Reproduction

Pre-Breeding Management of Rams and Ewes

David C. Van Metre, DVM, DACVIM Extension Veterinarian, Colorado State University
(Previously published online with Veterinary Extension through Colorado State University)

Important notes for both spring and fall breeding!

The pre-breeding period is defined as the 8-10 week period prior to the first day that rams are turned out with the ewes. Although it is traditionally a relatively quiet period for the sheep producer, the pre-breeding period involves multiple physiologic processes in the ram and ewe that can significantly impact fertility during breeding season, and therefore can subsequently impact the size and uniformity of the lamb flock. During this period of time, the sheep producer can conduct a few fairly simple management practices to ensure that the ram and ewe flock are in optimal physical condition for breeding.

Pre-Breeding Evaluation of the Ram Flock
Creation of sperm in rams requires approximately Continue reading →

Tips for Improving Out-of-season Reproduction

Richard Ehrhardt, Michigan State University Extension Specialist, Small Ruminants
(Previously published on MSU Extension, Sheep & Goat: January 27, 2020)

By now, 2020 fall lambing is a task of the past with lambs weaned and either sold at the sale barn or retained for feeding. Before winter and spring lambing floods our minds, now is an appropriate time to take a minute to review the fall lambing season. For most, fall lambing in 2021 is in the far distance; however, timely planning now will foster future improvements.

This article provides tips for improving out of season reproduction in sheep.

Lamb supply is seasonal in nature and is explained largely by the seasonal nature of sheep reproduction, yet demand for product is present year-round. In order to meet market demand, deficits in supply are met by imported product and by domestic lamb feeders who hold lambs to extend the season of supply. In some parts of North America, the holding of lambs has hurt product quality, as lambs entering the market are often overly fat and mature. Another strategy to fill in gaps in supply and to avoid product quality concerns is through out-of-season lamb production. Out-of-season production allows lambs with the optimal degree of maturity to be harvested throughout the year. This strategy, when combined with a decrease in the production birth interval, is referred to as accelerated production. Accelerated production has the potential to increase production efficiency and simultaneously remove the constraint caused by seasonal supply. Continue reading →

Spider Syndrome in the Sheep Flock

Gerald Q. Fitch, Extension Sheep Specialist, Oklahoma State University
(Previously published with Oklahoma State University Extension: March, 2017)

(Image Source: Thompson and Dittmer, 2008)

Spider Syndrome is a genetic problem, common in the Suffolk breed and becoming more common in the Hampshire breed. Spider syndrome has been compared to dwarfism in beef cattle. It has been prevalent since the 1950s. Spider syndrome has also been diagnosed in commercial flocks that keep brockle-faced lambs back as replacement ewes. Those ewes are coming from Suffolk or Hampshire rams that carry the syndrome. Researchers feel certain that spider syndrome is caused by a simple, autosomal, recessive gene. If a producer has a flock of carrier ewes and breeds them to a carrier ram, one-fourth of his or her lamb crop could have spider syndrome!!!

Diagnosis
Spider lambs are affected in one of two ways: 1) lambs are abnormal at birth and will probably never be able to stand, or 2) lambs appear normal at birth, but develop into a spider lamb at two weeks to six weeks of age.

Spider lambs usually Continue reading →

Increase Lamb Crop by Testing for Pregnancy

Geri Parsons and Cleon Kimberling, Optimal Livestock Services
Reviewed by: Jay Parsons, University of Nebraska-Lincoln and Bill DeMoss, Mountain Vet supply
(Previously published online with Agriview: September 5, 2019)

(Image Source: U.S. Lamb Resource Center)

Pregnancy detection in the ewe provides the opportunity to adjust nutritional and lambing management to save on feed and labor costs. The old adage that “one open ewe takes the profits of five producing ewes” may be true when all costs are calculated. Early determination of fetal numbers and gestational stage gives the option of sorting for nutritional demands in late pregnancy and early lactation. Without that information, the single-bearing ewe is being fed too much or the twin-bearing ewe too little. Open ewes are robbing the pregnant ewes of necessary nutrition. Grouping according to gestational stage will also save on labor and allow for better utilization of facilities and biosecurity.

The key in any type of business is producing an end product, or more simply put, production. The economic benefit of pregnancy testing in Continue reading →

Reproductive Management of the Ewe Flock and the Ram

Mike Neary, Extension Sheep Specialist, Purdue University
(Previously published on the Purdue University Extension web page)

(Image Source: Michigan State University)

The most important factor in determining profitability of a sheep enterprise is production rate. Productivity of the ewe flock is a direct reflection of reproductive efficiency. Regardless of genetic merit, eye appeal, price, or showring placing, if a sheep will not reproduce it is worth no more than current slaughter value.

To a large extent, the goals and objectives we have for our next lamb crop are determined before and during the breeding season. Increasing ewe productivity while decreasing labor, time and facilities requirements during the lambing season can be realistic objectives.

Reproduction in sheep is influenced by numerous factors. These include: Continue reading →

Reproductive Physiology of Sheep

Paula I. Menzies, DVM, MPVM, DECS-RHM, Ruminant Health Management Group, Department of Population Medicine, Ontario Veterinary College, University of Guelph
(Previously published in Merck Manual: Veterinary Manual: June, 2015)

(Image Source: Cornell Small Farms – Cornell University)

Ewes are seasonally polyestrous,cycling every 16–17 days during the breeding season. The major environmental factor controlling the estrous cycle is the photoperiod. Decreasing photoperiod after the summer solstice causes secretion of melatonin, which triggers the hypothalamus to produce gonadotropin-releasing hormone. Geographic location and environmental temperatures also modify the length of anestrus, as does the breed of sheep. Fine-wool breeds (eg. Rambouillet and Merino), tropical breeds, and Dorsets have a shorter anestrous period than other breeds such as the Suffolk, Hampshire, Border Leicester, and Columbia. Regardless of this breed-related variation in the length of the breeding season, all breeds are most fertile in the autumn, and anestrus is an unlikely problem associated with regular annual mating.

The duration of estrus (~30 hr.) is influenced by Continue reading →

Flushing Small Ruminants for a Higher Ovulation Rate

Michael Metzger, Michigan State University Extension Educator
(Previously published on MSU Extension, Sheep & Goat: August 6, 2018)

(Image Source: Sheep 101.info)

Increasing the level of nutrition for does and ewes 2-3 weeks prior to and 3 weeks into the breeding season can improve kid/lamb crop in some instances.

When managing a goat/sheep herd farmers are always looking for ways to improve their herd, increase production and raise profitability. One way that a farmer can accomplish this is to implement flushing into their breeding practices. Flushing is a temporary but purposeful increase in the level of nutrition around breeding time. This is done to boost ovulation, conception and embryo implantation rates. Flushing may also increase the proportion of females that exhibit estrus. Flushing can increase lambing and kidding rates by 10-20 percent. This is important because a flock’s lambing/kidding rate is one of the primary factors influencing profitability. Flushing works best in

Continue reading →

Breeding Soundness Examination of the Ram and Buck

David C. Van Metre, DVM, DACVIM Extension Veterinarian, Colorado State University
(Previously published online with Veterinary Extension through Colorado State University)

(Purdue Extension, Purdue University)

Veterinarians are well positioned to become valued participants in sheep flock and goat health programs through introduction of certain practices that have high potential to provide direct economic benefit to the producer. Opportune times for veterinary intervention include evaluation of the breeding flock in the fall prior to breeding, late fall / early winter pregnancy diagnosis, and lambing / kidding during the spring. To optimize the size of the following spring’s lamb or kid crop, the primary goal of the pre-breeding health program should be optimization of fertility through nutritional management and disease control measures, as well as documentation of Continue reading →

Preparing the Flock for the Breeding Season

Dr. Scott Greiner, Extension Animal Scientist – Sheep, Virginia Tech
(Previously published on the Virginia Cooperative Extension web page)

If you can believe it, we are already in the first week of June! The reality of breeding season is real for some of our breeders here in the state of Ohio. Others may be several months out, however, regardless of when you will begin the breeding season on your operation it is important to be prepared. Breeding season is more than just joining ewes and rams together, it takes months of preparation prior to this to ensure a successful season. Although this article has some age, it still remains to be a nice checklist on how to manage your rams and ewes prior to the breeding season.

Rams:
High temperatures can be detrimental to ram fertility, reducing pregnancy rates and lambing percentages. Heat stress occurs when the scrotum is not able to reduce the temperature of the testicles below normal body temperature. Although heat stressed rams may Continue reading →

Good Choices on Rams Now Translates to Good Flock Production Later

James Thompson, Sheep Specialist (retired), Oregon State University
(Previously published on with the Oregon State University Extension Service)

There is no room for snap judgments when selecting breeding sheep. Next year’s lamb crop depends on our choices now. Take the time and the gas to drive around and look at prospects. Always keep your improvement plan in mind; choose only rams and ewes that will move you toward your goal. The ram contributes 80% – 90% of the genetic improvement to the flock. A good ram does not cost—it pays. An outstanding sire can’t be purchased for market price, and you can’t expect outstanding lambs from a scrub ram. Keep the following in mind as you look at prospects: Continue reading →