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The following article was published by : Penn State Extension

Sheep producers can seek to ensure buyers that their sheep are free from specific genetic abnormalities or diseases through testing. Learn about testing options in this publication

One of the last things a sheep producer would like to hear from one of their customers is that they sold a sheep that produced lambs with genetic or disease issues. This would be a particularly unwanted call when that issue could be identified through testing. Some testing is commonplace, while other tests are increasing in significance.

The most common tests performed would probably be for scrapie susceptibility and spider lamb syndrome. Additional tests covered in this article include dwarfism, ectodermal dysplasia (hairy lamb syndrome), and ovine progressive pneumonia. None of these issues can be treated, so control involves identifying affected individuals and culling them from the flock.

Scrapie

Scrapie affects the central nervous system in sheep and goats. In cattle, this disease is called mad cow disease, and in deer, it is called chronic wasting disease. The disease is considered a transmissible spongiform encephalopathy (TSE) because it affects the brain and causes it to look like a sponge. The impact on the brain leads to problems with muscle control or incoordination and problems with moving and getting up from lying down. Sheep infected with scrapie may stumble and fall or lift their legs higher than normal when walking. Infected sheep often experience intense itching, which causes bare spots on their sides and sometimes open sores. The bare spots may also appear on their head due to head pressing.

Sheep producers can test for susceptibility to this disease using tissue samples or blood samples. Testing looks at the DNA genotype at codon 171 or 136. Codon 171 testing results identify genotypes as RR for sheep resistant to scrapie if exposed to the disease, QR for sheep that have some susceptibility to the disease, and QQ for sheep that are highly susceptible when exposed to the disease. Codon 136 testing works the same way, with AA sheep resistant to the disease, AV sheep having some susceptibility to the disease, and VV sheep being very susceptible to the disease. More information on scrapie and the scrapie eradication program can be found at USDA’s Sheep and Goat Disease or by contacting your local veterinarian.

Spider Lamb Syndrome (Ovine Hereditary Chondrodysplasia)

Spider lamb syndrome causes skeletal deformities in affected lambs. Some affected lambs may be born dead or aborted. However, most lambs are born alive. Often, these lambs have twisted spines and deformed legs that look like spider legs. The condition typically worsens as lambs grow, frequently resulting in lambs not surviving past six months. A gene mutation causes the disease, which impacts bone and cartilage growth. The mutation occurs most often in black-face sheep and crosses. Sheep with two copies of this gene mutation exhibit the disease. However, testing can identify gene mutation carriers, and therefore, producers can cull these individuals and prevent passing the gene mutation to offspring.

Producers can use hair, tissue, or blood samples to test for spider lamb syndrome. The results of these tests categorize lambs with the disease as SS, carriers of the gene mutation as SN, and lambs free of the gene mutation as NN.

Sheep Dwarfism

Dwarfism in sheep is a genetic defect that causes shortened extremities from abnormal cartilage development and bone growth, thus leading to a smaller overall size. Some lambs may be born with a domed head and shortened nose. Research by Thompson et al. (Inherited Chondrodysplasia in Texel Sheep) noted that affected lambs appeared normal at birth but grew slowly and developed a short neck and a wide-based stance. These lambs also showed an intolerance of exercise. Many of the severely affected lambs died within three to four months after birth. Researchers also noted abnormalities in the trachea. Lambs that survived to breeding age developed severe degenerative joint disease and had to be euthanized.

Producers can test for dwarfism using tissue samples or blood samples. The results of these tests categorize dwarf lambs as DD, which will pass the mutation to their offspring 100% of the time. Normal-sized lambs that are carriers of the mutation are categorized as FD and will pass the mutation to their offspring 50% of the time. Normal lambs that do not have the mutation are categorized as FF. They do not have the gene for dwarfism and, therefore, would not pass the mutation to offspring.

Hairy Lamb Syndrome (Ectodermal Dysplasia)

Hairy lamb syndrome is a genetic disorder that appears as fine wispy hair instead of wool on the lamb’s body. This syndrome is characterized by thin skin, abnormal teeth and jaw, and dysfunctional sweat glands. The disorder affects the development of the ectodermal layer in embryos, which plays a role in the animal’s hair, skin, teeth, and hoof development. Lambs often die within several weeks after birth.

Producers can test for hairy lamb syndrome using tissue samples or blood samples. The results of these tests categorize affected lambs as EDA. Normal-appearing lambs that are carriers of the mutation are categorized as EDC and will pass the mutation to their offspring 50% of the time. Normal-appearing lambs that do not have the mutation are categorized as EDF. They do not have the gene for hairy lamb syndrome and, therefore, would not pass the mutation to offspring.

Ovine Progressive Pneumonia (OPP)

Unlike the other issues above, OPP is caused by a lentivirus infection rather than a genetic mutation. This virus affects the lungs and udder. Many producers overlook OPP in their flock until mature ewes begin losing weight, develop respiratory problems, or develop a hard udder that does not produce milk for lambs. This disease is similar to caprine arthritis and encephalitis or CAE in goats. The American Association of Small Ruminant Practitioners fact sheet on Ovine Progressive Pneumonia describes OPP as a “slow-growing virus that causes wasting and replaces healthy tissue with solid non-functional tissue due to the cellular immune response of sheep to the virus.” They state that the virus cannot survive for very long outside of the sheep. The most common way sheep contract the virus is through respiratory particles.

Producers can test for OPP using a blood sample. Labs conduct one of two serologic tests to identify affected individuals. Affected individuals can also be identified through necropsy examination of the lungs or mammary tissue.

Any producers who suspect one or more of these issues within their flock should consult their local veterinarian and begin testing to identify carriers. Producers may also wish to select rams and replacement females with negative test results, particularly when purchasing breeding stock from other producers if they have concerns about these issues.

This article was first printed in the Dorset Connection, the newsletter published by the Continental Dorset Club.

The following links and information are provided by Cornell University of Ithaca, NY: Thanks to GSSB Member Marlene Halstead of Rocky Top Farm, PA, for forwarding these links for posting ….

The following was submitted by GSSB Member CB Katzenbach of Sweet Sourland Farm

We are forest farmers, make maple syrup, and participated in the silvopasture survey described below. It’s something we’ve been doing for many years, using small ruminants to control understory vegetation among the red and sugar maples and the sap collection tubing lines. Over the years we’ve followed Cornell’s Maple research programs, and Cornell SmallFarms. A film crew came to our farm (NJ) in the summer of 2022, and you can see fleeting images of our Barbados Blackbelly sheep in this introductory video from Farming With Trees:

From a 2022 Lancaster (PA) Farming article written by Chelsea Hill of the Penn State Extension Service comes this timely bit of information:

“Oh, Christmas tree, oh, Christmas tree, how lovely are thy branches.” One of the many wonderful traditions surrounding the holiday season this winter is the purchasing of a beautiful coniferous tree and decorating it with family for all to see.

But what, may you ask, do you do with a Christmas tree after the holidays are past? Unlike the Grinch, who may have taken the tree back, most families dispose of it in the regular trash, use it as part of their compost or, what seems to be growing in popularity in recent years, feed it as a treat to backyard livestock.

The positives of this new trend are that the trees can have a second life or purpose. They can provide varying levels of supplemental nutrition and may have anthelmintic properties due to high levels of naturally occurring tannins, predominantly found in the bark.

Unfortunately, there aren’t enough studies to verify exactly how high the levels of tannins after consumption would be, so it is merely a guess that a sheep or goat would consume enough to reap the benefits of a natural dewormer such as this.

The other variable that needs to be taken into consideration is that there are multiple species of Christmas trees available on today’s market: spruces (blue, white, Norway), firs (Douglas, balsam, Fraser, Canaan, noble, grand, concolor), pines (white, Virginia, Scotch), Leyland, Arizona and red cedar. For each species, there could be varying levels of nutritional benefits and anthelmintic properties or, in some cases, toxic properties.

Depending on the variety, coniferous trees could be poisonous when fed at high rates or even at low rates over a long period of time.

For example, ponderosa pine (Pinus ponderosa) needles contain isocupressic acid which, when fed to pregnant cattle in late pregnancy, can cause abortions, according to the USDA’s Agricultural Research Service.

Although ponderosa pine is not commonly found in Pennsylvania, there have been other coniferous species that have been found to have the same toxic acid, including Monterey cypress (Cupressus macrocarpa), lodgepole pine (P. contorta) and common juniper (Juniperus communis).

Another study from the USDA’s Agricultural Research Service titled “Pine needle toxicoses in cattle and goats” found that in a small case study of 24 mixed Spanish-breed goats, feeding varying levels of ponderosa pine needles, bark and needle tips did not cause abortions as hypothesized but was toxic in multiple groups of the study.

Are These Trees Right for Your Animals?

If feeding leftover Christmas trees is something you’re considering for your operation, remember that just like you wouldn’t randomly eat 10 pounds of chocolate because of the digestive upset sure to follow, the same could be said when feeding this coniferous treat to your stock. Only offer one tree at a time, and space them out so that your animals are only getting small amounts.

This is especially important for our ruminant species, as sudden changes in diet can lead to acidosis, bloat or worse if not monitored. Avoid feeding late-pregnancy dams to avoid the potential for abortion, especially when the variety of the tree is not known.

Make sure all trees taken in are clean and that the previous owners know where they were sourced. Some trees are sprayed with pesticides, preservatives or flame retardants before being sold to customers, and these trees should be avoided.

Remove all decorations that were previously on the tree, being careful to make sure each strand of tinsel is discarded and no leftover ornament hooks are on branches before feeding.

Always follow your intuition. If you’re ever unsure of the quality or source of a tree, it is better to use it for compost than potentially lose one of your animals.

Issuance Date: December 1, 2022

Effective Date: Immediately     

Effective immediately, sheep and goat in-vivo embryos and oocytes from the United Kingdom of Great Britain (England, Scotland, Wales) and Northern Ireland will be eligible for import into the United States. Importation of such commodities is only permitted for direct transfer to recipient females in U.S. flocks or herds listed in the National Scrapie Database, or to an Animal and Plant Health Inspection Service (APHIS)-approved embryo storage facility where they may be kept until transfer to the aforementioned recipient females.

The importer of record must meet post-entry requirements pertaining to further distribution of imported embryos/oocytes, identification of any progeny derived from the imported embryos/oocytes, and recordkeeping. The import requirements and post-entry requirements are available on the Live Animal Imports website.

APHIS requires an import permit for importation of sheep and goat embryos/oocytes from the United Kingdom. The shipment must also be accompanied by a health certificate endorsed by the competent authority of the exporting region (Department for Environment, Food and Rural Affairs in Great Britain; Department of Agriculture, Environment and Rural Affairs in Northern Ireland). Examples of the required health certificates can be found on the APHIS website.

For any questions regarding import of sheep and goat embryos/oocytes from the United Kingdom for transfer to eligible U.S. recipient females, please contact Dr. Mary Kate Anderson at (301)851-3300, Option 2 or e-mail LAIE@usda.gov.

For importation of sheep and goat embryos/oocytes for any purpose other than reproduction, please consult the Veterinary Services Permitting Assistant (VSPA) to determine the relevant import requirements.

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The following very timely article comes from Michael Metzger, Michigan State University/ Jackson County Extension’s Small Ruminant Instructor:

As fall approaches, so does the normal breeding season for most sheep and goats. Consideration for things like parasite count, hoof health, body condition scoring, and overall health of breeding stock should be evaluated prior to breeding.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).