinarian regarding preventative measures including designing a vaccine schedule.
There are a variety of reproductive management practices that can produce healthy, viable offspring able to contribute to the herd. Base your selection on the efficient use of available resources. Manageable aspects of reproduction include age, environment, and nutrition. Stress and disease-causing organisms often lead to a high infant mortality rate. Cleanliness, proper nutritional management, and a good health management plan can help to prevent production losses.